Intel(R) SGX is a set of CPU instructions that can be used by applications
to set aside private regions of code and data. The code outside the enclave
is disallowed to access the memory inside the enclave by the CPU access
control.
There is a new hardware unit in the processor called Memory Encryption
Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
one or many MEE regions that can hold enclave data by configuring them with
PRMRR registers.
The MEE automatically encrypts the data leaving the processor package to
the MEE regions. The data is encrypted using a random key whose life-time
is exactly one power cycle.
The current implementation requires that the firmware sets
IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
decide what enclaves it wants run. The implementation does not create
any bottlenecks to support read-only MSRs later on.
You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
cat /proc/cpuinfo | grep sgx
v29:
* The selftest has been moved to selftests/sgx. Because SGX is an execution
environment of its own, it really isn't a great fit with more "standard"
x86 tests.
The RSA key is now generated on fly and the whole signing process has
been made as part of the enclave loader instead of signing the enclave
during the compilation time.
Finally, the enclave loader loads now the test enclave directly from its
ELF file, which means that ELF file does not need to be coverted as raw
binary during the build process.
* Version the mm_list instead of using on synchronize_mm() when adding new
entries. We hold the write lock for the mm_struct, and dup_mm() can thus
deadlock with the page reclaimer, which could hold the lock for the old
mm_struct.
* Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
be used to reserve the address range. Now /dev/sgx supports only opaque
mappings to the (initialized) enclave data.
* Make the vDSO callable directly from C by preserving RBX and taking leaf
from RCX.
v28:
* Documented to Documentation/x86/sgx.rst how the kernel manages the
enclave ownership.
* Removed non-LC flow from sgx_einit().
* Removed struct sgx_einittoken since only the size of the corresponding
microarchitectural structure is used in the series ATM.
v27:
* Disallow RIE processes to use enclaves as there could a permission
conflict between VMA and enclave permissions.
* In the documentation, replace "grep /proc/cpuinfo" with
"grep sgx /proc/cpuinfo".
v26:
* Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
changed in v25 by mistake.
* Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
again for such a detailed feedback).
* Added back the MAINTAINERS update commit, which was mistakenly removed
in v25.
* EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
CPU does not allow to remove a SECS page before all of its children have
been removed, and a child page can be in some other section than the one
currently being processed. Thus, removed special SECS processing from
sgx_sanitize_page() and instead put sections through it twice. In the
2nd round the lists should only contain SECS pages.
v25:
* Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
fails on executing ENCLS[EADD]. The rollback path executed
radix_tree_delete() on the same address twice when this happened.
* Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
a signal is pending.
* As requested by Borislav, move the CPUID 0x12 features to their own word
in cpufeatures.
* Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
was called with an uninitialized pointer when sgx_encl_get_backing()
fails.
* Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
has 'groups' for setting up sysfs attributes for the device.
* Use device_initcall instead of subsys_initcall so that misc_class is
initialized before SGX is initialized.
* Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
enclave attributes that we the kernel does not allow it to set instead
of -EINVAL.
* Unless SGX public key MSRs are writable always deny the feature from
Linux. Previously this was only denied from driver. How VMs should be
supported is not really part of initial patch set, which makes this
an obvious choice.
* Cleaned up and refined documentation to be more approachable.
v24:
* Reclaim unmeasured and TCS pages (regression in v23).
* Replace usages of GFP_HIGHUSER with GFP_KERNEL.
* Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
and use the same rollback (destroy enclave). This can happen when host
suspends itself unknowingly to a VM running enclaves. From -EIO the user
space can deduce what happened.
* Have a separate @count in struct sgx_enclave_add_pages to output number
of bytes processed instead of overwriting the input parameters for
clarity and more importantly that the API provides means for partial
processing (@count could be less than @length in success case).
v23:
* Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
with %SGX_PAGE_MEASURE flag.
* Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
* In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
(because of OOM) even in legit behaviour and after EBLOCK the reclaiming
flow can be only reverted by killing the whole enclave.
* Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
it should have been bit 6 (Table 37-3 in the SDM).
* Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
error code.
v22:
* Refined bunch commit messages and added associated SDM references as
many of them were too exhausting and some outdated.
* Alignment checks have been removed from mmap() because it does not define the
ELRANGE. VMAs only act as windows to the enclave. The semantics compare
somewhat how mmap() works with regular files.
* We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
page aligned so that we can pass the page directly to EADD and do not have
to do an extra copy. This was made effectively possible by removing the
worker thread for adding pages.
* The selftest build files have been refined throughout of various glitches
and work properly in a cross compilation environment such as BuildRoot.
In addition, libcalls fail the build with an assertion in the linker
script, if they end up to the enclave binary.
* CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
for anything without having the driver. This could change when KVM support
is added.
* We require zero permissions in SECINFO for TCS pages because the CPU
overwrites SECINFO flags with zero permissions and measures the page
only after that. Allowing to pass TCS with non-zero permissions would
cause mismatching measurement between the one provided in SIGSTRUCT and
the one computed by the CPU.
* Obviously lots of small fixes and clean ups (does make sense to
document them all).
v21:
* Check on mmap() that the VMA does cover an area that does not have
enclave pages. Only mapping with PROT_NONE can do that to reserve
initial address space for an enclave.
* Check om mmap() and mprotect() that the VMA permissions do not
surpass the enclave permissions.
* Remove two refcounts from vma_close(): mm_list and encl->refcount.
Enclave refcount is only need for swapper/enclave sync and we can
remove mm_list refcount by destroying mm_struct when the process
is closed. By not having vm_close() the Linux MM can merge VMAs.
* Do not naturally align MAP_FIXED address.
* Numerous small fixes and clean ups.
* Use SRCU for synchronizing the list of mm_struct's.
* Move to stack based call convention in the vDSO.
v20:
* Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
dependency as MMU notifiers are no longer used in the driver.
* Use mm_users instead of mm_count as refcount for mm_struct as mm_count
only protects from deleting mm_struct, not removing its contents.
* Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
of them. They could be in initialized state when the kernel starts
because it might be spawned by kexec().
* Documentation overhaul.
* Use a device /dev/sgx/provision for delivering the provision token
instead of securityfs.
* Create a reference to the enclave when already when opening
/dev/sgx/enclave. The file is then associated with this enclave only.
mmap() can be done at free at any point and always get a reference to
the enclave. To summarize the file now represents the enclave.
v19:
* Took 3-4 months but in some sense this was more like a rewrite of most
of the corners of the source code. If I've forgotten to deal with some
feedback, please don't shout me. Make a remark and I will fix it for
the next version. Hopefully there won't be this big turnovers anymore.
* Validate SECS attributes properly against CPUID given attributes and
against allowed attributes. SECS attributes are the ones that are
enforced whereas SIGSTRUCT attributes tell what is required to run
the enclave.
* Add KSS (Key Sharing Support) to the enclave attributes.
* Deny MAP_PRIVATE as an enclave is always a shared memory entity.
* Revert back to shmem backing storage so that it can be easily shared
by multiple processes.
* Split the recognization of an ENCLS leaf failure by using three
functions to detect it: encsl_faulted(), encls_returned_code() and
sgx_failed(). encls_failed() is only caused by a spurious expections that
should never happen. Thus, it is not defined as an inline function in
order to easily insert a kprobe to it.
* Move low-level enclave management routines, page fault handler and page
reclaiming routines from driver to the core. These cannot be separated
from each other as they are heavily interdependent. The rationale is that
the core does not call any code from the driver.
* Allow the driver to be compiled as a module now that it no code is using
its routines and it only uses exported symbols. Now the driver is
essentially just a thin ioctl layer.
* Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
add new entries to this list as the process is forked. Each entry has
its own refcount because they have a different life-cycle as the enclave
does. In effect @tgid and @mm have been removed from struct sgx_encl
and we allow forking by removing VM_DONTCOPY from vm flags.
* Generate a cpu mask in the reclaimer from the cpu mask's of all
mm_struct's. This will kick out the hardware threads out of the enclave
from multiple processes. It is not a local variable because it would
eat too much of the stack space but instead a field in struct
sgx_encl.
* Allow forking i.e. remove VM_DONTCOPY. I did not change the API
because the old API scaled to the workload that Andy described. The
codebase is now mostly API independent i.e. changing the API is a
small task. For me the proper trigger to chanage it is a as concrete
as possible workload that cannot be fulfilled. I hope you understand
my thinking here. I don't want to change anything w/o proper basis
but I'm ready to change anything if there is a proper basis. I do
not have any kind of attachment to any particular type of API.
* Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
new vDSO.
v18:
* Update the ioctl-number.txt.
* Move the driver under arch/x86.
* Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
* Rename the selftest as test_sgx (previously sgx-selftest).
* In order to enable process accounting, swap EPC pages and PCMD's to a VMA
instead of shmem.
* Allow only to initialize and run enclaves with a subset of
{DEBUG, MODE64BIT} set.
* Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
attributes e.g. PROVISIONKEY.
v17:
* Add a simple selftest.
* Fix a null pointer dereference to section->pages when its
allocation fails.
* Add Sean's description of the exception handling to the documentation.
v16:
* Fixed SOB's in the commits that were a bit corrupted in v15.
* Implemented exceptio handling properly to detect_sgx().
* Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
* Updated the documentation to use rst definition lists.
* Added the missing Documentation/x86/index.rst, which has a link to
intel_sgx.rst. Now the SGX and uapi documentation is properly generated
with 'make htmldocs'.
* While enumerating EPC sections, if an undefined section is found, fail
the driver initialization instead of continuing the initialization.
* Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
* Remove copyright notice from arch/x86/include/asm/sgx.h.
* Migrated from ioremap_cache() to memremap().
v15:
* Split into more digestable size patches.
* Lots of small fixes and clean ups.
* Signal a "plain" SIGSEGV on an EPCM violation.
v14:
* Change the comment about X86_FEATURE_SGX_LC from “SGX launch
configuration” to “SGX launch control”.
* Move the SGX-related CPU feature flags as part of the Linux defined
virtual leaf 8.
* Add SGX_ prefix to the constants defining the ENCLS leaf functions.
* Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
* Refine the long description for CONFIG_INTEL_SGX_CORE.
* Do not use pr_*_ratelimited() in the driver. The use of the rate limited
versions is legacy cruft from the prototyping phase.
* Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
cycles.
* Manually prefix with “sgx:” in the core SGX code instead of redefining
pr_fmt.
* Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
instead of core because it is a driver requirement.
* Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
default is ‘n’.
* Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
the SDM.
* Allocate struct sgx_epc_page instances one at a time.
* Use “__iomem void *” pointers for the mapped EPC memory consistently.
* Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
cycles.
* Call enclave swapping operations directly from the driver instead of
calling them .indirectly through struct sgx_epc_page_ops because indirect
calls are not required yet as the patch set does not contain the KVM
support.
* Added special signal SEGV_SGXERR to notify about SGX EPCM violation
errors.
v13:
* Always use SGX_CPUID constant instead of a hardcoded value.
* Simplified and documented the macros and functions for ENCLS leaves.
* Enable sgx_free_page() to free active enclave pages on demand
in order to allow sgx_invalidate() to delete enclave pages.
It no longer performs EREMOVE if a page is in the process of
being reclaimed.
* Use PM notifier per enclave so that we don't have to traverse
the global list of active EPC pages to find enclaves.
* Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
* Always use ioremap() to map EPC banks as we only support 64-bit kernel.
* Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
to sleep.
v12:
* Split to more narrow scoped commits in order to ease the review process and
use co-developed-by tag for co-authors of commits instead of listing them in
the source files.
* Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
* Removed in-kernel LE i.e. this version of the SGX software stack only
supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
* Refined documentation on launching enclaves, swapping and enclave
construction.
* Refined sgx_arch.h to include alignment information for every struct that
requires it and removed structs that are not needed without an LE.
* Got rid of SGX_CPUID.
* SGX detection now prints log messages about firmware configuration issues.
v11:
* Polished ENCLS wrappers with refined exception handling.
* ksgxswapd was not stopped (regression in v5) in
sgx_page_cache_teardown(), which causes a leaked kthread after driver
deinitialization.
* Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
invalidated when resuming, which will cause it not function properly
anymore.
* Set EINITTOKEN.VALID to zero for a token that is passed when
SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
page.
* Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
around the flags field, which causes a #GP. Only flags read is readable.
* On read access memcpy() call inside sgx_vma_access() had src and dest
parameters in wrong order.
* The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
to LE even if “KASAN_SANITIZE := false” was set in the makefile.
* Fixed a regression in the #PF handler. If a page has
SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
It did not, which caused weird races when trying to change other parts of
swapping code.
* EPC management has been refactored to a flat LRU cache and moved to
arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
of them. It can now swap from multiple enclaves in the same round.
* For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
when an enclave is already initialized or dead instead of zero.
v10:
* Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
of the driver.
* Unset the reserved flag from an enclave page if EDBGRD/WR fails
(regression in v6).
* Close the anon inode when LE is stopped (regression in v9).
* Update the documentation with a more detailed description of SGX.
v9:
* Replaced kernel-LE IPC based on pipes with an anonymous inode.
The driver does not require anymore new exports.
v8:
* Check that public key MSRs match the LE public key hash in the
driver initialization when the MSRs are read-only.
* Fix the race in VA slot allocation by checking the fullness
immediately after succeesful allocation.
* Fix the race in hash mrsigner calculation between the launch
enclave and user enclaves by having a separate lock for hash
calculation.
v7:
* Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
when it should have been masked with ~PAGE_MASK.
* Fixed a memory leak in sgx_ioc_enclave_create().
* Simplified swapping code by using a pointer array for a cluster
instead of a linked list.
* Squeezed struct sgx_encl_page to 32 bytes.
* Fixed deferencing of an RSA key on OpenSSL 1.1.0.
* Modified TC's CMAC to use kernel AES-NI. Restructured the code
a bit in order to better align with kernel conventions.
v6:
* Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
* In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
* Removed virtualization chapter from the documentation.
* Changed the default filename for the signing key as signing_key.pem.
* Reworked EPC management in a way that instead of a linked list of
struct sgx_epc_page instances there is an array of integers that
encodes address and bank of an EPC page (the same data as 'pa' field
earlier). The locking has been moved to the EPC bank level instead
of a global lock.
* Relaxed locking requirements for EPC management. EPC pages can be
released back to the EPC bank concurrently.
* Cleaned up ptrace() code.
* Refined commit messages for new architectural constants.
* Sorted includes in every source file.
* Sorted local variable declarations according to the line length in
every function.
* Style fixes based on Darren's comments to sgx_le.c.
v5:
* Described IPC between the Launch Enclave and kernel in the commit messages.
* Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
versions except those that exist in the imported TinyCrypt code.
* Fixed spelling mistakes in the documentation.
* Forgot to check the return value of sgx_drv_subsys_init().
* Encapsulated properly page cache init and teardown.
* Collect epc pages to a temp list in sgx_add_epc_bank
* Removed SGX_ENCLAVE_INIT_ARCH constant.
v4:
* Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
* Removed __exit annotation from sgx_drv_subsys_exit().
* Fixed a leak of a backing page in sgx_process_add_page_req() in the
case when vm_insert_pfn() fails.
* Removed unused symbol exports for sgx_page_cache.c.
* Updated sgx_alloc_page() to require encl parameter and documented the
behavior (Sean Christopherson).
* Refactored a more lean API for sgx_encl_find() and documented the behavior.
* Moved #PF handler to sgx_fault.c.
* Replaced subsys_system_register() with plain bus_register().
* Retry EINIT 2nd time only if MSRs are not locked.
v3:
* Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
* Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
* Use unused bits in epc_page->pa to store the bank number.
* Removed #ifdef for WQ_NONREENTRANT.
* If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
* Added --remove-section=.got.plt to objcopy flags in order to prevent a
dummy .got.plt, which will cause an inconsistent size for the LE.
* Documented sgx_encl_* functions.
* Added remark about AES implementation used inside the LE.
* Removed redundant sgx_sys_exit() from le/main.c.
* Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
* Validate miscselect in sgx_encl_create().
* Fixed SSA frame size calculation to take the misc region into account.
* Implemented consistent exception handling to __encls() and __encls_ret().
* Implemented a proper device model in order to allow sysfs attributes
and in-kernel API.
* Cleaned up various "find enclave" implementations to the unified
sgx_encl_find().
* Validate that vm_pgoff is zero.
* Discard backing pages with shmem_truncate_range() after EADD.
* Added missing EEXTEND operations to LE signing and launch.
* Fixed SSA size for GPRS region from 168 to 184 bytes.
* Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
* Check that TCS addresses are in ELRANGE and not just page aligned.
* Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
* Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.
v2:
* get_rand_uint32() changed the value of the pointer instead of value
where it is pointing at.
* Launch enclave incorrectly used sigstruct attributes-field instead of
enclave attributes-field.
* Removed unused struct sgx_add_page_req from sgx_ioctl.c
* Removed unused sgx_has_sgx2.
* Updated arch/x86/include/asm/sgx.h so that it provides stub
implementations when sgx in not enabled.
* Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
* return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
* removed unused global sgx_nr_pids
* moved sgx_encl_release to sgx_encl.c
* return -ERESTARTSYS instead of -EINTR in sgx_encl_init()
Jarkko Sakkinen (10):
x86/sgx: Update MAINTAINERS
x86/sgx: Add SGX microarchitectural data structures
x86/sgx: Add wrappers for ENCLS leaf functions
x86/sgx: Add functions to allocate and free EPC pages
x86/sgx: Linux Enclave Driver
x86/sgx: Add provisioning
x86/sgx: Add a page reclaimer
x86/sgx: ptrace() support for the SGX driver
selftests/x86: Add a selftest for SGX
docs: x86/sgx: Document SGX micro architecture and kernel internals
Sean Christopherson (10):
x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
x86/cpu/intel: Detect SGX support
x86/sgx: Enumerate and track EPC sections
mm: Introduce vm_ops->may_mprotect()
x86/vdso: Add support for exception fixup in vDSO functions
x86/fault: Add helper function to sanitize error code
x86/traps: Attempt to fixup exceptions in vDSO before signaling
x86/vdso: Implement a vDSO for Intel SGX enclave call
.../userspace-api/ioctl/ioctl-number.rst | 1 +
Documentation/x86/index.rst | 1 +
Documentation/x86/sgx.rst | 206 +++++
MAINTAINERS | 11 +
arch/x86/Kconfig | 14 +
arch/x86/entry/vdso/Makefile | 8 +-
arch/x86/entry/vdso/extable.c | 46 +
arch/x86/entry/vdso/extable.h | 29 +
arch/x86/entry/vdso/vdso-layout.lds.S | 9 +-
arch/x86/entry/vdso/vdso.lds.S | 1 +
arch/x86/entry/vdso/vdso2c.h | 58 +-
arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++
arch/x86/include/asm/cpufeature.h | 5 +-
arch/x86/include/asm/cpufeatures.h | 8 +-
arch/x86/include/asm/disabled-features.h | 18 +-
arch/x86/include/asm/enclu.h | 8 +
arch/x86/include/asm/msr-index.h | 8 +
arch/x86/include/asm/required-features.h | 2 +-
arch/x86/include/asm/traps.h | 1 +
arch/x86/include/asm/vdso.h | 5 +
arch/x86/include/uapi/asm/sgx.h | 175 ++++
arch/x86/kernel/cpu/Makefile | 1 +
arch/x86/kernel/cpu/common.c | 4 +
arch/x86/kernel/cpu/feat_ctl.c | 32 +-
arch/x86/kernel/cpu/sgx/Makefile | 6 +
arch/x86/kernel/cpu/sgx/arch.h | 343 ++++++++
arch/x86/kernel/cpu/sgx/driver.c | 209 +++++
arch/x86/kernel/cpu/sgx/driver.h | 32 +
arch/x86/kernel/cpu/sgx/encl.c | 756 +++++++++++++++++
arch/x86/kernel/cpu/sgx/encl.h | 128 +++
arch/x86/kernel/cpu/sgx/encls.h | 238 ++++++
arch/x86/kernel/cpu/sgx/ioctl.c | 800 ++++++++++++++++++
arch/x86/kernel/cpu/sgx/main.c | 280 ++++++
arch/x86/kernel/cpu/sgx/reclaim.c | 471 +++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 108 +++
arch/x86/kernel/traps.c | 14 +
arch/x86/mm/fault.c | 45 +-
include/linux/mm.h | 2 +
mm/mprotect.c | 14 +-
tools/arch/x86/include/asm/cpufeatures.h | 7 +-
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/sgx/.gitignore | 2 +
tools/testing/selftests/sgx/Makefile | 53 ++
tools/testing/selftests/sgx/call.S | 54 ++
tools/testing/selftests/sgx/defines.h | 21 +
tools/testing/selftests/sgx/load.c | 282 ++++++
tools/testing/selftests/sgx/main.c | 199 +++++
tools/testing/selftests/sgx/main.h | 38 +
tools/testing/selftests/sgx/sigstruct.c | 395 +++++++++
tools/testing/selftests/sgx/test_encl.c | 20 +
tools/testing/selftests/sgx/test_encl.lds | 40 +
.../selftests/sgx/test_encl_bootstrap.S | 89 ++
52 files changed, 5398 insertions(+), 31 deletions(-)
create mode 100644 Documentation/x86/sgx.rst
create mode 100644 arch/x86/entry/vdso/extable.c
create mode 100644 arch/x86/entry/vdso/extable.h
create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
create mode 100644 arch/x86/include/asm/enclu.h
create mode 100644 arch/x86/include/uapi/asm/sgx.h
create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
create mode 100644 arch/x86/kernel/cpu/sgx/main.c
create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
create mode 100644 tools/testing/selftests/sgx/.gitignore
create mode 100644 tools/testing/selftests/sgx/Makefile
create mode 100644 tools/testing/selftests/sgx/call.S
create mode 100644 tools/testing/selftests/sgx/defines.h
create mode 100644 tools/testing/selftests/sgx/load.c
create mode 100644 tools/testing/selftests/sgx/main.c
create mode 100644 tools/testing/selftests/sgx/main.h
create mode 100644 tools/testing/selftests/sgx/sigstruct.c
create mode 100644 tools/testing/selftests/sgx/test_encl.c
create mode 100644 tools/testing/selftests/sgx/test_encl.lds
create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
--
2.25.1
From: Sean Christopherson <[email protected]>
Add X86_FEATURE_SGX from CPUID.(EAX=7, ECX=1), which informs whether the
CPU has SGX.
Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
which describe the level of SGX support available [1].
Remap CPUID.(EAX=12H, ECX=0) bits to the Linux fake CPUID 8 in order to
conserve some space. Keep the bit positions intact because KVM requires
this. Reserve bits 0-7 for SGX in order to maintain this invariant also
when new SGX specific feature bits get added.
Add IA32_FEATURE_CONTROL_SGX_ENABLE. BIOS can use this bit to opt-in SGX
before locking the feature control MSR [2].
[1] Intel SDM: 36.7.2 Intel® SGX Resource Enumeration Leaves
[2] Intel SDM: 36.7.1 Intel® SGX Opt-In Configuration
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/include/asm/cpufeature.h | 5 +++--
arch/x86/include/asm/cpufeatures.h | 7 ++++++-
arch/x86/include/asm/disabled-features.h | 18 +++++++++++++++---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/include/asm/required-features.h | 2 +-
arch/x86/kernel/cpu/common.c | 4 ++++
tools/arch/x86/include/asm/cpufeatures.h | 7 ++++++-
7 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 59bf91c57aa8..efbdba5170a3 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -30,6 +30,7 @@ enum cpuid_leafs
CPUID_7_ECX,
CPUID_8000_0007_EBX,
CPUID_7_EDX,
+ CPUID_12_EAX,
};
#ifdef CONFIG_X86_FEATURE_NAMES
@@ -89,7 +90,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) || \
REQUIRED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 20))
#define DISABLED_MASK_BIT_SET(feature_bit) \
( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \
@@ -112,7 +113,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) || \
DISABLED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 20))
#define cpu_has(c, bit) \
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index f3327cb56edf..42ae9fb06987 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@
/*
* Defines x86 CPU feature bits
*/
-#define NCAPINTS 19 /* N 32-bit words worth of info */
+#define NCAPINTS 20 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */
/*
@@ -238,6 +238,7 @@
/* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
#define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
#define X86_FEATURE_TSC_ADJUST ( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX ( 9*32+ 2) /* Software Guard Extensions */
#define X86_FEATURE_BMI1 ( 9*32+ 3) /* 1st group bit manipulation extensions */
#define X86_FEATURE_HLE ( 9*32+ 4) /* Hardware Lock Elision */
#define X86_FEATURE_AVX2 ( 9*32+ 5) /* AVX2 instructions */
@@ -369,6 +370,10 @@
#define X86_FEATURE_ARCH_CAPABILITIES (18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
#define X86_FEATURE_SPEC_CTRL_SSBD (18*32+31) /* "" Speculative Store Bypass Disable */
+/* Intel-defined SGX features, CPUID level 0x00000012:0 (EAX), word 19 */
+#define X86_FEATURE_SGX1 (19*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2 (19*32+ 1) /* SGX2 leaf functions */
+
/*
* BUG word(s)
*/
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 4ea8584682f9..dbe534d5153f 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -28,13 +28,18 @@
# define DISABLE_CYRIX_ARR (1<<(X86_FEATURE_CYRIX_ARR & 31))
# define DISABLE_CENTAUR_MCR (1<<(X86_FEATURE_CENTAUR_MCR & 31))
# define DISABLE_PCID 0
+# define DISABLE_SGX1 0
+# define DISABLE_SGX2 0
#else
# define DISABLE_VME 0
# define DISABLE_K6_MTRR 0
# define DISABLE_CYRIX_ARR 0
# define DISABLE_CENTAUR_MCR 0
# define DISABLE_PCID (1<<(X86_FEATURE_PCID & 31))
-#endif /* CONFIG_X86_64 */
+# define DISABLE_SGX1 (1<<(X86_FEATURE_SGX1 & 31))
+# define DISABLE_SGX2 (1<<(X86_FEATURE_SGX2 & 31))
+ #endif /* CONFIG_X86_64 */
+
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
# define DISABLE_PKU 0
@@ -56,6 +61,12 @@
# define DISABLE_PTI (1 << (X86_FEATURE_PTI & 31))
#endif
+#ifdef CONFIG_INTEL_SGX
+# define DISABLE_SGX 0
+#else
+# define DISABLE_SGX (1 << (X86_FEATURE_SGX & 31))
+#endif
+
/*
* Make sure to add features to the correct mask
*/
@@ -68,7 +79,7 @@
#define DISABLED_MASK6 0
#define DISABLED_MASK7 (DISABLE_PTI)
#define DISABLED_MASK8 0
-#define DISABLED_MASK9 (DISABLE_SMAP)
+#define DISABLED_MASK9 (DISABLE_SMAP|DISABLE_SGX)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 0
#define DISABLED_MASK12 0
@@ -78,6 +89,7 @@
#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP)
#define DISABLED_MASK17 0
#define DISABLED_MASK18 0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define DISABLED_MASK19 (DISABLE_SGX1|DISABLE_SGX2)
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index d5e517d1c3dd..e190293c8923 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -566,6 +566,7 @@
#define FEAT_CTL_LOCKED BIT(0)
#define FEAT_CTL_VMX_ENABLED_INSIDE_SMX BIT(1)
#define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX BIT(2)
+#define FEAT_CTL_SGX_ENABLED BIT(18)
#define FEAT_CTL_LMCE_ENABLED BIT(20)
#define MSR_IA32_TSC_ADJUST 0x0000003b
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 6847d85400a8..039e58be2fe6 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -101,6 +101,6 @@
#define REQUIRED_MASK16 0
#define REQUIRED_MASK17 0
#define REQUIRED_MASK18 0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 52c9bfbbdb2a..db0c676b2eb0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -915,6 +915,10 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_D_1_EAX] = eax;
}
+ /* Additional Intel-defined SGX flags: level 0x00000012 */
+ if (c->cpuid_level >= 0x00000012)
+ c->x86_capability[CPUID_12_EAX] = cpuid_eax(0x00000012);
+
/* AMD-defined flags: level 0x80000001 */
eax = cpuid_eax(0x80000000);
c->extended_cpuid_level = eax;
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index f3327cb56edf..42ae9fb06987 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@
/*
* Defines x86 CPU feature bits
*/
-#define NCAPINTS 19 /* N 32-bit words worth of info */
+#define NCAPINTS 20 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */
/*
@@ -238,6 +238,7 @@
/* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
#define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
#define X86_FEATURE_TSC_ADJUST ( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX ( 9*32+ 2) /* Software Guard Extensions */
#define X86_FEATURE_BMI1 ( 9*32+ 3) /* 1st group bit manipulation extensions */
#define X86_FEATURE_HLE ( 9*32+ 4) /* Hardware Lock Elision */
#define X86_FEATURE_AVX2 ( 9*32+ 5) /* AVX2 instructions */
@@ -369,6 +370,10 @@
#define X86_FEATURE_ARCH_CAPABILITIES (18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
#define X86_FEATURE_SPEC_CTRL_SSBD (18*32+31) /* "" Speculative Store Bypass Disable */
+/* Intel-defined SGX features, CPUID level 0x00000012:0 (EAX), word 19 */
+#define X86_FEATURE_SGX1 (19*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2 (19*32+ 1) /* SGX2 leaf functions */
+
/*
* BUG word(s)
*/
--
2.25.1
From: Sean Christopherson <[email protected]>
Add X86_FEATURE_SGX_LC, which informs whether or not the CPU supports SGX
Launch Control.
Add MSR_IA32_SGXLEPUBKEYHASH{0, 1, 2, 3}, which when combined contain a
SHA256 hash of a 3072-bit RSA public key. SGX backed software packages, so
called enclaves, are always signed. All enclaves signed with the public key
are unconditionally allowed to initialize. [1]
Add FEATURE_CONTROL_SGX_LE_WR bit of the feature control MSR, which informs
whether the formentioned MSRs are writable or not. If the bit is off, the
public key MSRs are read-only for the OS.
If the MSRs are read-only, the platform must provide a launch enclave (LE).
LE can create cryptographic tokens for other enclaves that they can pass
together with their signature to the ENCLS(EINIT) opcode, which is used
to initialize enclaves.
Linux is unlikely to support the locked configuration because it takes away
the control of the launch decisions from the kernel.
[1] Intel SDM: 38.1.4 Intel SGX Launch Control Configuration
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/msr-index.h | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 42ae9fb06987..bc5ad93cbeb6 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -350,6 +350,7 @@
#define X86_FEATURE_CLDEMOTE (16*32+25) /* CLDEMOTE instruction */
#define X86_FEATURE_MOVDIRI (16*32+27) /* MOVDIRI instruction */
#define X86_FEATURE_MOVDIR64B (16*32+28) /* MOVDIR64B instruction */
+#define X86_FEATURE_SGX_LC (16*32+30) /* Software Guard Extensions Launch Control */
/* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
#define X86_FEATURE_OVERFLOW_RECOV (17*32+ 0) /* MCA overflow recovery support */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index e190293c8923..bae17ea2c8fe 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -566,6 +566,7 @@
#define FEAT_CTL_LOCKED BIT(0)
#define FEAT_CTL_VMX_ENABLED_INSIDE_SMX BIT(1)
#define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX BIT(2)
+#define FEAT_CTL_SGX_LC_ENABLED BIT(17)
#define FEAT_CTL_SGX_ENABLED BIT(18)
#define FEAT_CTL_LMCE_ENABLED BIT(20)
@@ -586,6 +587,12 @@
#define MSR_IA32_UCODE_WRITE 0x00000079
#define MSR_IA32_UCODE_REV 0x0000008b
+/* Intel SGX Launch Enclave Public Key Hash MSRs */
+#define MSR_IA32_SGXLEPUBKEYHASH0 0x0000008C
+#define MSR_IA32_SGXLEPUBKEYHASH1 0x0000008D
+#define MSR_IA32_SGXLEPUBKEYHASH2 0x0000008E
+#define MSR_IA32_SGXLEPUBKEYHASH3 0x0000008F
+
#define MSR_IA32_SMM_MONITOR_CTL 0x0000009b
#define MSR_IA32_SMBASE 0x0000009e
--
2.25.1
From: Sean Christopherson <[email protected]>
Include SGX bit to the PF error codes and throw SIGSEGV with PF_SGX when
a #PF with SGX set happens.
CPU throws a #PF with the SGX bit in the event of Enclave Page Cache Map
(EPCM) conflict. The EPCM is a CPU-internal table, which describes the
properties for a enclave page. Enclaves are measured and signed software
entities, which SGX hosts. [1]
Although the primary purpose of the EPCM conflict checks is to prevent
malicious accesses to an enclave, an illegit access can happen also for
legit reasons.
All SGX reserved memory, including EPCM is encrypted with a transient
key that does not survive from the power transition. Throwing a SIGSEGV
allows user space software react when this happens (e.g. rec-create the
enclave, which was invalidated).
[1] Intel SDM: 36.5.1 Enclave Page Cache Map (EPCM)
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/include/asm/traps.h | 1 +
arch/x86/mm/fault.c | 13 +++++++++++++
2 files changed, 14 insertions(+)
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index ffa0dc8a535e..bb8d5ae74dbc 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -174,5 +174,6 @@ enum x86_pf_error_code {
X86_PF_RSVD = 1 << 3,
X86_PF_INSTR = 1 << 4,
X86_PF_PK = 1 << 5,
+ X86_PF_SGX = 1 << 15,
};
#endif /* _ASM_X86_TRAPS_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index fa4ea09593ab..dee9504cde79 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1179,6 +1179,19 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
if (error_code & X86_PF_PK)
return 1;
+ /*
+ * Access is blocked by the Enclave Page Cache Map (EPCM), i.e. the
+ * access is allowed by the PTE but not the EPCM. This usually happens
+ * when the EPCM is yanked out from under us, e.g. by hardware after a
+ * suspend/resume cycle. In any case, software, i.e. the kernel, can't
+ * fix the source of the fault as the EPCM can't be directly modified by
+ * software. Handle the fault as an access error in order to signal
+ * userspace so that userspace can rebuild their enclave(s), even though
+ * userspace may not have actually violated access permissions.
+ */
+ if (unlikely(error_code & X86_PF_SGX))
+ return 1;
+
/*
* Make sure to check the VMA so that we do not perform
* faults just to hit a X86_PF_PK as soon as we fill in a
--
2.25.1
From: Sean Christopherson <[email protected]>
Configure SGX as part of feature control MSR initialization and update
the associated X86_FEATURE flags accordingly. Because the kernel will
require the LE hash MSRs to be writable when running native enclaves,
disable X86_FEATURE_SGX (and all derivatives) if SGX Launch Control is
not (or cannot) be fully enabled via feature control MSR.
The check is done for every CPU, not just BSP, in order to verify that
MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. The other
parts of the kernel, like the enclave driver, expect the same
configuration from all CPUs.
Note, unlike VMX, clear the X86_FEATURE_SGX* flags for all CPUs if any
CPU lacks SGX support as the kernel expects SGX to be available on all
CPUs. X86_FEATURE_VMX is intentionally cleared only for the current CPU
so that KVM can provide additional information if KVM fails to load,
e.g. print which CPU doesn't support VMX. KVM/VMX requires additional
per-CPU enabling, e.g. to set CR4.VMXE and do VMXON, and so already has
the necessary infrastructure to do per-CPU checks. SGX on the other
hand doesn't require additional enabling, so clearing the feature flags
on all CPUs means the SGX subsystem doesn't need to manually do support
checks on a per-CPU basis.
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/feat_ctl.c | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 0268185bef94..ef4ddd6c8630 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -92,16 +92,35 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
}
#endif /* CONFIG_X86_VMX_FEATURE_NAMES */
+static void clear_sgx_caps(void)
+{
+ setup_clear_cpu_cap(X86_FEATURE_SGX);
+ setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
+ setup_clear_cpu_cap(X86_FEATURE_SGX1);
+ setup_clear_cpu_cap(X86_FEATURE_SGX2);
+}
+
void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
{
bool tboot = tboot_enabled();
+ bool enable_sgx;
u64 msr;
if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
clear_cpu_cap(c, X86_FEATURE_VMX);
+ clear_sgx_caps();
return;
}
+ /*
+ * Enable SGX if and only if the kernel supports SGX and Launch Control
+ * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
+ */
+ enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
+ cpu_has(c, X86_FEATURE_SGX1) &&
+ cpu_has(c, X86_FEATURE_SGX_LC) &&
+ IS_ENABLED(CONFIG_INTEL_SGX);
+
if (msr & FEAT_CTL_LOCKED)
goto update_caps;
@@ -123,13 +142,16 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
}
+ if (enable_sgx)
+ msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
+
wrmsrl(MSR_IA32_FEAT_CTL, msr);
update_caps:
set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
if (!cpu_has(c, X86_FEATURE_VMX))
- return;
+ goto update_sgx;
if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
(!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
@@ -142,4 +164,12 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
init_vmx_capabilities(c);
#endif
}
+
+update_sgx:
+ if (!(msr & FEAT_CTL_SGX_ENABLED) ||
+ !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
+ if (enable_sgx)
+ pr_err_once("SGX disabled by BIOS\n");
+ clear_sgx_caps();
+ }
}
--
2.25.1
From: Sean Christopherson <[email protected]>
Enumerate Enclave Page Cache (EPC) sections via CPUID and add the data
structures necessary to track EPC pages so that they can be allocated,
freed and managed. As a system may have multiple EPC sections, invoke CPUID
on SGX sub-leafs until an invalid leaf is encountered.
For simplicity, support a maximum of eight EPC sections. Existing client
hardware supports only a single section, while upcoming server hardware
will support at most eight sections. Bounding the number of sections also
allows the section ID to be embedded along with a page's offset in a single
unsigned long, enabling easy retrieval of both the VA and PA for a given
page.
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Serge Ayoun <[email protected]>
Signed-off-by: Serge Ayoun <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/Kconfig | 14 +++
arch/x86/kernel/cpu/Makefile | 1 +
arch/x86/kernel/cpu/sgx/Makefile | 3 +
arch/x86/kernel/cpu/sgx/main.c | 151 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/reclaim.c | 82 ++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 70 ++++++++++++++
6 files changed, 321 insertions(+)
create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
create mode 100644 arch/x86/kernel/cpu/sgx/main.c
create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index beea77046f9b..8bbb4313fae3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1950,6 +1950,20 @@ config X86_INTEL_TSX_MODE_AUTO
side channel attacks- equals the tsx=auto command line parameter.
endchoice
+config INTEL_SGX
+ bool "Intel SGX"
+ depends on X86_64 && CPU_SUP_INTEL
+ select SRCU
+ select MMU_NOTIFIER
+ help
+ Intel(R) SGX is a set of CPU instructions that can be used by
+ applications to set aside private regions of code and data, referred
+ to as enclaves. An enclave's private memory can only be accessed by
+ code running within the enclave. Accesses from outside the enclave,
+ including other enclaves, are disallowed by hardware.
+
+ If unsure, say N.
+
config EFI
bool "EFI runtime service support"
depends on ACPI
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 7dc4ad68eb41..45534fb81007 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_X86_MCE) += mce/
obj-$(CONFIG_MTRR) += mtrr/
obj-$(CONFIG_MICROCODE) += microcode/
obj-$(CONFIG_X86_CPU_RESCTRL) += resctrl/
+obj-$(CONFIG_INTEL_SGX) += sgx/
obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
new file mode 100644
index 000000000000..2dec75916a5e
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -0,0 +1,3 @@
+obj-y += \
+ main.o \
+ reclaim.o
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
new file mode 100644
index 000000000000..38424c1e8341
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-17 Intel Corporation.
+
+#include <linux/freezer.h>
+#include <linux/highmem.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/ratelimit.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include "encls.h"
+
+struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
+int sgx_nr_epc_sections;
+
+static void __init sgx_free_epc_section(struct sgx_epc_section *section)
+{
+ struct sgx_epc_page *page;
+
+ while (!list_empty(§ion->page_list)) {
+ page = list_first_entry(§ion->page_list,
+ struct sgx_epc_page, list);
+ list_del(&page->list);
+ kfree(page);
+ }
+
+ while (!list_empty(§ion->unsanitized_page_list)) {
+ page = list_first_entry(§ion->unsanitized_page_list,
+ struct sgx_epc_page, list);
+ list_del(&page->list);
+ kfree(page);
+ }
+
+ memunmap(section->va);
+}
+
+static bool __init sgx_alloc_epc_section(u64 addr, u64 size,
+ unsigned long index,
+ struct sgx_epc_section *section)
+{
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct sgx_epc_page *page;
+ unsigned long i;
+
+ section->va = memremap(addr, size, MEMREMAP_WB);
+ if (!section->va)
+ return false;
+
+ section->pa = addr;
+ spin_lock_init(§ion->lock);
+ INIT_LIST_HEAD(§ion->page_list);
+ INIT_LIST_HEAD(§ion->unsanitized_page_list);
+
+ for (i = 0; i < nr_pages; i++) {
+ page = kzalloc(sizeof(*page), GFP_KERNEL);
+ if (!page)
+ goto err_out;
+
+ page->desc = (addr + (i << PAGE_SHIFT)) | index;
+ list_add_tail(&page->list, §ion->unsanitized_page_list);
+ }
+
+ return true;
+
+err_out:
+ sgx_free_epc_section(section);
+ return false;
+}
+
+static void __init sgx_page_cache_teardown(void)
+{
+ int i;
+
+ for (i = 0; i < sgx_nr_epc_sections; i++)
+ sgx_free_epc_section(&sgx_epc_sections[i]);
+}
+
+/**
+ * A section metric is concatenated in a way that @low bits 12-31 define the
+ * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
+ * metric.
+ */
+static inline u64 __init sgx_calc_section_metric(u64 low, u64 high)
+{
+ return (low & GENMASK_ULL(31, 12)) +
+ ((high & GENMASK_ULL(19, 0)) << 32);
+}
+
+static bool __init sgx_page_cache_init(void)
+{
+ u32 eax, ebx, ecx, edx, type;
+ u64 pa, size;
+ int i;
+
+ for (i = 0; i <= ARRAY_SIZE(sgx_epc_sections); i++) {
+ cpuid_count(SGX_CPUID, i + SGX_CPUID_FIRST_VARIABLE_SUB_LEAF,
+ &eax, &ebx, &ecx, &edx);
+
+ type = eax & SGX_CPUID_SUB_LEAF_TYPE_MASK;
+ if (type == SGX_CPUID_SUB_LEAF_INVALID)
+ break;
+
+ if (type != SGX_CPUID_SUB_LEAF_EPC_SECTION) {
+ pr_err_once("Unknown EPC section type: %u\n", type);
+ break;
+ }
+
+ if (i == ARRAY_SIZE(sgx_epc_sections)) {
+ pr_warn("No free slot for an EPC section\n");
+ break;
+ }
+
+ pa = sgx_calc_section_metric(eax, ebx);
+ size = sgx_calc_section_metric(ecx, edx);
+
+ pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
+
+ if (!sgx_alloc_epc_section(pa, size, i, &sgx_epc_sections[i])) {
+ pr_err("No free memory for an EPC section\n");
+ break;
+ }
+
+ sgx_nr_epc_sections++;
+ }
+
+ if (!sgx_nr_epc_sections) {
+ pr_err("There are zero EPC sections.\n");
+ return false;
+ }
+
+ return true;
+}
+
+static void __init sgx_init(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_SGX))
+ return;
+
+ if (!sgx_page_cache_init())
+ return;
+
+ if (!sgx_page_reclaimer_init())
+ goto err_page_cache;
+
+ return;
+
+err_page_cache:
+ sgx_page_cache_teardown();
+}
+
+arch_initcall(sgx_init);
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
new file mode 100644
index 000000000000..215371588a25
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-19 Intel Corporation.
+
+#include <linux/freezer.h>
+#include <linux/highmem.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/ratelimit.h>
+#include <linux/slab.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include "encls.h"
+
+struct task_struct *ksgxswapd_tsk;
+
+static void sgx_sanitize_section(struct sgx_epc_section *section)
+{
+ struct sgx_epc_page *page;
+ LIST_HEAD(secs_list);
+ int ret;
+
+ while (!list_empty(§ion->unsanitized_page_list)) {
+ if (kthread_should_stop())
+ return;
+
+ spin_lock(§ion->lock);
+
+ page = list_first_entry(§ion->unsanitized_page_list,
+ struct sgx_epc_page, list);
+
+ ret = __eremove(sgx_epc_addr(page));
+ if (!ret)
+ list_move(&page->list, §ion->page_list);
+ else
+ list_move_tail(&page->list, &secs_list);
+
+ spin_unlock(§ion->lock);
+
+ cond_resched();
+ }
+}
+
+static int ksgxswapd(void *p)
+{
+ int i;
+
+ set_freezable();
+
+ /*
+ * Reset all pages to uninitialized state. Pages could be in initialized
+ * on kmemexec.
+ */
+ for (i = 0; i < sgx_nr_epc_sections; i++)
+ sgx_sanitize_section(&sgx_epc_sections[i]);
+
+ /*
+ * 2nd round for the SECS pages as they cannot be removed when they
+ * still hold child pages.
+ */
+ for (i = 0; i < sgx_nr_epc_sections; i++) {
+ sgx_sanitize_section(&sgx_epc_sections[i]);
+
+ /* Should never happen. */
+ if (!list_empty(&sgx_epc_sections[i].unsanitized_page_list))
+ WARN(1, "EPC section %d has unsanitized pages.\n", i);
+ }
+
+ return 0;
+}
+
+bool __init sgx_page_reclaimer_init(void)
+{
+ struct task_struct *tsk;
+
+ tsk = kthread_run(ksgxswapd, NULL, "ksgxswapd");
+ if (IS_ERR(tsk))
+ return false;
+
+ ksgxswapd_tsk = tsk;
+
+ return true;
+}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
new file mode 100644
index 000000000000..aad30980be32
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef _X86_SGX_H
+#define _X86_SGX_H
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <asm/asm.h>
+#include "arch.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "sgx: " fmt
+
+struct sgx_epc_page {
+ unsigned long desc;
+ struct list_head list;
+};
+
+/**
+ * struct sgx_epc_section
+ *
+ * The firmware can define multiple chunks of EPC to the different areas of the
+ * physical memory e.g. for memory areas of the each node. This structure is
+ * used to store EPC pages for one EPC section and virtual memory area where
+ * the pages have been mapped.
+ */
+struct sgx_epc_section {
+ unsigned long pa;
+ void *va;
+ struct list_head page_list;
+ struct list_head unsanitized_page_list;
+ spinlock_t lock;
+};
+
+/**
+ * enum sgx_epc_page_desc - bits and masks for an EPC page's descriptor
+ * %SGX_EPC_SECTION_MASK: SGX allows to have multiple EPC sections in the
+ * physical memory. The existing and near-future
+ * hardware defines at most eight sections, hence
+ * three bits to hold a section.
+ */
+enum sgx_epc_page_desc {
+ SGX_EPC_SECTION_MASK = GENMASK_ULL(3, 0),
+ /* bits 12-63 are reserved for the physical page address of the page */
+};
+
+#define SGX_MAX_EPC_SECTIONS (SGX_EPC_SECTION_MASK + 1)
+
+extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
+
+static inline struct sgx_epc_section *sgx_epc_section(struct sgx_epc_page *page)
+{
+ return &sgx_epc_sections[page->desc & SGX_EPC_SECTION_MASK];
+}
+
+static inline void *sgx_epc_addr(struct sgx_epc_page *page)
+{
+ struct sgx_epc_section *section = sgx_epc_section(page);
+
+ return section->va + (page->desc & PAGE_MASK) - section->pa;
+}
+
+extern int sgx_nr_epc_sections;
+extern struct task_struct *ksgxswapd_tsk;
+
+bool __init sgx_page_reclaimer_init(void);
+
+#endif /* _X86_SGX_H */
--
2.25.1
Add functions for allocating page from Enclave Page Cache (EPC). A page is
allocated by going through the EPC sections and returning the first free
page.
When a page is freed, it might have a valid state, which means that the
callee has assigned it to an enclave, which are protected memory ares used
to run code protected from outside access. The page is returned back to the
invalid state with ENCLS[EREMOVE] [1].
[1] Intel SDM: 40.3 INTEL® SGX SYSTEM LEAF FUNCTION REFERENCE
Co-developed-by: Sean Christopherson <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/sgx/main.c | 60 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 3 ++
2 files changed, 63 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 38424c1e8341..60d82e7537c8 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -13,6 +13,66 @@
struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
int sgx_nr_epc_sections;
+static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section)
+{
+ struct sgx_epc_page *page;
+
+ if (list_empty(§ion->page_list))
+ return NULL;
+
+ page = list_first_entry(§ion->page_list, struct sgx_epc_page, list);
+ list_del_init(&page->list);
+ return page;
+}
+
+/**
+ * sgx_try_alloc_page() - Allocate an EPC page
+ *
+ * Try to grab a page from the free EPC page list.
+ *
+ * Return:
+ * a pointer to a &struct sgx_epc_page instance,
+ * -errno on error
+ */
+struct sgx_epc_page *sgx_try_alloc_page(void)
+{
+ struct sgx_epc_section *section;
+ struct sgx_epc_page *page;
+ int i;
+
+ for (i = 0; i < sgx_nr_epc_sections; i++) {
+ section = &sgx_epc_sections[i];
+ spin_lock(§ion->lock);
+ page = __sgx_try_alloc_page(section);
+ spin_unlock(§ion->lock);
+
+ if (page)
+ return page;
+ }
+
+ return ERR_PTR(-ENOMEM);
+}
+
+/**
+ * sgx_free_page() - Free an EPC page
+ * @page: pointer a previously allocated EPC page
+ *
+ * EREMOVE an EPC page and insert it back to the list of free pages.
+ */
+void sgx_free_page(struct sgx_epc_page *page)
+{
+ struct sgx_epc_section *section = sgx_epc_section(page);
+ int ret;
+
+ ret = __eremove(sgx_epc_addr(page));
+ if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
+ return;
+
+ spin_lock(§ion->lock);
+ list_add_tail(&page->list, §ion->page_list);
+ spin_unlock(§ion->lock);
+}
+
static void __init sgx_free_epc_section(struct sgx_epc_section *section)
{
struct sgx_epc_page *page;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index aad30980be32..aa85f85412d8 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -67,4 +67,7 @@ extern struct task_struct *ksgxswapd_tsk;
bool __init sgx_page_reclaimer_init(void);
+struct sgx_epc_page *sgx_try_alloc_page(void);
+void sgx_free_page(struct sgx_epc_page *page);
+
#endif /* _X86_SGX_H */
--
2.25.1
Intel Software Guard eXtensions (SGX) is a set of CPU instructions that
can be used by applications to set aside private regions of code and
data. The code outside the SGX hosted software entity is disallowed to
access the memory inside the enclave enforced by the CPU. We call these
entities as enclaves.
This commit implements a driver that provides an ioctl API to construct
and run enclaves. Enclaves are constructed from pages residing in
reserved physical memory areas. The contents of these pages can only be
accessed when they are mapped as part of an enclave, by a hardware
thread running inside the enclave.
The starting state of an enclave consists of a fixed measured set of
pages that are copied to the EPC during the construction process by
using ENCLS leaf functions and Software Enclave Control Structure (SECS)
that defines the enclave properties.
Enclave are constructed by using ENCLS leaf functions ECREATE, EADD and
EINIT. ECREATE initializes SECS, EADD copies pages from system memory to
the EPC and EINIT check a given signed measurement and moves the enclave
into a state ready for execution.
An initialized enclave can only be accessed through special Thread Control
Structure (TCS) pages by using ENCLU (ring-3 only) leaf EENTER. This leaf
function converts a thread into enclave mode and continues the execution in
the offset defined by the TCS provided to EENTER. An enclave is exited
through syscall, exception, interrupts or by explicitly calling another
ENCLU leaf EEXIT.
The permissions, which enclave page is added will set the limit for maximum
permissions that can be set for mmap() and mprotect(). This will
effectively allow to build different security schemes between producers and
consumers of enclaves. Later on we can increase granularity with LSM hooks
for page addition (i.e. for producers) and mapping of the enclave (i.e. for
consumers)
Cc: [email protected]
Co-developed-by: Sean Christopherson <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Suresh Siddha <[email protected]>
Signed-off-by: Suresh Siddha <[email protected]>
Tested-by: Haitao Huang <[email protected]>
Tested-by: Jethro Beekman <[email protected]>
Tested-by: Chunyang Hui <[email protected]>
Tested-by: Jordan Hand <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
.../userspace-api/ioctl/ioctl-number.rst | 1 +
arch/x86/include/uapi/asm/sgx.h | 66 ++
arch/x86/kernel/cpu/sgx/Makefile | 3 +
arch/x86/kernel/cpu/sgx/driver.c | 194 +++++
arch/x86/kernel/cpu/sgx/driver.h | 30 +
arch/x86/kernel/cpu/sgx/encl.c | 332 +++++++++
arch/x86/kernel/cpu/sgx/encl.h | 87 +++
arch/x86/kernel/cpu/sgx/encls.h | 5 +-
arch/x86/kernel/cpu/sgx/ioctl.c | 687 ++++++++++++++++++
arch/x86/kernel/cpu/sgx/main.c | 12 +-
arch/x86/kernel/cpu/sgx/reclaim.c | 1 +
11 files changed, 1414 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/include/uapi/asm/sgx.h
create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 2e91370dc159..1c54dd2704db 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -321,6 +321,7 @@ Code Seq# Include File Comments
<mailto:[email protected]>
0xA3 90-9F linux/dtlk.h
0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
+0xA4 00-1F uapi/asm/sgx.h Intel SGX subsystem (a legit conflict as TEE and SGX do not co-exist)
0xAA 00-3F linux/uapi/linux/userfaultfd.h
0xAB 00-1F linux/nbd.h
0xAC 00-1F linux/raw.h
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
new file mode 100644
index 000000000000..5edb08ab8fd0
--- /dev/null
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+#ifndef _UAPI_ASM_X86_SGX_H
+#define _UAPI_ASM_X86_SGX_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+/**
+ * enum sgx_epage_flags - page control flags
+ * %SGX_PAGE_MEASURE: Measure the page contents with a sequence of
+ * ENCLS[EEXTEND] operations.
+ */
+enum sgx_page_flags {
+ SGX_PAGE_MEASURE = 0x01,
+};
+
+#define SGX_MAGIC 0xA4
+
+#define SGX_IOC_ENCLAVE_CREATE \
+ _IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
+#define SGX_IOC_ENCLAVE_ADD_PAGES \
+ _IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
+#define SGX_IOC_ENCLAVE_INIT \
+ _IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
+
+/**
+ * struct sgx_enclave_create - parameter structure for the
+ * %SGX_IOC_ENCLAVE_CREATE ioctl
+ * @src: address for the SECS page data
+ */
+struct sgx_enclave_create {
+ __u64 src;
+};
+
+/**
+ * struct sgx_enclave_add_pages - parameter structure for the
+ * %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
+ * @src: start address for the page data
+ * @offset: starting page offset
+ * @length: length of the data (multiple of the page size)
+ * @secinfo: address for the SECINFO data
+ * @flags: page control flags
+ * @count: number of bytes added (multiple of the page size)
+ */
+struct sgx_enclave_add_pages {
+ __u64 src;
+ __u64 offset;
+ __u64 length;
+ __u64 secinfo;
+ __u64 flags;
+ __u64 count;
+};
+
+/**
+ * struct sgx_enclave_init - parameter structure for the
+ * %SGX_IOC_ENCLAVE_INIT ioctl
+ * @sigstruct: address for the SIGSTRUCT data
+ */
+struct sgx_enclave_init {
+ __u64 sigstruct;
+};
+
+#endif /* _UAPI_ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
index 2dec75916a5e..f8d32da3a67a 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -1,3 +1,6 @@
obj-y += \
+ driver.o \
+ encl.o \
+ ioctl.o \
main.o \
reclaim.o
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
new file mode 100644
index 000000000000..b4aa7b9f8376
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/acpi.h>
+#include <linux/miscdevice.h>
+#include <linux/mman.h>
+#include <linux/security.h>
+#include <linux/suspend.h>
+#include <asm/traps.h>
+#include "driver.h"
+#include "encl.h"
+
+MODULE_DESCRIPTION("Intel SGX Enclave Driver");
+MODULE_AUTHOR("Jarkko Sakkinen <[email protected]>");
+MODULE_LICENSE("Dual BSD/GPL");
+
+u64 sgx_encl_size_max_32;
+u64 sgx_encl_size_max_64;
+u32 sgx_misc_reserved_mask;
+u64 sgx_attributes_reserved_mask;
+u64 sgx_xfrm_reserved_mask = ~0x3;
+u32 sgx_xsave_size_tbl[64];
+
+static int sgx_open(struct inode *inode, struct file *file)
+{
+ struct sgx_encl *encl;
+ int ret;
+
+ encl = kzalloc(sizeof(*encl), GFP_KERNEL);
+ if (!encl)
+ return -ENOMEM;
+
+ atomic_set(&encl->flags, 0);
+ kref_init(&encl->refcount);
+ INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
+ mutex_init(&encl->lock);
+ INIT_LIST_HEAD(&encl->mm_list);
+ spin_lock_init(&encl->mm_lock);
+
+ ret = init_srcu_struct(&encl->srcu);
+ if (ret) {
+ kfree(encl);
+ return ret;
+ }
+
+ file->private_data = encl;
+
+ return 0;
+}
+
+static int sgx_release(struct inode *inode, struct file *file)
+{
+ struct sgx_encl *encl = file->private_data;
+ struct sgx_encl_mm *encl_mm;
+
+ for ( ; ; ) {
+ spin_lock(&encl->mm_lock);
+
+ if (list_empty(&encl->mm_list)) {
+ encl_mm = NULL;
+ } else {
+ encl_mm = list_first_entry(&encl->mm_list,
+ struct sgx_encl_mm, list);
+ list_del_rcu(&encl_mm->list);
+ }
+
+ spin_unlock(&encl->mm_lock);
+
+ /* The list is empty, ready to go. */
+ if (!encl_mm)
+ break;
+
+ synchronize_srcu(&encl->srcu);
+ mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
+ kfree(encl_mm);
+ };
+
+ mutex_lock(&encl->lock);
+ atomic_or(SGX_ENCL_DEAD, &encl->flags);
+ mutex_unlock(&encl->lock);
+
+ kref_put(&encl->refcount, sgx_encl_release);
+ return 0;
+}
+
+#ifdef CONFIG_COMPAT
+static long sgx_compat_ioctl(struct file *filep, unsigned int cmd,
+ unsigned long arg)
+{
+ return sgx_ioctl(filep, cmd, arg);
+}
+#endif
+
+static int sgx_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct sgx_encl *encl = file->private_data;
+ int ret;
+
+ ret = sgx_encl_may_map(encl, vma->vm_start, vma->vm_end,
+ vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC));
+ if (ret)
+ return ret;
+
+ ret = sgx_encl_mm_add(encl, vma->vm_mm);
+ if (ret)
+ return ret;
+
+ vma->vm_ops = &sgx_vm_ops;
+ vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+ vma->vm_private_data = encl;
+
+ return 0;
+}
+
+static unsigned long sgx_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags)
+{
+ if (flags & MAP_PRIVATE)
+ return -EINVAL;
+
+ if (flags & MAP_FIXED)
+ return addr;
+
+ return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+static const struct file_operations sgx_encl_fops = {
+ .owner = THIS_MODULE,
+ .open = sgx_open,
+ .release = sgx_release,
+ .unlocked_ioctl = sgx_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = sgx_compat_ioctl,
+#endif
+ .mmap = sgx_mmap,
+ .get_unmapped_area = sgx_get_unmapped_area,
+};
+
+const struct file_operations sgx_provision_fops = {
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice sgx_dev_enclave = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "enclave",
+ .nodename = "sgx/enclave",
+ .fops = &sgx_encl_fops,
+};
+
+int __init sgx_drv_init(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ u64 attr_mask, xfrm_mask;
+ int ret;
+ int i;
+
+ if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
+ pr_info("The public key MSRs are not writable.\n");
+ return -ENODEV;
+ }
+
+ cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
+ sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
+ sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
+ sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
+
+ cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
+
+ attr_mask = (((u64)ebx) << 32) + (u64)eax;
+ sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
+
+ if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
+ xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
+
+ for (i = 2; i < 64; i++) {
+ cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
+ if ((1 << i) & xfrm_mask)
+ sgx_xsave_size_tbl[i] = eax + ebx;
+ }
+
+ sgx_xfrm_reserved_mask = ~xfrm_mask;
+ }
+
+ ret = misc_register(&sgx_dev_enclave);
+ if (ret) {
+ pr_err("Creating /dev/sgx/enclave failed with %d.\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
new file mode 100644
index 000000000000..e4063923115b
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef __ARCH_SGX_DRIVER_H__
+#define __ARCH_SGX_DRIVER_H__
+
+#include <crypto/hash.h>
+#include <linux/kref.h>
+#include <linux/mmu_notifier.h>
+#include <linux/radix-tree.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <uapi/asm/sgx.h>
+#include "sgx.h"
+
+#define SGX_EINIT_SPIN_COUNT 20
+#define SGX_EINIT_SLEEP_COUNT 50
+#define SGX_EINIT_SLEEP_TIME 20
+
+extern u64 sgx_encl_size_max_32;
+extern u64 sgx_encl_size_max_64;
+extern u32 sgx_misc_reserved_mask;
+extern u64 sgx_attributes_reserved_mask;
+extern u64 sgx_xfrm_reserved_mask;
+extern u32 sgx_xsave_size_tbl[64];
+
+long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
+
+int sgx_drv_init(void);
+
+#endif /* __ARCH_X86_SGX_DRIVER_H__ */
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
new file mode 100644
index 000000000000..17e44bf8fa56
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/lockdep.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/shmem_fs.h>
+#include <linux/suspend.h>
+#include <linux/sched/mm.h>
+#include "arch.h"
+#include "encl.h"
+#include "sgx.h"
+
+static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
+ unsigned long addr)
+{
+ struct sgx_encl_page *entry;
+ unsigned int flags;
+
+ /* If process was forked, VMA is still there but vm_private_data is set
+ * to NULL.
+ */
+ if (!encl)
+ return ERR_PTR(-EFAULT);
+
+ flags = atomic_read(&encl->flags);
+
+ if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
+ return ERR_PTR(-EFAULT);
+
+ entry = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT);
+ if (!entry)
+ return ERR_PTR(-EFAULT);
+
+ /* Page is already resident in the EPC. */
+ if (entry->epc_page)
+ return entry;
+
+ return ERR_PTR(-EFAULT);
+}
+
+static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
+ struct mm_struct *mm)
+{
+ struct sgx_encl_mm *encl_mm =
+ container_of(mn, struct sgx_encl_mm, mmu_notifier);
+ struct sgx_encl_mm *tmp = NULL;
+
+ /*
+ * The enclave itself can remove encl_mm. Note, objects can't be moved
+ * off an RCU protected list, but deletion is ok.
+ */
+ spin_lock(&encl_mm->encl->mm_lock);
+ list_for_each_entry(tmp, &encl_mm->encl->mm_list, list) {
+ if (tmp == encl_mm) {
+ list_del_rcu(&encl_mm->list);
+ break;
+ }
+ }
+ spin_unlock(&encl_mm->encl->mm_lock);
+
+ if (tmp == encl_mm) {
+ synchronize_srcu(&encl_mm->encl->srcu);
+ mmu_notifier_put(mn);
+ }
+}
+
+static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
+{
+ struct sgx_encl_mm *encl_mm =
+ container_of(mn, struct sgx_encl_mm, mmu_notifier);
+
+ kfree(encl_mm);
+}
+
+static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
+ .release = sgx_mmu_notifier_release,
+ .free_notifier = sgx_mmu_notifier_free,
+};
+
+static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
+ struct mm_struct *mm)
+{
+ struct sgx_encl_mm *encl_mm = NULL;
+ struct sgx_encl_mm *tmp;
+ int idx;
+
+ idx = srcu_read_lock(&encl->srcu);
+
+ list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
+ if (tmp->mm == mm) {
+ encl_mm = tmp;
+ break;
+ }
+ }
+
+ srcu_read_unlock(&encl->srcu, idx);
+
+ return encl_mm;
+}
+
+int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
+{
+ struct sgx_encl_mm *encl_mm;
+ int ret;
+
+ /* mm_list can be accessed only by a single thread at a time. */
+ lockdep_assert_held_write(&mm->mmap_sem);
+
+ if (atomic_read(&encl->flags) & SGX_ENCL_DEAD)
+ return -EINVAL;
+
+ /*
+ * mm_structs are kept on mm_list until the mm or the enclave dies,
+ * i.e. once an mm is off the list, it's gone for good, therefore it's
+ * impossible to get a false positive on @mm due to a stale mm_list.
+ */
+ if (sgx_encl_find_mm(encl, mm))
+ return 0;
+
+ encl_mm = kzalloc(sizeof(*encl_mm), GFP_KERNEL);
+ if (!encl_mm)
+ return -ENOMEM;
+
+ encl_mm->encl = encl;
+ encl_mm->mm = mm;
+ encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;
+
+ ret = __mmu_notifier_register(&encl_mm->mmu_notifier, mm);
+ if (ret) {
+ kfree(encl_mm);
+ return ret;
+ }
+
+ spin_lock(&encl->mm_lock);
+ list_add_rcu(&encl_mm->list, &encl->mm_list);
+ spin_unlock(&encl->mm_lock);
+
+ return 0;
+}
+
+static void sgx_vma_open(struct vm_area_struct *vma)
+{
+ struct sgx_encl *encl = vma->vm_private_data;
+
+ if (!encl)
+ return;
+
+ if (sgx_encl_mm_add(encl, vma->vm_mm))
+ vma->vm_private_data = NULL;
+}
+
+static unsigned int sgx_vma_fault(struct vm_fault *vmf)
+{
+ unsigned long addr = (unsigned long)vmf->address;
+ struct vm_area_struct *vma = vmf->vma;
+ struct sgx_encl *encl = vma->vm_private_data;
+ struct sgx_encl_page *entry;
+ int ret = VM_FAULT_NOPAGE;
+ unsigned long pfn;
+
+ if (!encl)
+ return VM_FAULT_SIGBUS;
+
+ mutex_lock(&encl->lock);
+
+ entry = sgx_encl_load_page(encl, addr);
+ if (IS_ERR(entry)) {
+ if (unlikely(PTR_ERR(entry) != -EBUSY))
+ ret = VM_FAULT_SIGBUS;
+
+ goto out;
+ }
+
+ if (!follow_pfn(vma, addr, &pfn))
+ goto out;
+
+ ret = vmf_insert_pfn(vma, addr, PFN_DOWN(entry->epc_page->desc));
+ if (ret != VM_FAULT_NOPAGE) {
+ ret = VM_FAULT_SIGBUS;
+ goto out;
+ }
+
+out:
+ mutex_unlock(&encl->lock);
+ return ret;
+}
+
+/**
+ * sgx_encl_may_map() - Check if a requested VMA mapping is allowed
+ * @encl: an enclave
+ * @start: lower bound of the address range, inclusive
+ * @end: upper bound of the address range, exclusive
+ * @vm_prot_bits: requested protections of the address range
+ *
+ * Iterate through the enclave pages contained within [@start, @end) to verify
+ * the permissions requested by @vm_prot_bits do not exceed that of any enclave
+ * page to be mapped.
+ *
+ * Return:
+ * 0 on success,
+ * -EACCES if VMA permissions exceed enclave page permissions
+ */
+int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
+ unsigned long end, unsigned long vm_prot_bits)
+{
+ unsigned long idx, idx_start, idx_end;
+ struct sgx_encl_page *page;
+
+ /*
+ * Disallow RIE tasks as their VMA permissions might conflict with the
+ * enclave page permissions.
+ */
+ if (!!(current->personality & READ_IMPLIES_EXEC))
+ return -EACCES;
+
+ idx_start = PFN_DOWN(start);
+ idx_end = PFN_DOWN(end - 1);
+
+ for (idx = idx_start; idx <= idx_end; ++idx) {
+ mutex_lock(&encl->lock);
+ page = radix_tree_lookup(&encl->page_tree, idx);
+ mutex_unlock(&encl->lock);
+
+ if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, unsigned long prot)
+{
+ return sgx_encl_may_map(vma->vm_private_data, start, end,
+ calc_vm_prot_bits(prot, 0));
+}
+
+const struct vm_operations_struct sgx_vm_ops = {
+ .open = sgx_vma_open,
+ .fault = sgx_vma_fault,
+ .may_mprotect = sgx_vma_mprotect,
+};
+
+/**
+ * sgx_encl_find - find an enclave
+ * @mm: mm struct of the current process
+ * @addr: address in the ELRANGE
+ * @vma: the resulting VMA
+ *
+ * Find an enclave identified by the given address. Give back a VMA that is
+ * part of the enclave and located in that address. The VMA is given back if it
+ * is a proper enclave VMA even if an &sgx_encl instance does not exist yet
+ * (enclave creation has not been performed).
+ *
+ * Return:
+ * 0 on success,
+ * -EINVAL if an enclave was not found,
+ * -ENOENT if the enclave has not been created yet
+ */
+int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
+ struct vm_area_struct **vma)
+{
+ struct vm_area_struct *result;
+ struct sgx_encl *encl;
+
+ result = find_vma(mm, addr);
+ if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
+ return -EINVAL;
+
+ encl = result->vm_private_data;
+ *vma = result;
+
+ return encl ? 0 : -ENOENT;
+}
+
+/**
+ * sgx_encl_destroy() - destroy enclave resources
+ * @encl: an &sgx_encl instance
+ */
+void sgx_encl_destroy(struct sgx_encl *encl)
+{
+ struct sgx_encl_page *entry;
+ struct radix_tree_iter iter;
+ void **slot;
+
+ atomic_or(SGX_ENCL_DEAD, &encl->flags);
+
+ radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
+ entry = *slot;
+
+ if (entry->epc_page) {
+ sgx_free_page(entry->epc_page);
+ encl->secs_child_cnt--;
+ entry->epc_page = NULL;
+ }
+
+ radix_tree_delete(&entry->encl->page_tree,
+ PFN_DOWN(entry->desc));
+ kfree(entry);
+ }
+
+ if (!encl->secs_child_cnt && encl->secs.epc_page) {
+ sgx_free_page(encl->secs.epc_page);
+ encl->secs.epc_page = NULL;
+ }
+}
+
+/**
+ * sgx_encl_release - Destroy an enclave instance
+ * @kref: address of a kref inside &sgx_encl
+ *
+ * Used together with kref_put(). Frees all the resources associated with the
+ * enclave and the instance itself.
+ */
+void sgx_encl_release(struct kref *ref)
+{
+ struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
+
+ sgx_encl_destroy(encl);
+
+ if (encl->backing)
+ fput(encl->backing);
+
+ WARN_ON_ONCE(!list_empty(&encl->mm_list));
+
+ /* Detect EPC page leak's. */
+ WARN_ON_ONCE(encl->secs_child_cnt);
+ WARN_ON_ONCE(encl->secs.epc_page);
+
+ kfree(encl);
+}
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
new file mode 100644
index 000000000000..1d1bc5d590ee
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+#ifndef _X86_ENCL_H
+#define _X86_ENCL_H
+
+#include <linux/cpumask.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mm_types.h>
+#include <linux/mmu_notifier.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/radix-tree.h>
+#include <linux/srcu.h>
+#include <linux/workqueue.h>
+#include "sgx.h"
+
+/**
+ * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
+ * %SGX_ENCL_PAGE_ADDR_MASK: Holds the virtual address of the page.
+ *
+ * The page address for SECS is zero and is used by the subsystem to recognize
+ * the SECS page.
+ */
+enum sgx_encl_page_desc {
+ /* Bits 11:3 are available when the page is not swapped. */
+ SGX_ENCL_PAGE_ADDR_MASK = PAGE_MASK,
+};
+
+#define SGX_ENCL_PAGE_ADDR(page) \
+ ((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
+
+struct sgx_encl_page {
+ unsigned long desc;
+ unsigned long vm_max_prot_bits;
+ struct sgx_epc_page *epc_page;
+ struct sgx_encl *encl;
+};
+
+enum sgx_encl_flags {
+ SGX_ENCL_CREATED = BIT(0),
+ SGX_ENCL_INITIALIZED = BIT(1),
+ SGX_ENCL_DEBUG = BIT(2),
+ SGX_ENCL_DEAD = BIT(3),
+ SGX_ENCL_IOCTL = BIT(4),
+};
+
+struct sgx_encl_mm {
+ struct sgx_encl *encl;
+ struct mm_struct *mm;
+ struct list_head list;
+ struct mmu_notifier mmu_notifier;
+};
+
+struct sgx_encl {
+ atomic_t flags;
+ u64 secs_attributes;
+ u64 allowed_attributes;
+ unsigned int page_cnt;
+ unsigned int secs_child_cnt;
+ struct mutex lock;
+ struct list_head mm_list;
+ spinlock_t mm_lock;
+ struct file *backing;
+ struct kref refcount;
+ struct srcu_struct srcu;
+ unsigned long base;
+ unsigned long size;
+ unsigned long ssaframesize;
+ struct radix_tree_root page_tree;
+ struct sgx_encl_page secs;
+ cpumask_t cpumask;
+};
+
+extern const struct vm_operations_struct sgx_vm_ops;
+
+int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
+ struct vm_area_struct **vma);
+void sgx_encl_destroy(struct sgx_encl *encl);
+void sgx_encl_release(struct kref *ref);
+int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
+int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
+ unsigned long end, unsigned long vm_prot_bits);
+
+#endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
index 376cdedb9a43..f716b4328614 100644
--- a/arch/x86/kernel/cpu/sgx/encls.h
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -186,10 +186,9 @@ static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
return __encls_2(EADD, pginfo, addr);
}
-static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
- void *secs)
+static inline int __einit(void *sigstruct, void *token, void *secs)
{
- return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
+ return __encls_ret_3(EINIT, sigstruct, secs, token);
}
static inline int __eremove(void *addr)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
new file mode 100644
index 000000000000..26d0425d7252
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -0,0 +1,687 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-19 Intel Corporation.
+
+#include <asm/mman.h>
+#include <linux/mman.h>
+#include <linux/delay.h>
+#include <linux/file.h>
+#include <linux/hashtable.h>
+#include <linux/highmem.h>
+#include <linux/ratelimit.h>
+#include <linux/sched/signal.h>
+#include <linux/shmem_fs.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include "driver.h"
+#include "encl.h"
+#include "encls.h"
+
+/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
+static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
+
+static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
+{
+ u32 size_max = PAGE_SIZE;
+ u32 size;
+ int i;
+
+ for (i = 2; i < 64; i++) {
+ if (!((1 << i) & xfrm))
+ continue;
+
+ size = SGX_SSA_GPRS_SIZE + sgx_xsave_size_tbl[i];
+ if (miscselect & SGX_MISC_EXINFO)
+ size += SGX_SSA_MISC_EXINFO_SIZE;
+
+ if (size > size_max)
+ size_max = size;
+ }
+
+ return PFN_UP(size_max);
+}
+
+static int sgx_validate_secs(const struct sgx_secs *secs,
+ unsigned long ssaframesize)
+{
+ if (secs->size < (2 * PAGE_SIZE) || !is_power_of_2(secs->size))
+ return -EINVAL;
+
+ if (secs->base & (secs->size - 1))
+ return -EINVAL;
+
+ if (secs->miscselect & sgx_misc_reserved_mask ||
+ secs->attributes & sgx_attributes_reserved_mask ||
+ secs->xfrm & sgx_xfrm_reserved_mask)
+ return -EINVAL;
+
+ if (secs->attributes & SGX_ATTR_MODE64BIT) {
+ if (secs->size > sgx_encl_size_max_64)
+ return -EINVAL;
+ } else if (secs->size > sgx_encl_size_max_32)
+ return -EINVAL;
+
+ if (!(secs->xfrm & XFEATURE_MASK_FP) ||
+ !(secs->xfrm & XFEATURE_MASK_SSE) ||
+ (((secs->xfrm >> XFEATURE_BNDREGS) & 1) !=
+ ((secs->xfrm >> XFEATURE_BNDCSR) & 1)))
+ return -EINVAL;
+
+ if (!secs->ssa_frame_size || ssaframesize > secs->ssa_frame_size)
+ return -EINVAL;
+
+ if (memchr_inv(secs->reserved1, 0, sizeof(secs->reserved1)) ||
+ memchr_inv(secs->reserved2, 0, sizeof(secs->reserved2)) ||
+ memchr_inv(secs->reserved3, 0, sizeof(secs->reserved3)) ||
+ memchr_inv(secs->reserved4, 0, sizeof(secs->reserved4)))
+ return -EINVAL;
+
+ return 0;
+}
+
+static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
+ unsigned long offset,
+ u64 secinfo_flags)
+{
+ struct sgx_encl_page *encl_page;
+ unsigned long prot;
+
+ encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
+ if (!encl_page)
+ return ERR_PTR(-ENOMEM);
+
+ encl_page->desc = encl->base + offset;
+ encl_page->encl = encl;
+
+ prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ) |
+ _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
+ _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
+
+ /*
+ * TCS pages must always RW set for CPU access while the SECINFO
+ * permissions are *always* zero - the CPU ignores the user provided
+ * values and silently overwrites them with zero permissions.
+ */
+ if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
+ prot |= PROT_READ | PROT_WRITE;
+
+ /* Calculate maximum of the VM flags for the page. */
+ encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
+
+ return encl_page;
+}
+
+static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
+{
+ unsigned long encl_size = secs->size + PAGE_SIZE;
+ struct sgx_epc_page *secs_epc;
+ unsigned long ssaframesize;
+ struct sgx_pageinfo pginfo;
+ struct sgx_secinfo secinfo;
+ struct file *backing;
+ long ret;
+
+ if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
+ return -EINVAL;
+
+ ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
+ if (sgx_validate_secs(secs, ssaframesize)) {
+ pr_debug("invalid SECS\n");
+ return -EINVAL;
+ }
+
+ backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
+ VM_NORESERVE);
+ if (IS_ERR(backing))
+ return PTR_ERR(backing);
+
+ encl->backing = backing;
+
+ secs_epc = sgx_try_alloc_page();
+ if (IS_ERR(secs_epc)) {
+ ret = PTR_ERR(secs_epc);
+ goto err_out_backing;
+ }
+
+ encl->secs.epc_page = secs_epc;
+
+ pginfo.addr = 0;
+ pginfo.contents = (unsigned long)secs;
+ pginfo.metadata = (unsigned long)&secinfo;
+ pginfo.secs = 0;
+ memset(&secinfo, 0, sizeof(secinfo));
+
+ ret = __ecreate((void *)&pginfo, sgx_epc_addr(secs_epc));
+ if (ret) {
+ pr_debug("ECREATE returned %ld\n", ret);
+ goto err_out;
+ }
+
+ if (secs->attributes & SGX_ATTR_DEBUG)
+ atomic_or(SGX_ENCL_DEBUG, &encl->flags);
+
+ encl->secs.encl = encl;
+ encl->secs_attributes = secs->attributes;
+ encl->allowed_attributes |= SGX_ATTR_ALLOWED_MASK;
+ encl->base = secs->base;
+ encl->size = secs->size;
+ encl->ssaframesize = secs->ssa_frame_size;
+
+ /*
+ * Set SGX_ENCL_CREATED only after the enclave is fully prepped. This
+ * allows setting and checking enclave creation without having to take
+ * encl->lock.
+ */
+ atomic_or(SGX_ENCL_CREATED, &encl->flags);
+
+ return 0;
+
+err_out:
+ sgx_free_page(encl->secs.epc_page);
+ encl->secs.epc_page = NULL;
+
+err_out_backing:
+ fput(encl->backing);
+ encl->backing = NULL;
+
+ return ret;
+}
+
+/**
+ * sgx_ioc_enclave_create - handler for %SGX_IOC_ENCLAVE_CREATE
+ * @filep: open file to /dev/sgx
+ * @arg: userspace pointer to a struct sgx_enclave_create instance
+ *
+ * Allocate kernel data structures for a new enclave and execute ECREATE after
+ * verifying the correctness of the provided SECS.
+ *
+ * Note, enforcement of restricted and disallowed attributes is deferred until
+ * sgx_ioc_enclave_init(), only the architectural correctness of the SECS is
+ * checked by sgx_ioc_enclave_create().
+ *
+ * Return:
+ * 0 on success,
+ * -errno otherwise
+ */
+static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
+{
+ struct sgx_enclave_create ecreate;
+ struct page *secs_page;
+ struct sgx_secs *secs;
+ int ret;
+
+ if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
+ return -EFAULT;
+
+ secs_page = alloc_page(GFP_KERNEL);
+ if (!secs_page)
+ return -ENOMEM;
+
+ secs = kmap(secs_page);
+ if (copy_from_user(secs, (void __user *)ecreate.src, sizeof(*secs))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = sgx_encl_create(encl, secs);
+
+out:
+ kunmap(secs_page);
+ __free_page(secs_page);
+ return ret;
+}
+
+static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
+{
+ u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
+ u64 pt = secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK;
+
+ if (pt != SGX_SECINFO_REG && pt != SGX_SECINFO_TCS)
+ return -EINVAL;
+
+ if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
+ return -EINVAL;
+
+ /*
+ * CPU will silently overwrite the permissions as zero, which means
+ * that we need to validate it ourselves.
+ */
+ if (pt == SGX_SECINFO_TCS && perm)
+ return -EINVAL;
+
+ if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
+ return -EINVAL;
+
+ if (memchr_inv(secinfo->reserved, 0, sizeof(secinfo->reserved)))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int __sgx_encl_add_page(struct sgx_encl *encl,
+ struct sgx_encl_page *encl_page,
+ struct sgx_epc_page *epc_page,
+ struct sgx_secinfo *secinfo, unsigned long src)
+{
+ struct sgx_pageinfo pginfo;
+ struct vm_area_struct *vma;
+ struct page *src_page;
+ int ret;
+
+ /* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
+ if (encl_page->vm_max_prot_bits & VM_EXEC) {
+ vma = find_vma(current->mm, src);
+ if (!vma)
+ return -EFAULT;
+
+ if (!(vma->vm_flags & VM_MAYEXEC))
+ return -EACCES;
+ }
+
+ ret = get_user_pages(src, 1, 0, &src_page, NULL);
+ if (ret < 1)
+ return ret;
+
+ pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
+ pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
+ pginfo.metadata = (unsigned long)secinfo;
+ pginfo.contents = (unsigned long)kmap_atomic(src_page);
+
+ ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
+
+ kunmap_atomic((void *)pginfo.contents);
+ put_page(src_page);
+
+ return ret ? -EIO : 0;
+}
+
+static int __sgx_encl_extend(struct sgx_encl *encl,
+ struct sgx_epc_page *epc_page)
+{
+ int ret;
+ int i;
+
+ for (i = 0; i < 16; i++) {
+ ret = __eextend(sgx_epc_addr(encl->secs.epc_page),
+ sgx_epc_addr(epc_page) + (i * 0x100));
+ if (ret) {
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "EEXTEND");
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+
+static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
+ unsigned long offset, unsigned long length,
+ struct sgx_secinfo *secinfo, unsigned long flags)
+{
+ struct sgx_encl_page *encl_page;
+ struct sgx_epc_page *epc_page;
+ int ret;
+
+ encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
+ if (IS_ERR(encl_page))
+ return PTR_ERR(encl_page);
+
+ epc_page = sgx_try_alloc_page();
+ if (IS_ERR(epc_page)) {
+ kfree(encl_page);
+ return PTR_ERR(epc_page);
+ }
+
+ if (atomic_read(&encl->flags) &
+ (SGX_ENCL_INITIALIZED | SGX_ENCL_DEAD)) {
+ ret = -EFAULT;
+ goto err_out_free;
+ }
+
+ down_read(¤t->mm->mmap_sem);
+ mutex_lock(&encl->lock);
+
+ /*
+ * Insert prior to EADD in case of OOM. EADD modifies MRENCLAVE, i.e.
+ * can't be gracefully unwound, while failure on EADD/EXTEND is limited
+ * to userspace errors (or kernel/hardware bugs).
+ */
+ ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
+ encl_page);
+ if (ret)
+ goto err_out_unlock;
+
+ ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
+ src);
+ if (ret)
+ goto err_out;
+
+ /*
+ * Complete the "add" before doing the "extend" so that the "add"
+ * isn't in a half-baked state in the extremely unlikely scenario the
+ * the enclave will be destroyed in response to EEXTEND failure.
+ */
+ encl_page->encl = encl;
+ encl_page->epc_page = epc_page;
+ encl->secs_child_cnt++;
+
+ if (flags & SGX_PAGE_MEASURE) {
+ ret = __sgx_encl_extend(encl, epc_page);
+ if (ret)
+ goto err_out;
+ }
+
+ mutex_unlock(&encl->lock);
+ up_read(¤t->mm->mmap_sem);
+ return ret;
+
+err_out:
+ radix_tree_delete(&encl_page->encl->page_tree,
+ PFN_DOWN(encl_page->desc));
+
+err_out_unlock:
+ mutex_unlock(&encl->lock);
+ up_read(¤t->mm->mmap_sem);
+
+err_out_free:
+ sgx_free_page(epc_page);
+ kfree(encl_page);
+
+ /*
+ * Destroy enclave on ENCLS failure as this means that EPC has been
+ * invalidated.
+ */
+ if (ret == -EIO)
+ sgx_encl_destroy(encl);
+
+ return ret;
+}
+
+/**
+ * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
+ * @encl: pointer to an enclave instance (via ioctl() file pointer)
+ * @arg: a user pointer to a struct sgx_enclave_add_pages instance
+ *
+ * Add one or more pages to an uninitialized enclave, and optionally extend the
+ * measurement with the contents of the page. The address range of pages must
+ * be contiguous. The SECINFO and measurement mask are applied to all pages.
+ *
+ * A SECINFO for a TCS is required to always contain zero permissions because
+ * CPU silently zeros them. Allowing anything else would cause a mismatch in
+ * the measurement.
+ *
+ * mmap()'s protection bits are capped by the page permissions. For each page
+ * address, the maximum protection bits are computed with the following
+ * heuristics:
+ *
+ * 1. A regular page: PROT_R, PROT_W and PROT_X match the SECINFO permissions.
+ * 2. A TCS page: PROT_R | PROT_W.
+ *
+ * mmap() is not allowed to surpass the minimum of the maximum protection bits
+ * within the given address range.
+ *
+ * If ENCLS opcode fails, that effectively means that EPC has been invalidated.
+ * When this happens the enclave is destroyed and -EIO is returned to the
+ * caller.
+ *
+ * Return:
+ * 0 on success,
+ * -EACCES if an executable source page is located in a noexec partition,
+ * -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails
+ * -errno otherwise
+ */
+static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
+{
+ struct sgx_enclave_add_pages addp;
+ struct sgx_secinfo secinfo;
+ unsigned long c;
+ int ret;
+
+ if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
+ return -EINVAL;
+
+ if (copy_from_user(&addp, arg, sizeof(addp)))
+ return -EFAULT;
+
+ if (!IS_ALIGNED(addp.offset, PAGE_SIZE) ||
+ !IS_ALIGNED(addp.src, PAGE_SIZE))
+ return -EINVAL;
+
+ if (!(access_ok(addp.src, PAGE_SIZE)))
+ return -EFAULT;
+
+ if (addp.length & (PAGE_SIZE - 1))
+ return -EINVAL;
+
+ if (addp.offset + addp.length - PAGE_SIZE >= encl->size)
+ return -EINVAL;
+
+ if (copy_from_user(&secinfo, (void __user *)addp.secinfo,
+ sizeof(secinfo)))
+ return -EFAULT;
+
+ if (sgx_validate_secinfo(&secinfo))
+ return -EINVAL;
+
+ for (c = 0 ; c < addp.length; c += PAGE_SIZE) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
+ if (need_resched())
+ cond_resched();
+
+ ret = sgx_encl_add_page(encl, addp.src + c, addp.offset + c,
+ addp.length - c, &secinfo, addp.flags);
+ if (ret)
+ break;
+ }
+
+ addp.count = c;
+
+ if (copy_to_user(arg, &addp, sizeof(addp)))
+ return -EFAULT;
+
+ return ret;
+}
+
+static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
+ void *hash)
+{
+ SHASH_DESC_ON_STACK(shash, tfm);
+
+ shash->tfm = tfm;
+
+ return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
+}
+
+static int sgx_get_key_hash(const void *modulus, void *hash)
+{
+ struct crypto_shash *tfm;
+ int ret;
+
+ tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ ret = __sgx_get_key_hash(tfm, modulus, hash);
+
+ crypto_free_shash(tfm);
+ return ret;
+}
+
+static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
+{
+ u64 *cache;
+ int i;
+
+ cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
+ for (i = 0; i < 4; i++) {
+ if (enforce || (lepubkeyhash[i] != cache[i])) {
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
+ cache[i] = lepubkeyhash[i];
+ }
+ }
+}
+
+static int sgx_einit(struct sgx_sigstruct *sigstruct, void *token,
+ struct sgx_epc_page *secs, u64 *lepubkeyhash)
+{
+ int ret;
+
+ preempt_disable();
+ sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
+ ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+ if (ret == SGX_INVALID_EINITTOKEN) {
+ sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
+ ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+ }
+ preempt_enable();
+ return ret;
+}
+
+static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
+ void *token)
+{
+ u64 mrsigner[4];
+ int ret;
+ int i;
+ int j;
+
+ /* Check that the required attributes have been authorized. */
+ if (encl->secs_attributes & ~encl->allowed_attributes)
+ return -EACCES;
+
+ ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
+ if (ret)
+ return ret;
+
+ mutex_lock(&encl->lock);
+
+ if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
+ ret = -EFAULT;
+ goto err_out;
+ }
+
+ for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
+ for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
+ ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
+ mrsigner);
+ if (ret == SGX_UNMASKED_EVENT)
+ continue;
+ else
+ break;
+ }
+
+ if (ret != SGX_UNMASKED_EVENT)
+ break;
+
+ msleep_interruptible(SGX_EINIT_SLEEP_TIME);
+
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ goto err_out;
+ }
+ }
+
+ if (ret & ENCLS_FAULT_FLAG) {
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "EINIT");
+
+ sgx_encl_destroy(encl);
+ ret = -EFAULT;
+ } else if (ret) {
+ pr_debug("EINIT returned %d\n", ret);
+ ret = -EPERM;
+ } else {
+ atomic_or(SGX_ENCL_INITIALIZED, &encl->flags);
+ }
+
+err_out:
+ mutex_unlock(&encl->lock);
+ return ret;
+}
+
+/**
+ * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
+ *
+ * @filep: open file to /dev/sgx
+ * @arg: userspace pointer to a struct sgx_enclave_init instance
+ *
+ * Flush any outstanding enqueued EADD operations and perform EINIT. The
+ * Launch Enclave Public Key Hash MSRs are rewritten as necessary to match
+ * the enclave's MRSIGNER, which is caculated from the provided sigstruct.
+ *
+ * Return:
+ * 0 on success,
+ * SGX error code on EINIT failure,
+ * -errno otherwise
+ */
+static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
+{
+ struct sgx_sigstruct *sigstruct;
+ struct sgx_enclave_init einit;
+ struct page *initp_page;
+ void *token;
+ int ret;
+
+ if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
+ return -EINVAL;
+
+ if (copy_from_user(&einit, arg, sizeof(einit)))
+ return -EFAULT;
+
+ initp_page = alloc_page(GFP_KERNEL);
+ if (!initp_page)
+ return -ENOMEM;
+
+ sigstruct = kmap(initp_page);
+ token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
+ memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
+
+ if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
+ sizeof(*sigstruct))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = sgx_encl_init(encl, sigstruct, token);
+
+out:
+ kunmap(initp_page);
+ __free_page(initp_page);
+ return ret;
+}
+
+
+long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+ struct sgx_encl *encl = filep->private_data;
+ int ret, encl_flags;
+
+ encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
+ if (encl_flags & SGX_ENCL_IOCTL)
+ return -EBUSY;
+
+ if (encl_flags & SGX_ENCL_DEAD)
+ return -EFAULT;
+
+ switch (cmd) {
+ case SGX_IOC_ENCLAVE_CREATE:
+ ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
+ break;
+ case SGX_IOC_ENCLAVE_ADD_PAGES:
+ ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
+ break;
+ case SGX_IOC_ENCLAVE_INIT:
+ ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+
+ atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
+
+ return ret;
+}
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 60d82e7537c8..842f9abba1c0 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -8,6 +8,7 @@
#include <linux/ratelimit.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
+#include "driver.h"
#include "encls.h"
struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
@@ -193,6 +194,8 @@ static bool __init sgx_page_cache_init(void)
static void __init sgx_init(void)
{
+ int ret;
+
if (!boot_cpu_has(X86_FEATURE_SGX))
return;
@@ -202,10 +205,17 @@ static void __init sgx_init(void)
if (!sgx_page_reclaimer_init())
goto err_page_cache;
+ ret = sgx_drv_init();
+ if (ret)
+ goto err_kthread;
+
return;
+err_kthread:
+ kthread_stop(ksgxswapd_tsk);
+
err_page_cache:
sgx_page_cache_teardown();
}
-arch_initcall(sgx_init);
+device_initcall(sgx_init);
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index 215371588a25..9e6d3e147aa2 100644
--- a/arch/x86/kernel/cpu/sgx/reclaim.c
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -10,6 +10,7 @@
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include "encls.h"
+#include "driver.h"
struct task_struct *ksgxswapd_tsk;
--
2.25.1
From: Sean Christopherson <[email protected]>
The basic concept and implementation is very similar to the kernel's
exception fixup mechanism. The key differences are that the kernel
handler is hardcoded and the fixup entry addresses are relative to
the overall table as opposed to individual entries.
Hardcoding the kernel handler avoids the need to figure out how to
get userspace code to point at a kernel function. Given that the
expected usage is to propagate information to userspace, dumping all
fault information into registers is likely the desired behavior for
the vast majority of yet-to-be-created functions. Use registers
DI, SI and DX to communicate fault information, which follows Linux's
ABI for register consumption and hopefully avoids conflict with
hardware features that might leverage the fixup capabilities, e.g.
register usage for SGX instructions was at least partially designed
with calling conventions in mind.
Making fixup addresses relative to the overall table allows the table
to be stripped from the final vDSO image (it's a kernel construct)
without complicating the offset logic, e.g. entry-relative addressing
would also need to account for the table's location relative to the
image.
Regarding stripping the table, modify vdso2c to extract the table from
the raw, a.k.a. unstripped, data and dump it as a standalone byte array
in the resulting .c file. The original base of the table, its length
and a pointer to the byte array are captured in struct vdso_image.
Alternatively, the table could be dumped directly into the struct,
but because the number of entries can vary per image, that would
require either hardcoding a max sized table into the struct definition
or defining the table as a flexible length array. The flexible length
array approach has zero benefits, e.g. the base/size are still needed,
and prevents reusing the extraction code, while hardcoding the max size
adds ongoing maintenance just to avoid exporting the explicit size.
The immediate use case is for Intel Software Guard Extensions (SGX).
SGX introduces a new CPL3-only "enclave" mode that runs as a sort of
black box shared object that is hosted by an untrusted "normal" CPl3
process.
Entering an enclave can only be done through SGX-specific instructions,
EENTER and ERESUME, and is a non-trivial process. Because of the
complexity of transitioning to/from an enclave, the vast majority of
enclaves are expected to utilize a library to handle the actual
transitions. This is roughly analogous to how e.g. libc implementations
are used by most applications.
Another crucial characteristic of SGX enclaves is that they can generate
exceptions as part of their normal (at least as "normal" as SGX can be)
operation that need to be handled *in* the enclave and/or are unique
to SGX.
And because they are essentially fancy shared objects, a process can
host any number of enclaves, each of which can execute multiple threads
simultaneously.
Putting everything together, userspace enclaves will utilize a library
that must be prepared to handle any and (almost) all exceptions any time
at least one thread may be executing in an enclave. Leveraging signals
to handle the enclave exceptions is unpleasant, to put it mildly, e.g.
the SGX library must constantly (un)register its signal handler based
on whether or not at least one thread is executing in an enclave, and
filter and forward exceptions that aren't related to its enclaves. This
becomes particularly nasty when using multiple levels of libraries that
register signal handlers, e.g. running an enclave via cgo inside of the
Go runtime.
Enabling exception fixup in vDSO allows the kernel to provide a vDSO
function that wraps the low-level transitions to/from the enclave, i.e.
the EENTER and ERESUME instructions. The vDSO function can intercept
exceptions that would otherwise generate a signal and return the fault
information directly to its caller, thus avoiding the need to juggle
signal handlers.
Note that unlike the kernel's _ASM_EXTABLE_HANDLE implementation, the
'C' version of _ASM_VDSO_EXTABLE_HANDLE doesn't use a pre-compiled
assembly macro. Duplicating four lines of code is simpler than adding
the necessary infrastructure to generate pre-compiled assembly and the
intended benefit of massaging GCC's inlining algorithm is unlikely to
realized in the vDSO any time soon, if ever.
Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/entry/vdso/Makefile | 6 +--
arch/x86/entry/vdso/extable.c | 46 +++++++++++++++++++++
arch/x86/entry/vdso/extable.h | 29 ++++++++++++++
arch/x86/entry/vdso/vdso-layout.lds.S | 9 ++++-
arch/x86/entry/vdso/vdso2c.h | 58 +++++++++++++++++++++++----
arch/x86/include/asm/vdso.h | 5 +++
6 files changed, 141 insertions(+), 12 deletions(-)
create mode 100644 arch/x86/entry/vdso/extable.c
create mode 100644 arch/x86/entry/vdso/extable.h
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 433a1259f61d..657e01d34d02 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -26,7 +26,7 @@ VDSO32-$(CONFIG_IA32_EMULATION) := y
vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
# files to link into kernel
-obj-y += vma.o
+obj-y += vma.o extable.o
OBJECT_FILES_NON_STANDARD_vma.o := n
# vDSO images to build
@@ -120,8 +120,8 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE
targets += vdsox32.lds $(vobjx32s-y)
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
+$(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table
+$(obj)/%.so: $(obj)/%.so.dbg
$(call if_changed,objcopy)
$(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
diff --git a/arch/x86/entry/vdso/extable.c b/arch/x86/entry/vdso/extable.c
new file mode 100644
index 000000000000..afcf5b65beef
--- /dev/null
+++ b/arch/x86/entry/vdso/extable.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <asm/current.h>
+#include <asm/traps.h>
+#include <asm/vdso.h>
+
+struct vdso_exception_table_entry {
+ int insn, fixup;
+};
+
+bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
+ unsigned long error_code, unsigned long fault_addr)
+{
+ const struct vdso_image *image = current->mm->context.vdso_image;
+ const struct vdso_exception_table_entry *extable;
+ unsigned int nr_entries, i;
+ unsigned long base;
+
+ /*
+ * Do not attempt to fixup #DB or #BP. It's impossible to identify
+ * whether or not a #DB/#BP originated from within an SGX enclave and
+ * SGX enclaves are currently the only use case for vDSO fixup.
+ */
+ if (trapnr == X86_TRAP_DB || trapnr == X86_TRAP_BP)
+ return false;
+
+ if (!current->mm->context.vdso)
+ return false;
+
+ base = (unsigned long)current->mm->context.vdso + image->extable_base;
+ nr_entries = image->extable_len / (sizeof(*extable));
+ extable = image->extable;
+
+ for (i = 0; i < nr_entries; i++) {
+ if (regs->ip == base + extable[i].insn) {
+ regs->ip = base + extable[i].fixup;
+ regs->di = trapnr;
+ regs->si = error_code;
+ regs->dx = fault_addr;
+ return true;
+ }
+ }
+
+ return false;
+}
diff --git a/arch/x86/entry/vdso/extable.h b/arch/x86/entry/vdso/extable.h
new file mode 100644
index 000000000000..aafdac396948
--- /dev/null
+++ b/arch/x86/entry/vdso/extable.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_EXTABLE_H
+#define __VDSO_EXTABLE_H
+
+/*
+ * Inject exception fixup for vDSO code. Unlike normal exception fixup,
+ * vDSO uses a dedicated handler the addresses are relative to the overall
+ * exception table, not each individual entry.
+ */
+#ifdef __ASSEMBLY__
+#define _ASM_VDSO_EXTABLE_HANDLE(from, to) \
+ ASM_VDSO_EXTABLE_HANDLE from to
+
+.macro ASM_VDSO_EXTABLE_HANDLE from:req to:req
+ .pushsection __ex_table, "a"
+ .long (\from) - __ex_table
+ .long (\to) - __ex_table
+ .popsection
+.endm
+#else
+#define _ASM_VDSO_EXTABLE_HANDLE(from, to) \
+ ".pushsection __ex_table, \"a\"\n" \
+ ".long (" #from ") - __ex_table\n" \
+ ".long (" #to ") - __ex_table\n" \
+ ".popsection\n"
+#endif
+
+#endif /* __VDSO_EXTABLE_H */
+
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index ea7e0155c604..e9994ee62fdd 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -68,11 +68,18 @@ SECTIONS
* stuff that isn't used at runtime in between.
*/
- .text : { *(.text*) } :text =0x90909090,
+ .text : {
+ *(.text*)
+ *(.fixup)
+ } :text =0x90909090,
+
+
.altinstructions : { *(.altinstructions) } :text
.altinstr_replacement : { *(.altinstr_replacement) } :text
+ __ex_table : { *(__ex_table) } :text
+
/DISCARD/ : {
*(.discard)
*(.discard.*)
diff --git a/arch/x86/entry/vdso/vdso2c.h b/arch/x86/entry/vdso/vdso2c.h
index a20b134de2a8..04d04e46c98c 100644
--- a/arch/x86/entry/vdso/vdso2c.h
+++ b/arch/x86/entry/vdso/vdso2c.h
@@ -5,6 +5,41 @@
* are built for 32-bit userspace.
*/
+static void BITSFUNC(copy)(FILE *outfile, const unsigned char *data, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++) {
+ if (i % 10 == 0)
+ fprintf(outfile, "\n\t");
+ fprintf(outfile, "0x%02X, ", (int)(data)[i]);
+ }
+}
+
+
+/*
+ * Extract a section from the input data into a standalone blob. Used to
+ * capture kernel-only data that needs to persist indefinitely, e.g. the
+ * exception fixup tables, but only in the kernel, i.e. the section can
+ * be stripped from the final vDSO image.
+ */
+static void BITSFUNC(extract)(const unsigned char *data, size_t data_len,
+ FILE *outfile, ELF(Shdr) *sec, const char *name)
+{
+ unsigned long offset;
+ size_t len;
+
+ offset = (unsigned long)GET_LE(&sec->sh_offset);
+ len = (size_t)GET_LE(&sec->sh_size);
+
+ if (offset + len > data_len)
+ fail("section to extract overruns input data");
+
+ fprintf(outfile, "static const unsigned char %s[%lu] = {", name, len);
+ BITSFUNC(copy)(outfile, data + offset, len);
+ fprintf(outfile, "\n};\n\n");
+}
+
static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
void *stripped_addr, size_t stripped_len,
FILE *outfile, const char *image_name)
@@ -14,9 +49,8 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
unsigned long mapping_size;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
int i;
- unsigned long j;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
- *alt_sec = NULL;
+ *alt_sec = NULL, *extable_sec = NULL;
ELF(Dyn) *dyn = 0, *dyn_end = 0;
const char *secstrings;
INT_BITS syms[NSYMS] = {};
@@ -78,6 +112,8 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
if (!strcmp(secstrings + GET_LE(&sh->sh_name),
".altinstructions"))
alt_sec = sh;
+ if (!strcmp(secstrings + GET_LE(&sh->sh_name), "__ex_table"))
+ extable_sec = sh;
}
if (!symtab_hdr)
@@ -150,13 +186,11 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
fprintf(outfile,
"static unsigned char raw_data[%lu] __ro_after_init __aligned(PAGE_SIZE) = {",
mapping_size);
- for (j = 0; j < stripped_len; j++) {
- if (j % 10 == 0)
- fprintf(outfile, "\n\t");
- fprintf(outfile, "0x%02X, ",
- (int)((unsigned char *)stripped_addr)[j]);
- }
+ BITSFUNC(copy)(outfile, stripped_addr, stripped_len);
fprintf(outfile, "\n};\n\n");
+ if (extable_sec)
+ BITSFUNC(extract)(raw_addr, raw_len, outfile,
+ extable_sec, "extable");
fprintf(outfile, "const struct vdso_image %s = {\n", image_name);
fprintf(outfile, "\t.data = raw_data,\n");
@@ -167,6 +201,14 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
fprintf(outfile, "\t.alt_len = %lu,\n",
(unsigned long)GET_LE(&alt_sec->sh_size));
}
+ if (extable_sec) {
+ fprintf(outfile, "\t.extable_base = %lu,\n",
+ (unsigned long)GET_LE(&extable_sec->sh_offset));
+ fprintf(outfile, "\t.extable_len = %lu,\n",
+ (unsigned long)GET_LE(&extable_sec->sh_size));
+ fprintf(outfile, "\t.extable = extable,\n");
+ }
+
for (i = 0; i < NSYMS; i++) {
if (required_syms[i].export && syms[i])
fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index bbcdc7b8f963..b5d23470f56b 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -15,6 +15,8 @@ struct vdso_image {
unsigned long size; /* Always a multiple of PAGE_SIZE */
unsigned long alt, alt_len;
+ unsigned long extable_base, extable_len;
+ const void *extable;
long sym_vvar_start; /* Negative offset to the vvar area */
@@ -45,6 +47,9 @@ extern void __init init_vdso_image(const struct vdso_image *image);
extern int map_vdso_once(const struct vdso_image *image, unsigned long addr);
+extern bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr);
#endif /* __ASSEMBLER__ */
#endif /* _ASM_X86_VDSO_H */
--
2.25.1
From: Sean Christopherson <[email protected]>
Add helper function to sanitize error code to prepare for vDSO exception
fixup, which will expose the error code to userspace and runs before
set_signal_archinfo(), i.e. suppresses the signal when fixup is successful.
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/mm/fault.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index dee9504cde79..6b662d272af6 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -682,6 +682,18 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code,
oops_end(flags, regs, sig);
}
+static void sanitize_error_code(unsigned long address,
+ unsigned long *error_code)
+{
+ /*
+ * To avoid leaking information about the kernel page
+ * table layout, pretend that user-mode accesses to
+ * kernel addresses are always protection faults.
+ */
+ if (address >= TASK_SIZE_MAX)
+ *error_code |= X86_PF_PROT;
+}
+
static void set_signal_archinfo(unsigned long address,
unsigned long error_code)
{
@@ -738,6 +750,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
* faulting through the emulate_vsyscall() logic.
*/
if (current->thread.sig_on_uaccess_err && signal) {
+ sanitize_error_code(address, &error_code);
+
set_signal_archinfo(address, error_code);
/* XXX: hwpoison faults will set the wrong code. */
@@ -886,13 +900,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
if (is_errata100(regs, address))
return;
- /*
- * To avoid leaking information about the kernel page table
- * layout, pretend that user-mode accesses to kernel addresses
- * are always protection faults.
- */
- if (address >= TASK_SIZE_MAX)
- error_code |= X86_PF_PROT;
+ sanitize_error_code(address, &error_code);
if (likely(show_unhandled_signals))
show_signal_msg(regs, error_code, address, tsk);
@@ -1009,6 +1017,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
if (is_prefetch(regs, error_code, address))
return;
+ sanitize_error_code(address, &error_code);
+
set_signal_archinfo(address, error_code);
#ifdef CONFIG_MEMORY_FAILURE
--
2.25.1
Define the SGX microarchitectural data structures used by various SGX
opcodes. This is not an exhaustive representation of all SGX data
structures but only those needed by the kernel.
The data structures are described in:
Intel SDM: 37.6 INTEL® SGX DATA STRUCTURES OVERVIEW
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/sgx/arch.h | 343 +++++++++++++++++++++++++++++++++
1 file changed, 343 insertions(+)
create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/kernel/cpu/sgx/arch.h
new file mode 100644
index 000000000000..ddae55e9d4d8
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/arch.h
@@ -0,0 +1,343 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+ * Copyright(c) 2016-18 Intel Corporation.
+ *
+ * Contains data structures defined by the SGX architecture. Data structures
+ * defined by the Linux software stack should not be placed here.
+ */
+#ifndef _ASM_X86_SGX_ARCH_H
+#define _ASM_X86_SGX_ARCH_H
+
+#include <linux/bits.h>
+#include <linux/types.h>
+
+#define SGX_CPUID 0x12
+#define SGX_CPUID_FIRST_VARIABLE_SUB_LEAF 2
+
+/**
+ * enum sgx_return_code - The return code type for ENCLS, ENCLU and ENCLV
+ * %SGX_NOT_TRACKED: Previous ETRACK's shootdown sequence has not
+ * been completed yet.
+ * %SGX_INVALID_EINITTOKEN: EINITTOKEN is invalid and enclave signer's
+ * public key does not match IA32_SGXLEPUBKEYHASH.
+ * %SGX_UNMASKED_EVENT: An unmasked event, e.g. INTR, was received
+ */
+enum sgx_return_code {
+ SGX_NOT_TRACKED = 11,
+ SGX_INVALID_EINITTOKEN = 16,
+ SGX_UNMASKED_EVENT = 128,
+};
+
+/**
+ * enum sgx_sub_leaf_types - SGX CPUID variable sub-leaf types
+ * %SGX_CPUID_SUB_LEAF_INVALID: Indicates this sub-leaf is invalid.
+ * %SGX_CPUID_SUB_LEAF_EPC_SECTION: Sub-leaf enumerates an EPC section.
+ */
+enum sgx_sub_leaf_types {
+ SGX_CPUID_SUB_LEAF_INVALID = 0x0,
+ SGX_CPUID_SUB_LEAF_EPC_SECTION = 0x1,
+};
+
+#define SGX_CPUID_SUB_LEAF_TYPE_MASK GENMASK(3, 0)
+
+#define SGX_MODULUS_SIZE 384
+
+/**
+ * enum sgx_miscselect - additional information to an SSA frame
+ * %SGX_MISC_EXINFO: Report #PF or #GP to the SSA frame.
+ *
+ * Save State Area (SSA) is a stack inside the enclave used to store processor
+ * state when an exception or interrupt occurs. This enum defines additional
+ * information stored to an SSA frame.
+ */
+enum sgx_miscselect {
+ SGX_MISC_EXINFO = BIT(0),
+};
+
+#define SGX_MISC_RESERVED_MASK GENMASK_ULL(63, 1)
+
+#define SGX_SSA_GPRS_SIZE 184
+#define SGX_SSA_MISC_EXINFO_SIZE 16
+
+/**
+ * enum sgx_attributes - the attributes field in &struct sgx_secs
+ * %SGX_ATTR_INIT: Enclave can be entered (is initialized).
+ * %SGX_ATTR_DEBUG: Allow ENCLS(EDBGRD) and ENCLS(EDBGWR).
+ * %SGX_ATTR_MODE64BIT: Tell that this a 64-bit enclave.
+ * %SGX_ATTR_PROVISIONKEY: Allow to use provisioning keys for remote
+ * attestation.
+ * %SGX_ATTR_KSS: Allow to use key separation and sharing (KSS).
+ * %SGX_ATTR_EINITTOKENKEY: Allow to use token signing key that is used to
+ * sign cryptographic tokens that can be passed to
+ * EINIT as an authorization to run an enclave.
+ */
+enum sgx_attribute {
+ SGX_ATTR_INIT = BIT(0),
+ SGX_ATTR_DEBUG = BIT(1),
+ SGX_ATTR_MODE64BIT = BIT(2),
+ SGX_ATTR_PROVISIONKEY = BIT(4),
+ SGX_ATTR_EINITTOKENKEY = BIT(5),
+ SGX_ATTR_KSS = BIT(7),
+};
+
+#define SGX_ATTR_RESERVED_MASK (BIT_ULL(3) | BIT_ULL(6) | GENMASK_ULL(63, 8))
+#define SGX_ATTR_ALLOWED_MASK (SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | \
+ SGX_ATTR_KSS)
+
+/**
+ * struct sgx_secs - SGX Enclave Control Structure (SECS)
+ * @size: size of the address space
+ * @base: base address of the address space
+ * @ssa_frame_size: size of an SSA frame
+ * @miscselect: additional information stored to an SSA frame
+ * @attributes: attributes for enclave
+ * @xfrm: XSave-Feature Request Mask (subset of XCR0)
+ * @mrenclave: SHA256-hash of the enclave contents
+ * @mrsigner: SHA256-hash of the public key used to sign the SIGSTRUCT
+ * @config_id: a user-defined value that is used in key derivation
+ * @isv_prod_id: a user-defined value that is used in key derivation
+ * @isv_svn: a user-defined value that is used in key derivation
+ * @config_svn: a user-defined value that is used in key derivation
+ *
+ * SGX Enclave Control Structure (SECS) is a special enclave page that is not
+ * visible in the address space. In fact, this structure defines the address
+ * range and other global attributes for the enclave and it is the first EPC
+ * page created for any enclave. It is moved from a temporary buffer to an EPC
+ * by the means of ENCLS(ECREATE) leaf.
+ */
+struct sgx_secs {
+ u64 size;
+ u64 base;
+ u32 ssa_frame_size;
+ u32 miscselect;
+ u8 reserved1[24];
+ u64 attributes;
+ u64 xfrm;
+ u32 mrenclave[8];
+ u8 reserved2[32];
+ u32 mrsigner[8];
+ u8 reserved3[32];
+ u32 config_id[16];
+ u16 isv_prod_id;
+ u16 isv_svn;
+ u16 config_svn;
+ u8 reserved4[3834];
+} __packed;
+
+/**
+ * enum sgx_tcs_flags - execution flags for TCS
+ * %SGX_TCS_DBGOPTIN: If enabled allows single-stepping and breakpoints
+ * inside an enclave. It is cleared by EADD but can
+ * be set later with EDBGWR.
+ */
+enum sgx_tcs_flags {
+ SGX_TCS_DBGOPTIN = 0x01,
+};
+
+#define SGX_TCS_RESERVED_MASK GENMASK_ULL(63, 1)
+#define SGX_TCS_RESERVED_SIZE 4024
+
+/**
+ * struct sgx_tcs - Thread Control Structure (TCS)
+ * @state: used to mark an entered TCS
+ * @flags: execution flags (cleared by EADD)
+ * @ssa_offset: SSA stack offset relative to the enclave base
+ * @ssa_index: the current SSA frame index (cleard by EADD)
+ * @nr_ssa_frames: the number of frame in the SSA stack
+ * @entry_offset: entry point offset relative to the enclave base
+ * @exit_addr: address outside the enclave to exit on an exception or
+ * interrupt
+ * @fs_offset: offset relative to the enclave base to become FS
+ * segment inside the enclave
+ * @gs_offset: offset relative to the enclave base to become GS
+ * segment inside the enclave
+ * @fs_limit: size to become a new FS-limit (only 32-bit enclaves)
+ * @gs_limit: size to become a new GS-limit (only 32-bit enclaves)
+ *
+ * Thread Control Structure (TCS) is an enclave page visible in its address
+ * space that defines an entry point inside the enclave. A thread enters inside
+ * an enclave by supplying address of TCS to ENCLU(EENTER). A TCS can be entered
+ * by only one thread at a time.
+ */
+struct sgx_tcs {
+ u64 state;
+ u64 flags;
+ u64 ssa_offset;
+ u32 ssa_index;
+ u32 nr_ssa_frames;
+ u64 entry_offset;
+ u64 exit_addr;
+ u64 fs_offset;
+ u64 gs_offset;
+ u32 fs_limit;
+ u32 gs_limit;
+ u8 reserved[SGX_TCS_RESERVED_SIZE];
+} __packed;
+
+/**
+ * struct sgx_pageinfo - an enclave page descriptor
+ * @addr: address of the enclave page
+ * @contents: pointer to the page contents
+ * @metadata: pointer either to a SECINFO or PCMD instance
+ * @secs: address of the SECS page
+ */
+struct sgx_pageinfo {
+ u64 addr;
+ u64 contents;
+ u64 metadata;
+ u64 secs;
+} __packed __aligned(32);
+
+
+/**
+ * enum sgx_page_type - bits in the SECINFO flags defining the page type
+ * %SGX_PAGE_TYPE_SECS: a SECS page
+ * %SGX_PAGE_TYPE_TCS: a TCS page
+ * %SGX_PAGE_TYPE_REG: a regular page
+ * %SGX_PAGE_TYPE_VA: a VA page
+ * %SGX_PAGE_TYPE_TRIM: a page in trimmed state
+ */
+enum sgx_page_type {
+ SGX_PAGE_TYPE_SECS,
+ SGX_PAGE_TYPE_TCS,
+ SGX_PAGE_TYPE_REG,
+ SGX_PAGE_TYPE_VA,
+ SGX_PAGE_TYPE_TRIM,
+};
+
+#define SGX_NR_PAGE_TYPES 5
+#define SGX_PAGE_TYPE_MASK GENMASK(7, 0)
+
+/**
+ * enum sgx_secinfo_flags - the flags field in &struct sgx_secinfo
+ * %SGX_SECINFO_R: allow read
+ * %SGX_SECINFO_W: allow write
+ * %SGX_SECINFO_X: allow execution
+ * %SGX_SECINFO_SECS: a SECS page
+ * %SGX_SECINFO_TCS: a TCS page
+ * %SGX_SECINFO_REG: a regular page
+ * %SGX_SECINFO_VA: a VA page
+ * %SGX_SECINFO_TRIM: a page in trimmed state
+ */
+enum sgx_secinfo_flags {
+ SGX_SECINFO_R = BIT(0),
+ SGX_SECINFO_W = BIT(1),
+ SGX_SECINFO_X = BIT(2),
+ SGX_SECINFO_SECS = (SGX_PAGE_TYPE_SECS << 8),
+ SGX_SECINFO_TCS = (SGX_PAGE_TYPE_TCS << 8),
+ SGX_SECINFO_REG = (SGX_PAGE_TYPE_REG << 8),
+ SGX_SECINFO_VA = (SGX_PAGE_TYPE_VA << 8),
+ SGX_SECINFO_TRIM = (SGX_PAGE_TYPE_TRIM << 8),
+};
+
+#define SGX_SECINFO_PERMISSION_MASK GENMASK_ULL(2, 0)
+#define SGX_SECINFO_PAGE_TYPE_MASK (SGX_PAGE_TYPE_MASK << 8)
+#define SGX_SECINFO_RESERVED_MASK ~(SGX_SECINFO_PERMISSION_MASK | \
+ SGX_SECINFO_PAGE_TYPE_MASK)
+
+/**
+ * struct sgx_secinfo - describes attributes of an EPC page
+ * @flags: permissions and type
+ *
+ * Used together with ENCLS leaves that add or modify an EPC page to an
+ * enclave to define page permissions and type.
+ */
+struct sgx_secinfo {
+ u64 flags;
+ u8 reserved[56];
+} __packed __aligned(64);
+
+#define SGX_PCMD_RESERVED_SIZE 40
+
+/**
+ * struct sgx_pcmd - Paging Crypto Metadata (PCMD)
+ * @enclave_id: enclave identifier
+ * @mac: MAC over PCMD, page contents and isvsvn
+ *
+ * PCMD is stored for every swapped page to the regular memory. When ELDU loads
+ * the page back it recalculates the MAC by using a isvsvn number stored in a
+ * VA page. Together these two structures bring integrity and rollback
+ * protection.
+ */
+struct sgx_pcmd {
+ struct sgx_secinfo secinfo;
+ u64 enclave_id;
+ u8 reserved[SGX_PCMD_RESERVED_SIZE];
+ u8 mac[16];
+} __packed __aligned(128);
+
+#define SGX_SIGSTRUCT_RESERVED1_SIZE 84
+#define SGX_SIGSTRUCT_RESERVED2_SIZE 20
+#define SGX_SIGSTRUCT_RESERVED3_SIZE 32
+#define SGX_SIGSTRUCT_RESERVED4_SIZE 12
+
+/**
+ * struct sgx_sigstruct_header - defines author of the enclave
+ * @header1: constant byte string
+ * @vendor: must be either 0x0000 or 0x8086
+ * @date: YYYYMMDD in BCD
+ * @header2: costant byte string
+ * @swdefined: software defined value
+ */
+struct sgx_sigstruct_header {
+ u64 header1[2];
+ u32 vendor;
+ u32 date;
+ u64 header2[2];
+ u32 swdefined;
+ u8 reserved1[84];
+} __packed;
+
+/**
+ * struct sgx_sigstruct_body - defines contents of the enclave
+ * @miscselect: additional information stored to an SSA frame
+ * @misc_mask: required miscselect in SECS
+ * @attributes: attributes for enclave
+ * @xfrm: XSave-Feature Request Mask (subset of XCR0)
+ * @attributes_mask: required attributes in SECS
+ * @xfrm_mask: required XFRM in SECS
+ * @mrenclave: SHA256-hash of the enclave contents
+ * @isvprodid: a user-defined value that is used in key derivation
+ * @isvsvn: a user-defined value that is used in key derivation
+ */
+struct sgx_sigstruct_body {
+ u32 miscselect;
+ u32 misc_mask;
+ u8 reserved2[20];
+ u64 attributes;
+ u64 xfrm;
+ u64 attributes_mask;
+ u64 xfrm_mask;
+ u8 mrenclave[32];
+ u8 reserved3[32];
+ u16 isvprodid;
+ u16 isvsvn;
+} __packed;
+
+/**
+ * struct sgx_sigstruct - an enclave signature
+ * @header: defines author of the enclave
+ * @modulus: the modulus of the public key
+ * @exponent: the exponent of the public key
+ * @signature: the signature calculated over the fields except modulus,
+ * @body: defines contents of the enclave
+ * @q1: a value used in RSA signature verification
+ * @q2: a value used in RSA signature verification
+ *
+ * Header and body are the parts that are actual signed. The remaining fields
+ * define the signature of the enclave.
+ */
+struct sgx_sigstruct {
+ struct sgx_sigstruct_header header;
+ u8 modulus[SGX_MODULUS_SIZE];
+ u32 exponent;
+ u8 signature[SGX_MODULUS_SIZE];
+ struct sgx_sigstruct_body body;
+ u8 reserved4[12];
+ u8 q1[SGX_MODULUS_SIZE];
+ u8 q2[SGX_MODULUS_SIZE];
+} __packed;
+
+#define SGX_LAUNCH_TOKEN_SIZE 304
+
+#endif /* _ASM_X86_SGX_ARCH_H */
--
2.25.1
From: Sean Christopherson <[email protected]>
vDSO functions can now leverage an exception fixup mechanism similar to
kernel exception fixup. For vDSO exception fixup, the initial user is
Intel's Software Guard Extensions (SGX), which will wrap the low-level
transitions to/from the enclave, i.e. EENTER and ERESUME instructions,
in a vDSO function and leverage fixup to intercept exceptions that would
otherwise generate a signal. This allows the vDSO wrapper to return the
fault information directly to its caller, obviating the need for SGX
applications and libraries to juggle signal handlers.
Attempt to fixup vDSO exceptions immediately prior to populating and
sending signal information. Except for the delivery mechanism, an
exception in a vDSO function should be treated like any other exception
in userspace, e.g. any fault that is successfully handled by the kernel
should not be directly visible to userspace.
Although it's debatable whether or not all exceptions are of interest to
enclaves, defer to the vDSO fixup to decide whether to do fixup or
generate a signal. Future users of vDSO fixup, if there ever are any,
will undoubtedly have different requirements than SGX enclaves, e.g. the
fixup vs. signal logic can be made function specific if/when necessary.
Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/traps.c | 14 ++++++++++++++
arch/x86/mm/fault.c | 8 ++++++++
2 files changed, 22 insertions(+)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 6ef00eb6fbb9..a814b1aea94d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -56,6 +56,7 @@
#include <asm/umip.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
+#include <asm/vdso.h>
#ifdef CONFIG_X86_64
#include <asm/x86_init.h>
@@ -205,6 +206,9 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str,
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = trapnr;
die(str, regs, error_code);
+ } else {
+ if (fixup_vdso_exception(regs, trapnr, error_code, 0))
+ return 0;
}
/*
@@ -518,6 +522,9 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = X86_TRAP_GP;
+ if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0))
+ return;
+
show_signal(tsk, SIGSEGV, "", desc, regs, error_code);
force_sig(SIGSEGV);
@@ -762,6 +769,10 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
SIGTRAP) == NOTIFY_STOP)
goto exit;
+ if (user_mode(regs) &&
+ fixup_vdso_exception(regs, X86_TRAP_DB, error_code, 0))
+ goto exit;
+
/*
* Let others (NMI) know that the debug stack is in use
* as we may switch to the interrupt stack.
@@ -842,6 +853,9 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
if (!si_code)
return;
+ if (fixup_vdso_exception(regs, trapnr, error_code, 0))
+ return;
+
force_sig_fault(SIGFPE, si_code,
(void __user *)uprobe_get_trap_addr(regs));
}
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 6b662d272af6..42965b47b52f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -30,6 +30,7 @@
#include <asm/desc.h> /* store_idt(), ... */
#include <asm/cpu_entry_area.h> /* exception stack */
#include <asm/pgtable_areas.h> /* VMALLOC_START, ... */
+#include <asm/vdso.h> /* fixup_vdso_exception() */
#define CREATE_TRACE_POINTS
#include <asm/trace/exceptions.h>
@@ -902,6 +903,10 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
sanitize_error_code(address, &error_code);
+ if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code,
+ address))
+ return;
+
if (likely(show_unhandled_signals))
show_signal_msg(regs, error_code, address, tsk);
@@ -1019,6 +1024,9 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
sanitize_error_code(address, &error_code);
+ if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+ return;
+
set_signal_archinfo(address, error_code);
#ifdef CONFIG_MEMORY_FAILURE
--
2.25.1
Add a selftest for SGX. It is a trivial test where a simple enclave
copies one 64-bit word of memory between two memory locations.
Cc: [email protected]
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/sgx/.gitignore | 2 +
tools/testing/selftests/sgx/Makefile | 53 +++
tools/testing/selftests/sgx/call.S | 54 +++
tools/testing/selftests/sgx/defines.h | 21 +
tools/testing/selftests/sgx/load.c | 282 +++++++++++++
tools/testing/selftests/sgx/main.c | 199 +++++++++
tools/testing/selftests/sgx/main.h | 38 ++
tools/testing/selftests/sgx/sigstruct.c | 395 ++++++++++++++++++
tools/testing/selftests/sgx/test_encl.c | 20 +
tools/testing/selftests/sgx/test_encl.lds | 40 ++
.../selftests/sgx/test_encl_bootstrap.S | 89 ++++
12 files changed, 1194 insertions(+)
create mode 100644 tools/testing/selftests/sgx/.gitignore
create mode 100644 tools/testing/selftests/sgx/Makefile
create mode 100644 tools/testing/selftests/sgx/call.S
create mode 100644 tools/testing/selftests/sgx/defines.h
create mode 100644 tools/testing/selftests/sgx/load.c
create mode 100644 tools/testing/selftests/sgx/main.c
create mode 100644 tools/testing/selftests/sgx/main.h
create mode 100644 tools/testing/selftests/sgx/sigstruct.c
create mode 100644 tools/testing/selftests/sgx/test_encl.c
create mode 100644 tools/testing/selftests/sgx/test_encl.lds
create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 6ec503912bea..183a050b5bda 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -63,6 +63,7 @@ TARGETS += user
TARGETS += vm
TARGETS += x86
TARGETS += zram
+TARGETS += sgx
#Please keep the TARGETS list alphabetically sorted
# Run "make quicktest=1 run_tests" or
# "make quicktest=1 kselftest" from top level Makefile
diff --git a/tools/testing/selftests/sgx/.gitignore b/tools/testing/selftests/sgx/.gitignore
new file mode 100644
index 000000000000..fbaf0bda9a92
--- /dev/null
+++ b/tools/testing/selftests/sgx/.gitignore
@@ -0,0 +1,2 @@
+test_sgx
+test_encl.elf
diff --git a/tools/testing/selftests/sgx/Makefile b/tools/testing/selftests/sgx/Makefile
new file mode 100644
index 000000000000..95e5c4df8014
--- /dev/null
+++ b/tools/testing/selftests/sgx/Makefile
@@ -0,0 +1,53 @@
+top_srcdir = ../../../..
+
+include ../lib.mk
+
+.PHONY: all clean
+
+CAN_BUILD_X86_64 := $(shell ../x86/check_cc.sh $(CC) \
+ ../x86/trivial_64bit_program.c)
+
+ifndef OBJCOPY
+OBJCOPY := $(CROSS_COMPILE)objcopy
+endif
+
+INCLUDES := -I$(top_srcdir)/tools/include
+HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack
+ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \
+ -fno-stack-protector -mrdrnd $(INCLUDES)
+
+TEST_CUSTOM_PROGS := $(OUTPUT)/test_sgx $(OUTPUT)/test_encl.elf
+
+ifeq ($(CAN_BUILD_X86_64), 1)
+all: $(TEST_CUSTOM_PROGS)
+endif
+
+$(OUTPUT)/test_sgx: $(OUTPUT)/main.o \
+ $(OUTPUT)/load.o \
+ $(OUTPUT)/sigstruct.o \
+ $(OUTPUT)/call.o
+ $(CC) $(HOST_CFLAGS) -o $@ $^ -lcrypto
+
+$(OUTPUT)/main.o: main.c
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/load.o: load.c
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/sigstruct.o: sigstruct.c
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/call.o: call.S
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/test_encl.elf: test_encl.lds test_encl.c test_encl_bootstrap.S
+ $(CC) $(ENCL_CFLAGS) -T $^ -o $@
+
+EXTRA_CLEAN := \
+ $(OUTPUT)/test_encl.elf \
+ $(OUTPUT)/load.o \
+ $(OUTPUT)/call.o \
+ $(OUTPUT)/main.o \
+ $(OUTPUT)/sigstruct.o \
+ $(OUTPUT)/test_sgx \
+ $(OUTPUT)/test_sgx.o \
diff --git a/tools/testing/selftests/sgx/call.S b/tools/testing/selftests/sgx/call.S
new file mode 100644
index 000000000000..77131e83db42
--- /dev/null
+++ b/tools/testing/selftests/sgx/call.S
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+* Copyright(c) 2016-18 Intel Corporation.
+*/
+
+ .text
+
+ .macro ENCLU
+ .byte 0x0f, 0x01, 0xd7
+ .endm
+
+ .text
+
+ .global sgx_call_vdso
+sgx_call_vdso:
+ .cfi_startproc
+ push %r15
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %r15, 0
+ push %r14
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %r14, 0
+ push %r13
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %r13, 0
+ push %r12
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %r12, 0
+ push %rbx
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %rbx, 0
+ push $0
+ .cfi_adjust_cfa_offset 8
+ push 0x48(%rsp)
+ .cfi_adjust_cfa_offset 8
+ push 0x48(%rsp)
+ .cfi_adjust_cfa_offset 8
+ push 0x48(%rsp)
+ .cfi_adjust_cfa_offset 8
+ call *eenter(%rip)
+ add $0x20, %rsp
+ .cfi_adjust_cfa_offset -0x20
+ pop %rbx
+ .cfi_adjust_cfa_offset -8
+ pop %r12
+ .cfi_adjust_cfa_offset -8
+ pop %r13
+ .cfi_adjust_cfa_offset -8
+ pop %r14
+ .cfi_adjust_cfa_offset -8
+ pop %r15
+ .cfi_adjust_cfa_offset -8
+ ret
+ .cfi_endproc
diff --git a/tools/testing/selftests/sgx/defines.h b/tools/testing/selftests/sgx/defines.h
new file mode 100644
index 000000000000..be8969922804
--- /dev/null
+++ b/tools/testing/selftests/sgx/defines.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef DEFINES_H
+#define DEFINES_H
+
+#include <stdint.h>
+
+#define PAGE_SIZE 4096
+#define PAGE_MASK (~(PAGE_SIZE - 1))
+
+#define __aligned(x) __attribute__((__aligned__(x)))
+#define __packed __attribute__((packed))
+
+#include "../../../../arch/x86/kernel/cpu/sgx/arch.h"
+#include "../../../../arch/x86/include/asm/enclu.h"
+#include "../../../../arch/x86/include/uapi/asm/sgx.h"
+
+#endif /* DEFINES_H */
diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c
new file mode 100644
index 000000000000..53c565347e9e
--- /dev/null
+++ b/tools/testing/selftests/sgx/load.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <assert.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "defines.h"
+#include "main.h"
+
+void encl_delete(struct encl *encl)
+{
+ if (encl->encl_base)
+ munmap((void *)encl->encl_base, encl->encl_size);
+
+ if (encl->bin)
+ munmap(encl->bin, encl->bin_size);
+
+ if (encl->fd)
+ close(encl->fd);
+
+ if (encl->segment_tbl)
+ free(encl->segment_tbl);
+
+ memset(encl, 0, sizeof(*encl));
+}
+
+static bool encl_map_bin(const char *path, struct encl *encl)
+{
+ struct stat sb;
+ void *bin;
+ int ret;
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1) {
+ perror("open()");
+ return false;
+ }
+
+ ret = stat(path, &sb);
+ if (ret) {
+ perror("stat()");
+ goto err;
+ }
+
+ bin = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (bin == MAP_FAILED) {
+ perror("mmap()");
+ goto err;
+ }
+
+ encl->bin = bin;
+ encl->bin_size = sb.st_size;
+
+ close(fd);
+ return true;
+
+err:
+ close(fd);
+ return false;
+}
+
+static bool encl_ioc_create(struct encl *encl)
+{
+ struct sgx_secs *secs = &encl->secs;
+ struct sgx_enclave_create ioc;
+ int rc;
+
+ assert(encl->encl_base != 0);
+
+ memset(secs, 0, sizeof(*secs));
+ secs->ssa_frame_size = 1;
+ secs->attributes = SGX_ATTR_MODE64BIT;
+ secs->xfrm = 3;
+ secs->base = encl->encl_base;
+ secs->size = encl->encl_size;
+
+ ioc.src = (unsigned long)secs;
+ rc = ioctl(encl->fd, SGX_IOC_ENCLAVE_CREATE, &ioc);
+ if (rc) {
+ fprintf(stderr, "SGX_IOC_ENCLAVE_CREATE failed: errno=%d\n",
+ errno);
+ munmap((void *)secs->base, encl->encl_size);
+ return false;
+ }
+
+ return true;
+}
+
+static bool encl_ioc_add_pages(struct encl *encl, struct encl_segment *seg)
+{
+ struct sgx_enclave_add_pages ioc;
+ struct sgx_secinfo secinfo;
+ int rc;
+
+ memset(&secinfo, 0, sizeof(secinfo));
+ secinfo.flags = seg->flags;
+
+ ioc.src = (uint64_t)encl->src + seg->offset;
+ ioc.offset = seg->offset;
+ ioc.length = seg->size;
+ ioc.secinfo = (unsigned long)&secinfo;
+ ioc.flags = SGX_PAGE_MEASURE;
+
+ rc = ioctl(encl->fd, SGX_IOC_ENCLAVE_ADD_PAGES, &ioc);
+ if (rc) {
+ fprintf(stderr, "SGX_IOC_ENCLAVE_ADD_PAGES failed: errno=%d.\n",
+ errno);
+ return false;
+ }
+
+ if (ioc.count != ioc.length) {
+ fprintf(stderr, "A segment not fully processed.\n");
+ return false;
+ }
+
+ return true;
+}
+
+bool encl_load(const char *path, struct encl *encl)
+{
+ Elf64_Phdr *phdr_tbl;
+ off_t src_offset;
+ Elf64_Ehdr *ehdr;
+ int i, j;
+ int ret;
+
+ memset(encl, 0, sizeof(*encl));
+
+ ret = open("/dev/sgx/enclave", O_RDWR);
+ if (ret < 0) {
+ fprintf(stderr, "Unable to open /dev/sgx\n");
+ goto err;
+ }
+
+ encl->fd = ret;
+
+ if (!encl_map_bin(path, encl))
+ goto err;
+
+ ehdr = encl->bin;
+ phdr_tbl = encl->bin + ehdr->e_phoff;
+
+ for (i = 0; i < ehdr->e_phnum; i++) {
+ Elf64_Phdr *phdr = &phdr_tbl[i];
+
+ if (phdr->p_type == PT_LOAD)
+ encl->nr_segments++;
+ }
+
+ encl->segment_tbl = calloc(encl->nr_segments,
+ sizeof(struct encl_segment));
+ if (!encl->segment_tbl)
+ goto err;
+
+ for (i = 0, j = 0; i < ehdr->e_phnum; i++) {
+ Elf64_Phdr *phdr = &phdr_tbl[i];
+ unsigned int flags = phdr->p_flags;
+ struct encl_segment *seg;
+
+ if (phdr->p_type != PT_LOAD)
+ continue;
+
+ seg = &encl->segment_tbl[j];
+
+ if (!!(flags & ~(PF_R | PF_W | PF_X))) {
+ fprintf(stderr,
+ "%d has invalid segment flags 0x%02x.\n", i,
+ phdr->p_flags);
+ goto err;
+ }
+
+ if (j == 0 && flags != (PF_R | PF_W)) {
+ fprintf(stderr,
+ "TCS has invalid segment flags 0x%02x.\n",
+ phdr->p_flags);
+ goto err;
+ }
+
+ if (j == 0) {
+ src_offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+
+ seg->prot = PROT_READ | PROT_WRITE;
+ seg->flags = SGX_PAGE_TYPE_TCS << 8;
+ } else {
+ seg->prot = (phdr->p_flags & PF_R) ? PROT_READ : 0;
+ seg->prot |= (phdr->p_flags & PF_W) ? PROT_WRITE : 0;
+ seg->prot |= (phdr->p_flags & PF_X) ? PROT_EXEC : 0;
+ seg->flags = (SGX_PAGE_TYPE_REG << 8) | seg->prot;
+ }
+
+ seg->offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+ seg->size = (phdr->p_filesz + PAGE_SIZE - 1) & PAGE_MASK;
+
+ printf("0x%016lx 0x%016lx 0x%02x\n", seg->offset, seg->size,
+ seg->prot);
+
+ j++;
+ }
+
+ assert(j == encl->nr_segments);
+
+ encl->src = encl->bin + src_offset;
+ encl->src_size = encl->segment_tbl[j - 1].offset +
+ encl->segment_tbl[j - 1].size;
+
+ for (encl->encl_size = 4096; encl->encl_size < encl->src_size; )
+ encl->encl_size <<= 1;
+
+ return true;
+
+err:
+ encl_delete(encl);
+ return false;
+}
+
+static bool encl_map_area(struct encl *encl)
+{
+ size_t encl_size = encl->encl_size;
+ void *area;
+
+ area = mmap(NULL, encl_size * 2, PROT_NONE,
+ MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+ if (area == MAP_FAILED) {
+ perror("mmap");
+ return false;
+ }
+
+ encl->encl_base = ((uint64_t)area + encl_size - 1) & ~(encl_size - 1);
+
+ munmap(area, encl->encl_base - (uint64_t)area);
+ munmap((void *)(encl->encl_base + encl_size),
+ (uint64_t)area + encl_size - encl->encl_base);
+
+ return true;
+}
+
+bool encl_build(struct encl *encl)
+{
+ struct sgx_enclave_init ioc;
+ int ret;
+ int i;
+
+ if (!encl_map_area(encl))
+ return false;
+
+ if (!encl_ioc_create(encl))
+ return false;
+
+ /*
+ * Pages must be added before mapping VMAs because their permissions
+ * cap the VMA permissions.
+ */
+ for (i = 0; i < encl->nr_segments; i++) {
+ struct encl_segment *seg = &encl->segment_tbl[i];
+
+ if (!encl_ioc_add_pages(encl, seg))
+ return false;
+ }
+
+ ioc.sigstruct = (uint64_t)&encl->sigstruct;
+ ret = ioctl(encl->fd, SGX_IOC_ENCLAVE_INIT, &ioc);
+ if (ret) {
+ fprintf(stderr, "SGX_IOC_ENCLAVE_INIT failed: errno=%d\n",
+ errno);
+ return false;
+ }
+
+ return true;
+}
diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
new file mode 100644
index 000000000000..5394b2f6af8e
--- /dev/null
+++ b/tools/testing/selftests/sgx/main.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "defines.h"
+#include "main.h"
+
+static const uint64_t MAGIC = 0x1122334455667788ULL;
+vdso_sgx_enter_enclave_t eenter;
+
+struct vdso_symtab {
+ Elf64_Sym *elf_symtab;
+ const char *elf_symstrtab;
+ Elf64_Word *elf_hashtab;
+};
+
+static void *vdso_get_base_addr(char *envp[])
+{
+ Elf64_auxv_t *auxv;
+ int i;
+
+ for (i = 0; envp[i]; i++)
+ ;
+
+ auxv = (Elf64_auxv_t *)&envp[i + 1];
+
+ for (i = 0; auxv[i].a_type != AT_NULL; i++) {
+ if (auxv[i].a_type == AT_SYSINFO_EHDR)
+ return (void *)auxv[i].a_un.a_val;
+ }
+
+ return NULL;
+}
+
+static Elf64_Dyn *vdso_get_dyntab(void *addr)
+{
+ Elf64_Ehdr *ehdr = addr;
+ Elf64_Phdr *phdrtab = addr + ehdr->e_phoff;
+ int i;
+
+ for (i = 0; i < ehdr->e_phnum; i++)
+ if (phdrtab[i].p_type == PT_DYNAMIC)
+ return addr + phdrtab[i].p_offset;
+
+ return NULL;
+}
+
+static void *vdso_get_dyn(void *addr, Elf64_Dyn *dyntab, Elf64_Sxword tag)
+{
+ int i;
+
+ for (i = 0; dyntab[i].d_tag != DT_NULL; i++)
+ if (dyntab[i].d_tag == tag)
+ return addr + dyntab[i].d_un.d_ptr;
+
+ return NULL;
+}
+
+static bool vdso_get_symtab(void *addr, struct vdso_symtab *symtab)
+{
+ Elf64_Dyn *dyntab = vdso_get_dyntab(addr);
+
+ symtab->elf_symtab = vdso_get_dyn(addr, dyntab, DT_SYMTAB);
+ if (!symtab->elf_symtab)
+ return false;
+
+ symtab->elf_symstrtab = vdso_get_dyn(addr, dyntab, DT_STRTAB);
+ if (!symtab->elf_symstrtab)
+ return false;
+
+ symtab->elf_hashtab = vdso_get_dyn(addr, dyntab, DT_HASH);
+ if (!symtab->elf_hashtab)
+ return false;
+
+ return true;
+}
+
+static unsigned long elf_sym_hash(const char *name)
+{
+ unsigned long h = 0, high;
+
+ while (*name) {
+ h = (h << 4) + *name++;
+ high = h & 0xf0000000;
+
+ if (high)
+ h ^= high >> 24;
+
+ h &= ~high;
+ }
+
+ return h;
+}
+
+static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name)
+{
+ Elf64_Word bucketnum = symtab->elf_hashtab[0];
+ Elf64_Word *buckettab = &symtab->elf_hashtab[2];
+ Elf64_Word *chaintab = &symtab->elf_hashtab[2 + bucketnum];
+ Elf64_Sym *sym;
+ Elf64_Word i;
+
+ for (i = buckettab[elf_sym_hash(name) % bucketnum]; i != STN_UNDEF;
+ i = chaintab[i]) {
+ sym = &symtab->elf_symtab[i];
+ if (!strcmp(name, &symtab->elf_symstrtab[sym->st_name]))
+ return sym;
+ }
+
+ return NULL;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+ struct sgx_enclave_exception exception;
+ struct vdso_symtab symtab;
+ Elf64_Sym *eenter_sym;
+ uint64_t result = 0;
+ struct encl encl;
+ unsigned int i;
+ void *addr;
+
+ if (!encl_load("test_encl.elf", &encl))
+ goto err;
+
+ if (!encl_measure(&encl))
+ goto err;
+
+ if (!encl_build(&encl))
+ goto err;
+
+ /*
+ * An enclave consumer only must do this.
+ */
+ for (i = 0; i < encl.nr_segments; i++) {
+ struct encl_segment *seg = &encl.segment_tbl[i];
+
+ addr = mmap((void *)encl.encl_base + seg->offset, seg->size,
+ seg->prot, MAP_SHARED | MAP_FIXED, encl.fd, 0);
+ if (addr == MAP_FAILED) {
+ fprintf(stderr, "mmap() failed, errno=%d.\n", errno);
+ return false;
+ }
+ }
+
+ memset(&exception, 0, sizeof(exception));
+
+ addr = vdso_get_base_addr(envp);
+ if (!addr)
+ goto err;
+
+ if (!vdso_get_symtab(addr, &symtab))
+ goto err;
+
+ eenter_sym = vdso_symtab_get(&symtab, "__vdso_sgx_enter_enclave");
+ if (!eenter_sym)
+ goto err;
+
+ eenter = addr + eenter_sym->st_value;
+
+ sgx_call_vdso((void *)&MAGIC, &result, 0, EENTER, NULL, NULL,
+ (void *)encl.encl_base, &exception, NULL);
+ if (result != MAGIC) {
+ printf("FAIL: sgx_call_vdso(), expected: 0x%lx, got: 0x%lx\n",
+ MAGIC, result);
+ goto err;
+ }
+
+ /* Invoke the vDSO directly. */
+ result = 0;
+ eenter((unsigned long)&MAGIC, (unsigned long)&result, 0, EENTER, 0, 0,
+ (void *)encl.encl_base, &exception, NULL);
+ if (result != MAGIC) {
+ printf("FAIL: eenter(), expected: 0x%lx, got: 0x%lx\n",
+ MAGIC, result);
+ goto err;
+ }
+
+ printf("SUCCESS\n");
+ encl_delete(&encl);
+ exit(0);
+
+err:
+ encl_delete(&encl);
+ exit(1);
+}
diff --git a/tools/testing/selftests/sgx/main.h b/tools/testing/selftests/sgx/main.h
new file mode 100644
index 000000000000..999422cc7343
--- /dev/null
+++ b/tools/testing/selftests/sgx/main.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef MAIN_H
+#define MAIN_H
+
+struct encl_segment {
+ off_t offset;
+ size_t size;
+ unsigned int prot;
+ unsigned int flags;
+};
+
+struct encl {
+ int fd;
+ void *bin;
+ off_t bin_size;
+ void *src;
+ size_t src_size;
+ size_t encl_size;
+ off_t encl_base;
+ unsigned int nr_segments;
+ struct encl_segment *segment_tbl;
+ struct sgx_secs secs;
+ struct sgx_sigstruct sigstruct;
+};
+
+void encl_delete(struct encl *ctx);
+bool encl_load(const char *path, struct encl *encl);
+bool encl_measure(struct encl *encl);
+bool encl_build(struct encl *encl);
+
+int sgx_call_vdso(void *rdi, void *rsi, long rdx, u32 leaf, void *r8, void *r9,
+ void *tcs, struct sgx_enclave_exception *ei, void *cb);
+
+#endif /* MAIN_H */
diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
new file mode 100644
index 000000000000..ceddad478672
--- /dev/null
+++ b/tools/testing/selftests/sgx/sigstruct.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#define _GNU_SOURCE
+#include <assert.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <openssl/err.h>
+#include <openssl/pem.h>
+#include "defines.h"
+#include "main.h"
+
+struct q1q2_ctx {
+ BN_CTX *bn_ctx;
+ BIGNUM *m;
+ BIGNUM *s;
+ BIGNUM *q1;
+ BIGNUM *qr;
+ BIGNUM *q2;
+};
+
+static void free_q1q2_ctx(struct q1q2_ctx *ctx)
+{
+ BN_CTX_free(ctx->bn_ctx);
+ BN_free(ctx->m);
+ BN_free(ctx->s);
+ BN_free(ctx->q1);
+ BN_free(ctx->qr);
+ BN_free(ctx->q2);
+}
+
+static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m,
+ struct q1q2_ctx *ctx)
+{
+ ctx->bn_ctx = BN_CTX_new();
+ ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL);
+ ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL);
+ ctx->q1 = BN_new();
+ ctx->qr = BN_new();
+ ctx->q2 = BN_new();
+
+ if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr ||
+ !ctx->q2) {
+ free_q1q2_ctx(ctx);
+ return false;
+ }
+
+ return true;
+}
+
+static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1,
+ uint8_t *q2)
+{
+ struct q1q2_ctx ctx;
+
+ if (!alloc_q1q2_ctx(s, m, &ctx)) {
+ fprintf(stderr, "Not enough memory for Q1Q2 calculation\n");
+ return false;
+ }
+
+ if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx))
+ goto out;
+
+ if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx))
+ goto out;
+
+ if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) {
+ fprintf(stderr, "Too large Q1 %d bytes\n",
+ BN_num_bytes(ctx.q1));
+ goto out;
+ }
+
+ if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx))
+ goto out;
+
+ if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx))
+ goto out;
+
+ if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) {
+ fprintf(stderr, "Too large Q2 %d bytes\n",
+ BN_num_bytes(ctx.q2));
+ goto out;
+ }
+
+ BN_bn2bin(ctx.q1, q1);
+ BN_bn2bin(ctx.q2, q2);
+
+ free_q1q2_ctx(&ctx);
+ return true;
+out:
+ free_q1q2_ctx(&ctx);
+ return false;
+}
+
+struct sgx_sigstruct_payload {
+ struct sgx_sigstruct_header header;
+ struct sgx_sigstruct_body body;
+};
+
+static bool check_crypto_errors(void)
+{
+ int err;
+ bool had_errors = false;
+ const char *filename;
+ int line;
+ char str[256];
+
+ for ( ; ; ) {
+ if (ERR_peek_error() == 0)
+ break;
+
+ had_errors = true;
+ err = ERR_get_error_line(&filename, &line);
+ ERR_error_string_n(err, str, sizeof(str));
+ fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line);
+ }
+
+ return had_errors;
+}
+
+static inline const BIGNUM *get_modulus(RSA *key)
+{
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+ return key->n;
+#else
+ const BIGNUM *n;
+
+ RSA_get0_key(key, &n, NULL, NULL);
+ return n;
+#endif
+}
+
+static RSA *gen_sign_key(void)
+{
+ BIGNUM *e;
+ RSA *key;
+ int ret;
+
+ e = BN_new();
+ key = RSA_new();
+
+ if (!e || !key)
+ goto err;
+
+ ret = BN_set_word(e, RSA_3);
+ if (ret != 1)
+ goto err;
+
+ ret = RSA_generate_key_ex(key, 3072, e, NULL);
+ if (ret != 1)
+ goto err;
+
+ BN_free(e);
+
+ return key;
+
+err:
+ RSA_free(key);
+ BN_free(e);
+
+ return NULL;
+}
+
+static void reverse_bytes(void *data, int length)
+{
+ int i = 0;
+ int j = length - 1;
+ uint8_t temp;
+ uint8_t *ptr = data;
+
+ while (i < j) {
+ temp = ptr[i];
+ ptr[i] = ptr[j];
+ ptr[j] = temp;
+ i++;
+ j--;
+ }
+}
+
+enum mrtags {
+ MRECREATE = 0x0045544145524345,
+ MREADD = 0x0000000044444145,
+ MREEXTEND = 0x00444E4554584545,
+};
+
+static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data)
+{
+ if (!EVP_DigestUpdate(ctx, data, 64)) {
+ fprintf(stderr, "digest update failed\n");
+ return false;
+ }
+
+ return true;
+}
+
+static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave)
+{
+ unsigned int size;
+
+ if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) {
+ fprintf(stderr, "digest commit failed\n");
+ return false;
+ }
+
+ if (size != 32) {
+ fprintf(stderr, "invalid digest size = %u\n", size);
+ return false;
+ }
+
+ return true;
+}
+
+struct mrecreate {
+ uint64_t tag;
+ uint32_t ssaframesize;
+ uint64_t size;
+ uint8_t reserved[44];
+} __attribute__((__packed__));
+
+
+static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size)
+{
+ struct mrecreate mrecreate;
+ uint64_t encl_size;
+
+ for (encl_size = 0x1000; encl_size < blob_size; )
+ encl_size <<= 1;
+
+ memset(&mrecreate, 0, sizeof(mrecreate));
+ mrecreate.tag = MRECREATE;
+ mrecreate.ssaframesize = 1;
+ mrecreate.size = encl_size;
+
+ if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
+ return false;
+
+ return mrenclave_update(ctx, &mrecreate);
+}
+
+struct mreadd {
+ uint64_t tag;
+ uint64_t offset;
+ uint64_t flags; /* SECINFO flags */
+ uint8_t reserved[40];
+} __attribute__((__packed__));
+
+static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags)
+{
+ struct mreadd mreadd;
+
+ memset(&mreadd, 0, sizeof(mreadd));
+ mreadd.tag = MREADD;
+ mreadd.offset = offset;
+ mreadd.flags = flags;
+
+ return mrenclave_update(ctx, &mreadd);
+}
+
+struct mreextend {
+ uint64_t tag;
+ uint64_t offset;
+ uint8_t reserved[48];
+} __attribute__((__packed__));
+
+static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset,
+ const uint8_t *data)
+{
+ struct mreextend mreextend;
+ int i;
+
+ for (i = 0; i < 0x1000; i += 0x100) {
+ memset(&mreextend, 0, sizeof(mreextend));
+ mreextend.tag = MREEXTEND;
+ mreextend.offset = offset + i;
+
+ if (!mrenclave_update(ctx, &mreextend))
+ return false;
+
+ if (!mrenclave_update(ctx, &data[i + 0x00]))
+ return false;
+
+ if (!mrenclave_update(ctx, &data[i + 0x40]))
+ return false;
+
+ if (!mrenclave_update(ctx, &data[i + 0x80]))
+ return false;
+
+ if (!mrenclave_update(ctx, &data[i + 0xC0]))
+ return false;
+ }
+
+ return true;
+}
+
+static bool mrenclave_segment(EVP_MD_CTX *ctx, struct encl *encl,
+ struct encl_segment *seg)
+{
+ uint64_t end = seg->offset + seg->size;
+ uint64_t offset;
+
+ for (offset = seg->offset; offset < end; offset += PAGE_SIZE) {
+ if (!mrenclave_eadd(ctx, offset, seg->flags))
+ return false;
+
+ if (!mrenclave_eextend(ctx, offset, encl->src + offset))
+ return false;
+ }
+
+ return true;
+}
+
+bool encl_measure(struct encl *encl)
+{
+ uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
+ uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
+ struct sgx_sigstruct *sigstruct = &encl->sigstruct;
+ struct sgx_sigstruct_payload payload;
+ uint8_t digest[SHA256_DIGEST_LENGTH];
+ unsigned int siglen;
+ RSA *key = NULL;
+ EVP_MD_CTX *ctx;
+ int i;
+
+ memset(sigstruct, 0, sizeof(*sigstruct));
+
+ sigstruct->header.header1[0] = header1[0];
+ sigstruct->header.header1[1] = header1[1];
+ sigstruct->header.header2[0] = header2[0];
+ sigstruct->header.header2[1] = header2[1];
+ sigstruct->exponent = 3;
+ sigstruct->body.attributes = SGX_ATTR_MODE64BIT;
+ sigstruct->body.xfrm = 3;
+
+ /* sanity check */
+ if (check_crypto_errors())
+ goto err;
+
+ key = gen_sign_key();
+ if (!key)
+ goto err;
+
+ BN_bn2bin(get_modulus(key), sigstruct->modulus);
+
+ ctx = EVP_MD_CTX_create();
+ if (!ctx)
+ goto err;
+
+ if (!mrenclave_ecreate(ctx, encl->src_size))
+ goto err;
+
+ for (i = 0; i < encl->nr_segments; i++) {
+ struct encl_segment *seg = &encl->segment_tbl[i];
+
+ if (!mrenclave_segment(ctx, encl, seg))
+ goto err;
+ }
+
+ if (!mrenclave_commit(ctx, sigstruct->body.mrenclave))
+ goto err;
+
+ memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header));
+ memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body));
+
+ SHA256((unsigned char *)&payload, sizeof(payload), digest);
+
+ if (!RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH,
+ sigstruct->signature, &siglen, key))
+ goto err;
+
+ if (!calc_q1q2(sigstruct->signature, sigstruct->modulus, sigstruct->q1,
+ sigstruct->q2))
+ goto err;
+
+ /* BE -> LE */
+ reverse_bytes(sigstruct->signature, SGX_MODULUS_SIZE);
+ reverse_bytes(sigstruct->modulus, SGX_MODULUS_SIZE);
+ reverse_bytes(sigstruct->q1, SGX_MODULUS_SIZE);
+ reverse_bytes(sigstruct->q2, SGX_MODULUS_SIZE);
+
+ EVP_MD_CTX_destroy(ctx);
+ RSA_free(key);
+ return true;
+
+err:
+ EVP_MD_CTX_destroy(ctx);
+ RSA_free(key);
+ return false;
+}
diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c
new file mode 100644
index 000000000000..ede915399742
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <stddef.h>
+#include "defines.h"
+
+static void *memcpy(void *dest, const void *src, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++)
+ ((char *)dest)[i] = ((char *)src)[i];
+
+ return dest;
+}
+
+void encl_body(void *rdi, void *rsi)
+{
+ memcpy(rsi, rdi, 8);
+}
diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds
new file mode 100644
index 000000000000..0fbbda7e665e
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl.lds
@@ -0,0 +1,40 @@
+OUTPUT_FORMAT(elf64-x86-64)
+
+PHDRS
+{
+ tcs PT_LOAD;
+ text PT_LOAD;
+ data PT_LOAD;
+}
+
+SECTIONS
+{
+ . = 0;
+ .tcs : {
+ *(.tcs*)
+ } : tcs
+
+ . = ALIGN(4096);
+ .text : {
+ *(.text*)
+ *(.rodata*)
+ } : text
+
+ . = ALIGN(4096);
+ .data : {
+ *(.data*)
+ } : data
+
+ /DISCARD/ : {
+ *(.comment*)
+ *(.note*)
+ *(.debug*)
+ *(.eh_frame*)
+ }
+}
+
+ASSERT(!DEFINED(.altinstructions), "ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.altinstr_replacement), "ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.discard.retpoline_safe), "RETPOLINE ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.discard.nospec), "RETPOLINE ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.got.plt), "Libcalls are not supported in enclaves")
diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
new file mode 100644
index 000000000000..6836ea86126e
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/*
+ * Copyright(c) 2016-18 Intel Corporation.
+ */
+
+ .macro ENCLU
+ .byte 0x0f, 0x01, 0xd7
+ .endm
+
+ .section ".tcs", "aw"
+ .balign 4096
+
+ .fill 1, 8, 0 # STATE (set by CPU)
+ .fill 1, 8, 0 # FLAGS
+ .quad encl_ssa # OSSA
+ .fill 1, 4, 0 # CSSA (set by CPU)
+ .fill 1, 4, 1 # NSSA
+ .quad encl_entry # OENTRY
+ .fill 1, 8, 0 # AEP (set by EENTER and ERESUME)
+ .fill 1, 8, 0 # OFSBASE
+ .fill 1, 8, 0 # OGSBASE
+ .fill 1, 4, 0xFFFFFFFF # FSLIMIT
+ .fill 1, 4, 0xFFFFFFFF # GSLIMIT
+ .fill 4024, 1, 0 # Reserved
+
+ # Identical to the previous TCS.
+ .fill 1, 8, 0 # STATE (set by CPU)
+ .fill 1, 8, 0 # FLAGS
+ .quad encl_ssa # OSSA
+ .fill 1, 4, 0 # CSSA (set by CPU)
+ .fill 1, 4, 1 # NSSA
+ .quad encl_entry # OENTRY
+ .fill 1, 8, 0 # AEP (set by EENTER and ERESUME)
+ .fill 1, 8, 0 # OFSBASE
+ .fill 1, 8, 0 # OGSBASE
+ .fill 1, 4, 0xFFFFFFFF # FSLIMIT
+ .fill 1, 4, 0xFFFFFFFF # GSLIMIT
+ .fill 4024, 1, 0 # Reserved
+
+ .text
+
+encl_entry:
+ # RBX contains the base address for TCS, which is also the first address
+ # inside the enclave. By adding the value of le_stack_end to it, we get
+ # the absolute address for the stack.
+ lea (encl_stack)(%rbx), %rax
+ xchg %rsp, %rax
+ push %rax
+
+ push %rcx # push the address after EENTER
+ push %rbx # push the enclave base address
+
+ call encl_body
+
+ pop %rbx # pop the enclave base address
+
+ /* Clear volatile GPRs, except RAX (EEXIT leaf). */
+ xor %rcx, %rcx
+ xor %rdx, %rdx
+ xor %rdi, %rdi
+ xor %rsi, %rsi
+ xor %r8, %r8
+ xor %r9, %r9
+ xor %r10, %r10
+ xor %r11, %r11
+
+ # Reset status flags.
+ add %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1
+
+ # Prepare EEXIT target by popping the address of the instruction after
+ # EENTER to RBX.
+ pop %rbx
+
+ # Restore the caller stack.
+ pop %rax
+ mov %rax, %rsp
+
+ # EEXIT
+ mov $4, %rax
+ enclu
+
+ .section ".data", "aw"
+
+encl_ssa:
+ .space 4096
+
+ .balign 4096
+ .space 8192
+encl_stack:
--
2.25.1
Add VMA callbacks for ptrace() that can be used with debug enclaves.
With debug enclaves data can be read and write the memory word at a time
by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/sgx/encl.c | 88 ++++++++++++++++++++++++++++++++++
1 file changed, 88 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index fe7dbca40bb4..0c5ea2968868 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -326,6 +326,7 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
return 0;
}
+
static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned long prot)
{
@@ -333,10 +334,97 @@ static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
calc_vm_prot_bits(prot, 0));
}
+static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+ unsigned long offset = addr & ~PAGE_MASK;
+ int ret;
+
+
+ ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
+
+static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+ unsigned long offset = addr & ~PAGE_MASK;
+ int ret;
+
+ ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct sgx_encl *encl = vma->vm_private_data;
+ struct sgx_encl_page *entry = NULL;
+ char data[sizeof(unsigned long)];
+ unsigned long align;
+ unsigned int flags;
+ int offset;
+ int cnt;
+ int ret = 0;
+ int i;
+
+ /* If process was forked, VMA is still there but vm_private_data is set
+ * to NULL.
+ */
+ if (!encl)
+ return -EFAULT;
+
+ flags = atomic_read(&encl->flags);
+
+ if (!(flags & SGX_ENCL_DEBUG) || !(flags & SGX_ENCL_INITIALIZED) ||
+ (flags & SGX_ENCL_DEAD))
+ return -EFAULT;
+
+ for (i = 0; i < len; i += cnt) {
+ entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK);
+ if (IS_ERR(entry)) {
+ ret = PTR_ERR(entry);
+ break;
+ }
+
+ align = ALIGN_DOWN(addr + i, sizeof(unsigned long));
+ offset = (addr + i) & (sizeof(unsigned long) - 1);
+ cnt = sizeof(unsigned long) - offset;
+ cnt = min(cnt, len - i);
+
+ ret = sgx_edbgrd(encl, entry, align, data);
+ if (ret)
+ goto out;
+
+ if (write) {
+ memcpy(data + offset, buf + i, cnt);
+ ret = sgx_edbgwr(encl, entry, align, data);
+ if (ret)
+ goto out;
+ } else
+ memcpy(buf + i, data + offset, cnt);
+
+out:
+ mutex_unlock(&encl->lock);
+
+ if (ret)
+ break;
+ }
+
+ return ret < 0 ? ret : i;
+}
+
const struct vm_operations_struct sgx_vm_ops = {
.open = sgx_vma_open,
.fault = sgx_vma_fault,
.may_mprotect = sgx_vma_mprotect,
+ .access = sgx_vma_access,
};
/**
--
2.25.1
ENCLS is a ring 0 instruction, which contains a set of leaf functions for
managing an enclave. Enclaves are measured and signed software entities,
which are protected by asserting the outside memory accesses and memory
encryption.
Add a two-layer macro system along with an encoding scheme to allow
wrappers to return trap numbers along ENCLS-specific error codes. The
bottom layer of the macro system splits between the leafs that return an
error code and those that do not. The second layer generates the correct
input/output annotations based on the number of operands for each leaf
function.
ENCLS leaf functions are documented in
Intel SDM: 36.6 ENCLAVE INSTRUCTIONS AND INTEL®
Co-developed-by: Sean Christopherson <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/sgx/encls.h | 239 ++++++++++++++++++++++++++++++++
1 file changed, 239 insertions(+)
create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
new file mode 100644
index 000000000000..376cdedb9a43
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -0,0 +1,239 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef _X86_ENCLS_H
+#define _X86_ENCLS_H
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <asm/asm.h>
+#include <asm/traps.h>
+#include "sgx.h"
+
+enum sgx_encls_leaf {
+ ECREATE = 0x00,
+ EADD = 0x01,
+ EINIT = 0x02,
+ EREMOVE = 0x03,
+ EDGBRD = 0x04,
+ EDGBWR = 0x05,
+ EEXTEND = 0x06,
+ ELDU = 0x08,
+ EBLOCK = 0x09,
+ EPA = 0x0A,
+ EWB = 0x0B,
+ ETRACK = 0x0C,
+};
+
+/**
+ * ENCLS_FAULT_FLAG - flag signifying an ENCLS return code is a trapnr
+ *
+ * ENCLS has its own (positive value) error codes and also generates
+ * ENCLS specific #GP and #PF faults. And the ENCLS values get munged
+ * with system error codes as everything percolates back up the stack.
+ * Unfortunately (for us), we need to precisely identify each unique
+ * error code, e.g. the action taken if EWB fails varies based on the
+ * type of fault and on the exact SGX error code, i.e. we can't simply
+ * convert all faults to -EFAULT.
+ *
+ * To make all three error types coexist, we set bit 30 to identify an
+ * ENCLS fault. Bit 31 (technically bits N:31) is used to differentiate
+ * between positive (faults and SGX error codes) and negative (system
+ * error codes) values.
+ */
+#define ENCLS_FAULT_FLAG 0x40000000
+
+/* Retrieve the encoded trapnr from the specified return code. */
+#define ENCLS_TRAPNR(r) ((r) & ~ENCLS_FAULT_FLAG)
+
+/* Issue a WARN() about an ENCLS leaf. */
+#define ENCLS_WARN(r, name) { \
+ do { \
+ int _r = (r); \
+ WARN_ONCE(_r, "%s returned %d (0x%x)\n", (name), _r, _r); \
+ } while (0); \
+}
+
+/**
+ * encls_failed() - Check if an ENCLS leaf function failed
+ * @ret: the return value of an ENCLS leaf function call
+ *
+ * Check if an ENCLS leaf function failed. This happens when the leaf function
+ * causes a fault that is not caused by an EPCM conflict or when the leaf
+ * function returns a non-zero value.
+ */
+static inline bool encls_failed(int ret)
+{
+ int epcm_trapnr;
+
+ if (boot_cpu_has(X86_FEATURE_SGX2))
+ epcm_trapnr = X86_TRAP_PF;
+ else
+ epcm_trapnr = X86_TRAP_GP;
+
+ if (ret & ENCLS_FAULT_FLAG)
+ return ENCLS_TRAPNR(ret) != epcm_trapnr;
+
+ return !!ret;
+}
+
+/**
+ * __encls_ret_N - encode an ENCLS leaf that returns an error code in EAX
+ * @rax: leaf number
+ * @inputs: asm inputs for the leaf
+ *
+ * Emit assembly for an ENCLS leaf that returns an error code, e.g. EREMOVE.
+ * And because SGX isn't complex enough as it is, leafs that return an error
+ * code also modify flags.
+ *
+ * Return:
+ * 0 on success,
+ * SGX error code on failure
+ */
+#define __encls_ret_N(rax, inputs...) \
+ ({ \
+ int ret; \
+ asm volatile( \
+ "1: .byte 0x0f, 0x01, 0xcf;\n\t" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_FAULT(1b, 3b) \
+ : "=a"(ret) \
+ : "a"(rax), inputs \
+ : "memory", "cc"); \
+ ret; \
+ })
+
+#define __encls_ret_1(rax, rcx) \
+ ({ \
+ __encls_ret_N(rax, "c"(rcx)); \
+ })
+
+#define __encls_ret_2(rax, rbx, rcx) \
+ ({ \
+ __encls_ret_N(rax, "b"(rbx), "c"(rcx)); \
+ })
+
+#define __encls_ret_3(rax, rbx, rcx, rdx) \
+ ({ \
+ __encls_ret_N(rax, "b"(rbx), "c"(rcx), "d"(rdx)); \
+ })
+
+/**
+ * __encls_N - encode an ENCLS leaf that doesn't return an error code
+ * @rax: leaf number
+ * @rbx_out: optional output variable
+ * @inputs: asm inputs for the leaf
+ *
+ * Emit assembly for an ENCLS leaf that does not return an error code,
+ * e.g. ECREATE. Leaves without error codes either succeed or fault.
+ * @rbx_out is an optional parameter for use by EDGBRD, which returns
+ * the the requested value in RBX.
+ *
+ * Return:
+ * 0 on success,
+ * trapnr with ENCLS_FAULT_FLAG set on fault
+ */
+#define __encls_N(rax, rbx_out, inputs...) \
+ ({ \
+ int ret; \
+ asm volatile( \
+ "1: .byte 0x0f, 0x01, 0xcf;\n\t" \
+ " xor %%eax,%%eax;\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_FAULT(1b, 3b) \
+ : "=a"(ret), "=b"(rbx_out) \
+ : "a"(rax), inputs \
+ : "memory"); \
+ ret; \
+ })
+
+#define __encls_2(rax, rbx, rcx) \
+ ({ \
+ unsigned long ign_rbx_out; \
+ __encls_N(rax, ign_rbx_out, "b"(rbx), "c"(rcx)); \
+ })
+
+#define __encls_1_1(rax, data, rcx) \
+ ({ \
+ unsigned long rbx_out; \
+ int ret = __encls_N(rax, rbx_out, "c"(rcx)); \
+ if (!ret) \
+ data = rbx_out; \
+ ret; \
+ })
+
+static inline int __ecreate(struct sgx_pageinfo *pginfo, void *secs)
+{
+ return __encls_2(ECREATE, pginfo, secs);
+}
+
+static inline int __eextend(void *secs, void *addr)
+{
+ return __encls_2(EEXTEND, secs, addr);
+}
+
+static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
+{
+ return __encls_2(EADD, pginfo, addr);
+}
+
+static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
+ void *secs)
+{
+ return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
+}
+
+static inline int __eremove(void *addr)
+{
+ return __encls_ret_1(EREMOVE, addr);
+}
+
+static inline int __edbgwr(void *addr, unsigned long *data)
+{
+ return __encls_2(EDGBWR, *data, addr);
+}
+
+static inline int __edbgrd(void *addr, unsigned long *data)
+{
+ return __encls_1_1(EDGBRD, *data, addr);
+}
+
+static inline int __etrack(void *addr)
+{
+ return __encls_ret_1(ETRACK, addr);
+}
+
+static inline int __eldu(struct sgx_pageinfo *pginfo, void *addr,
+ void *va)
+{
+ return __encls_ret_3(ELDU, pginfo, addr, va);
+}
+
+static inline int __eblock(void *addr)
+{
+ return __encls_ret_1(EBLOCK, addr);
+}
+
+static inline int __epa(void *addr)
+{
+ unsigned long rbx = SGX_PAGE_TYPE_VA;
+
+ return __encls_2(EPA, rbx, addr);
+}
+
+static inline int __ewb(struct sgx_pageinfo *pginfo, void *addr,
+ void *va)
+{
+ return __encls_ret_3(EWB, pginfo, addr, va);
+}
+
+#endif /* _X86_ENCLS_H */
--
2.25.1
Add the maintainer information for the SGX subsystem.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
MAINTAINERS | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index fcd79fc38928..6dca914d6926 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8722,6 +8722,17 @@ F: Documentation/x86/intel_txt.rst
F: include/linux/tboot.h
F: arch/x86/kernel/tboot.c
+INTEL SGX
+M: Jarkko Sakkinen <[email protected]>
+M: Sean Christopherson <[email protected]>
+L: [email protected]
+S: Maintained
+Q: https://patchwork.kernel.org/project/intel-sgx/list/
+T: git https://github.com/jsakkine-intel/linux-sgx.git
+F: arch/x86/include/uapi/asm/sgx.h
+F: arch/x86/kernel/cpu/sgx/*
+K: \bSGX_
+
INTERCONNECT API
M: Georgi Djakov <[email protected]>
L: [email protected]
--
2.25.1
From: Sean Christopherson <[email protected]>
Add vm_ops()->may_mprotect() to check additional constrains set by a
subsystem for a mprotect() call.
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
include/linux/mm.h | 2 ++
mm/mprotect.c | 14 +++++++++++---
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 52269e56c514..ad08eb666e1c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -464,6 +464,8 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
int (*split)(struct vm_area_struct * area, unsigned long addr);
int (*mremap)(struct vm_area_struct * area);
+ int (*may_mprotect)(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, unsigned long prot);
vm_fault_t (*fault)(struct vm_fault *vmf);
vm_fault_t (*huge_fault)(struct vm_fault *vmf,
enum page_entry_size pe_size);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 7a8e84f86831..c0cb40e23b43 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -543,13 +543,21 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
goto out;
}
+ tmp = vma->vm_end;
+ if (tmp > end)
+ tmp = end;
+
+ if (vma->vm_ops && vma->vm_ops->may_mprotect) {
+ error = vma->vm_ops->may_mprotect(vma, nstart, tmp,
+ prot);
+ if (error)
+ goto out;
+ }
+
error = security_file_mprotect(vma, reqprot, prot);
if (error)
goto out;
- tmp = vma->vm_end;
- if (tmp > end)
- tmp = end;
error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
if (error)
goto out;
--
2.25.1
In order to provide a mechanism for devilering provisoning rights:
1. Add a new device file /dev/sgx/provision that works as a token for
allowing an enclave to have the provisioning privileges.
2. Add a new ioctl called SGX_IOC_ENCLAVE_SET_ATTRIBUTE that accepts the
following data structure:
struct sgx_enclave_set_attribute {
__u64 addr;
__u64 attribute_fd;
};
A daemon could sit on top of /dev/sgx/provision and send a file
descriptor of this file to a process that needs to be able to provision
enclaves.
The way this API is used is straight-forward. Lets assume that dev_fd is
a handle to /dev/sgx/enclave and prov_fd is a handle to
/dev/sgx/provision. You would allow SGX_IOC_ENCLAVE_CREATE to
initialize an enclave with the PROVISIONKEY attribute by
params.addr = <enclave address>;
params.token_fd = prov_fd;
ioctl(dev_fd, SGX_IOC_ENCLAVE_SET_ATTRIBUTE, ¶ms);
Cc: [email protected]
Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/include/uapi/asm/sgx.h | 11 ++++++++
arch/x86/kernel/cpu/sgx/driver.c | 14 ++++++++++
arch/x86/kernel/cpu/sgx/driver.h | 2 ++
arch/x86/kernel/cpu/sgx/ioctl.c | 47 ++++++++++++++++++++++++++++++++
4 files changed, 74 insertions(+)
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index 5edb08ab8fd0..57d0d30c79b3 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -25,6 +25,8 @@ enum sgx_page_flags {
_IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
#define SGX_IOC_ENCLAVE_INIT \
_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
+#define SGX_IOC_ENCLAVE_SET_ATTRIBUTE \
+ _IOW(SGX_MAGIC, 0x03, struct sgx_enclave_set_attribute)
/**
* struct sgx_enclave_create - parameter structure for the
@@ -63,4 +65,13 @@ struct sgx_enclave_init {
__u64 sigstruct;
};
+/**
+ * struct sgx_enclave_set_attribute - parameter structure for the
+ * %SGX_IOC_ENCLAVE_SET_ATTRIBUTE ioctl
+ * @attribute_fd: file handle of the attribute file in the securityfs
+ */
+struct sgx_enclave_set_attribute {
+ __u64 attribute_fd;
+};
+
#endif /* _UAPI_ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index b4aa7b9f8376..d90114cec1c3 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -150,6 +150,13 @@ static struct miscdevice sgx_dev_enclave = {
.fops = &sgx_encl_fops,
};
+static struct miscdevice sgx_dev_provision = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "provision",
+ .nodename = "sgx/provision",
+ .fops = &sgx_provision_fops,
+};
+
int __init sgx_drv_init(void)
{
unsigned int eax, ebx, ecx, edx;
@@ -190,5 +197,12 @@ int __init sgx_drv_init(void)
return ret;
}
+ ret = misc_register(&sgx_dev_provision);
+ if (ret) {
+ pr_err("Creating /dev/sgx/provision failed with %d.\n", ret);
+ misc_deregister(&sgx_dev_enclave);
+ return ret;
+ }
+
return 0;
}
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
index e4063923115b..72747d01c046 100644
--- a/arch/x86/kernel/cpu/sgx/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -23,6 +23,8 @@ extern u64 sgx_attributes_reserved_mask;
extern u64 sgx_xfrm_reserved_mask;
extern u32 sgx_xsave_size_tbl[64];
+extern const struct file_operations sgx_provision_fops;
+
long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
int sgx_drv_init(void);
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 26d0425d7252..aea3e82a7ab9 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -653,6 +653,50 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
return ret;
}
+/**
+ * sgx_ioc_enclave_set_attribute - handler for %SGX_IOC_ENCLAVE_SET_ATTRIBUTE
+ * @filep: open file to /dev/sgx
+ * @arg: userspace pointer to a struct sgx_enclave_set_attribute instance
+ *
+ * Mark the enclave as being allowed to access a restricted attribute bit.
+ * The requested attribute is specified via the attribute_fd field in the
+ * provided struct sgx_enclave_set_attribute. The attribute_fd must be a
+ * handle to an SGX attribute file, e.g. “/dev/sgx/provision".
+ *
+ * Failure to explicitly request access to a restricted attribute will cause
+ * sgx_ioc_enclave_init() to fail. Currently, the only restricted attribute
+ * is access to the PROVISION_KEY.
+ *
+ * Note, access to the EINITTOKEN_KEY is disallowed entirely.
+ *
+ * Return: 0 on success, -errno otherwise
+ */
+static long sgx_ioc_enclave_set_attribute(struct sgx_encl *encl,
+ void __user *arg)
+{
+ struct sgx_enclave_set_attribute params;
+ struct file *attribute_file;
+ int ret;
+
+ if (copy_from_user(¶ms, arg, sizeof(params)))
+ return -EFAULT;
+
+ attribute_file = fget(params.attribute_fd);
+ if (!attribute_file)
+ return -EINVAL;
+
+ if (attribute_file->f_op != &sgx_provision_fops) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ encl->allowed_attributes |= SGX_ATTR_PROVISIONKEY;
+ ret = 0;
+
+out:
+ fput(attribute_file);
+ return ret;
+}
long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
@@ -676,6 +720,9 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
case SGX_IOC_ENCLAVE_INIT:
ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
break;
+ case SGX_IOC_ENCLAVE_SET_ATTRIBUTE:
+ ret = sgx_ioc_enclave_set_attribute(encl, (void __user *)arg);
+ break;
default:
ret = -ENOIOCTLCMD;
break;
--
2.25.1
From: Sean Christopherson <[email protected]>
An SGX runtime must be aware of the exceptions, which happen inside an
enclave. Introduce a vDSO call that wraps EENTER/ERESUME cycle and returns
the CPU exception back to the caller exactly when it happens.
Kernel fixups the exception information to RDI, RSI and RDX. The SGX call
vDSO handler fills this information to the user provided buffer or
alternatively trigger user provided callback at the time of the exception.
The calling convention is custom and does not follow System V x86-64 ABI.
Suggested-by: Andy Lutomirski <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Cedric Xing <[email protected]>
Signed-off-by: Cedric Xing <[email protected]>
Tested-by: Jethro Beekman <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/entry/vdso/Makefile | 2 +
arch/x86/entry/vdso/vdso.lds.S | 1 +
arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++++++++++++++++++++++
arch/x86/include/asm/enclu.h | 8 ++
arch/x86/include/uapi/asm/sgx.h | 98 +++++++++++++++++
5 files changed, 240 insertions(+)
create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
create mode 100644 arch/x86/include/asm/enclu.h
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 657e01d34d02..fa50c76a17a8 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -24,6 +24,7 @@ VDSO32-$(CONFIG_IA32_EMULATION) := y
# files to link into the vdso
vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
+vobjs-$(VDSO64-y) += vsgx_enter_enclave.o
# files to link into kernel
obj-y += vma.o extable.o
@@ -90,6 +91,7 @@ $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS
CFLAGS_REMOVE_vclock_gettime.o = -pg
CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
CFLAGS_REMOVE_vgetcpu.o = -pg
+CFLAGS_REMOVE_vsgx_enter_enclave.o = -pg
#
# X32 processes use x32 vDSO to access 64bit kernel data.
diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S
index 36b644e16272..4bf48462fca7 100644
--- a/arch/x86/entry/vdso/vdso.lds.S
+++ b/arch/x86/entry/vdso/vdso.lds.S
@@ -27,6 +27,7 @@ VERSION {
__vdso_time;
clock_getres;
__vdso_clock_getres;
+ __vdso_sgx_enter_enclave;
local: *;
};
}
diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S
new file mode 100644
index 000000000000..be7e467e1efb
--- /dev/null
+++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+#include <asm/errno.h>
+#include <asm/enclu.h>
+
+#include "extable.h"
+
+#define EX_LEAF 0*8
+#define EX_TRAPNR 0*8+4
+#define EX_ERROR_CODE 0*8+6
+#define EX_ADDRESS 1*8
+
+.code64
+.section .text, "ax"
+
+SYM_FUNC_START(__vdso_sgx_enter_enclave)
+ /* Prolog */
+ .cfi_startproc
+ push %rbp
+ .cfi_adjust_cfa_offset 8
+ .cfi_rel_offset %rbp, 0
+ mov %rsp, %rbp
+ .cfi_def_cfa_register %rbp
+ push %rbx
+ .cfi_rel_offset %rbx, -8
+
+ mov %ecx, %eax
+.Lenter_enclave:
+ /* EENTER <= leaf <= ERESUME */
+ cmp $EENTER, %eax
+ jb .Linvalid_leaf
+ cmp $ERESUME, %eax
+ ja .Linvalid_leaf
+
+ /* Load TCS and AEP */
+ mov 0x10(%rbp), %rbx
+ lea .Lasync_exit_pointer(%rip), %rcx
+
+ /* Single ENCLU serving as both EENTER and AEP (ERESUME) */
+.Lasync_exit_pointer:
+.Lenclu_eenter_eresume:
+ enclu
+
+ /* EEXIT jumps here unless the enclave is doing something fancy. */
+ xor %eax, %eax
+
+ /* Invoke userspace's exit handler if one was provided. */
+.Lhandle_exit:
+ cmp $0, 0x20(%rbp)
+ jne .Linvoke_userspace_handler
+
+.Lout:
+ pop %rbx
+ leave
+ .cfi_def_cfa %rsp, 8
+ ret
+
+ /* The out-of-line code runs with the pre-leave stack frame. */
+ .cfi_def_cfa %rbp, 16
+
+.Linvalid_leaf:
+ mov $(-EINVAL), %eax
+ jmp .Lout
+
+.Lhandle_exception:
+ mov 0x18(%rbp), %rcx
+ test %rcx, %rcx
+ je .Lskip_exception_info
+
+ /* Fill optional exception info. */
+ mov %eax, EX_LEAF(%rcx)
+ mov %di, EX_TRAPNR(%rcx)
+ mov %si, EX_ERROR_CODE(%rcx)
+ mov %rdx, EX_ADDRESS(%rcx)
+.Lskip_exception_info:
+ mov $(-EFAULT), %eax
+ jmp .Lhandle_exit
+
+.Linvoke_userspace_handler:
+ /* Pass the untrusted RSP (at exit) to the callback via %rcx. */
+ mov %rsp, %rcx
+
+ /* Save the untrusted RSP offset in %rbx (non-volatile register). */
+ mov %rsp, %rbx
+ and $0xf, %rbx
+
+ /*
+ * Align stack per x86_64 ABI. Note, %rsp needs to be 16-byte aligned
+ * _after_ pushing the parameters on the stack, hence the bonus push.
+ */
+ and $-0x10, %rsp
+ push %rax
+
+ /* Push @e, the "return" value and @tcs as params to the callback. */
+ push 0x18(%rbp)
+ push %rax
+ push 0x10(%rbp)
+
+ /* Clear RFLAGS.DF per x86_64 ABI */
+ cld
+
+ /* Load the callback pointer to %rax and invoke it via retpoline. */
+ mov 0x20(%rbp), %rax
+ call .Lretpoline
+
+ /* Undo the post-exit %rsp adjustment. */
+ lea 0x20(%rsp, %rbx), %rsp
+
+ /*
+ * If the return from callback is zero or negative, return immediately,
+ * else re-execute ENCLU with the postive return value interpreted as
+ * the requested ENCLU leaf.
+ */
+ cmp $0, %eax
+ jle .Lout
+ jmp .Lenter_enclave
+
+.Lretpoline:
+ call 2f
+1: pause
+ lfence
+ jmp 1b
+2: mov %rax, (%rsp)
+ ret
+ .cfi_endproc
+
+_ASM_VDSO_EXTABLE_HANDLE(.Lenclu_eenter_eresume, .Lhandle_exception)
+
+SYM_FUNC_END(__vdso_sgx_enter_enclave)
diff --git a/arch/x86/include/asm/enclu.h b/arch/x86/include/asm/enclu.h
new file mode 100644
index 000000000000..06157b3e9ede
--- /dev/null
+++ b/arch/x86/include/asm/enclu.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_ENCLU_H
+#define _ASM_X86_ENCLU_H
+
+#define EENTER 0x02
+#define ERESUME 0x03
+
+#endif /* _ASM_X86_ENCLU_H */
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index 57d0d30c79b3..3760e5d5dc0c 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -74,4 +74,102 @@ struct sgx_enclave_set_attribute {
__u64 attribute_fd;
};
+/**
+ * struct sgx_enclave_exception - structure to report exceptions encountered in
+ * __vdso_sgx_enter_enclave()
+ *
+ * @leaf: ENCLU leaf from \%eax at time of exception
+ * @trapnr: exception trap number, a.k.a. fault vector
+ * @error_code: exception error code
+ * @address: exception address, e.g. CR2 on a #PF
+ * @reserved: reserved for future use
+ */
+struct sgx_enclave_exception {
+ __u32 leaf;
+ __u16 trapnr;
+ __u16 error_code;
+ __u64 address;
+ __u64 reserved[2];
+};
+
+/**
+ * typedef sgx_enclave_exit_handler_t - Exit handler function accepted by
+ * __vdso_sgx_enter_enclave()
+ *
+ * @rdi: RDI at the time of enclave exit
+ * @rsi: RSI at the time of enclave exit
+ * @rdx: RDX at the time of enclave exit
+ * @ursp: RSP at the time of enclave exit (untrusted stack)
+ * @r8: R8 at the time of enclave exit
+ * @r9: R9 at the time of enclave exit
+ * @tcs: Thread Control Structure used to enter enclave
+ * @ret: 0 on success (EEXIT), -EFAULT on an exception
+ * @e: Pointer to struct sgx_enclave_exception (as provided by caller)
+ */
+typedef int (*sgx_enclave_exit_handler_t)(long rdi, long rsi, long rdx,
+ long ursp, long r8, long r9,
+ void *tcs, int ret,
+ struct sgx_enclave_exception *e);
+
+/**
+ * __vdso_sgx_enter_enclave() - Enter an SGX enclave
+ * @rdi: Pass-through value for RDI
+ * @rsi: Pass-through value for RSI
+ * @rdx: Pass-through value for RDX
+ * @leaf: ENCLU leaf, must be EENTER or ERESUME
+ * @r8: Pass-through value for R8
+ * @r9: Pass-through value for R9
+ * @tcs: TCS, must be non-NULL
+ * @e: Optional struct sgx_enclave_exception instance
+ * @handler: Optional enclave exit handler
+ *
+ * NOTE: __vdso_sgx_enter_enclave() does not ensure full compliance with the
+ * x86-64 ABI, e.g. doesn't explicitly clear EFLAGS.DF after EEXIT. Except for
+ * non-volatile general purpose registers, preserving/setting state in
+ * accordance with the x86-64 ABI is the responsibility of the enclave and its
+ * runtime, i.e. __vdso_sgx_enter_enclave() cannot be called from C code
+ * without careful consideration by both the enclave and its runtime.
+ *
+ * All general purpose registers except RAX, RBX and RCX are passed as-is to
+ * the enclave. RAX, RBX and RCX are consumed by EENTER and ERESUME and are
+ * loaded with @leaf, asynchronous exit pointer, and @tcs respectively.
+ *
+ * RBP and the stack are used to anchor __vdso_sgx_enter_enclave() to the
+ * pre-enclave state, e.g. to retrieve @e and @handler after an enclave exit.
+ * All other registers are available for use by the enclave and its runtime,
+ * e.g. an enclave can push additional data onto the stack (and modify RSP) to
+ * pass information to the optional exit handler (see below).
+ *
+ * Most exceptions reported on ENCLU, including those that occur within the
+ * enclave, are fixed up and reported synchronously instead of being delivered
+ * via a standard signal. Debug Exceptions (#DB) and Breakpoints (#BP) are
+ * never fixed up and are always delivered via standard signals. On synchrously
+ * reported exceptions, -EFAULT is returned and details about the exception are
+ * recorded in @e, the optional sgx_enclave_exception struct.
+
+ * If an exit handler is provided, the handler will be invoked on synchronous
+ * exits from the enclave and for all synchronously reported exceptions. In
+ * latter case, @e is filled prior to invoking the handler.
+ *
+ * The exit handler's return value is interpreted as follows:
+ * >0: continue, restart __vdso_sgx_enter_enclave() with @ret as @leaf
+ * 0: success, return @ret to the caller
+ * <0: error, return @ret to the caller
+ *
+ * The exit handler may transfer control, e.g. via longjmp() or C++ exception,
+ * without returning to __vdso_sgx_enter_enclave().
+ *
+ * Return:
+ * 0 on success,
+ * -EINVAL if ENCLU leaf is not allowed,
+ * -EFAULT if an exception occurs on ENCLU or within the enclave
+ * -errno for all other negative values returned by the userspace exit handler
+ */
+typedef int (*vdso_sgx_enter_enclave_t)(unsigned long rdi, unsigned long rsi,
+ unsigned long rdx, unsigned int leaf,
+ unsigned long r8, unsigned long r9,
+ void *tcs,
+ struct sgx_enclave_exception *e,
+ sgx_enclave_exit_handler_t handler);
+
#endif /* _UAPI_ASM_X86_SGX_H */
--
2.25.1
Document the Intel SGX kernel architecture. The fine-grained micro
architecture details can be looked up from Intel SDM Volume 3D.
Cc: [email protected]
Co-developed-by: Sean Christopherson <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Acked-by: Randy Dunlap <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/x86/index.rst | 1 +
Documentation/x86/sgx.rst | 206 ++++++++++++++++++++++++++++++++++++
2 files changed, 207 insertions(+)
create mode 100644 Documentation/x86/sgx.rst
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
index a8de2fbc1caa..971f30a7d166 100644
--- a/Documentation/x86/index.rst
+++ b/Documentation/x86/index.rst
@@ -31,3 +31,4 @@ x86-specific Documentation
usb-legacy-support
i386/index
x86_64/index
+ sgx
diff --git a/Documentation/x86/sgx.rst b/Documentation/x86/sgx.rst
new file mode 100644
index 000000000000..9609a3409ad1
--- /dev/null
+++ b/Documentation/x86/sgx.rst
@@ -0,0 +1,206 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+Architecture
+============
+
+*Software Guard eXtensions (SGX)* is a set of instructions that enable ring-3
+applications to set aside private regions of code and data. These regions are
+called enclaves. An enclave can be entered to a fixed set of entry points. Only
+a CPU running inside the enclave can access its code and data.
+
+The support can be determined by
+
+ ``grep sgx /proc/cpuinfo``
+
+Enclave Page Cache
+==================
+
+SGX utilizes an *Enclave Page Cache (EPC)* to store pages that are associated
+with an enclave. It is contained in a BIOS reserved region of physical memory.
+Unlike pages used for regular memory, pages can only be accessed outside the
+enclave for different purposes with the instructions **ENCLS**, **ENCLV** and
+**ENCLU**.
+
+Direct memory accesses to an enclave can be only done by a CPU executing inside
+the enclave. An enclave can be entered with **ENCLU[EENTER]** to a fixed set of
+entry points. However, a CPU executing inside the enclave can do outside memory
+accesses.
+
+Page Types
+----------
+
+**SGX Enclave Control Structure (SECS)**
+ Enclave's address range, attributes and other global data are defined
+ by this structure.
+
+**Regular (REG)**
+ Regular EPC pages contain the code and data of an enclave.
+
+**Thread Control Structure (TCS)**
+ Thread Control Structure pages define the entry points to an enclave and
+ track the execution state of an enclave thread.
+
+**Version Array (VA)**
+ Version Array pages contain 512 slots, each of which can contain a version
+ number for a page evicted from the EPC.
+
+Enclave Page Cache Map
+----------------------
+
+The processor tracks EPC pages via the *Enclave Page Cache Map (EPCM)*. EPCM
+contains an entry for each EPC page, which describes the owning enclave, access
+rights and page type among the other things.
+
+The permissions from EPCM is consulted if and only if walking the kernel page
+tables succeeds. The total permissions are thus a conjunction between page table
+and EPCM permissions.
+
+For all intents and purposes the SGX architecture allows the processor to
+invalidate all EPCM entries at will, i.e. requires that software be prepared to
+handle an EPCM fault at any time. The contents of EPC are encrypted with an
+ephemeral key, which is lost on power transitions.
+
+EPC management
+==============
+
+EPC pages do not have ``struct page`` instances. They are IO memory from kernel
+perspective. The consequence is that they are always mapped as shared memory.
+Kernel defines ``/dev/sgx/enclave`` that can be mapped as ``MAP_SHARED`` to
+define the address range for an enclave.
+
+EPC Over-subscription
+=====================
+
+When the amount of free EPC pages goes below a low watermark the swapping thread
+starts reclaiming pages. The pages that do not have the **A** bit set are
+selected as victim pages.
+
+Launch Control
+==============
+
+SGX provides a launch control mechanism. After all enclave pages have been
+copied, kernel executes **ENCLS[EINIT]**, which initializes the enclave. Only
+after this the CPU can execute inside the enclave.
+
+This leaf function takes an RSA-3072 signature of the enclave measurement and an
+optional cryptographic token. Linux does not take advantage of launch tokens.
+The instruction checks that the signature is signed with the key defined in
+**IA32_SGXLEPUBKEYHASH?** MSRs and the measurement is correct. If so, the
+enclave is allowed to be executed.
+
+MSRs can be configured by the BIOS to be either readable or writable. Linux
+supports only writable configuration in order to give full control to the kernel
+on launch control policy. Readable configuration requires the use of previously
+mentioned launch tokens.
+
+The current kernel implementation supports only writable MSRs. The launch is
+performed by setting the MSRs to the hash of the enclave signer's public key.
+The alternative would be to have *a launch enclave* that would be signed with
+the key set into MSRs, which would then generate launch tokens for other
+enclaves. This would only make sense with read-only MSRs, and thus the option
+has been discarded.
+
+Attestation
+===========
+
+Local Attestation
+-----------------
+
+In local attestation an enclave creates a **REPORT** data structure with
+**ENCLS[EREPORT]**, which describes the origin of an enclave. In particular, it
+contains a AES-CMAC of the enclave contents signed with a report key unique to
+each processor. All enclaves have access to this key.
+
+This mechanism can also be used in addition as a communication channel as the
+**REPORT** data structure includes a 64-byte field for variable information.
+
+Remote Attestation
+------------------
+
+For remote attestation (or provisioning) there are schemes available:
+
+* EPID scheme, which requires the use of Intel managed attestation service.
+* ECDSA scheme, which allows a 3rd party to act as an attestation service.
+
+Intel has released an open source *Quoting Enclave (QE)* and *Provisioning
+Certification Enclave (PCE)* for the ECDSA based scheme. A PCE is used to
+certify the locally used QE's.
+
+Intel also provides a proprietary of the PCE. This is a necessary when one
+needs to be able to prove that an enclave is running on real hardware. To
+achieve this the enclave needs to be rooted to the Intel's PKI, which obviously
+cannot be exposed to 3rd parties.
+
+Both schemes require **ATTRIBUTES.PROVISIONKEY** but only EPID scheme uses the
+on-die provisioning key. This privilege should be under normal conditions given
+only to QE's because uncontrolled use of attestation could be used by malware
+for benefit.
+
+Encryption engines
+==================
+
+In order to conceal the enclave data while it is out of the CPU package,
+memory controller has to be extended with an encryption engine. MC can then
+route incoming requests coming from CPU cores running in enclave mode to the
+encryption engine.
+
+In CPUs prior to Icelake, Memory Encryption Engine (MEE) is used to
+encrypt pages leaving the CPU caches. MEE uses a n-ary Merkle tree with root in
+SRAM to maintain integrity of the encrypted data. This provides integrity and
+anti-replay protection but does not scale to large memory sizes because the time
+required to update the Merkle tree grows logarithmically in relation to the
+memory size.
+
+CPUs starting from Icelake use Total Memory Encryption (TME) in the place of
+MEE. TME throws away the Merkle tree, which means losing integrity and
+anti-replay protection but also enables variable size memory pools for EPC.
+Using this attack for benefit would require an interposer on the system bus.
+
+Backing storage
+===============
+
+Backing storage is shared and not accounted. It is implemented as a private
+shmem file. Providing a backing storage in some form from user space is not
+possible - accounting would go to invalid state as reclaimed pages would get
+accounted to the processes of which behalf the kernel happened to be acting on.
+
+Access control
+==============
+
+`mmap()` permissions are capped by the enclave permissions. A direct
+consequence of this is that all the pages for an address range must be added
+before `mmap()` can be applied. Effectively an enclave page with minimum
+permission in the address range sets the permission cap for the mapping
+operation.
+
+Usage Models
+============
+
+Shared Library
+--------------
+
+Sensitive data and the code that acts on it is partitioned from the application
+into a separate library. The library is then linked as a DSO which can be loaded
+into an enclave. The application can then make individual function calls into
+the enclave through special SGX instructions. A run-time within the enclave is
+configured to marshal function parameters into and out of the enclave and to
+call the correct library function.
+
+Application Container
+---------------------
+
+An application may be loaded into a container enclave which is specially
+configured with a library OS and run-time which permits the application to run.
+The enclave run-time and library OS work together to execute the application
+when a thread enters the enclave.
+
+References
+==========
+
+"Intel® Software Guard Extensions: EPID Provisioning and Attestation Services"
+ https://software.intel.com/sites/default/files/managed/57/0e/ww10-2016-sgx-provisioning-and-attestation-final.pdf
+
+"Supporting Third Party Attestation for Intel® SGX with Intel® Data Center
+Attestation Primitives"
+ https://software.intel.com/sites/default/files/managed/f1/b8/intel-sgx-support-for-third-party-attestation.pdf
--
2.25.1
There is a limited amount of SGX reserved memory available. Therefore,
some of it must be copied to the regular memory, and only subset kept in
the SGX reserved memory. While kernel cannot directly access enclave
memory, SGX provides ENCLS leaf functions to perform reclaiming
functionality.
This commits implements a page reclaimer by using these leaf functions,
which picks the victim pages in LRU fashion from all enclaves running in
an enclave's pages back to the SGX reserved memory.
The thread ksgxswapd reclaims pages on the event when the number of free
EPC pages goes below %SGX_NR_LOW_PAGES up until it reaches
%SGX_NR_HIGH_PAGES.
sgx_alloc_page() can now optionally reclaim pages with @reclaim boolean
parameter. The caller must also supply owner for each page so that the
reclaimer can access the associated enclaves. This is needed for locking,
as most of the ENCLS leafs cannot be executed concurrently for an enclave,
and accessing SECS, which is required to be resident when its child pages
are being reclaimed.
Cc: [email protected]
Co-developed-by: Sean Christopherson <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
arch/x86/kernel/cpu/sgx/driver.c | 1 +
arch/x86/kernel/cpu/sgx/encl.c | 340 +++++++++++++++++++++++++-
arch/x86/kernel/cpu/sgx/encl.h | 41 ++++
arch/x86/kernel/cpu/sgx/ioctl.c | 76 +++++-
arch/x86/kernel/cpu/sgx/main.c | 61 ++++-
arch/x86/kernel/cpu/sgx/reclaim.c | 388 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 35 +++
7 files changed, 934 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index d90114cec1c3..997a7f4117c5 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -32,6 +32,7 @@ static int sgx_open(struct inode *inode, struct file *file)
atomic_set(&encl->flags, 0);
kref_init(&encl->refcount);
+ INIT_LIST_HEAD(&encl->va_pages);
INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
mutex_init(&encl->lock);
INIT_LIST_HEAD(&encl->mm_list);
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 17e44bf8fa56..fe7dbca40bb4 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -9,11 +9,86 @@
#include <linux/sched/mm.h>
#include "arch.h"
#include "encl.h"
+#include "encls.h"
#include "sgx.h"
+static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
+ struct sgx_epc_page *epc_page,
+ struct sgx_epc_page *secs_page)
+{
+ unsigned long va_offset = SGX_ENCL_PAGE_VA_OFFSET(encl_page);
+ struct sgx_encl *encl = encl_page->encl;
+ struct sgx_pageinfo pginfo;
+ struct sgx_backing b;
+ pgoff_t page_index;
+ int ret;
+
+ if (secs_page)
+ page_index = SGX_ENCL_PAGE_INDEX(encl_page);
+ else
+ page_index = PFN_DOWN(encl->size);
+
+ ret = sgx_encl_get_backing(encl, page_index, &b);
+ if (ret)
+ return ret;
+
+ pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
+ pginfo.contents = (unsigned long)kmap_atomic(b.contents);
+ pginfo.metadata = (unsigned long)kmap_atomic(b.pcmd) +
+ b.pcmd_offset;
+
+ if (secs_page)
+ pginfo.secs = (u64)sgx_epc_addr(secs_page);
+ else
+ pginfo.secs = 0;
+
+ ret = __eldu(&pginfo, sgx_epc_addr(epc_page),
+ sgx_epc_addr(encl_page->va_page->epc_page) + va_offset);
+ if (ret) {
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "ELDU");
+
+ ret = -EFAULT;
+ }
+
+ kunmap_atomic((void *)(unsigned long)(pginfo.metadata - b.pcmd_offset));
+ kunmap_atomic((void *)(unsigned long)pginfo.contents);
+
+ sgx_encl_put_backing(&b, false);
+
+ return ret;
+}
+
+static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page,
+ struct sgx_epc_page *secs_page)
+{
+ unsigned long va_offset = SGX_ENCL_PAGE_VA_OFFSET(encl_page);
+ struct sgx_encl *encl = encl_page->encl;
+ struct sgx_epc_page *epc_page;
+ int ret;
+
+ epc_page = sgx_alloc_page(encl_page, false);
+ if (IS_ERR(epc_page))
+ return epc_page;
+
+ ret = __sgx_encl_eldu(encl_page, epc_page, secs_page);
+ if (ret) {
+ sgx_free_page(epc_page);
+ return ERR_PTR(ret);
+ }
+
+ sgx_free_va_slot(encl_page->va_page, va_offset);
+ list_move(&encl_page->va_page->list, &encl->va_pages);
+ encl_page->desc &= ~SGX_ENCL_PAGE_VA_OFFSET_MASK;
+ encl_page->epc_page = epc_page;
+
+ return epc_page;
+}
+
static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
unsigned long addr)
{
+ struct sgx_epc_page *epc_page;
struct sgx_encl_page *entry;
unsigned int flags;
@@ -33,10 +108,27 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
return ERR_PTR(-EFAULT);
/* Page is already resident in the EPC. */
- if (entry->epc_page)
+ if (entry->epc_page) {
+ if (entry->desc & SGX_ENCL_PAGE_RECLAIMED)
+ return ERR_PTR(-EBUSY);
+
return entry;
+ }
+
+ if (!(encl->secs.epc_page)) {
+ epc_page = sgx_encl_eldu(&encl->secs, NULL);
+ if (IS_ERR(epc_page))
+ return ERR_CAST(epc_page);
+ }
+
+ epc_page = sgx_encl_eldu(entry, encl->secs.epc_page);
+ if (IS_ERR(epc_page))
+ return ERR_CAST(epc_page);
- return ERR_PTR(-EFAULT);
+ encl->secs_child_cnt++;
+ sgx_mark_page_reclaimable(entry->epc_page);
+
+ return entry;
}
static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
@@ -134,6 +226,9 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
spin_lock(&encl->mm_lock);
list_add_rcu(&encl_mm->list, &encl->mm_list);
+ /* Pairs with smp_rmb() in sgx_reclaimer_block(). */
+ smp_wmb();
+ encl->mm_list_version++;
spin_unlock(&encl->mm_lock);
return 0;
@@ -181,6 +276,8 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf)
goto out;
}
+ sgx_encl_test_and_clear_young(vma->vm_mm, entry);
+
out:
mutex_unlock(&encl->lock);
return ret;
@@ -280,6 +377,7 @@ int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
*/
void sgx_encl_destroy(struct sgx_encl *encl)
{
+ struct sgx_va_page *va_page;
struct sgx_encl_page *entry;
struct radix_tree_iter iter;
void **slot;
@@ -290,6 +388,13 @@ void sgx_encl_destroy(struct sgx_encl *encl)
entry = *slot;
if (entry->epc_page) {
+ /*
+ * The page and its radix tree entry cannot be freed
+ * if the page is being held by the reclaimer.
+ */
+ if (sgx_unmark_page_reclaimable(entry->epc_page))
+ continue;
+
sgx_free_page(entry->epc_page);
encl->secs_child_cnt--;
entry->epc_page = NULL;
@@ -304,6 +409,19 @@ void sgx_encl_destroy(struct sgx_encl *encl)
sgx_free_page(encl->secs.epc_page);
encl->secs.epc_page = NULL;
}
+
+ /*
+ * The reclaimer is responsible for checking SGX_ENCL_DEAD before doing
+ * EWB, thus it's safe to free VA pages even if the reclaimer holds a
+ * reference to the enclave.
+ */
+ while (!list_empty(&encl->va_pages)) {
+ va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
+ list);
+ list_del(&va_page->list);
+ sgx_free_page(va_page->epc_page);
+ kfree(va_page);
+ }
}
/**
@@ -330,3 +448,221 @@ void sgx_encl_release(struct kref *ref)
kfree(encl);
}
+
+static struct page *sgx_encl_get_backing_page(struct sgx_encl *encl,
+ pgoff_t index)
+{
+ struct inode *inode = encl->backing->f_path.dentry->d_inode;
+ struct address_space *mapping = inode->i_mapping;
+ gfp_t gfpmask = mapping_gfp_mask(mapping);
+
+ return shmem_read_mapping_page_gfp(mapping, index, gfpmask);
+}
+
+/**
+ * sgx_encl_get_backing() - Pin the backing storage
+ * @encl: an enclave
+ * @page_index: enclave page index
+ * @backing: data for accessing backing storage for the page
+ *
+ * Pin the backing storage pages for storing the encrypted contents and Paging
+ * Crypto MetaData (PCMD) of an enclave page.
+ *
+ * Return:
+ * 0 on success,
+ * -errno otherwise.
+ */
+int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
+ struct sgx_backing *backing)
+{
+ pgoff_t pcmd_index = PFN_DOWN(encl->size) + 1 + (page_index >> 5);
+ struct page *contents;
+ struct page *pcmd;
+
+ contents = sgx_encl_get_backing_page(encl, page_index);
+ if (IS_ERR(contents))
+ return PTR_ERR(contents);
+
+ pcmd = sgx_encl_get_backing_page(encl, pcmd_index);
+ if (IS_ERR(pcmd)) {
+ put_page(contents);
+ return PTR_ERR(pcmd);
+ }
+
+ backing->page_index = page_index;
+ backing->contents = contents;
+ backing->pcmd = pcmd;
+ backing->pcmd_offset =
+ (page_index & (PAGE_SIZE / sizeof(struct sgx_pcmd) - 1)) *
+ sizeof(struct sgx_pcmd);
+
+ return 0;
+}
+
+/**
+ * sgx_encl_put_backing() - Unpin the backing storage
+ * @backing: data for accessing backing storage for the page
+ * @do_write: mark pages dirty
+ */
+void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write)
+{
+ if (do_write) {
+ set_page_dirty(backing->pcmd);
+ set_page_dirty(backing->contents);
+ }
+
+ put_page(backing->pcmd);
+ put_page(backing->contents);
+}
+
+static int sgx_encl_test_and_clear_young_cb(pte_t *ptep, unsigned long addr,
+ void *data)
+{
+ pte_t pte;
+ int ret;
+
+ ret = pte_young(*ptep);
+ if (ret) {
+ pte = pte_mkold(*ptep);
+ set_pte_at((struct mm_struct *)data, addr, ptep, pte);
+ }
+
+ return ret;
+}
+
+/**
+ * sgx_encl_test_and_clear_young() - Test and reset the accessed bit
+ * @mm: mm_struct that is checked
+ * @page: enclave page to be tested for recent access
+ *
+ * Checks the Access (A) bit from the PTE corresponding to the enclave page and
+ * clears it.
+ *
+ * Return: 1 if the page has been recently accessed and 0 if not.
+ */
+int sgx_encl_test_and_clear_young(struct mm_struct *mm,
+ struct sgx_encl_page *page)
+{
+ unsigned long addr = SGX_ENCL_PAGE_ADDR(page);
+ struct sgx_encl *encl = page->encl;
+ struct vm_area_struct *vma;
+ int ret;
+
+ ret = sgx_encl_find(mm, addr, &vma);
+ if (ret)
+ return 0;
+
+ if (encl != vma->vm_private_data)
+ return 0;
+
+ ret = apply_to_page_range(vma->vm_mm, addr, PAGE_SIZE,
+ sgx_encl_test_and_clear_young_cb, vma->vm_mm);
+ if (ret < 0)
+ return 0;
+
+ return ret;
+}
+
+/**
+ * sgx_encl_reserve_page() - Reserve an enclave page
+ * @encl: an enclave
+ * @addr: a page address
+ *
+ * Load an enclave page and lock the enclave so that the page can be used by
+ * EDBG* and EMOD*.
+ *
+ * Return:
+ * an enclave page on success
+ * -EFAULT if the load fails
+ */
+struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl,
+ unsigned long addr)
+{
+ struct sgx_encl_page *entry;
+
+ for ( ; ; ) {
+ mutex_lock(&encl->lock);
+
+ entry = sgx_encl_load_page(encl, addr);
+ if (PTR_ERR(entry) != -EBUSY)
+ break;
+
+ mutex_unlock(&encl->lock);
+ }
+
+ if (IS_ERR(entry))
+ mutex_unlock(&encl->lock);
+
+ return entry;
+}
+
+/**
+ * sgx_alloc_page - allocate a VA page
+ *
+ * Allocates an &sgx_epc_page instance and converts it to a VA page.
+ *
+ * Return:
+ * a &struct sgx_va_page instance,
+ * -errno otherwise
+ */
+struct sgx_epc_page *sgx_alloc_va_page(void)
+{
+ struct sgx_epc_page *epc_page;
+ int ret;
+
+ epc_page = sgx_alloc_page(NULL, true);
+ if (IS_ERR(epc_page))
+ return ERR_CAST(epc_page);
+
+ ret = __epa(sgx_epc_addr(epc_page));
+ if (ret) {
+ WARN_ONCE(1, "EPA returned %d (0x%x)", ret, ret);
+ sgx_free_page(epc_page);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return epc_page;
+}
+
+/**
+ * sgx_alloc_va_slot - allocate a VA slot
+ * @va_page: a &struct sgx_va_page instance
+ *
+ * Allocates a slot from a &struct sgx_va_page instance.
+ *
+ * Return: offset of the slot inside the VA page
+ */
+unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page)
+{
+ int slot = find_first_zero_bit(va_page->slots, SGX_VA_SLOT_COUNT);
+
+ if (slot < SGX_VA_SLOT_COUNT)
+ set_bit(slot, va_page->slots);
+
+ return slot << 3;
+}
+
+/**
+ * sgx_free_va_slot - free a VA slot
+ * @va_page: a &struct sgx_va_page instance
+ * @offset: offset of the slot inside the VA page
+ *
+ * Frees a slot from a &struct sgx_va_page instance.
+ */
+void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset)
+{
+ clear_bit(offset >> 3, va_page->slots);
+}
+
+/**
+ * sgx_va_page_full - is the VA page full?
+ * @va_page: a &struct sgx_va_page instance
+ *
+ * Return: true if all slots have been taken
+ */
+bool sgx_va_page_full(struct sgx_va_page *va_page)
+{
+ int slot = find_first_zero_bit(va_page->slots, SGX_VA_SLOT_COUNT);
+
+ return slot == SGX_VA_SLOT_COUNT;
+}
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 1d1bc5d590ee..f0f72e591244 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -19,6 +19,10 @@
/**
* enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
+ * %SGX_ENCL_PAGE_RECLAIMED: The page is in the process of being
+ * reclaimed.
+ * %SGX_ENCL_PAGE_VA_OFFSET_MASK: Holds the offset in the Version Array
+ * (VA) page for a swapped page.
* %SGX_ENCL_PAGE_ADDR_MASK: Holds the virtual address of the page.
*
* The page address for SECS is zero and is used by the subsystem to recognize
@@ -26,16 +30,23 @@
*/
enum sgx_encl_page_desc {
/* Bits 11:3 are available when the page is not swapped. */
+ SGX_ENCL_PAGE_RECLAIMED = BIT(3),
+ SGX_ENCL_PAGE_VA_OFFSET_MASK = GENMASK_ULL(11, 3),
SGX_ENCL_PAGE_ADDR_MASK = PAGE_MASK,
};
#define SGX_ENCL_PAGE_ADDR(page) \
((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
+#define SGX_ENCL_PAGE_VA_OFFSET(page) \
+ ((page)->desc & SGX_ENCL_PAGE_VA_OFFSET_MASK)
+#define SGX_ENCL_PAGE_INDEX(page) \
+ PFN_DOWN((page)->desc - (page)->encl->base)
struct sgx_encl_page {
unsigned long desc;
unsigned long vm_max_prot_bits;
struct sgx_epc_page *epc_page;
+ struct sgx_va_page *va_page;
struct sgx_encl *encl;
};
@@ -63,17 +74,27 @@ struct sgx_encl {
struct mutex lock;
struct list_head mm_list;
spinlock_t mm_lock;
+ unsigned long mm_list_version;
struct file *backing;
struct kref refcount;
struct srcu_struct srcu;
unsigned long base;
unsigned long size;
unsigned long ssaframesize;
+ struct list_head va_pages;
struct radix_tree_root page_tree;
struct sgx_encl_page secs;
cpumask_t cpumask;
};
+#define SGX_VA_SLOT_COUNT 512
+
+struct sgx_va_page {
+ struct sgx_epc_page *epc_page;
+ DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
+ struct list_head list;
+};
+
extern const struct vm_operations_struct sgx_vm_ops;
int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
@@ -84,4 +105,24 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
unsigned long end, unsigned long vm_prot_bits);
+struct sgx_backing {
+ pgoff_t page_index;
+ struct page *contents;
+ struct page *pcmd;
+ unsigned long pcmd_offset;
+};
+
+int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
+ struct sgx_backing *backing);
+void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write);
+int sgx_encl_test_and_clear_young(struct mm_struct *mm,
+ struct sgx_encl_page *page);
+struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl,
+ unsigned long addr);
+
+struct sgx_epc_page *sgx_alloc_va_page(void);
+unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
+void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset);
+bool sgx_va_page_full(struct sgx_va_page *va_page);
+
#endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index aea3e82a7ab9..3af0596530a8 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -19,6 +19,43 @@
/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
+static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
+{
+ struct sgx_va_page *va_page = NULL;
+ void *err;
+
+ BUILD_BUG_ON(SGX_VA_SLOT_COUNT !=
+ (SGX_ENCL_PAGE_VA_OFFSET_MASK >> 3) + 1);
+
+ if (!(encl->page_cnt % SGX_VA_SLOT_COUNT)) {
+ va_page = kzalloc(sizeof(*va_page), GFP_KERNEL);
+ if (!va_page)
+ return ERR_PTR(-ENOMEM);
+
+ va_page->epc_page = sgx_alloc_va_page();
+ if (IS_ERR(va_page->epc_page)) {
+ err = ERR_CAST(va_page->epc_page);
+ kfree(va_page);
+ return err;
+ }
+
+ WARN_ON_ONCE(encl->page_cnt % SGX_VA_SLOT_COUNT);
+ }
+ encl->page_cnt++;
+ return va_page;
+}
+
+static void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page)
+{
+ encl->page_cnt--;
+
+ if (va_page) {
+ sgx_free_page(va_page->epc_page);
+ list_del(&va_page->list);
+ kfree(va_page);
+ }
+}
+
static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
{
u32 size_max = PAGE_SIZE;
@@ -114,6 +151,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
{
unsigned long encl_size = secs->size + PAGE_SIZE;
struct sgx_epc_page *secs_epc;
+ struct sgx_va_page *va_page;
unsigned long ssaframesize;
struct sgx_pageinfo pginfo;
struct sgx_secinfo secinfo;
@@ -123,20 +161,29 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
return -EINVAL;
+ va_page = sgx_encl_grow(encl);
+ if (IS_ERR(va_page))
+ return PTR_ERR(va_page);
+ else if (va_page)
+ list_add(&va_page->list, &encl->va_pages);
+
ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
if (sgx_validate_secs(secs, ssaframesize)) {
pr_debug("invalid SECS\n");
- return -EINVAL;
+ ret = -EINVAL;
+ goto err_out_shrink;
}
backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
VM_NORESERVE);
- if (IS_ERR(backing))
- return PTR_ERR(backing);
+ if (IS_ERR(backing)) {
+ ret = PTR_ERR(backing);
+ goto err_out_shrink;
+ }
encl->backing = backing;
- secs_epc = sgx_try_alloc_page();
+ secs_epc = sgx_alloc_page(&encl->secs, true);
if (IS_ERR(secs_epc)) {
ret = PTR_ERR(secs_epc);
goto err_out_backing;
@@ -183,6 +230,9 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
fput(encl->backing);
encl->backing = NULL;
+err_out_shrink:
+ sgx_encl_shrink(encl, va_page);
+
return ret;
}
@@ -319,13 +369,14 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
{
struct sgx_encl_page *encl_page;
struct sgx_epc_page *epc_page;
+ struct sgx_va_page *va_page;
int ret;
encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
if (IS_ERR(encl_page))
return PTR_ERR(encl_page);
- epc_page = sgx_try_alloc_page();
+ epc_page = sgx_alloc_page(encl_page, true);
if (IS_ERR(epc_page)) {
kfree(encl_page);
return PTR_ERR(epc_page);
@@ -337,9 +388,22 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
goto err_out_free;
}
+ va_page = sgx_encl_grow(encl);
+ if (IS_ERR(va_page)) {
+ ret = PTR_ERR(va_page);
+ goto err_out_free;
+ }
+
down_read(¤t->mm->mmap_sem);
mutex_lock(&encl->lock);
+ /*
+ * Adding to encl->va_pages must be done under encl->lock. Ditto for
+ * deleting (via sgx_encl_shrink()) in the error path.
+ */
+ if (va_page)
+ list_add(&va_page->list, &encl->va_pages);
+
/*
* Insert prior to EADD in case of OOM. EADD modifies MRENCLAVE, i.e.
* can't be gracefully unwound, while failure on EADD/EXTEND is limited
@@ -370,6 +434,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
goto err_out;
}
+ sgx_mark_page_reclaimable(encl_page->epc_page);
mutex_unlock(&encl->lock);
up_read(¤t->mm->mmap_sem);
return ret;
@@ -379,6 +444,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
PFN_DOWN(encl_page->desc));
err_out_unlock:
+ sgx_encl_shrink(encl, va_page);
mutex_unlock(&encl->lock);
up_read(¤t->mm->mmap_sem);
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 842f9abba1c0..5ce77e554676 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -23,6 +23,8 @@ static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section
page = list_first_entry(§ion->page_list, struct sgx_epc_page, list);
list_del_init(&page->list);
+ section->free_cnt--;
+
return page;
}
@@ -54,23 +56,79 @@ struct sgx_epc_page *sgx_try_alloc_page(void)
return ERR_PTR(-ENOMEM);
}
+/**
+ * sgx_alloc_page() - Allocate an EPC page
+ * @owner: the owner of the EPC page
+ * @reclaim: reclaim pages if necessary
+ *
+ * Try to grab a page from the free EPC page list. If there is a free page
+ * available, it is returned to the caller. The @reclaim parameter hints
+ * the EPC memory manager to swap pages when required.
+ *
+ * Return:
+ * a pointer to a &struct sgx_epc_page instance,
+ * -errno on error
+ */
+struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim)
+{
+ struct sgx_epc_page *entry;
+
+ for ( ; ; ) {
+ entry = sgx_try_alloc_page();
+ if (!IS_ERR(entry)) {
+ entry->owner = owner;
+ break;
+ }
+
+ if (list_empty(&sgx_active_page_list))
+ return ERR_PTR(-ENOMEM);
+
+ if (!reclaim) {
+ entry = ERR_PTR(-EBUSY);
+ break;
+ }
+
+ if (signal_pending(current)) {
+ entry = ERR_PTR(-ERESTARTSYS);
+ break;
+ }
+
+ sgx_reclaim_pages();
+ schedule();
+ }
+
+ if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
+ wake_up(&ksgxswapd_waitq);
+
+ return entry;
+}
+
/**
* sgx_free_page() - Free an EPC page
* @page: pointer a previously allocated EPC page
*
- * EREMOVE an EPC page and insert it back to the list of free pages.
+ * EREMOVE an EPC page and insert it back to the list of free pages. The page
+ * must not be reclaimable.
*/
void sgx_free_page(struct sgx_epc_page *page)
{
struct sgx_epc_section *section = sgx_epc_section(page);
int ret;
+ /*
+ * Don't take sgx_active_page_list_lock when asserting the page isn't
+ * reclaimable, missing a WARN in the very rare case is preferable to
+ * unnecessarily taking a global lock in the common case.
+ */
+ WARN_ON_ONCE(page->desc & SGX_EPC_PAGE_RECLAIMABLE);
+
ret = __eremove(sgx_epc_addr(page));
if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
return;
spin_lock(§ion->lock);
list_add_tail(&page->list, §ion->page_list);
+ section->free_cnt++;
spin_unlock(§ion->lock);
}
@@ -121,6 +179,7 @@ static bool __init sgx_alloc_epc_section(u64 addr, u64 size,
list_add_tail(&page->list, §ion->unsanitized_page_list);
}
+ section->free_cnt = nr_pages;
return true;
err_out:
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index 9e6d3e147aa2..fb521f314fb7 100644
--- a/arch/x86/kernel/cpu/sgx/reclaim.c
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -9,10 +9,14 @@
#include <linux/slab.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
+#include "encl.h"
#include "encls.h"
#include "driver.h"
struct task_struct *ksgxswapd_tsk;
+DECLARE_WAIT_QUEUE_HEAD(ksgxswapd_waitq);
+LIST_HEAD(sgx_active_page_list);
+DEFINE_SPINLOCK(sgx_active_page_list_lock);
static void sgx_sanitize_section(struct sgx_epc_section *section)
{
@@ -66,6 +70,20 @@ static int ksgxswapd(void *p)
WARN(1, "EPC section %d has unsanitized pages.\n", i);
}
+ while (!kthread_should_stop()) {
+ if (try_to_freeze())
+ continue;
+
+ wait_event_freezable(ksgxswapd_waitq,
+ kthread_should_stop() ||
+ sgx_should_reclaim(SGX_NR_HIGH_PAGES));
+
+ if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
+ sgx_reclaim_pages();
+
+ cond_resched();
+ }
+
return 0;
}
@@ -81,3 +99,373 @@ bool __init sgx_page_reclaimer_init(void)
return true;
}
+
+/**
+ * sgx_mark_page_reclaimable() - Mark a page as reclaimable
+ * @page: EPC page
+ *
+ * Mark a page as reclaimable and add it to the active page list. Pages
+ * are automatically removed from the active list when freed.
+ */
+void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
+{
+ spin_lock(&sgx_active_page_list_lock);
+ page->desc |= SGX_EPC_PAGE_RECLAIMABLE;
+ list_add_tail(&page->list, &sgx_active_page_list);
+ spin_unlock(&sgx_active_page_list_lock);
+}
+
+/**
+ * sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
+ * @page: EPC page
+ *
+ * Clear the reclaimable flag and remove the page from the active page list.
+ *
+ * Return:
+ * 0 on success,
+ * -EBUSY if the page is in the process of being reclaimed
+ */
+int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
+{
+ /*
+ * Remove the page from the active list if necessary. If the page
+ * is actively being reclaimed, i.e. RECLAIMABLE is set but the
+ * page isn't on the active list, return -EBUSY as we can't free
+ * the page at this time since it is "owned" by the reclaimer.
+ */
+ spin_lock(&sgx_active_page_list_lock);
+ if (page->desc & SGX_EPC_PAGE_RECLAIMABLE) {
+ if (list_empty(&page->list)) {
+ spin_unlock(&sgx_active_page_list_lock);
+ return -EBUSY;
+ }
+ list_del(&page->list);
+ page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+ }
+ spin_unlock(&sgx_active_page_list_lock);
+
+ return 0;
+}
+
+static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page)
+{
+ struct sgx_encl_page *page = epc_page->owner;
+ struct sgx_encl *encl = page->encl;
+ struct sgx_encl_mm *encl_mm;
+ bool ret = true;
+ int idx;
+
+ idx = srcu_read_lock(&encl->srcu);
+
+ list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+ if (!mmget_not_zero(encl_mm->mm))
+ continue;
+
+ down_read(&encl_mm->mm->mmap_sem);
+ ret = !sgx_encl_test_and_clear_young(encl_mm->mm, page);
+ up_read(&encl_mm->mm->mmap_sem);
+
+ mmput_async(encl_mm->mm);
+
+ if (!ret || (atomic_read(&encl->flags) & SGX_ENCL_DEAD))
+ break;
+ }
+
+ srcu_read_unlock(&encl->srcu, idx);
+
+ if (!ret && !(atomic_read(&encl->flags) & SGX_ENCL_DEAD))
+ return false;
+
+ return true;
+}
+
+static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
+{
+ struct sgx_encl_page *page = epc_page->owner;
+ unsigned long addr = SGX_ENCL_PAGE_ADDR(page);
+ struct sgx_encl *encl = page->encl;
+ unsigned long mm_list_version;
+ struct sgx_encl_mm *encl_mm;
+ struct vm_area_struct *vma;
+ int idx, ret;
+
+ do {
+ mm_list_version = encl->mm_list_version;
+
+ /* Pairs with smp_rmb() in sgx_encl_mm_add(). */
+ smp_rmb();
+
+ idx = srcu_read_lock(&encl->srcu);
+
+ list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+ if (!mmget_not_zero(encl_mm->mm))
+ continue;
+
+ down_read(&encl_mm->mm->mmap_sem);
+
+ ret = sgx_encl_find(encl_mm->mm, addr, &vma);
+ if (!ret && encl == vma->vm_private_data)
+ zap_vma_ptes(vma, addr, PAGE_SIZE);
+
+ up_read(&encl_mm->mm->mmap_sem);
+
+ mmput_async(encl_mm->mm);
+ }
+
+ srcu_read_unlock(&encl->srcu, idx);
+ } while (unlikely(encl->mm_list_version != mm_list_version));
+
+ mutex_lock(&encl->lock);
+
+ if (!(atomic_read(&encl->flags) & SGX_ENCL_DEAD)) {
+ ret = __eblock(sgx_epc_addr(epc_page));
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "EBLOCK");
+ }
+
+ mutex_unlock(&encl->lock);
+}
+
+static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
+ struct sgx_backing *backing)
+{
+ struct sgx_pageinfo pginfo;
+ int ret;
+
+ pginfo.addr = 0;
+ pginfo.secs = 0;
+
+ pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
+ pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
+ backing->pcmd_offset;
+
+ ret = __ewb(&pginfo, sgx_epc_addr(epc_page), va_slot);
+
+ kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
+ backing->pcmd_offset));
+ kunmap_atomic((void *)(unsigned long)pginfo.contents);
+
+ return ret;
+}
+
+static void sgx_ipi_cb(void *info)
+{
+}
+
+static const cpumask_t *sgx_encl_ewb_cpumask(struct sgx_encl *encl)
+{
+ cpumask_t *cpumask = &encl->cpumask;
+ struct sgx_encl_mm *encl_mm;
+ int idx;
+
+ /*
+ * Can race with sgx_encl_mm_add(), but ETRACK has already been
+ * executed, which means that the CPUs running in the new mm will enter
+ * into the enclave with a fresh epoch.
+ */
+ cpumask_clear(cpumask);
+
+ idx = srcu_read_lock(&encl->srcu);
+
+ list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+ if (!mmget_not_zero(encl_mm->mm))
+ continue;
+
+ cpumask_or(cpumask, cpumask, mm_cpumask(encl_mm->mm));
+
+ mmput_async(encl_mm->mm);
+ }
+
+ srcu_read_unlock(&encl->srcu, idx);
+
+ return cpumask;
+}
+
+static void sgx_encl_ewb(struct sgx_epc_page *epc_page,
+ struct sgx_backing *backing)
+{
+ struct sgx_encl_page *encl_page = epc_page->owner;
+ struct sgx_encl *encl = encl_page->encl;
+ struct sgx_va_page *va_page;
+ unsigned int va_offset;
+ void *va_slot;
+ int ret;
+
+ encl_page->desc &= ~SGX_ENCL_PAGE_RECLAIMED;
+
+ va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
+ list);
+ va_offset = sgx_alloc_va_slot(va_page);
+ va_slot = sgx_epc_addr(va_page->epc_page) + va_offset;
+ if (sgx_va_page_full(va_page))
+ list_move_tail(&va_page->list, &encl->va_pages);
+
+ ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+ if (ret == SGX_NOT_TRACKED) {
+ ret = __etrack(sgx_epc_addr(encl->secs.epc_page));
+ if (ret) {
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "ETRACK");
+ }
+
+ ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+ if (ret == SGX_NOT_TRACKED) {
+ /*
+ * Slow path, send IPIs to kick cpus out of the
+ * enclave. Note, it's imperative that the cpu
+ * mask is generated *after* ETRACK, else we'll
+ * miss cpus that entered the enclave between
+ * generating the mask and incrementing epoch.
+ */
+ on_each_cpu_mask(sgx_encl_ewb_cpumask(encl),
+ sgx_ipi_cb, NULL, 1);
+ ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+ }
+ }
+
+ if (ret) {
+ if (encls_failed(ret))
+ ENCLS_WARN(ret, "EWB");
+
+ sgx_free_va_slot(va_page, va_offset);
+ } else {
+ encl_page->desc |= va_offset;
+ encl_page->va_page = va_page;
+ }
+}
+
+static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
+ struct sgx_backing *backing)
+{
+ struct sgx_encl_page *encl_page = epc_page->owner;
+ struct sgx_encl *encl = encl_page->encl;
+ struct sgx_backing secs_backing;
+ int ret;
+
+ mutex_lock(&encl->lock);
+
+ if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
+ ret = __eremove(sgx_epc_addr(epc_page));
+ ENCLS_WARN(ret, "EREMOVE returned %d\n");
+ } else {
+ sgx_encl_ewb(epc_page, backing);
+ }
+
+ encl_page->epc_page = NULL;
+ encl->secs_child_cnt--;
+
+ if (!encl->secs_child_cnt) {
+ if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
+ sgx_free_page(encl->secs.epc_page);
+ encl->secs.epc_page = NULL;
+ } else if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
+ ret = sgx_encl_get_backing(encl, PFN_DOWN(encl->size),
+ &secs_backing);
+ if (ret)
+ goto out;
+
+ sgx_encl_ewb(encl->secs.epc_page, &secs_backing);
+
+ sgx_free_page(encl->secs.epc_page);
+ encl->secs.epc_page = NULL;
+
+ sgx_encl_put_backing(&secs_backing, true);
+ }
+ }
+
+out:
+ mutex_unlock(&encl->lock);
+}
+
+/**
+ * sgx_reclaim_pages() - Reclaim EPC pages from the consumers
+ *
+ * Take a fixed number of pages from the head of the active page pool and
+ * reclaim them to the enclave's private shmem files. Skip the pages, which
+ * have been accessed since the last scan. Move those pages to the tail of
+ * active page pool so that the pages get scanned in LRU like fashion.
+ */
+void sgx_reclaim_pages(void)
+{
+ struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
+ struct sgx_backing backing[SGX_NR_TO_SCAN];
+ struct sgx_epc_section *section;
+ struct sgx_encl_page *encl_page;
+ struct sgx_epc_page *epc_page;
+ int cnt = 0;
+ int ret;
+ int i;
+
+ spin_lock(&sgx_active_page_list_lock);
+ for (i = 0; i < SGX_NR_TO_SCAN; i++) {
+ if (list_empty(&sgx_active_page_list))
+ break;
+
+ epc_page = list_first_entry(&sgx_active_page_list,
+ struct sgx_epc_page, list);
+ list_del_init(&epc_page->list);
+ encl_page = epc_page->owner;
+
+ if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
+ chunk[cnt++] = epc_page;
+ else
+ /* The owner is freeing the page. No need to add the
+ * page back to the list of reclaimable pages.
+ */
+ epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+ }
+ spin_unlock(&sgx_active_page_list_lock);
+
+ for (i = 0; i < cnt; i++) {
+ epc_page = chunk[i];
+ encl_page = epc_page->owner;
+
+ if (!sgx_reclaimer_age(epc_page))
+ goto skip;
+
+ ret = sgx_encl_get_backing(encl_page->encl,
+ SGX_ENCL_PAGE_INDEX(encl_page),
+ &backing[i]);
+ if (ret)
+ goto skip;
+
+ mutex_lock(&encl_page->encl->lock);
+ encl_page->desc |= SGX_ENCL_PAGE_RECLAIMED;
+ mutex_unlock(&encl_page->encl->lock);
+ continue;
+
+skip:
+ kref_put(&encl_page->encl->refcount, sgx_encl_release);
+
+ spin_lock(&sgx_active_page_list_lock);
+ list_add_tail(&epc_page->list, &sgx_active_page_list);
+ spin_unlock(&sgx_active_page_list_lock);
+
+ chunk[i] = NULL;
+ }
+
+ for (i = 0; i < cnt; i++) {
+ epc_page = chunk[i];
+ if (epc_page)
+ sgx_reclaimer_block(epc_page);
+ }
+
+ for (i = 0; i < cnt; i++) {
+ epc_page = chunk[i];
+ if (!epc_page)
+ continue;
+
+ encl_page = epc_page->owner;
+ sgx_reclaimer_write(epc_page, &backing[i]);
+ sgx_encl_put_backing(&backing[i], true);
+
+ kref_put(&encl_page->encl->refcount, sgx_encl_release);
+ epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+
+ section = sgx_epc_section(epc_page);
+ spin_lock(§ion->lock);
+ list_add_tail(&epc_page->list, §ion->page_list);
+ section->free_cnt++;
+ spin_unlock(§ion->lock);
+ }
+}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index aa85f85412d8..0c481e6f2c95 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -15,6 +15,7 @@
struct sgx_epc_page {
unsigned long desc;
+ struct sgx_encl_page *owner;
struct list_head list;
};
@@ -29,6 +30,7 @@ struct sgx_epc_page {
struct sgx_epc_section {
unsigned long pa;
void *va;
+ unsigned long free_cnt;
struct list_head page_list;
struct list_head unsanitized_page_list;
spinlock_t lock;
@@ -40,9 +42,14 @@ struct sgx_epc_section {
* physical memory. The existing and near-future
* hardware defines at most eight sections, hence
* three bits to hold a section.
+ * %SGX_EPC_PAGE_RECLAIMABLE: The page has been been marked as reclaimable.
+ * Pages need to be colored this way because a page
+ * can be out of the active page list in the
+ * process of being swapped out.
*/
enum sgx_epc_page_desc {
SGX_EPC_SECTION_MASK = GENMASK_ULL(3, 0),
+ SGX_EPC_PAGE_RECLAIMABLE = BIT(4),
/* bits 12-63 are reserved for the physical page address of the page */
};
@@ -62,12 +69,40 @@ static inline void *sgx_epc_addr(struct sgx_epc_page *page)
return section->va + (page->desc & PAGE_MASK) - section->pa;
}
+#define SGX_NR_TO_SCAN 16
+#define SGX_NR_LOW_PAGES 32
+#define SGX_NR_HIGH_PAGES 64
+
extern int sgx_nr_epc_sections;
extern struct task_struct *ksgxswapd_tsk;
+extern struct wait_queue_head(ksgxswapd_waitq);
+extern struct list_head sgx_active_page_list;
+extern spinlock_t sgx_active_page_list_lock;
+
+static inline unsigned long sgx_nr_free_pages(void)
+{
+ unsigned long cnt = 0;
+ int i;
+
+ for (i = 0; i < sgx_nr_epc_sections; i++)
+ cnt += sgx_epc_sections[i].free_cnt;
+
+ return cnt;
+}
+
+static inline bool sgx_should_reclaim(unsigned long watermark)
+{
+ return sgx_nr_free_pages() < watermark &&
+ !list_empty(&sgx_active_page_list);
+}
bool __init sgx_page_reclaimer_init(void);
+void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
+int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
+void sgx_reclaim_pages(void);
struct sgx_epc_page *sgx_try_alloc_page(void);
+struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim);
void sgx_free_page(struct sgx_epc_page *page);
#endif /* _X86_SGX_H */
--
2.25.1
On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
> environment of its own, it really isn't a great fit with more "standard"
> x86 tests.
>
> The RSA key is now generated on fly and the whole signing process has
> been made as part of the enclave loader instead of signing the enclave
> during the compilation time.
>
> Finally, the enclave loader loads now the test enclave directly from its
> ELF file, which means that ELF file does not need to be coverted as raw
> binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
> entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> deadlock with the page reclaimer, which could hold the lock for the old
> mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> be used to reserve the address range. Now /dev/sgx supports only opaque
> mappings to the (initialized) enclave data.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
> from RCX.
Hi all,
I've been producing Fedora 32 kernel builds with the SGX patches applied
for a few of weeks and I've just produced a build with this latest
revision[1]. We've been using these kernels to enable SGX for some of
our development/test machines.
We wanted to offer them here in the hopes that others might find them
useful for testing the SGX patchsets on their own machines to send
feedback to this list. Please note that these are *not* meant to replace
your distro kernel and these are for testing purposes only.
I'll continue to upload builds to a Fedora Copr[2] as long as the
patches continue to apply cleanly to the Fedora kernels.
Best,
Connor
[1]
https://download.copr.fedorainfracloud.org/results/npmccallum/enarx/fedora-32-x86_64/01344404-kernel/
[2] https://copr.fedorainfracloud.org/coprs/npmccallum/enarx/
[3] This is the packaging branch that I work from and rebase on top of
the f32 kernels:
https://github.com/connorkuehl/fedora-kernel-enarx-pkg/commits/f32-enarx
The patch I discussed in my previous mail.
--
Implement cryptographic initialization control.
This patch introduces the ability of the platform owner to
implement cryptographically controlled enclave initialization
policy. This functionality provides the platform owner with the
ability to use the identity modulus signature of an enclave
signer (SHA256 hash of the modulus of the signing key) to gate
access to enclave initialization, rather then simply relying
on discretionary access controls that are applied to the SGX
relevant device driver nodes.
The following policy functionality is introduced in this commit:
1.) Control over which keys are allowed to initialize an
enclave.
2.) Control over which keys are allowed to implement launch
enclaves.
3.) Control over which keys are allowed to initialize enclaves
that have access to the PROVISION_KEY attribute.
For each policy type a plurality of key signatures are allowed.
Absent an intent by the platform owner/administrator to use
cryptographic initialization policies, this functionality does
not change the standard behavior of the driver, which is to
allow any enclave presented to the driver to be initialized.
Cryptographic initialization policy is accessed through the
following three pseudo-files that are implemented by this patch:
/sys/kernel/security/signing_keys
/sys/kernel/security/launch_keys
/sys/kernel/security/provisioning_keys
Policy keys are registered with the driver by writing the identity
modulus signature to these files in simple hexadecimal format, ie:
0000000000000000000000000000000000000000000000000000000000000000
The current list of policy keys can be displayed by reading the
contents of the pseudo-files.
In addition to a key signature, the following keywords are
accepted as valid entries for a policy file:
clear
lock
The 'clear' keyword causes all existing entries in a policy list
to be deleted.
The 'lock' keyword causes any further modifications or access to
a policy list to be denied.
All of the policy code is implemented in a single file, policy.c,
with minimal impact to the driver at large. Since the calculation
of the identity modulus signature needed to program a launch control
register is effectively a policy decision, the code to compute the
signature was moved from the ioctl.c file to the policy.c file.
In order to support a plurality of launch keys the code that
loops over initialization attempts was pushed downward into a new
function that is named as follows:
sgx_try_init()
Primarily to avoid excessive indentation that would otherwise be
needed in the sgx_encl_init() function.
Signed-off-by: Dr. Greg <[email protected]>
---
arch/x86/Kconfig | 1 +
arch/x86/include/uapi/asm/sgx.h | 1 +
arch/x86/kernel/cpu/sgx/Makefile | 3 +-
arch/x86/kernel/cpu/sgx/driver.c | 8 +
arch/x86/kernel/cpu/sgx/driver.h | 2 +
arch/x86/kernel/cpu/sgx/encl.h | 2 +
arch/x86/kernel/cpu/sgx/ioctl.c | 82 ++++---
arch/x86/kernel/cpu/sgx/policy.c | 513 +++++++++++++++++++++++++++++++++++++++
8 files changed, 573 insertions(+), 39 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8bbb4313fae3..5cfde1d36dc9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1955,6 +1955,7 @@ config INTEL_SGX
depends on X86_64 && CPU_SUP_INTEL
select SRCU
select MMU_NOTIFIER
+ select SECURITYFS
help
Intel(R) SGX is a set of CPU instructions that can be used by
applications to set aside private regions of code and data, referred
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index e196cfd44b70..1c3cdbce533d 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -63,6 +63,7 @@ struct sgx_enclave_add_pages {
*/
struct sgx_enclave_init {
__u64 sigstruct;
+ __u64 token;
};
/**
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
index f8d32da3a67a..d8ee2a889ca1 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -3,4 +3,5 @@ obj-y += \
encl.o \
ioctl.o \
main.o \
- reclaim.o
+ reclaim.o \
+ policy.o
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index 997a7f4117c5..d4330b32c243 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -205,5 +205,13 @@ int __init sgx_drv_init(void)
return ret;
}
+ ret = sgx_policy_fs_init();
+ if (ret) {
+ pr_err("SGX policy fs creation failed with %d.\n", ret);
+ misc_deregister(&sgx_dev_provision);
+ misc_deregister(&sgx_dev_enclave);
+ return ret;
+ }
+
return 0;
}
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
index 72747d01c046..8293f4d12e82 100644
--- a/arch/x86/kernel/cpu/sgx/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -29,4 +29,6 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
int sgx_drv_init(void);
+int sgx_policy_fs_init(void);
+u64 *sgx_policy_get_launch_signer(u64 *signature);
#endif /* __ARCH_X86_SGX_DRIVER_H__ */
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 44b353aa8866..b5be1f2233ea 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -124,4 +124,6 @@ unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset);
bool sgx_va_page_full(struct sgx_va_page *va_page);
+int sgx_policy_get_params(struct sgx_encl *encl, void *modulus, u64 *signer,
+ int *signcnt);
#endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 12e1496f8a8b..e960be8f924c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -556,31 +556,6 @@ static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
return ret;
}
-static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
- void *hash)
-{
- SHASH_DESC_ON_STACK(shash, tfm);
-
- shash->tfm = tfm;
-
- return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
-}
-
-static int sgx_get_key_hash(const void *modulus, void *hash)
-{
- struct crypto_shash *tfm;
- int ret;
-
- tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(tfm))
- return PTR_ERR(tfm);
-
- ret = __sgx_get_key_hash(tfm, modulus, hash);
-
- crypto_free_shash(tfm);
- return ret;
-}
-
static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
{
u64 *cache;
@@ -611,22 +586,14 @@ static int sgx_einit(struct sgx_sigstruct *sigstruct, void *token,
return ret;
}
-static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
- void *token)
+static int sgx_try_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
+ void *token, u64 *lepubkeyhash)
+
{
- u64 mrsigner[4];
int ret;
int i;
int j;
- /* Check that the required attributes have been authorized. */
- if (encl->secs_attributes & ~encl->allowed_attributes)
- return -EACCES;
-
- ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
- if (ret)
- return ret;
-
mutex_lock(&encl->lock);
if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
@@ -637,7 +604,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
- mrsigner);
+ lepubkeyhash);
if (ret == SGX_UNMASKED_EVENT)
continue;
else
@@ -673,6 +640,36 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
return ret;
}
+static int sgx_encl_init(struct sgx_encl *encl,
+ struct sgx_sigstruct *sigstruct, void *token)
+{
+ u64 mrsigner[4];
+ u64 *signer;
+ int ret;
+ int signcnt = 1;
+
+ /* Configure the launch policy. */
+ ret = sgx_policy_get_params(encl, sigstruct->modulus, mrsigner,
+ &signcnt);
+ if (ret)
+ return ret;
+
+ /* Check that the required attributes have been authorized. */
+ if (encl->secs_attributes & ~encl->allowed_attributes)
+ return -EACCES;
+
+ signer = mrsigner;
+ while (signcnt--) {
+ ret = sgx_try_init(encl, sigstruct, token, signer);
+ if (!ret)
+ return ret;
+ if (signcnt)
+ signer = sgx_policy_get_launch_signer(signer);
+ }
+
+ return ret;
+}
+
/**
* sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
*
@@ -708,7 +705,16 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
sigstruct = kmap(initp_page);
token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
- memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
+ if (!einit.token)
+ memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
+ else {
+ if (copy_from_user((uint8_t *) token,
+ (void __user *) einit.token,
+ SGX_LAUNCH_TOKEN_SIZE)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ }
if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
sizeof(*sigstruct))) {
diff --git a/arch/x86/kernel/cpu/sgx/policy.c b/arch/x86/kernel/cpu/sgx/policy.c
new file mode 100644
index 000000000000..04ff13e4ce73
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/policy.c
@@ -0,0 +1,513 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) Enjellic Systems Development, LLC
+
+#define KEY_SIZE 32
+
+#include <linux/types.h>
+#include <linux/seq_file.h>
+#include <linux/atomic.h>
+#include <linux/security.h>
+#include "driver.h"
+#include "encl.h"
+
+static struct dentry *sgx_fs;
+
+struct list_key {
+ struct list_head list;
+ u64 key[KEY_SIZE / 8];
+};
+
+struct list_key_iterator {
+ char *type;
+ atomic_t *opencount;
+ unsigned int *count;
+ struct mutex *lock;
+ struct list_head *list;
+ bool *lockfile;
+};
+
+static struct dentry *launch_keys;
+static atomic_t launch_keys_opencount = ATOMIC_INIT(1);
+static unsigned int launch_keys_count;
+static bool launch_keys_locked;
+static DEFINE_MUTEX(launch_key_list_mutex);
+static LIST_HEAD(launch_key_list);
+
+static struct dentry *provision_keys;
+static atomic_t provision_keys_opencount = ATOMIC_INIT(1);
+static unsigned int provision_keys_count;
+static bool provision_keys_locked;
+static DEFINE_MUTEX(provision_key_list_mutex);
+static LIST_HEAD(provision_key_list);
+
+static struct dentry *signing_keys;
+static atomic_t signing_keys_opencount = ATOMIC_INIT(1);
+static unsigned int signing_keys_count;
+static bool signing_keys_locked;
+static DEFINE_MUTEX(signing_key_list_mutex);
+static LIST_HEAD(signing_key_list);
+
+/**
+ * have_signer - Verify the presence presence of a key signer.
+ *
+ * @signature: Pointer to signature of signer.
+ *
+ * Return:
+ * 0 Signer signature was not found.
+ * 1 Signer signature was found.
+ */
+static bool have_signer(struct list_head *keylist, struct mutex *lock,
+ uint8_t *signature)
+{
+ bool retn = false;
+ struct list_key *kp;
+
+ mutex_lock(lock);
+ list_for_each_entry(kp, keylist, list) {
+ pr_debug("%s: Checking signer=%*phN, ks=%*phN\n", __func__,
+ KEY_SIZE, signature, KEY_SIZE, kp->key);
+ if (memcmp(kp->key, signature, KEY_SIZE) == 0) {
+ retn = true;
+ goto done;
+ }
+ }
+
+ done:
+ mutex_unlock(lock);
+ return retn;
+}
+
+static int process_write_key(const char __user *buf, size_t datalen,
+ unsigned int *keycnt, struct mutex *lock,
+ struct list_head *keylist)
+{
+ ssize_t retn;
+
+ char *p, keybufr[KEY_SIZE*2 + 1], key[KEY_SIZE];
+
+ struct list_key *kp;
+
+ if (datalen != sizeof(keybufr)) {
+ retn = -EINVAL;
+ goto done;
+ }
+
+ memset(keybufr, '\0', sizeof(keybufr));
+ if (copy_from_user(keybufr, buf, datalen)) {
+ retn = -EFAULT;
+ goto done;
+ }
+
+ p = strchr(keybufr, '\n');
+ if (!p) {
+ retn = -EINVAL;
+ goto done;
+ }
+ *p = '\0';
+ if (hex2bin(key, keybufr, sizeof(key))) {
+ retn = -EINVAL;
+ goto done;
+ }
+
+ kp = kzalloc(sizeof(*kp), GFP_KERNEL);
+ if (!kp) {
+ retn = -ENOMEM;
+ goto done;
+ }
+ memcpy(kp->key, key, sizeof(kp->key));
+
+ mutex_lock(lock);
+ list_add_tail(&kp->list, keylist);
+ ++*keycnt;
+ mutex_unlock(lock);
+
+ retn = datalen;
+ pr_debug("%s: Added key: %*phN\n", __func__, KEY_SIZE, key);
+
+ done:
+ return retn;
+}
+
+static int process_lock(const char __user *buf, size_t datalen, bool *lockfile)
+{
+ char bufr[5];
+
+ if (datalen != strlen("lock") + 1)
+ return 0;
+
+ memset(bufr, '\0', sizeof(bufr));
+ if (copy_from_user(bufr, buf, datalen-1))
+ return -EFAULT;
+ if (strcmp(bufr, "lock") != 0)
+ return 0;
+
+ *lockfile = true;
+ return datalen;
+}
+
+static int process_clear(const char __user *buf, size_t datalen, char *type,
+ unsigned int *keycnt, struct mutex *lock,
+ struct list_head *keylist)
+{
+ char bufr[6];
+ struct list_key *kp, *kp_tmp;
+
+ if (datalen != strlen("clear") + 1)
+ return 0;
+
+ memset(bufr, '\0', sizeof(bufr));
+ if (copy_from_user(bufr, buf, datalen-1))
+ return -EFAULT;
+ if (strcmp(bufr, "clear") != 0)
+ return 0;
+
+ mutex_lock(lock);
+ list_for_each_entry_safe(kp, kp_tmp, keylist, list) {
+ pr_debug("[%s]: Freeing signature: %*phN\n", __FILE__,
+ KEY_SIZE, kp->key);
+ list_del(&kp->list);
+ kfree(kp);
+ }
+ *keycnt = 0;
+ mutex_unlock(lock);
+
+ pr_info("Cleared %s signatures.\n", type);
+ return datalen;
+}
+
+static void *key_start(struct seq_file *c, loff_t *pos)
+{
+ struct list_key_iterator *ki = (struct list_key_iterator *) c->private;
+
+ if (*pos >= *ki->count)
+ return NULL;
+
+ mutex_lock(ki->lock);
+ return seq_list_start(ki->list, *pos);
+}
+
+static void *key_next(struct seq_file *c, void *p, loff_t *pos)
+{
+ struct list_key_iterator *ki = (struct list_key_iterator *) c->private;
+
+ return seq_list_next(p, ki->list, pos);
+}
+
+static void key_stop(struct seq_file *c, void *p)
+{
+ struct list_key_iterator *ki = (struct list_key_iterator *) c->private;
+
+ mutex_unlock(ki->lock);
+}
+
+static int key_show(struct seq_file *c, void *key)
+{
+ struct list_key *kp;
+
+ kp = list_entry(key, struct list_key, list);
+ seq_printf(c, "%*phN\n", KEY_SIZE, kp->key);
+ return 0;
+}
+
+static const struct seq_operations keys_seqops = {
+ .start = key_start,
+ .next = key_next,
+ .stop = key_stop,
+ .show = key_show
+};
+
+static ssize_t write_keys(struct file *file, const char __user *buf,
+ size_t datalen, loff_t *ppos)
+{
+ struct seq_file *s = file->private_data;
+ struct list_key_iterator *ki = (struct list_key_iterator *) s->private;
+ ssize_t retn;
+
+ if (*ppos != 0)
+ return -EINVAL;
+
+ retn = process_lock(buf, datalen, ki->lockfile);
+ if (retn != 0)
+ return retn;
+
+ retn = process_clear(buf, datalen, ki->type, ki->count, ki->lock,
+ ki->list);
+ if (retn != 0)
+ return retn;
+
+ retn = process_write_key(buf, datalen, ki->count, ki->lock, ki->list);
+ return retn;
+}
+
+static int release_keys(struct inode *inode, struct file *file)
+{
+ struct seq_file *s = file->private_data;
+ struct list_key_iterator *ki = (struct list_key_iterator *) s->private;
+
+ atomic_set(ki->opencount, 1);
+ seq_release_private(inode, file);
+ return 0;
+}
+
+static int open_launch_keys(struct inode *inode, struct file *filp)
+{
+ struct list_key_iterator *ki;
+
+ if (launch_keys_locked)
+ return -EACCES;
+
+ if (!atomic_dec_and_test(&launch_keys_opencount))
+ return -EBUSY;
+
+ ki = __seq_open_private(filp, &keys_seqops, sizeof(*ki));
+ if (!ki)
+ return -ENOMEM;
+
+ ki->type = "launch control";
+ ki->opencount = &launch_keys_opencount;
+ ki->count = &launch_keys_count;
+ ki->lock = &launch_key_list_mutex;
+ ki->list = &launch_key_list;
+ ki->lockfile = &launch_keys_locked;
+
+ return 0;
+}
+
+static const struct file_operations launch_keys_ops = {
+ .open = open_launch_keys,
+ .write = write_keys,
+ .release = release_keys,
+ .read = seq_read,
+ .llseek = seq_lseek,
+};
+
+/* Provisioning control. */
+
+static int open_provision_keys(struct inode *inode, struct file *filp)
+{
+ struct list_key_iterator *ki;
+
+ if (provision_keys_locked)
+ return -EACCES;
+
+ if (!atomic_dec_and_test(&provision_keys_opencount))
+ return -EBUSY;
+
+ ki = __seq_open_private(filp, &keys_seqops, sizeof(*ki));
+ if (!ki)
+ return -ENOMEM;
+
+ ki->type = "provisioning control";
+ ki->opencount = &provision_keys_opencount;
+ ki->count = &provision_keys_count;
+ ki->lock = &provision_key_list_mutex;
+ ki->list = &provision_key_list;
+
+ return 0;
+}
+
+static const struct file_operations provision_keys_ops = {
+ .open = open_provision_keys,
+ .write = write_keys,
+ .release = release_keys,
+ .read = seq_read,
+ .llseek = seq_lseek,
+};
+
+/* Signing control. */
+
+static int open_signing_keys(struct inode *inode, struct file *filp)
+{
+ struct list_key_iterator *ki;
+
+ if (signing_keys_locked)
+ return -EACCES;
+
+ if (!atomic_dec_and_test(&signing_keys_opencount))
+ return -EBUSY;
+
+ ki = __seq_open_private(filp, &keys_seqops, sizeof(*ki));
+ if (!ki)
+ return -ENOMEM;
+
+ ki->type = "signing control";
+ ki->opencount = &signing_keys_opencount;
+ ki->count = &signing_keys_count;
+ ki->lock = &signing_key_list_mutex;
+ ki->list = &signing_key_list;
+
+ return 0;
+}
+
+static const struct file_operations signing_keys_ops = {
+ .open = open_signing_keys,
+ .write = write_keys,
+ .release = release_keys,
+ .read = seq_read,
+ .llseek = seq_lseek,
+};
+
+static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
+ void *hash)
+{
+ SHASH_DESC_ON_STACK(shash, tfm);
+
+ shash->tfm = tfm;
+
+ return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
+}
+
+static int sgx_get_key_hash(const void *modulus, void *hash)
+{
+ struct crypto_shash *tfm;
+ int ret;
+
+ tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ ret = __sgx_get_key_hash(tfm, modulus, hash);
+
+ crypto_free_shash(tfm);
+ return ret;
+}
+
+/**
+ * sgx_policy_get_params
+ *
+ * This function sets the cryptographically configured initialization
+ * policy parameters. These include the identity modulus signature to
+ * be used as well as the configuration of the allowed enclave
+ * attributes.
+ *
+ * Return:
+ * 0 on success.
+ * -errno otherwise
+ */
+
+int sgx_policy_get_params(struct sgx_encl *encl, void *modulus, u64 *signer,
+ int *signcnt)
+{
+ int retn = -EINVAL;
+ uint8_t mrsigner[KEY_SIZE];
+ struct list_key *kp;
+
+ retn = sgx_get_key_hash(modulus, mrsigner);
+ if (retn)
+ goto no_signer;
+
+ if (provision_keys_count > 0 &&
+ have_signer(&provision_key_list, &provision_key_list_mutex,
+ mrsigner))
+ encl->allowed_attributes |= SGX_ATTR_PROVISIONKEY;
+
+ if (signing_keys_count > 0 &&
+ have_signer(&signing_key_list, &signing_key_list_mutex, mrsigner))
+ goto have_signer;
+
+ if (encl->secs_attributes & SGX_ATTR_EINITTOKENKEY &&
+ launch_keys_count > 0) {
+ if (have_signer(&launch_key_list, &launch_key_list_mutex,
+ mrsigner)) {
+ encl->allowed_attributes |= SGX_ATTR_EINITTOKENKEY;
+ goto have_signer;
+ } else
+ goto no_signer;
+ }
+
+ if (launch_keys_count > 0) {
+ *signcnt = launch_keys_count;
+ kp = list_first_entry(&launch_key_list, struct list_key, list);
+ memcpy(mrsigner, kp->key, KEY_SIZE);
+ }
+
+ have_signer:
+ memcpy(signer, mrsigner, KEY_SIZE);
+ pr_debug("%s: Using signer: %*phN\n", __func__, KEY_SIZE, signer);
+ return 0;
+ no_signer:
+ memset(signer, '\0', KEY_SIZE);
+ return retn;
+}
+
+/**
+ * sgx_policy_get_launch_signer - Iterate through list of enclave authorizers.
+ *
+ * @signer: The last returned enclave signer.
+ *
+ * This function iterates through the list of enclave signers from the
+ * last signature. Calling the function with a NULL value
+ * resets the iteration to the beginning of the list.
+ *
+ * Return:
+ * NULL indicates end of list
+ * non-NULL the next enclave signature on the list.
+ */
+
+u64 *sgx_policy_get_launch_signer(u64 *signer)
+{
+ bool seeking = false;
+ u64 *retn = NULL;
+ struct list_key *kp;
+
+ if (!signer) {
+ kp = list_first_entry(&launch_key_list, struct list_key, list);
+ return kp->key;
+ }
+ kp = list_last_entry(&launch_key_list, struct list_key, list);
+ if (memcmp(kp->key, signer, sizeof(kp->key)) == 0)
+ return NULL;
+
+ mutex_lock(&launch_key_list_mutex);
+ list_for_each_entry(kp, &launch_key_list, list) {
+ if (seeking) {
+ retn = kp->key;
+ goto done;
+ }
+ pr_debug("%s: Skipping: %*phN\n", __func__, KEY_SIZE, kp->key);
+ if (memcmp(kp->key, signer, KEY_SIZE) == 0)
+ seeking = true;
+ }
+
+ done:
+ mutex_unlock(&launch_key_list_mutex);
+ return retn;
+}
+
+int __init sgx_policy_fs_init(void)
+{
+ int retn = -1;
+
+ sgx_fs = securityfs_create_dir("sgx", NULL);
+ if (IS_ERR(sgx_fs)) {
+ retn = PTR_ERR(sgx_fs);
+ goto err;
+ }
+
+ launch_keys = securityfs_create_file("launch_keys", 0600, sgx_fs,
+ NULL, &launch_keys_ops);
+ if (IS_ERR(launch_keys)) {
+ retn = PTR_ERR(launch_keys);
+ goto err;
+ }
+
+ provision_keys = securityfs_create_file("provisioning_keys", 0600,
+ sgx_fs, NULL,
+ &provision_keys_ops);
+ if (IS_ERR(provision_keys)) {
+ retn = PTR_ERR(provision_keys);
+ goto err;
+ }
+
+ signing_keys = securityfs_create_file("signing_keys", 0600, sgx_fs,
+ NULL, &signing_keys_ops);
+ if (IS_ERR(signing_keys)) {
+ retn = PTR_ERR(signing_keys);
+ goto err;
+ }
+
+ return 0;
+
+ err:
+ return retn;
+}
On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
Good day, I hope the weekend is going well for everyone.
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> ... [ elided ] ..
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
It seems highly unlikely that a driver implementation with any type of
support for read-only launch control registers would ever get into the
kernel. All one needs to do is review the conversations that Matthew
Garrett's lockdown patches engender to get a sense of that, ie:
https://lwn.net/Articles/818277/
As a result, the proposed SGX driver needs support for cryptographic
policy management before it goes into the kernel. Either the patch
that we have offered or something equivalent.
Absent that, the driver won't address the full needs of the
development community implementing runtimes. In addition it also
poses security and privacy issues that are well documented in the
literature.
As an aside, for those who haven't spent the last 5+ years of their
life working with this technology. SGX2 hardware platforms have the
ability to allow unrestricted code execution in enclave context. No
amount of LSM or IMA interventions can provide any control over that.
In fact, the Confidential Computing Consortium, sponsored by none
other then the Linux Foundation, has at its fundamental tenant, the
notion of developing an eco-system that allows the execution of code
and processing of data, over which, the owner or administrator of the
platform has no visibility or control. It would seem only logical
that adversarial interests would indulge themseleves in those
capabilities as well.
With respect to SGX and these issues, cryptographic policy management
is important for the same reason that 2-factor authentication is now
considered standard practice in the security industry.
We appreciate, Jarkko, that you feel that such infrastructure is
optional, like virtualization support, and is something that can go in
after the driver is mainlined. As the diffstat for our patch points
out, the proposed support has virtually no impact on the driver, the
same cannot be said for virtualization capabilities.
Moreover, adding support for key based policy management later would
require the addition of another ioctl in order to avoid ABI
compatibility issues. The current initialization ioctl is best
suited, from an engineering perspective, to support this type of
infrastructure. In fact, the necessary support was removed from the
ioctl for political reasons rather then for any valid engineering
rationale on flexible launch control platforms, particularly with our
patch or an equivalent approach.
For the benefit of the kernel community at large, I will follow up this
e-mail with a copy of our patch for review. In case anyone misses it,
or it is corrupted, the patch can be pulled from the following URL:
ftp://ftp.enjellic.com/pub/sgx/kernel/SFLC-current.patch
We believe the patch or an equivalent approach deserves consideration
for the following reasons:
1.) It does not modify the default behavior of the driver. ie. any
enclave will be initialized that is presented.
2.) It enables needed functionality only at the discretion and control
of the platform owner/administrator.
3.) The impact on the architecture of the driver is negligible.
In closing, it is important to note that the proposed SGX driver is
not available as a module. This effectively excludes any alternative
implementations of the driver without replacement of the kernel at
large. It also means that any platform, with SGX hardware support,
running a kernel with this driver, has the potential for the
security/privacy issues noted above.
If key based policy management is not allowed, then the driver needs
to be re-architected to have modular support so that alternative
implementations or the absence of any driver support are at least
tenable.
Hopefully this is a reasoned technical approach to what has been a
long standing issue surrounding this technology.
Best wishes for a productive week.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker SGX secured infrastructure and
Enjellic Systems Development, LLC autonomously self-defensive
4206 N. 19th Ave. platforms.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"Opportunity is missed by most people because it is dressed in overalls
and looks like work."
-- Thomas Edison
On Wed, Apr 22, 2020 at 09:48:58AM -0700, Connor Kuehl wrote:
> On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
> > v29:
> > * The selftest has been moved to selftests/sgx. Because SGX is an execution
> > environment of its own, it really isn't a great fit with more "standard"
> > x86 tests.
> >
> > The RSA key is now generated on fly and the whole signing process has
> > been made as part of the enclave loader instead of signing the enclave
> > during the compilation time.
> >
> > Finally, the enclave loader loads now the test enclave directly from its
> > ELF file, which means that ELF file does not need to be coverted as raw
> > binary during the build process.
> > * Version the mm_list instead of using on synchronize_mm() when adding new
> > entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> > deadlock with the page reclaimer, which could hold the lock for the old
> > mm_struct.
> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> > be used to reserve the address range. Now /dev/sgx supports only opaque
> > mappings to the (initialized) enclave data.
> > * Make the vDSO callable directly from C by preserving RBX and taking leaf
> > from RCX.
>
> Hi all,
>
> I've been producing Fedora 32 kernel builds with the SGX patches applied for
> a few of weeks and I've just produced a build with this latest revision[1].
> We've been using these kernels to enable SGX for some of our
> development/test machines.
Thanks a lot!
/Jarkko
On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
>
> Good day, I hope the weekend is going well for everyone.
>
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> >
> > ... [ elided ] ..
> >
> > The current implementation requires that the firmware sets
> > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > decide what enclaves it wants run. The implementation does not create
> > any bottlenecks to support read-only MSRs later on.
>
> It seems highly unlikely that a driver implementation with any type of
> support for read-only launch control registers would ever get into the
> kernel. All one needs to do is review the conversations that Matthew
> Garrett's lockdown patches engender to get a sense of that, ie:
>
> https://lwn.net/Articles/818277/
We do not require read-only MSRs.
/Jarkko
On Wed, Apr 29, 2020 at 08:23:29AM +0300, Jarkko Sakkinen wrote:
> On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> > On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> >
> > Good day, I hope the weekend is going well for everyone.
> >
> > > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > > to set aside private regions of code and data. The code outside the enclave
> > > is disallowed to access the memory inside the enclave by the CPU access
> > > control.
> > >
> > > ... [ elided ] ..
> > >
> > > The current implementation requires that the firmware sets
> > > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > > decide what enclaves it wants run. The implementation does not create
> > > any bottlenecks to support read-only MSRs later on.
> >
> > It seems highly unlikely that a driver implementation with any type of
> > support for read-only launch control registers would ever get into the
> > kernel. All one needs to do is review the conversations that Matthew
> > Garrett's lockdown patches engender to get a sense of that, ie:
> >
> > https://lwn.net/Articles/818277/
>
> We do not require read-only MSRs.
Greg is pointing out the opposite, that supporting read-only MSRs is highly
unlikely to ever be supported in the mainline kernel.
On 2020-04-21 23:52, Jarkko Sakkinen wrote:
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
>
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
>
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>
> cat /proc/cpuinfo | grep sgx
Let's merge this.
--
Jethro Beekman | Fortanix
On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> In closing, it is important to note that the proposed SGX driver is
> not available as a module. This effectively excludes any alternative
> implementations of the driver without replacement of the kernel at
> large.
No it doesn't. The SGX subsytem won't allocate EPC pages unless userspace
creates an enclave, i.e. preventing unprivileged userspace from accessing
/dev/sgx/enclave will allow loading an alternative out-of-tree SGX module.
Yes, SGX sanitizes the EPC on boot, but that's arguably a good thing for
out-of-tree modules.
And if you want to get crafty and squash in-kernel SGX altogether, boot
with "clearcpuid=<SGX_LC>" and/or "clearcpuid=<SGX>" to disable in-kernel
support entirely. SGX won't be correctly enumerated in /proc/cpuinfo
relative to the existence of an out-of-tree module, but that seems like a
very minor issue if you're running with a completely different SGX driver.
> It also means that any platform, with SGX hardware support,
> running a kernel with this driver, has the potential for the
> security/privacy issues noted above.
Unless I'm mistaken, /dev/sgx is root-only by default. There are far
scarier mechanisms available to root for hosing the system.
> If key based policy management is not allowed, then the driver needs
> to be re-architected to have modular support so that alternative
> implementations or the absence of any driver support are at least
> tenable.
As above, using an alternative implementation is teneble, albeit a bit
kludgy.
On Wed, Apr 29, 2020 at 05:27:48PM +0200, Jethro Beekman wrote:
> On 2020-04-21 23:52, Jarkko Sakkinen wrote:
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> >
> > There is a new hardware unit in the processor called Memory Encryption
> > Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> > one or many MEE regions that can hold enclave data by configuring them with
> > PRMRR registers.
> >
> > The MEE automatically encrypts the data leaving the processor package to
> > the MEE regions. The data is encrypted using a random key whose life-time
> > is exactly one power cycle.
> >
> > The current implementation requires that the firmware sets
> > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > decide what enclaves it wants run. The implementation does not create
> > any bottlenecks to support read-only MSRs later on.
> >
> > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >
> > cat /proc/cpuinfo | grep sgx
>
> Let's merge this.
So can I tag reviewed-by's?
/Jarkko
On Wed, Apr 29, 2020 at 08:14:59AM -0700, Sean Christopherson wrote:
> On Wed, Apr 29, 2020 at 08:23:29AM +0300, Jarkko Sakkinen wrote:
> > On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> > > On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> > >
> > > Good day, I hope the weekend is going well for everyone.
> > >
> > > > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > > > to set aside private regions of code and data. The code outside the enclave
> > > > is disallowed to access the memory inside the enclave by the CPU access
> > > > control.
> > > >
> > > > ... [ elided ] ..
> > > >
> > > > The current implementation requires that the firmware sets
> > > > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > > > decide what enclaves it wants run. The implementation does not create
> > > > any bottlenecks to support read-only MSRs later on.
> > >
> > > It seems highly unlikely that a driver implementation with any type of
> > > support for read-only launch control registers would ever get into the
> > > kernel. All one needs to do is review the conversations that Matthew
> > > Garrett's lockdown patches engender to get a sense of that, ie:
> > >
> > > https://lwn.net/Articles/818277/
> >
> > We do not require read-only MSRs.
>
> Greg is pointing out the opposite, that supporting read-only MSRs is highly
> unlikely to ever be supported in the mainline kernel.
In a nutshell, what is wrong in the current code changes and what
*exactly* should we change? This is way too high level at the moment at
least for my limited brain capacity.
/Jarkko
On 2020-04-30 05:46, Jarkko Sakkinen wrote:
> On Wed, Apr 29, 2020 at 05:27:48PM +0200, Jethro Beekman wrote:
>> On 2020-04-21 23:52, Jarkko Sakkinen wrote:
>>> Intel(R) SGX is a set of CPU instructions that can be used by applications
>>> to set aside private regions of code and data. The code outside the enclave
>>> is disallowed to access the memory inside the enclave by the CPU access
>>> control.
>>>
>>> There is a new hardware unit in the processor called Memory Encryption
>>> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
>>> one or many MEE regions that can hold enclave data by configuring them with
>>> PRMRR registers.
>>>
>>> The MEE automatically encrypts the data leaving the processor package to
>>> the MEE regions. The data is encrypted using a random key whose life-time
>>> is exactly one power cycle.
>>>
>>> The current implementation requires that the firmware sets
>>> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
>>> decide what enclaves it wants run. The implementation does not create
>>> any bottlenecks to support read-only MSRs later on.
>>>
>>> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>>>
>>> cat /proc/cpuinfo | grep sgx
>>
>> Let's merge this.
>
> So can I tag reviewed-by's?
>
No, but you already have my tested-by's.
If it helps I can try to review some patches, but 1) I know nothing about kernel coding guidelines and best practices and 2) I know little about most kernel internals, so I won't be able to review every patch.
--
Jethro Beekman | Fortanix
On Thu, Apr 30, 2020 at 09:19:48AM +0200, Jethro Beekman wrote:
> On 2020-04-30 05:46, Jarkko Sakkinen wrote:
> > On Wed, Apr 29, 2020 at 05:27:48PM +0200, Jethro Beekman wrote:
> >> On 2020-04-21 23:52, Jarkko Sakkinen wrote:
> >>> Intel(R) SGX is a set of CPU instructions that can be used by applications
> >>> to set aside private regions of code and data. The code outside the enclave
> >>> is disallowed to access the memory inside the enclave by the CPU access
> >>> control.
> >>>
> >>> There is a new hardware unit in the processor called Memory Encryption
> >>> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> >>> one or many MEE regions that can hold enclave data by configuring them with
> >>> PRMRR registers.
> >>>
> >>> The MEE automatically encrypts the data leaving the processor package to
> >>> the MEE regions. The data is encrypted using a random key whose life-time
> >>> is exactly one power cycle.
> >>>
> >>> The current implementation requires that the firmware sets
> >>> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> >>> decide what enclaves it wants run. The implementation does not create
> >>> any bottlenecks to support read-only MSRs later on.
> >>>
> >>> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >>>
> >>> cat /proc/cpuinfo | grep sgx
> >>
> >> Let's merge this.
> >
> > So can I tag reviewed-by's?
> >
>
> No, but you already have my tested-by's.
>
> If it helps I can try to review some patches, but 1) I know nothing
> about kernel coding guidelines and best practices and 2) I know little
> about most kernel internals, so I won't be able to review every patch.
Ackd-by *acknowledges* that the patches work for you. I think that would
be then the correct choice for the driver patch and patches before that.
Lets go with that if that is cool for you of course.
Did you run the selftest only or possibly also some internal Fortanix
tests?
/Jarkko
On 2020-04-30 10:23, Jarkko Sakkinen wrote:
> On Thu, Apr 30, 2020 at 09:19:48AM +0200, Jethro Beekman wrote:
>> On 2020-04-30 05:46, Jarkko Sakkinen wrote:
>>> On Wed, Apr 29, 2020 at 05:27:48PM +0200, Jethro Beekman wrote:
>>>> On 2020-04-21 23:52, Jarkko Sakkinen wrote:
>>>>> Intel(R) SGX is a set of CPU instructions that can be used by applications
>>>>> to set aside private regions of code and data. The code outside the enclave
>>>>> is disallowed to access the memory inside the enclave by the CPU access
>>>>> control.
>>>>>
>>>>> There is a new hardware unit in the processor called Memory Encryption
>>>>> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
>>>>> one or many MEE regions that can hold enclave data by configuring them with
>>>>> PRMRR registers.
>>>>>
>>>>> The MEE automatically encrypts the data leaving the processor package to
>>>>> the MEE regions. The data is encrypted using a random key whose life-time
>>>>> is exactly one power cycle.
>>>>>
>>>>> The current implementation requires that the firmware sets
>>>>> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
>>>>> decide what enclaves it wants run. The implementation does not create
>>>>> any bottlenecks to support read-only MSRs later on.
>>>>>
>>>>> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>>>>>
>>>>> cat /proc/cpuinfo | grep sgx
>>>>
>>>> Let's merge this.
>>>
>>> So can I tag reviewed-by's?
>>>
>>
>> No, but you already have my tested-by's.
>>
>> If it helps I can try to review some patches, but 1) I know nothing
>> about kernel coding guidelines and best practices and 2) I know little
>> about most kernel internals, so I won't be able to review every patch.
>
> Ackd-by *acknowledges* that the patches work for you. I think that would
> be then the correct choice for the driver patch and patches before that.
>
> Lets go with that if that is cool for you of course.
>
> Did you run the selftest only or possibly also some internal Fortanix
> tests?
>
v29 patches 2 through 18:
Acked-by: Jethro Beekman <[email protected]>
I only ran production SGX software. I didn't run the self test.
--
Jethro Beekman | Fortanix
On Thu, Apr 30, 2020 at 06:59:11AM +0300, Jarkko Sakkinen wrote:
Good afternoon, I hope the weekend is going well for everyone.
> On Wed, Apr 29, 2020 at 08:14:59AM -0700, Sean Christopherson wrote:
> > On Wed, Apr 29, 2020 at 08:23:29AM +0300, Jarkko Sakkinen wrote:
> > > On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> > > > On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> > >
> > > > > The current implementation requires that the firmware sets
> > > > > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately
> > > > > the kernel can decide what enclaves it wants run. The
> > > > > implementation does not create any bottlenecks to support
> > > > > read-only MSRs later on.
> > >
> > > > It seems highly unlikely that a driver implementation with any type of
> > > > support for read-only launch control registers would ever get into the
> > > > kernel. All one needs to do is review the conversations that Matthew
> > > > Garrett's lockdown patches engender to get a sense of that, ie:
> > > >
> > > > https://lwn.net/Articles/818277/
> > >
> > > We do not require read-only MSRs.
> >
> > Greg is pointing out the opposite, that supporting read-only MSRs is highly
> > unlikely to ever be supported in the mainline kernel.
> In a nutshell, what is wrong in the current code changes and what
> *exactly* should we change? This is way too high level at the moment
> at least for my limited brain capacity.
In a nutshell, the driver needs our patch that implements
cryptographic policy management.
A patch that:
1.) Does not change the default behavior of the driver.
2.) Implements capabilities that are consistent with what the hardware
was designed to do, but only at the discretion of the platform owner.
3.) Has no impact on the driver architecture.
The only consumer for this driver are SGX runtimes. To our knowledge,
there exist only two complete runtime implementations, Intel's and
ours. It us unclear why our approach to the use of the technology
should be discriminated against when it doesn't impact the other user
community.
The Linux kernel that I have worked on and supported since 1992 has
always focused on technical rationale and meritocracy rather then
politics. We would be interested in why our proposal for the driver
fails on the former grounds rather then the latter.
> /Jarkko
Best wishes for a productive week.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
Enjellic Systems Development, LLC self-defensive IOT platforms
4206 N. 19th Ave. and edge devices.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"The best way to predict the future is to invent it."
-- Alan Kay
> On May 2, 2020, at 4:05 PM, Dr. Greg <[email protected]> wrote:
>
> On Thu, Apr 30, 2020 at 06:59:11AM +0300, Jarkko Sakkinen wrote:
>
> Good afternoon, I hope the weekend is going well for everyone.
>
>>> On Wed, Apr 29, 2020 at 08:14:59AM -0700, Sean Christopherson wrote:
>>> On Wed, Apr 29, 2020 at 08:23:29AM +0300, Jarkko Sakkinen wrote:
>>>> On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
>>>>> On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
>>>>
>>>>>> The current implementation requires that the firmware sets
>>>>>> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately
>>>>>> the kernel can decide what enclaves it wants run. The
>>>>>> implementation does not create any bottlenecks to support
>>>>>> read-only MSRs later on.
>>>>
>>>>> It seems highly unlikely that a driver implementation with any type of
>>>>> support for read-only launch control registers would ever get into the
>>>>> kernel. All one needs to do is review the conversations that Matthew
>>>>> Garrett's lockdown patches engender to get a sense of that, ie:
>>>>>
>>>>> https://lwn.net/Articles/818277/
>>>>
>>>> We do not require read-only MSRs.
>>>
>>> Greg is pointing out the opposite, that supporting read-only MSRs is highly
>>> unlikely to ever be supported in the mainline kernel.
>
>> In a nutshell, what is wrong in the current code changes and what
>> *exactly* should we change? This is way too high level at the moment
>> at least for my limited brain capacity.
>
> In a nutshell, the driver needs our patch that implements
> cryptographic policy management.
>
> A patch that:
>
> 1.) Does not change the default behavior of the driver.
>
> 2.) Implements capabilities that are consistent with what the hardware
> was designed to do, but only at the discretion of the platform owner.
>
> 3.) Has no impact on the driver architecture.
>
> The only consumer for this driver are SGX runtimes. To our knowledge,
> there exist only two complete runtime implementations, Intel's and
> ours. It us unclear why our approach to the use of the technology
> should be discriminated against when it doesn't impact the other user
> community.
Can you clarify how exactly this patch set discriminates against your stack?
>
> The Linux kernel that I have worked on and supported since 1992 has
> always focused on technical rationale and meritocracy rather then
> politics. We would be interested in why our proposal for the driver
> fails on the former grounds rather then the latter.
>
>> /Jarkko
>
> Best wishes for a productive week.
>
> Dr. Greg
>
> As always,
> Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
> Enjellic Systems Development, LLC self-defensive IOT platforms
> 4206 N. 19th Ave. and edge devices.
> Fargo, ND 58102
> PH: 701-281-1686 EMAIL: [email protected]
> ------------------------------------------------------------------------------
> "The best way to predict the future is to invent it."
> -- Alan Kay
On Sat, May 02, 2020 at 05:48:30PM -0700, Andy Lutomirski wrote:
Good morning, I hope the week is starting well for everyone.
> > On May 2, 2020, at 4:05 PM, Dr. Greg <[email protected]> wrote:
> > In a nutshell, the driver needs our patch that implements
> > cryptographic policy management.
> >
> > A patch that:
> >
> > 1.) Does not change the default behavior of the driver.
> >
> > 2.) Implements capabilities that are consistent with what the hardware
> > was designed to do, but only at the discretion of the platform owner.
> >
> > 3.) Has no impact on the driver architecture.
> >
> > The only consumer for this driver are SGX runtimes. To our knowledge,
> > there exist only two complete runtime implementations, Intel's and
> > ours. It us unclear why our approach to the use of the technology
> > should be discriminated against when it doesn't impact the other user
> > community.
> Can you clarify how exactly this patch set discriminates against
> your stack?
The driver has no provisions for implementing cryptographically based
SGX policy management of any type.
Our stack is extremely lightweight with no external dependencies and
is used in privacy and security sensitive applications, including
financial services of certain types. There is a desire in this, and
other venues, to use cloud and edge resources with a strong guarantee
that the platforms have only had a known set of behaviors. The
current DAC based controls in the driver are insufficient to provide
those guarantees.
I believe I have discussed our use of SGX previously. In a nutshell,
we use SGX based modeling engines to supervise kernel based behavioral
namespaces, one enclave per namespace. The closest equivalent work
that we have seen may be the IPE architecture advanced by Deven Bowers
at Microsoft but we address a number of issues that work does not,
including non-kernel based behavioral supervision.
We support the concern over hardware locked platforms and do not
disagree with the driver not supporting those platforms. That being
said, there is no technical rationale for not providing cryptographic
policy management on FLC based platforms, as I believe our patch
demonstrates.
Best wishes for a productive week.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
Enjellic Systems Development, LLC self-defensive platforms.
4206 N. 19th Ave.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"Can't they?
A 64bit number incremented every millisecond can grow for half a
billion years. As far as I'm concerned, that is forever."
-- Neil Brown
linux-raid
On Thu, Apr 30, 2020 at 04:12:07PM +0200, Jethro Beekman wrote:
> On 2020-04-30 10:23, Jarkko Sakkinen wrote:
> > On Thu, Apr 30, 2020 at 09:19:48AM +0200, Jethro Beekman wrote:
> >> On 2020-04-30 05:46, Jarkko Sakkinen wrote:
> >>> On Wed, Apr 29, 2020 at 05:27:48PM +0200, Jethro Beekman wrote:
> >>>> On 2020-04-21 23:52, Jarkko Sakkinen wrote:
> >>>>> Intel(R) SGX is a set of CPU instructions that can be used by applications
> >>>>> to set aside private regions of code and data. The code outside the enclave
> >>>>> is disallowed to access the memory inside the enclave by the CPU access
> >>>>> control.
> >>>>>
> >>>>> There is a new hardware unit in the processor called Memory Encryption
> >>>>> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> >>>>> one or many MEE regions that can hold enclave data by configuring them with
> >>>>> PRMRR registers.
> >>>>>
> >>>>> The MEE automatically encrypts the data leaving the processor package to
> >>>>> the MEE regions. The data is encrypted using a random key whose life-time
> >>>>> is exactly one power cycle.
> >>>>>
> >>>>> The current implementation requires that the firmware sets
> >>>>> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> >>>>> decide what enclaves it wants run. The implementation does not create
> >>>>> any bottlenecks to support read-only MSRs later on.
> >>>>>
> >>>>> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >>>>>
> >>>>> cat /proc/cpuinfo | grep sgx
> >>>>
> >>>> Let's merge this.
> >>>
> >>> So can I tag reviewed-by's?
> >>>
> >>
> >> No, but you already have my tested-by's.
> >>
> >> If it helps I can try to review some patches, but 1) I know nothing
> >> about kernel coding guidelines and best practices and 2) I know little
> >> about most kernel internals, so I won't be able to review every patch.
> >
> > Ackd-by *acknowledges* that the patches work for you. I think that would
> > be then the correct choice for the driver patch and patches before that.
> >
> > Lets go with that if that is cool for you of course.
> >
> > Did you run the selftest only or possibly also some internal Fortanix
> > tests?
> >
>
> v29 patches 2 through 18:
>
> Acked-by: Jethro Beekman <[email protected]>
>
> I only ran production SGX software. I didn't run the self test.
That's great to hear thank you.
Updated my tree accordingly.
/Jarkko
On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
>
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
>
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>
> cat /proc/cpuinfo | grep sgx
>
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
> environment of its own, it really isn't a great fit with more "standard"
> x86 tests.
>
> The RSA key is now generated on fly and the whole signing process has
> been made as part of the enclave loader instead of signing the enclave
> during the compilation time.
>
> Finally, the enclave loader loads now the test enclave directly from its
> ELF file, which means that ELF file does not need to be coverted as raw
> binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
> entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> deadlock with the page reclaimer, which could hold the lock for the old
> mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> be used to reserve the address range. Now /dev/sgx supports only opaque
> mappings to the (initialized) enclave data.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
> from RCX.
>
Tested with the Open Enclave SDK on top of Intel PSW. Specifically built
the Intel PSW with changes to support /dev/sgx mapping[1] new in v29.
Tested-by: Jordan Hand <[email protected]>
[1] https://github.com/intel/linux-sgx/pull/530
Tested on Enarx. This requires a patch[0] for v29 support.
Tested-by: Nathaniel McCallum <[email protected]>
However, we did uncover a small usability issue. See below.
[0]: https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
On Tue, Apr 21, 2020 at 5:53 PM Jarkko Sakkinen
<[email protected]> wrote:
>
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
>
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
>
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>
> cat /proc/cpuinfo | grep sgx
>
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
> environment of its own, it really isn't a great fit with more "standard"
> x86 tests.
>
> The RSA key is now generated on fly and the whole signing process has
> been made as part of the enclave loader instead of signing the enclave
> during the compilation time.
>
> Finally, the enclave loader loads now the test enclave directly from its
> ELF file, which means that ELF file does not need to be coverted as raw
> binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
> entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> deadlock with the page reclaimer, which could hold the lock for the old
> mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> be used to reserve the address range. Now /dev/sgx supports only opaque
> mappings to the (initialized) enclave data.
The statement "Any mapping..." isn't actually true.
Enarx creates a large enclave (currently 64GiB). This worked when we
created a file-backed mapping on /dev/sgx/enclave. However, switching
to an anonymous mapping fails with ENOMEM. We suspect this is because
the kernel attempts to allocate all the pages and zero them but there
is insufficient RAM available. We currently work around this by
creating a shared mapping on /dev/zero.
If we want to keep this mmap() strategy, we probably don't want to
advise mmap(ANON) if it allocates all the memory for the enclave ahead
of time, even if it won't be used. This would be wasteful.
OTOH, having to mmap("/dev/zero") seems a bit awkward.
Currently, the selftest uses mmap(ANON) and the patch message above
recommends it.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
> from RCX.
>
> v28:
> * Documented to Documentation/x86/sgx.rst how the kernel manages the
> enclave ownership.
> * Removed non-LC flow from sgx_einit().
> * Removed struct sgx_einittoken since only the size of the corresponding
> microarchitectural structure is used in the series ATM.
>
> v27:
> * Disallow RIE processes to use enclaves as there could a permission
> conflict between VMA and enclave permissions.
> * In the documentation, replace "grep /proc/cpuinfo" with
> "grep sgx /proc/cpuinfo".
>
> v26:
> * Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
> changed in v25 by mistake.
> * Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
> again for such a detailed feedback).
> * Added back the MAINTAINERS update commit, which was mistakenly removed
> in v25.
> * EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
> CPU does not allow to remove a SECS page before all of its children have
> been removed, and a child page can be in some other section than the one
> currently being processed. Thus, removed special SECS processing from
> sgx_sanitize_page() and instead put sections through it twice. In the
> 2nd round the lists should only contain SECS pages.
>
> v25:
> * Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
> fails on executing ENCLS[EADD]. The rollback path executed
> radix_tree_delete() on the same address twice when this happened.
> * Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
> a signal is pending.
> * As requested by Borislav, move the CPUID 0x12 features to their own word
> in cpufeatures.
> * Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
> was called with an uninitialized pointer when sgx_encl_get_backing()
> fails.
> * Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
> has 'groups' for setting up sysfs attributes for the device.
> * Use device_initcall instead of subsys_initcall so that misc_class is
> initialized before SGX is initialized.
> * Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
> enclave attributes that we the kernel does not allow it to set instead
> of -EINVAL.
> * Unless SGX public key MSRs are writable always deny the feature from
> Linux. Previously this was only denied from driver. How VMs should be
> supported is not really part of initial patch set, which makes this
> an obvious choice.
> * Cleaned up and refined documentation to be more approachable.
>
> v24:
> * Reclaim unmeasured and TCS pages (regression in v23).
> * Replace usages of GFP_HIGHUSER with GFP_KERNEL.
> * Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
> and use the same rollback (destroy enclave). This can happen when host
> suspends itself unknowingly to a VM running enclaves. From -EIO the user
> space can deduce what happened.
> * Have a separate @count in struct sgx_enclave_add_pages to output number
> of bytes processed instead of overwriting the input parameters for
> clarity and more importantly that the API provides means for partial
> processing (@count could be less than @length in success case).
>
> v23:
> * Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
> with %SGX_PAGE_MEASURE flag.
> * Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
> * In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
> (because of OOM) even in legit behaviour and after EBLOCK the reclaiming
> flow can be only reverted by killing the whole enclave.
> * Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
> it should have been bit 6 (Table 37-3 in the SDM).
> * Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
> error code.
>
> v22:
> * Refined bunch commit messages and added associated SDM references as
> many of them were too exhausting and some outdated.
> * Alignment checks have been removed from mmap() because it does not define the
> ELRANGE. VMAs only act as windows to the enclave. The semantics compare
> somewhat how mmap() works with regular files.
> * We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
> page aligned so that we can pass the page directly to EADD and do not have
> to do an extra copy. This was made effectively possible by removing the
> worker thread for adding pages.
> * The selftest build files have been refined throughout of various glitches
> and work properly in a cross compilation environment such as BuildRoot.
> In addition, libcalls fail the build with an assertion in the linker
> script, if they end up to the enclave binary.
> * CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
> for anything without having the driver. This could change when KVM support
> is added.
> * We require zero permissions in SECINFO for TCS pages because the CPU
> overwrites SECINFO flags with zero permissions and measures the page
> only after that. Allowing to pass TCS with non-zero permissions would
> cause mismatching measurement between the one provided in SIGSTRUCT and
> the one computed by the CPU.
> * Obviously lots of small fixes and clean ups (does make sense to
> document them all).
>
> v21:
> * Check on mmap() that the VMA does cover an area that does not have
> enclave pages. Only mapping with PROT_NONE can do that to reserve
> initial address space for an enclave.
> * Check om mmap() and mprotect() that the VMA permissions do not
> surpass the enclave permissions.
> * Remove two refcounts from vma_close(): mm_list and encl->refcount.
> Enclave refcount is only need for swapper/enclave sync and we can
> remove mm_list refcount by destroying mm_struct when the process
> is closed. By not having vm_close() the Linux MM can merge VMAs.
> * Do not naturally align MAP_FIXED address.
> * Numerous small fixes and clean ups.
> * Use SRCU for synchronizing the list of mm_struct's.
> * Move to stack based call convention in the vDSO.
>
> v20:
> * Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
> dependency as MMU notifiers are no longer used in the driver.
> * Use mm_users instead of mm_count as refcount for mm_struct as mm_count
> only protects from deleting mm_struct, not removing its contents.
> * Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
> of them. They could be in initialized state when the kernel starts
> because it might be spawned by kexec().
> * Documentation overhaul.
> * Use a device /dev/sgx/provision for delivering the provision token
> instead of securityfs.
> * Create a reference to the enclave when already when opening
> /dev/sgx/enclave. The file is then associated with this enclave only.
> mmap() can be done at free at any point and always get a reference to
> the enclave. To summarize the file now represents the enclave.
>
> v19:
> * Took 3-4 months but in some sense this was more like a rewrite of most
> of the corners of the source code. If I've forgotten to deal with some
> feedback, please don't shout me. Make a remark and I will fix it for
> the next version. Hopefully there won't be this big turnovers anymore.
> * Validate SECS attributes properly against CPUID given attributes and
> against allowed attributes. SECS attributes are the ones that are
> enforced whereas SIGSTRUCT attributes tell what is required to run
> the enclave.
> * Add KSS (Key Sharing Support) to the enclave attributes.
> * Deny MAP_PRIVATE as an enclave is always a shared memory entity.
> * Revert back to shmem backing storage so that it can be easily shared
> by multiple processes.
> * Split the recognization of an ENCLS leaf failure by using three
> functions to detect it: encsl_faulted(), encls_returned_code() and
> sgx_failed(). encls_failed() is only caused by a spurious expections that
> should never happen. Thus, it is not defined as an inline function in
> order to easily insert a kprobe to it.
> * Move low-level enclave management routines, page fault handler and page
> reclaiming routines from driver to the core. These cannot be separated
> from each other as they are heavily interdependent. The rationale is that
> the core does not call any code from the driver.
> * Allow the driver to be compiled as a module now that it no code is using
> its routines and it only uses exported symbols. Now the driver is
> essentially just a thin ioctl layer.
> * Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
> add new entries to this list as the process is forked. Each entry has
> its own refcount because they have a different life-cycle as the enclave
> does. In effect @tgid and @mm have been removed from struct sgx_encl
> and we allow forking by removing VM_DONTCOPY from vm flags.
> * Generate a cpu mask in the reclaimer from the cpu mask's of all
> mm_struct's. This will kick out the hardware threads out of the enclave
> from multiple processes. It is not a local variable because it would
> eat too much of the stack space but instead a field in struct
> sgx_encl.
> * Allow forking i.e. remove VM_DONTCOPY. I did not change the API
> because the old API scaled to the workload that Andy described. The
> codebase is now mostly API independent i.e. changing the API is a
> small task. For me the proper trigger to chanage it is a as concrete
> as possible workload that cannot be fulfilled. I hope you understand
> my thinking here. I don't want to change anything w/o proper basis
> but I'm ready to change anything if there is a proper basis. I do
> not have any kind of attachment to any particular type of API.
> * Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
> new vDSO.
>
> v18:
> * Update the ioctl-number.txt.
> * Move the driver under arch/x86.
> * Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
> * Rename the selftest as test_sgx (previously sgx-selftest).
> * In order to enable process accounting, swap EPC pages and PCMD's to a VMA
> instead of shmem.
> * Allow only to initialize and run enclaves with a subset of
> {DEBUG, MODE64BIT} set.
> * Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
> attributes e.g. PROVISIONKEY.
>
> v17:
> * Add a simple selftest.
> * Fix a null pointer dereference to section->pages when its
> allocation fails.
> * Add Sean's description of the exception handling to the documentation.
>
> v16:
> * Fixed SOB's in the commits that were a bit corrupted in v15.
> * Implemented exceptio handling properly to detect_sgx().
> * Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
> * Updated the documentation to use rst definition lists.
> * Added the missing Documentation/x86/index.rst, which has a link to
> intel_sgx.rst. Now the SGX and uapi documentation is properly generated
> with 'make htmldocs'.
> * While enumerating EPC sections, if an undefined section is found, fail
> the driver initialization instead of continuing the initialization.
> * Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
> * Remove copyright notice from arch/x86/include/asm/sgx.h.
> * Migrated from ioremap_cache() to memremap().
>
> v15:
> * Split into more digestable size patches.
> * Lots of small fixes and clean ups.
> * Signal a "plain" SIGSEGV on an EPCM violation.
>
> v14:
> * Change the comment about X86_FEATURE_SGX_LC from “SGX launch
> configuration” to “SGX launch control”.
> * Move the SGX-related CPU feature flags as part of the Linux defined
> virtual leaf 8.
> * Add SGX_ prefix to the constants defining the ENCLS leaf functions.
> * Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
> * Refine the long description for CONFIG_INTEL_SGX_CORE.
> * Do not use pr_*_ratelimited() in the driver. The use of the rate limited
> versions is legacy cruft from the prototyping phase.
> * Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
> cycles.
> * Manually prefix with “sgx:” in the core SGX code instead of redefining
> pr_fmt.
> * Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
> instead of core because it is a driver requirement.
> * Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
> default is ‘n’.
> * Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
> the SDM.
> * Allocate struct sgx_epc_page instances one at a time.
> * Use “__iomem void *” pointers for the mapped EPC memory consistently.
> * Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
> cycles.
> * Call enclave swapping operations directly from the driver instead of
> calling them .indirectly through struct sgx_epc_page_ops because indirect
> calls are not required yet as the patch set does not contain the KVM
> support.
> * Added special signal SEGV_SGXERR to notify about SGX EPCM violation
> errors.
>
> v13:
> * Always use SGX_CPUID constant instead of a hardcoded value.
> * Simplified and documented the macros and functions for ENCLS leaves.
> * Enable sgx_free_page() to free active enclave pages on demand
> in order to allow sgx_invalidate() to delete enclave pages.
> It no longer performs EREMOVE if a page is in the process of
> being reclaimed.
> * Use PM notifier per enclave so that we don't have to traverse
> the global list of active EPC pages to find enclaves.
> * Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
> * Always use ioremap() to map EPC banks as we only support 64-bit kernel.
> * Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
> to sleep.
>
> v12:
> * Split to more narrow scoped commits in order to ease the review process and
> use co-developed-by tag for co-authors of commits instead of listing them in
> the source files.
> * Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
> * Removed in-kernel LE i.e. this version of the SGX software stack only
> supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
> * Refined documentation on launching enclaves, swapping and enclave
> construction.
> * Refined sgx_arch.h to include alignment information for every struct that
> requires it and removed structs that are not needed without an LE.
> * Got rid of SGX_CPUID.
> * SGX detection now prints log messages about firmware configuration issues.
>
> v11:
> * Polished ENCLS wrappers with refined exception handling.
> * ksgxswapd was not stopped (regression in v5) in
> sgx_page_cache_teardown(), which causes a leaked kthread after driver
> deinitialization.
> * Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
> invalidated when resuming, which will cause it not function properly
> anymore.
> * Set EINITTOKEN.VALID to zero for a token that is passed when
> SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
> page.
> * Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
> around the flags field, which causes a #GP. Only flags read is readable.
> * On read access memcpy() call inside sgx_vma_access() had src and dest
> parameters in wrong order.
> * The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
> to LE even if “KASAN_SANITIZE := false” was set in the makefile.
> * Fixed a regression in the #PF handler. If a page has
> SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
> It did not, which caused weird races when trying to change other parts of
> swapping code.
> * EPC management has been refactored to a flat LRU cache and moved to
> arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
> of them. It can now swap from multiple enclaves in the same round.
> * For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
> when an enclave is already initialized or dead instead of zero.
>
> v10:
> * Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
> of the driver.
> * Unset the reserved flag from an enclave page if EDBGRD/WR fails
> (regression in v6).
> * Close the anon inode when LE is stopped (regression in v9).
> * Update the documentation with a more detailed description of SGX.
>
> v9:
> * Replaced kernel-LE IPC based on pipes with an anonymous inode.
> The driver does not require anymore new exports.
>
> v8:
> * Check that public key MSRs match the LE public key hash in the
> driver initialization when the MSRs are read-only.
> * Fix the race in VA slot allocation by checking the fullness
> immediately after succeesful allocation.
> * Fix the race in hash mrsigner calculation between the launch
> enclave and user enclaves by having a separate lock for hash
> calculation.
>
> v7:
> * Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
> when it should have been masked with ~PAGE_MASK.
> * Fixed a memory leak in sgx_ioc_enclave_create().
> * Simplified swapping code by using a pointer array for a cluster
> instead of a linked list.
> * Squeezed struct sgx_encl_page to 32 bytes.
> * Fixed deferencing of an RSA key on OpenSSL 1.1.0.
> * Modified TC's CMAC to use kernel AES-NI. Restructured the code
> a bit in order to better align with kernel conventions.
>
> v6:
> * Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
> * In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
> * Removed virtualization chapter from the documentation.
> * Changed the default filename for the signing key as signing_key.pem.
> * Reworked EPC management in a way that instead of a linked list of
> struct sgx_epc_page instances there is an array of integers that
> encodes address and bank of an EPC page (the same data as 'pa' field
> earlier). The locking has been moved to the EPC bank level instead
> of a global lock.
> * Relaxed locking requirements for EPC management. EPC pages can be
> released back to the EPC bank concurrently.
> * Cleaned up ptrace() code.
> * Refined commit messages for new architectural constants.
> * Sorted includes in every source file.
> * Sorted local variable declarations according to the line length in
> every function.
> * Style fixes based on Darren's comments to sgx_le.c.
>
> v5:
> * Described IPC between the Launch Enclave and kernel in the commit messages.
> * Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
> versions except those that exist in the imported TinyCrypt code.
> * Fixed spelling mistakes in the documentation.
> * Forgot to check the return value of sgx_drv_subsys_init().
> * Encapsulated properly page cache init and teardown.
> * Collect epc pages to a temp list in sgx_add_epc_bank
> * Removed SGX_ENCLAVE_INIT_ARCH constant.
>
> v4:
> * Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
> * Removed __exit annotation from sgx_drv_subsys_exit().
> * Fixed a leak of a backing page in sgx_process_add_page_req() in the
> case when vm_insert_pfn() fails.
> * Removed unused symbol exports for sgx_page_cache.c.
> * Updated sgx_alloc_page() to require encl parameter and documented the
> behavior (Sean Christopherson).
> * Refactored a more lean API for sgx_encl_find() and documented the behavior.
> * Moved #PF handler to sgx_fault.c.
> * Replaced subsys_system_register() with plain bus_register().
> * Retry EINIT 2nd time only if MSRs are not locked.
>
> v3:
> * Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
> * Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
> * Use unused bits in epc_page->pa to store the bank number.
> * Removed #ifdef for WQ_NONREENTRANT.
> * If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
> * Added --remove-section=.got.plt to objcopy flags in order to prevent a
> dummy .got.plt, which will cause an inconsistent size for the LE.
> * Documented sgx_encl_* functions.
> * Added remark about AES implementation used inside the LE.
> * Removed redundant sgx_sys_exit() from le/main.c.
> * Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
> * Validate miscselect in sgx_encl_create().
> * Fixed SSA frame size calculation to take the misc region into account.
> * Implemented consistent exception handling to __encls() and __encls_ret().
> * Implemented a proper device model in order to allow sysfs attributes
> and in-kernel API.
> * Cleaned up various "find enclave" implementations to the unified
> sgx_encl_find().
> * Validate that vm_pgoff is zero.
> * Discard backing pages with shmem_truncate_range() after EADD.
> * Added missing EEXTEND operations to LE signing and launch.
> * Fixed SSA size for GPRS region from 168 to 184 bytes.
> * Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
> * Check that TCS addresses are in ELRANGE and not just page aligned.
> * Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
> * Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.
>
> v2:
> * get_rand_uint32() changed the value of the pointer instead of value
> where it is pointing at.
> * Launch enclave incorrectly used sigstruct attributes-field instead of
> enclave attributes-field.
> * Removed unused struct sgx_add_page_req from sgx_ioctl.c
> * Removed unused sgx_has_sgx2.
> * Updated arch/x86/include/asm/sgx.h so that it provides stub
> implementations when sgx in not enabled.
> * Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
> * return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
> * removed unused global sgx_nr_pids
> * moved sgx_encl_release to sgx_encl.c
> * return -ERESTARTSYS instead of -EINTR in sgx_encl_init()
>
> Jarkko Sakkinen (10):
> x86/sgx: Update MAINTAINERS
> x86/sgx: Add SGX microarchitectural data structures
> x86/sgx: Add wrappers for ENCLS leaf functions
> x86/sgx: Add functions to allocate and free EPC pages
> x86/sgx: Linux Enclave Driver
> x86/sgx: Add provisioning
> x86/sgx: Add a page reclaimer
> x86/sgx: ptrace() support for the SGX driver
> selftests/x86: Add a selftest for SGX
> docs: x86/sgx: Document SGX micro architecture and kernel internals
>
> Sean Christopherson (10):
> x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
> x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
> x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
> x86/cpu/intel: Detect SGX support
> x86/sgx: Enumerate and track EPC sections
> mm: Introduce vm_ops->may_mprotect()
> x86/vdso: Add support for exception fixup in vDSO functions
> x86/fault: Add helper function to sanitize error code
> x86/traps: Attempt to fixup exceptions in vDSO before signaling
> x86/vdso: Implement a vDSO for Intel SGX enclave call
>
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> Documentation/x86/index.rst | 1 +
> Documentation/x86/sgx.rst | 206 +++++
> MAINTAINERS | 11 +
> arch/x86/Kconfig | 14 +
> arch/x86/entry/vdso/Makefile | 8 +-
> arch/x86/entry/vdso/extable.c | 46 +
> arch/x86/entry/vdso/extable.h | 29 +
> arch/x86/entry/vdso/vdso-layout.lds.S | 9 +-
> arch/x86/entry/vdso/vdso.lds.S | 1 +
> arch/x86/entry/vdso/vdso2c.h | 58 +-
> arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++
> arch/x86/include/asm/cpufeature.h | 5 +-
> arch/x86/include/asm/cpufeatures.h | 8 +-
> arch/x86/include/asm/disabled-features.h | 18 +-
> arch/x86/include/asm/enclu.h | 8 +
> arch/x86/include/asm/msr-index.h | 8 +
> arch/x86/include/asm/required-features.h | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/include/asm/vdso.h | 5 +
> arch/x86/include/uapi/asm/sgx.h | 175 ++++
> arch/x86/kernel/cpu/Makefile | 1 +
> arch/x86/kernel/cpu/common.c | 4 +
> arch/x86/kernel/cpu/feat_ctl.c | 32 +-
> arch/x86/kernel/cpu/sgx/Makefile | 6 +
> arch/x86/kernel/cpu/sgx/arch.h | 343 ++++++++
> arch/x86/kernel/cpu/sgx/driver.c | 209 +++++
> arch/x86/kernel/cpu/sgx/driver.h | 32 +
> arch/x86/kernel/cpu/sgx/encl.c | 756 +++++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 128 +++
> arch/x86/kernel/cpu/sgx/encls.h | 238 ++++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 800 ++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 280 ++++++
> arch/x86/kernel/cpu/sgx/reclaim.c | 471 +++++++++++
> arch/x86/kernel/cpu/sgx/sgx.h | 108 +++
> arch/x86/kernel/traps.c | 14 +
> arch/x86/mm/fault.c | 45 +-
> include/linux/mm.h | 2 +
> mm/mprotect.c | 14 +-
> tools/arch/x86/include/asm/cpufeatures.h | 7 +-
> tools/testing/selftests/Makefile | 1 +
> tools/testing/selftests/sgx/.gitignore | 2 +
> tools/testing/selftests/sgx/Makefile | 53 ++
> tools/testing/selftests/sgx/call.S | 54 ++
> tools/testing/selftests/sgx/defines.h | 21 +
> tools/testing/selftests/sgx/load.c | 282 ++++++
> tools/testing/selftests/sgx/main.c | 199 +++++
> tools/testing/selftests/sgx/main.h | 38 +
> tools/testing/selftests/sgx/sigstruct.c | 395 +++++++++
> tools/testing/selftests/sgx/test_encl.c | 20 +
> tools/testing/selftests/sgx/test_encl.lds | 40 +
> .../selftests/sgx/test_encl_bootstrap.S | 89 ++
> 52 files changed, 5398 insertions(+), 31 deletions(-)
> create mode 100644 Documentation/x86/sgx.rst
> create mode 100644 arch/x86/entry/vdso/extable.c
> create mode 100644 arch/x86/entry/vdso/extable.h
> create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
> create mode 100644 arch/x86/include/asm/enclu.h
> create mode 100644 arch/x86/include/uapi/asm/sgx.h
> create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
> create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
> create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/main.c
> create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
> create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
> create mode 100644 tools/testing/selftests/sgx/.gitignore
> create mode 100644 tools/testing/selftests/sgx/Makefile
> create mode 100644 tools/testing/selftests/sgx/call.S
> create mode 100644 tools/testing/selftests/sgx/defines.h
> create mode 100644 tools/testing/selftests/sgx/load.c
> create mode 100644 tools/testing/selftests/sgx/main.c
> create mode 100644 tools/testing/selftests/sgx/main.h
> create mode 100644 tools/testing/selftests/sgx/sigstruct.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.lds
> create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
>
> --
> 2.25.1
>
On Wed, Apr 22, 2020 at 12:53:10AM +0300, Jarkko Sakkinen wrote:
> Add VMA callbacks for ptrace() that can be used with debug enclaves.
> With debug enclaves data can be read and write the memory word at a time
> by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.
>
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> arch/x86/kernel/cpu/sgx/encl.c | 88 ++++++++++++++++++++++++++++++++++
> 1 file changed, 88 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index fe7dbca40bb4..0c5ea2968868 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -326,6 +326,7 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> return 0;
> }
>
> +
Unnecessary whitespace change.
> static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
> unsigned long end, unsigned long prot)
> {
On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
> Tested on Enarx. This requires a patch[0] for v29 support.
>
> Tested-by: Nathaniel McCallum <[email protected]>
>
> However, we did uncover a small usability issue. See below.
>
> [0]: https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
...
> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> > be used to reserve the address range. Now /dev/sgx supports only opaque
> > mappings to the (initialized) enclave data.
>
> The statement "Any mapping..." isn't actually true.
>
> Enarx creates a large enclave (currently 64GiB). This worked when we
> created a file-backed mapping on /dev/sgx/enclave. However, switching
> to an anonymous mapping fails with ENOMEM. We suspect this is because
> the kernel attempts to allocate all the pages and zero them but there
> is insufficient RAM available. We currently work around this by
> creating a shared mapping on /dev/zero.
Hmm, the kernel shouldn't actually allocate physical pages unless they're
written. I'll see if I can reproduce.
> If we want to keep this mmap() strategy, we probably don't want to
> advise mmap(ANON) if it allocates all the memory for the enclave ahead
> of time, even if it won't be used. This would be wasteful.
>
> OTOH, having to mmap("/dev/zero") seems a bit awkward.
Greg,
"Dr. Greg" <[email protected]> writes:
> As an aside, for those who haven't spent the last 5+ years of their
> life working with this technology. SGX2 hardware platforms have the
> ability to allow unrestricted code execution in enclave context.
Unrestricted code execution even before loaded? Unrestricted by
priviledge levels?
> No amount of LSM or IMA interventions can provide any control over
> that.
They can restrict what is started and loaded before anything SGX
happens.
If you want to make real technical arguments then please be specific and
precise and spare us the handwaving marketing speak.
> In fact, the Confidential Computing Consortium, sponsored by none
> other then the Linux Foundation, has at its fundamental tenant,
And that's relevant to the technical question in which way?
> the notion of developing an eco-system that allows the execution of
> code and processing of data, over which, the owner or administrator of
> the platform has no visibility or control. It would seem only logical
> that adversarial interests would indulge themseleves in those
> capabilities as well.
>
> With respect to SGX and these issues, cryptographic policy management
> is important for the same reason that 2-factor authentication is now
> considered standard practice in the security industry.
>
> We appreciate, Jarkko, that you feel that such infrastructure is
> optional, like virtualization support, and is something that can go in
> after the driver is mainlined. As the diffstat for our patch points
> out, the proposed support has virtually no impact on the driver, the
> same cannot be said for virtualization capabilities.
The diffstat of your patch is irrelevant. What's relevant is the fact
that it is completely unreviewed and that it creates yet another user
space visible ABI with a noticable lack of documentation.
> Moreover, adding support for key based policy management later would
> require the addition of another ioctl in order to avoid ABI
> compatibility issues.
And that's a problem because?
> The current initialization ioctl is best suited, from an engineering
> perspective, to support this type of infrastructure.
What's wrong with having IOCTL_INIT_TYPE_A and IOCTL_INIT_TYPE_B?
Nothing at all. It's pretty straight forward and in fact a better
solution than a duct taped multiplexing all in one IOCTL_INIT_PONIES
approach.
> In fact, the necessary support was removed from the ioctl for
> political reasons rather then for any valid engineering rationale on
> flexible launch control platforms, particularly with our patch or an
> equivalent approach.
You're surely making a convincing technical argument by claiming that
this was a political decision. The amount of non-technical, i.e.
political arguments in your mail is definitely larger than the technical
content.
> Hopefully this is a reasoned technical approach to what has been a
> long standing issue surrounding this technology.
It's an approach which guarantees that the driver will miss the next
merge window. If that's your intention, then please let us know.
Merging the current set of patches does not prevent anything you want to
be added. It's an extension to the base implementation and not a
prerequisite.
> Best wishes for a productive week.
>
> Dr. Greg
Thanks a lot for the best wishes. Unfortunately reading this email was
not necessarily productive for me, but I surely wish that you can make
productive use of my reply.
Thanks,
tglx
> ------------------------------------------------------------------------------
> "Opportunity is missed by most people because it is dressed in overalls
> and looks like work."
> -- Thomas Edison
------------------------------------------------------------------------------
"Failure is simply the opportunity to begin again, this time more
intelligently"
-- Henry Ford
On Wed, 06 May 2020 17:14:22 -0500, Sean Christopherson
<[email protected]> wrote:
> On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
>> Tested on Enarx. This requires a patch[0] for v29 support.
>>
>> Tested-by: Nathaniel McCallum <[email protected]>
>>
>> However, we did uncover a small usability issue. See below.
>>
>> [0]:
>> https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
>
> ...
>
>> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g.
>> anonymous) can
>> > be used to reserve the address range. Now /dev/sgx supports only
>> opaque
>> > mappings to the (initialized) enclave data.
>>
>> The statement "Any mapping..." isn't actually true.
>>
>> Enarx creates a large enclave (currently 64GiB). This worked when we
>> created a file-backed mapping on /dev/sgx/enclave. However, switching
>> to an anonymous mapping fails with ENOMEM. We suspect this is because
>> the kernel attempts to allocate all the pages and zero them but there
>> is insufficient RAM available. We currently work around this by
>> creating a shared mapping on /dev/zero.
>
> Hmm, the kernel shouldn't actually allocate physical pages unless they're
> written. I'll see if I can reproduce.
>
For larger size mmap, I think it requires enabling vm overcommit mode 1:
echo 1 | sudo tee /proc/sys/vm/overcommit_memory
>> If we want to keep this mmap() strategy, we probably don't want to
>> advise mmap(ANON) if it allocates all the memory for the enclave ahead
>> of time, even if it won't be used. This would be wasteful.
>>
>> OTOH, having to mmap("/dev/zero") seems a bit awkward.
--
Using Opera's mail client: http://www.opera.com/mail/
On Thu, May 7, 2020 at 1:03 AM Haitao Huang
<[email protected]> wrote:
>
> On Wed, 06 May 2020 17:14:22 -0500, Sean Christopherson
> <[email protected]> wrote:
>
> > On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
> >> Tested on Enarx. This requires a patch[0] for v29 support.
> >>
> >> Tested-by: Nathaniel McCallum <[email protected]>
> >>
> >> However, we did uncover a small usability issue. See below.
> >>
> >> [0]:
> >> https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
> >
> > ...
> >
> >> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g.
> >> anonymous) can
> >> > be used to reserve the address range. Now /dev/sgx supports only
> >> opaque
> >> > mappings to the (initialized) enclave data.
> >>
> >> The statement "Any mapping..." isn't actually true.
> >>
> >> Enarx creates a large enclave (currently 64GiB). This worked when we
> >> created a file-backed mapping on /dev/sgx/enclave. However, switching
> >> to an anonymous mapping fails with ENOMEM. We suspect this is because
> >> the kernel attempts to allocate all the pages and zero them but there
> >> is insufficient RAM available. We currently work around this by
> >> creating a shared mapping on /dev/zero.
> >
> > Hmm, the kernel shouldn't actually allocate physical pages unless they're
> > written. I'll see if I can reproduce.
> >
>
> For larger size mmap, I think it requires enabling vm overcommit mode 1:
> echo 1 | sudo tee /proc/sys/vm/overcommit_memory
Which means the default experience isn't good.
On Wed, May 06, 2020 at 09:39:55AM -0700, Jordan Hand wrote:
Good afternoon, I hope the week is going well for everyone.
> On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
> > Make the vDSO callable directly from C by preserving RBX and taking leaf
> > from RCX.
> Tested with the Open Enclave SDK on top of Intel PSW. Specifically built
> the Intel PSW with changes to support /dev/sgx mapping[1] new in v29.
>
> Tested-by: Jordan Hand <[email protected]>
>
> [1] https://github.com/intel/linux-sgx/pull/530
Did you re-wire your SDK to convert all your ECALL and exception
handling to the new VDSO architecture?
Failures in enclave loading and initialization demonstrate themselves
pretty clearly and are in the domain of the PSW being used. If there
are going to be subtle SGX application operability issues that need to
be found they will be in the new ECALL and exception handling
mechanisms.
Have a good remainder of the day.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
Enjellic Systems Development, LLC self-defensive IOT platforms
4206 N. 19th Ave. and edge devices.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"Davidsen's first rule of system administration: He learns to swim fastest
who is thrown in the deepest water."
-- Bill Davidsen
On Thu, May 07, 2020 at 12:49:15PM -0400, Nathaniel McCallum wrote:
> On Thu, May 7, 2020 at 1:03 AM Haitao Huang
> <[email protected]> wrote:
> >
> > On Wed, 06 May 2020 17:14:22 -0500, Sean Christopherson
> > <[email protected]> wrote:
> >
> > > On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
> > >> Tested on Enarx. This requires a patch[0] for v29 support.
> > >>
> > >> Tested-by: Nathaniel McCallum <[email protected]>
> > >>
> > >> However, we did uncover a small usability issue. See below.
> > >>
> > >> [0]:
> > >> https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
> > >
> > > ...
> > >
> > >> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g.
> > >> anonymous) can
> > >> > be used to reserve the address range. Now /dev/sgx supports only
> > >> opaque
> > >> > mappings to the (initialized) enclave data.
> > >>
> > >> The statement "Any mapping..." isn't actually true.
Yeah, this definitely misleading. I haven't looked at our most recent docs,
but I'm going to go out on a limb and assume we haven't documented the
preferred mechanism for carving out virtual memory for the enclave. That
absolutely should be done.
> > >> Enarx creates a large enclave (currently 64GiB). This worked when we
> > >> created a file-backed mapping on /dev/sgx/enclave. However, switching
> > >> to an anonymous mapping fails with ENOMEM. We suspect this is because
> > >> the kernel attempts to allocate all the pages and zero them but there
> > >> is insufficient RAM available. We currently work around this by
> > >> creating a shared mapping on /dev/zero.
> > >
> > > Hmm, the kernel shouldn't actually allocate physical pages unless they're
> > > written. I'll see if I can reproduce.
> > >
> >
> > For larger size mmap, I think it requires enabling vm overcommit mode 1:
> > echo 1 | sudo tee /proc/sys/vm/overcommit_memory
It shouldn't unless the initial mmap is "broken". Not truly broken, but
broken in the sense that what Enarx is asking for is not actually what it
desires.
> Which means the default experience isn't good.
What PROT_* and MAP_* flags are passed to mmap()? Overcommit only applies
to
VM_WRITE (a.k.a. PROT_WRITE) && !VM_SHARED && !VM_NORESERVED
and, ignoring rlimits, VM expansion only applies to
VM_WRITE && !VM_SHARED && !VM_STACK
So hopefully Enarx is doing something like
base = mmap(NULL, 64gb, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
because that means this is effectively a userspace bug. This goes back to
my comment about the mmap() being "broken". Userspace is asking for a
writable, private mapping, in which case it absolutely should be accounted.
If using
base = mmap(NULL, 64gb, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
works, then updating the SGX docs to better explain how to establish ELRANGE
is sufficient (we need to that in any case). If the above still fails then
something else is in play.
On Thu, 07 May 2020 11:49:15 -0500, Nathaniel McCallum
<[email protected]> wrote:
> On Thu, May 7, 2020 at 1:03 AM Haitao Huang
> <[email protected]> wrote:
>>
>> On Wed, 06 May 2020 17:14:22 -0500, Sean Christopherson
>> <[email protected]> wrote:
>>
>> > On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
>> >> Tested on Enarx. This requires a patch[0] for v29 support.
>> >>
>> >> Tested-by: Nathaniel McCallum <[email protected]>
>> >>
>> >> However, we did uncover a small usability issue. See below.
>> >>
>> >> [0]:
>> >>
>> https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
>> >
>> > ...
>> >
>> >> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g.
>> >> anonymous) can
>> >> > be used to reserve the address range. Now /dev/sgx supports only
>> >> opaque
>> >> > mappings to the (initialized) enclave data.
>> >>
>> >> The statement "Any mapping..." isn't actually true.
>> >>
>> >> Enarx creates a large enclave (currently 64GiB). This worked when we
>> >> created a file-backed mapping on /dev/sgx/enclave. However, switching
>> >> to an anonymous mapping fails with ENOMEM. We suspect this is because
>> >> the kernel attempts to allocate all the pages and zero them but there
>> >> is insufficient RAM available. We currently work around this by
>> >> creating a shared mapping on /dev/zero.
>> >
>> > Hmm, the kernel shouldn't actually allocate physical pages unless
>> they're
>> > written. I'll see if I can reproduce.
>> >
>>
>> For larger size mmap, I think it requires enabling vm overcommit mode 1:
>> echo 1 | sudo tee /proc/sys/vm/overcommit_memory
>
> Which means the default experience isn't good.
>
Yes, it is not good default. But this is not sgx specific IIUC. Normal
applications would have the same issue if they ask for large mapping than
whatever limit kernel enforces by default.
On Thu, 07 May 2020 14:34:59 -0500, Sean Christopherson
<[email protected]> wrote:
> On Thu, May 07, 2020 at 12:49:15PM -0400, Nathaniel McCallum wrote:
>> On Thu, May 7, 2020 at 1:03 AM Haitao Huang
>> <[email protected]> wrote:
>> >
>> > On Wed, 06 May 2020 17:14:22 -0500, Sean Christopherson
>> > <[email protected]> wrote:
>> >
>> > > On Wed, May 06, 2020 at 05:42:42PM -0400, Nathaniel McCallum wrote:
>> > >> Tested on Enarx. This requires a patch[0] for v29 support.
>> > >>
>> > >> Tested-by: Nathaniel McCallum <[email protected]>
>> > >>
>> > >> However, we did uncover a small usability issue. See below.
>> > >>
>> > >> [0]:
>> > >>
>> https://github.com/enarx/enarx/pull/507/commits/80da2352aba46aa7bc6b4d1fccf20fe1bda58662
>> > >
>> > > ...
>> > >
>> > >> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g.
>> > >> anonymous) can
>> > >> > be used to reserve the address range. Now /dev/sgx supports
>> only
>> > >> opaque
>> > >> > mappings to the (initialized) enclave data.
>> > >>
>> > >> The statement "Any mapping..." isn't actually true.
>
> Yeah, this definitely misleading. I haven't looked at our most recent
> docs,
> but I'm going to go out on a limb and assume we haven't documented the
> preferred mechanism for carving out virtual memory for the enclave. That
> absolutely should be done.
>
>> > >> Enarx creates a large enclave (currently 64GiB). This worked when
>> we
>> > >> created a file-backed mapping on /dev/sgx/enclave. However,
>> switching
>> > >> to an anonymous mapping fails with ENOMEM. We suspect this is
>> because
>> > >> the kernel attempts to allocate all the pages and zero them but
>> there
>> > >> is insufficient RAM available. We currently work around this by
>> > >> creating a shared mapping on /dev/zero.
>> > >
>> > > Hmm, the kernel shouldn't actually allocate physical pages unless
>> they're
>> > > written. I'll see if I can reproduce.
>> > >
>> >
>> > For larger size mmap, I think it requires enabling vm overcommit mode
>> 1:
>> > echo 1 | sudo tee /proc/sys/vm/overcommit_memory
>
> It shouldn't unless the initial mmap is "broken". Not truly broken, but
> broken in the sense that what Enarx is asking for is not actually what it
> desires.
>
So I tried, this passes with mode 1 but fail with ENOMEM by default:
mmap(NULL, 0x100000000000UL, PROT_NONE, MAP_SHARED| MAP_ANONYMOUS, -1, 0);
On Thu, May 07, 2020 at 05:35:31PM -0500, Haitao Huang wrote:
> On Thu, 07 May 2020 14:34:59 -0500, Sean Christopherson
> <[email protected]> wrote:
>
> >On Thu, May 07, 2020 at 12:49:15PM -0400, Nathaniel McCallum wrote:
> >>> For larger size mmap, I think it requires enabling vm overcommit mode
> >>1:
> >>> echo 1 | sudo tee /proc/sys/vm/overcommit_memory
> >
> >It shouldn't unless the initial mmap is "broken". Not truly broken, but
> >broken in the sense that what Enarx is asking for is not actually what it
> >desires.
> >
> So I tried, this passes with mode 1 but fail with ENOMEM by default:
>
> mmap(NULL, 0x100000000000UL, PROT_NONE, MAP_SHARED| MAP_ANONYMOUS, -1, 0);
Ah, fudge. shmem_zero_setup() triggers shmem_acct_size() and thus
__vm_enough_memory(). Which I should have rememered because I've stared
at that code several times when dealing with the enclave's backing store.
I wasn't seeing the issue because I happened to use MAP_PRIVATE.
So, bad analysis, good conclusion, i.e. the kernel is still doing the
right thing, it's just not ideal for userspace.
Jarkko, we should update the docs and selftest to recommend and use
PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS
or
PROT_NONE, MAP_SHARED | MAP_NORESERVE | MAP_ANONYMOUS"
when carving out ELRANGE, with an explicit comment that all the normal
rules for mapping memory still apply.
On Wed, Apr 29, 2020 at 8:30 AM Sean Christopherson
<[email protected]> wrote:
>
> On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> > In closing, it is important to note that the proposed SGX driver is
> > not available as a module. This effectively excludes any alternative
> > implementations of the driver without replacement of the kernel at
> > large.
>
> No it doesn't. The SGX subsytem won't allocate EPC pages unless userspace
> creates an enclave, i.e. preventing unprivileged userspace from accessing
> /dev/sgx/enclave will allow loading an alternative out-of-tree SGX module.
> Yes, SGX sanitizes the EPC on boot, but that's arguably a good thing for
> out-of-tree modules.
>
> And if you want to get crafty and squash in-kernel SGX altogether, boot
> with "clearcpuid=<SGX_LC>" and/or "clearcpuid=<SGX>" to disable in-kernel
> support entirely. SGX won't be correctly enumerated in /proc/cpuinfo
> relative to the existence of an out-of-tree module, but that seems like a
> very minor issue if you're running with a completely different SGX driver.
>
> > It also means that any platform, with SGX hardware support,
> > running a kernel with this driver, has the potential for the
> > security/privacy issues noted above.
>
> Unless I'm mistaken, /dev/sgx is root-only by default. There are far
> scarier mechanisms available to root for hosing the system.
>
> > If key based policy management is not allowed, then the driver needs
> > to be re-architected to have modular support so that alternative
> > implementations or the absence of any driver support are at least
> > tenable.
>
> As above, using an alternative implementation is teneble, albeit a bit
> kludgy.
It is worth noting that, if someone actualy does this, and a future
kernel patch breaks it, the upstream developers are unlikely to
apologize or even feel particularly bad. See, for example, the
current situation with VirtualBox.
On 5/7/20 11:06 AM, Dr. Greg wrote:
> On Wed, May 06, 2020 at 09:39:55AM -0700, Jordan Hand wrote:
>
> Good afternoon, I hope the week is going well for everyone.
>
>> On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
>>> Make the vDSO callable directly from C by preserving RBX and taking leaf
>>> from RCX.
>
>> Tested with the Open Enclave SDK on top of Intel PSW. Specifically built
>> the Intel PSW with changes to support /dev/sgx mapping[1] new in v29.
>>
>> Tested-by: Jordan Hand <[email protected]>
>>
>> [1] https://github.com/intel/linux-sgx/pull/530
>
> Did you re-wire your SDK to convert all your ECALL and exception
> handling to the new VDSO architecture?
>
No. We have many users of our SDK who rely on the out-of-tree driver and
will for the foreseeable future. I aim to support both in-tree and
out-of-tree with minimal code diff.
>
> Failures in enclave loading and initialization demonstrate themselves
> pretty clearly and are in the domain of the PSW being used. If there
> are going to be subtle SGX application operability issues that need to
> be found they will be in the new ECALL and exception handling
> mechanisms.
Fair enough, no I have not tested those mechanisms. Apologies, I should
have removed that line from the quoted text.
-Jordan
On Thu, May 07, 2020 at 02:41:30AM +0200, Thomas Gleixner wrote:
> Greg,
Good morning Thomas, I hope the week has gone well for you, the same
to everyone else reading this.
> "Dr. Greg" <[email protected]> writes:
> > As an aside, for those who haven't spent the last 5+ years of their
> > life working with this technology. SGX2 hardware platforms have the
> > ability to allow unrestricted code execution in enclave context.
> Unrestricted code execution even before loaded? Unrestricted by
> priviledge levels?
The LSM/IMA infrastructure will have no visibility into code that will
be executed and data processed in enclave context, see immediately
below.
> > No amount of LSM or IMA interventions can provide any control over
> > that.
> They can restrict what is started and loaded before anything SGX
> happens.
At best, the visibility and inspection will be over a standard
bootstrap loader of some type is in no way related to the actual code
that will be executed or data processed in enclave context.
Furthermore, given what is becoming the excepted software architecture
for the SGX industry, that code will largely have full access to
system resources.
> If you want to make real technical arguments then please be specific
> and precise and spare us the handwaving marketing speak.
Thomas, you don't know me from boo, those that do know me and have
worked for me would tell you with absolute certainty that being a
'handwavy marketing type' is the complete antithesis of my character
and how I practice engineering.
Andy wanted to know why I felt the current driver disadvantaged our
work, I provided a technical summary, omitted completely in your
response, that indicated how we are using SGX technology in a manner
that is inherently different from the rest of the industry.
> > In fact, the Confidential Computing Consortium, sponsored by none
> > other then the Linux Foundation, has at its fundamental tenant,
> And that's relevant to the technical question in which way?
It speaks directly to the primary marketing objective that is driving
the economics of what this technology is going to turn into. The
metaphor for objective, that now seems to be generally accepted, is
'Runtime Encryption'.
One of the most common threads on the SGX developer's list is how
developers can restrict the ability of other's to see what their
enclaves are doing or the code in them. The standard response is
'nothing', a security context has to be established through remote
attestation and the confidential material then conveyed into the
enclave using appropriate confidentiality and integrity protections.
As further technical evidence for all of this, I would refer readers
to the following tag in the Intel Linux SGX SDK:
sgx_2.1.3
That tags the release that introduced the implementation of Protected
Code Loader (PCL) support. This allows developers to create enclaves
that are encrypted at rest and then decrypted, loaded and executed by
a second bootstrap loader enclave that protects the confidentiality of
the first enclave.
SGX2 hardware support makes the concept of protected code loading, at
once, more practical, more efficient and closes a visibility
vulnerability that the current PCL model has.
The impact of this has to be viewed in the context of the economic
market forces that are driving 'runtime encryption'.
The original SGX programming model promoted by Intel was to partition
applications so that sensitive data, and the code that operated on it,
were inside of an enclave. That approach was doomed by the economic
factors driving software development which are roughly as follows:
1.) Ease of development.
2.) Cost of development.
3.) Time to market.
4.) Return on investment.
5.) Security
In about that order, although there are probably a half dozen other
factors between 4 and 5.
As a result, the 'runtime encryption' industry moved to a library OS
model where unmodified applications can be run in an enclave along
along with full interpreter environments such as Java, Python,
Javascript and WASM. In this architecture all of the requests for
operating system resources are shimmed through OCALL's to be serviced
by the OS.
If you combine all of these factors and influences, you end up with,
looking forward, to an architecture that will favor a small bootstrap
loader that downloads and executes code, over protected channels, that
has almost full access to operating system resources. In this model
the only visibility that the platform owner has, and by extension the
LSM/IMA infrastructure, is the bootstrap loader itself.
This architecture will also be driven by how attractive the concept is
to the devops model and cloud orchestration in general.
Our technical arguement is that it does not seem unreasonable for the
Linux driver, at the discretion of the platform owner, to be able to
implement the equivalent of 2-factor authentication over the
initiation of such execution.
I apologize for the detail and hope it is at once both suitably
technical and 'non-hand-wavy'.
> > the notion of developing an eco-system that allows the execution of
> > code and processing of data, over which, the owner or administrator of
> > the platform has no visibility or control. It would seem only logical
> > that adversarial interests would indulge themseleves in those
> > capabilities as well.
> >
> > With respect to SGX and these issues, cryptographic policy management
> > is important for the same reason that 2-factor authentication is now
> > considered standard practice in the security industry.
> >
> > We appreciate, Jarkko, that you feel that such infrastructure is
> > optional, like virtualization support, and is something that can go in
> > after the driver is mainlined. As the diffstat for our patch points
> > out, the proposed support has virtually no impact on the driver, the
> > same cannot be said for virtualization capabilities.
> The diffstat of your patch is irrelevant. What's relevant is the
> fact that it is completely unreviewed and that it creates yet
> another user space visible ABI with a noticable lack of
> documentation.
A number of points on this issue.
If anyone cares to review the patch, it has a 73 line commit message
that describes how the architecture works. That would obviously be
embellished and added to the general documentation.
We posted the initial concept implementation of this infrastructure 14
months ago. Andy, rightly so, indicated the design was unclean. The
simplification of the SGX driver at large over the last year allowed a
much more straight forward implementation of the patch.
This version of the patch has been posted twice in the last three
months, in response to the two major architectural revisions to the
driver that have occurred.
Jarkko indicated a year ago that our approach would 'bloat' the
driver. A common criticism of patches in general on LKML is that they
complicate sub-systems. I believe that diffstats are generally
recognized as cognitive indicators of the amount of bloat, complexity
and impact that a proposed patch introduces.
As to lack of review, we would certainly welcome technical and API
comments but we cannot force them. Candidly, the only people capable
of working with the patch are groups that have full and complete
runtime implementations that they can modify and test and that group
is extremely limited.
> > Moreover, adding support for key based policy management later would
> > require the addition of another ioctl in order to avoid ABI
> > compatibility issues.
> And that's a problem because?
See below.
> > The current initialization ioctl is best suited, from an engineering
> > perspective, to support this type of infrastructure.
> What's wrong with having IOCTL_INIT_TYPE_A and IOCTL_INIT_TYPE_B?
>
> Nothing at all. It's pretty straight forward and in fact a better
> solution than a duct taped multiplexing all in one IOCTL_INIT_PONIES
> approach.
I believe that a review of our patch would indicate that a 'duct taped
multplexing INIT_PONIES ioctl' is not a technically honest assessment
of what we are proposing. There is no flag or multi-case variable
implementation, the patch simply re-adds a pointer to a structure that
was in the previously out of tree driver.
In fact, anyone who reviews the patch will see that the current driver
creates a pointer in the ioctl call to pass downward into the hardware
initialization routines. Our code simply replaces that pointer with
one supplied by userspace.
That being said, we could certainly wire up a second ioctl and use
that. Candidly, under normal circumstances, that would arguably raise
a bloat accusation, since why would a second ioctl be implemented when
there is an already fully functional and mono-purpose ioctl that
triggers enclave initialization.
> > In fact, the necessary support was removed from the ioctl for
> > political reasons rather then for any valid engineering rationale on
> > flexible launch control platforms, particularly with our patch or an
> > equivalent approach.
> You're surely making a convincing technical argument by claiming
> that this was a political decision. The amount of non-technical,
> i.e. political arguments in your mail is definitely larger than the
> technical content.
There is the adage out here in the Upper Midwest, shared elsewhere,
that you shouldn't bring a knife to a gunfight, to date the issue of
cryptographic policy management has been exclusively political and
decidedly non-technical.
We have tried to respond by demonstrating, with code, that a minimum
impact technical approach is possible. To date the only response has
been that we need to get this driver into the kernel as fast as we
can and then deal with other issues.
Candidly, this is equivalent to, 'lets hurry up and ship it and then
we can worry about bugs and security issues', that plagues the rest of
the software industry.
> > Hopefully this is a reasoned technical approach to what has been a
> > long standing issue surrounding this technology.
> It's an approach which guarantees that the driver will miss the next
> merge window. If that's your intention, then please let us know.
I believe that a dispassionate observer, reviewing the last 2-3 years
of LKML conversations surrounding SGX, would not conclude that our
actions have delayed the driver.
Candidly, the issue may be coming down to a question as to whether or
not the driver should go into the kernel.
I pride myself on extreme technical honesty, I assume everyone else
does, so it probably needs to be taken into consideration that it is
now common knowledge that Intel is dropping support for SGX, at least
on the client side:
https://software.intel.com/en-us/forums/intel-software-guard-extensions-intel-sgx/topic/850599
https://www.techspot.com/news/84506-leaked-intel-rocket-lake-s-diagram-highlights-platform.html
My understanding is that getting SGX enabled on Comet Lake platforms
requires a discussion with vendors regarding a customized
BIOS/firmware implementation for the platform that enables the SGX
technology that is now being left silent on the chip/firmware.
A pity really, the technology arguably had a lot of legs with respect
to the capabilities that it brought to edge security but that is
another topic in and of itself.
SGX takes a lot of expensive silicon real estate. Whether or not that
price continues to get paid is going to depend on whether or not there
is sufficient market 'pull' from entities who want to push code and
data up into the cloud so that it can be executed without anyone
knowing what it is doing.
Hence our continued advocacy for a driver architecture that allows
stronger protections to be applied to that process, without affecting
the default behavior of the driver.
At the very least a modular form of the driver should be considered
that would allow alternate implementations. Sean indicated that there
was a 'kludgy' approach that would allow an alternate modular
implementation alongside the in-kernel driver. I believe that Andy
has already indicated that may not be an advisable approach.
> Merging the current set of patches does not prevent anything you want to
> be added. It's an extension to the base implementation and not a
> prerequisite.
My response to that is that a method for the driver to implement the
equivalent of 2-factor authentication over unrestricted code execution
and data manipulation, that does not affect the standard driver
behavior, needs to be part of the base implementation.
> > Best wishes for a productive week.
> >
> > Dr. Greg
> Thanks a lot for the best wishes. Unfortunately reading this email was
> not necessarily productive for me, but I surely wish that you can make
> productive use of my reply.
I'm sorry that you found reading my e-mail to be a waste of your time,
hopefully the time you took to respond has now allowed everyone
reading along at home to enjoy a thorough review of the issues at
hand.
In a precise and non-handwavy sort of fashion....
> Thanks,
>
> tglx
At the risk of wasting more of everyone's time, best wishes for a
productive weekend.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Developers of autonomously
Enjellic Systems Development, LLC self-defensive IOT platforms
4206 N. 19th Ave. and edge devices.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"Don't worry about people stealing your ideas. If your ideas are any
good, you'll have to ram them down people's throats."
-- Howard Aiken
Adding some Google folks to the party.
On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
>
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
>
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>
> cat /proc/cpuinfo | grep sgx
>
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
> environment of its own, it really isn't a great fit with more "standard"
> x86 tests.
>
> The RSA key is now generated on fly and the whole signing process has
> been made as part of the enclave loader instead of signing the enclave
> during the compilation time.
>
> Finally, the enclave loader loads now the test enclave directly from its
> ELF file, which means that ELF file does not need to be coverted as raw
> binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
> entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> deadlock with the page reclaimer, which could hold the lock for the old
> mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> be used to reserve the address range. Now /dev/sgx supports only opaque
> mappings to the (initialized) enclave data.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
> from RCX.
>
> v28:
> * Documented to Documentation/x86/sgx.rst how the kernel manages the
> enclave ownership.
> * Removed non-LC flow from sgx_einit().
> * Removed struct sgx_einittoken since only the size of the corresponding
> microarchitectural structure is used in the series ATM.
>
> v27:
> * Disallow RIE processes to use enclaves as there could a permission
> conflict between VMA and enclave permissions.
> * In the documentation, replace "grep /proc/cpuinfo" with
> "grep sgx /proc/cpuinfo".
>
> v26:
> * Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
> changed in v25 by mistake.
> * Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
> again for such a detailed feedback).
> * Added back the MAINTAINERS update commit, which was mistakenly removed
> in v25.
> * EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
> CPU does not allow to remove a SECS page before all of its children have
> been removed, and a child page can be in some other section than the one
> currently being processed. Thus, removed special SECS processing from
> sgx_sanitize_page() and instead put sections through it twice. In the
> 2nd round the lists should only contain SECS pages.
>
> v25:
> * Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
> fails on executing ENCLS[EADD]. The rollback path executed
> radix_tree_delete() on the same address twice when this happened.
> * Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
> a signal is pending.
> * As requested by Borislav, move the CPUID 0x12 features to their own word
> in cpufeatures.
> * Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
> was called with an uninitialized pointer when sgx_encl_get_backing()
> fails.
> * Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
> has 'groups' for setting up sysfs attributes for the device.
> * Use device_initcall instead of subsys_initcall so that misc_class is
> initialized before SGX is initialized.
> * Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
> enclave attributes that we the kernel does not allow it to set instead
> of -EINVAL.
> * Unless SGX public key MSRs are writable always deny the feature from
> Linux. Previously this was only denied from driver. How VMs should be
> supported is not really part of initial patch set, which makes this
> an obvious choice.
> * Cleaned up and refined documentation to be more approachable.
>
> v24:
> * Reclaim unmeasured and TCS pages (regression in v23).
> * Replace usages of GFP_HIGHUSER with GFP_KERNEL.
> * Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
> and use the same rollback (destroy enclave). This can happen when host
> suspends itself unknowingly to a VM running enclaves. From -EIO the user
> space can deduce what happened.
> * Have a separate @count in struct sgx_enclave_add_pages to output number
> of bytes processed instead of overwriting the input parameters for
> clarity and more importantly that the API provides means for partial
> processing (@count could be less than @length in success case).
>
> v23:
> * Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
> with %SGX_PAGE_MEASURE flag.
> * Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
> * In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
> (because of OOM) even in legit behaviour and after EBLOCK the reclaiming
> flow can be only reverted by killing the whole enclave.
> * Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
> it should have been bit 6 (Table 37-3 in the SDM).
> * Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
> error code.
>
> v22:
> * Refined bunch commit messages and added associated SDM references as
> many of them were too exhausting and some outdated.
> * Alignment checks have been removed from mmap() because it does not define the
> ELRANGE. VMAs only act as windows to the enclave. The semantics compare
> somewhat how mmap() works with regular files.
> * We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
> page aligned so that we can pass the page directly to EADD and do not have
> to do an extra copy. This was made effectively possible by removing the
> worker thread for adding pages.
> * The selftest build files have been refined throughout of various glitches
> and work properly in a cross compilation environment such as BuildRoot.
> In addition, libcalls fail the build with an assertion in the linker
> script, if they end up to the enclave binary.
> * CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
> for anything without having the driver. This could change when KVM support
> is added.
> * We require zero permissions in SECINFO for TCS pages because the CPU
> overwrites SECINFO flags with zero permissions and measures the page
> only after that. Allowing to pass TCS with non-zero permissions would
> cause mismatching measurement between the one provided in SIGSTRUCT and
> the one computed by the CPU.
> * Obviously lots of small fixes and clean ups (does make sense to
> document them all).
>
> v21:
> * Check on mmap() that the VMA does cover an area that does not have
> enclave pages. Only mapping with PROT_NONE can do that to reserve
> initial address space for an enclave.
> * Check om mmap() and mprotect() that the VMA permissions do not
> surpass the enclave permissions.
> * Remove two refcounts from vma_close(): mm_list and encl->refcount.
> Enclave refcount is only need for swapper/enclave sync and we can
> remove mm_list refcount by destroying mm_struct when the process
> is closed. By not having vm_close() the Linux MM can merge VMAs.
> * Do not naturally align MAP_FIXED address.
> * Numerous small fixes and clean ups.
> * Use SRCU for synchronizing the list of mm_struct's.
> * Move to stack based call convention in the vDSO.
>
> v20:
> * Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
> dependency as MMU notifiers are no longer used in the driver.
> * Use mm_users instead of mm_count as refcount for mm_struct as mm_count
> only protects from deleting mm_struct, not removing its contents.
> * Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
> of them. They could be in initialized state when the kernel starts
> because it might be spawned by kexec().
> * Documentation overhaul.
> * Use a device /dev/sgx/provision for delivering the provision token
> instead of securityfs.
> * Create a reference to the enclave when already when opening
> /dev/sgx/enclave. The file is then associated with this enclave only.
> mmap() can be done at free at any point and always get a reference to
> the enclave. To summarize the file now represents the enclave.
>
> v19:
> * Took 3-4 months but in some sense this was more like a rewrite of most
> of the corners of the source code. If I've forgotten to deal with some
> feedback, please don't shout me. Make a remark and I will fix it for
> the next version. Hopefully there won't be this big turnovers anymore.
> * Validate SECS attributes properly against CPUID given attributes and
> against allowed attributes. SECS attributes are the ones that are
> enforced whereas SIGSTRUCT attributes tell what is required to run
> the enclave.
> * Add KSS (Key Sharing Support) to the enclave attributes.
> * Deny MAP_PRIVATE as an enclave is always a shared memory entity.
> * Revert back to shmem backing storage so that it can be easily shared
> by multiple processes.
> * Split the recognization of an ENCLS leaf failure by using three
> functions to detect it: encsl_faulted(), encls_returned_code() and
> sgx_failed(). encls_failed() is only caused by a spurious expections that
> should never happen. Thus, it is not defined as an inline function in
> order to easily insert a kprobe to it.
> * Move low-level enclave management routines, page fault handler and page
> reclaiming routines from driver to the core. These cannot be separated
> from each other as they are heavily interdependent. The rationale is that
> the core does not call any code from the driver.
> * Allow the driver to be compiled as a module now that it no code is using
> its routines and it only uses exported symbols. Now the driver is
> essentially just a thin ioctl layer.
> * Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
> add new entries to this list as the process is forked. Each entry has
> its own refcount because they have a different life-cycle as the enclave
> does. In effect @tgid and @mm have been removed from struct sgx_encl
> and we allow forking by removing VM_DONTCOPY from vm flags.
> * Generate a cpu mask in the reclaimer from the cpu mask's of all
> mm_struct's. This will kick out the hardware threads out of the enclave
> from multiple processes. It is not a local variable because it would
> eat too much of the stack space but instead a field in struct
> sgx_encl.
> * Allow forking i.e. remove VM_DONTCOPY. I did not change the API
> because the old API scaled to the workload that Andy described. The
> codebase is now mostly API independent i.e. changing the API is a
> small task. For me the proper trigger to chanage it is a as concrete
> as possible workload that cannot be fulfilled. I hope you understand
> my thinking here. I don't want to change anything w/o proper basis
> but I'm ready to change anything if there is a proper basis. I do
> not have any kind of attachment to any particular type of API.
> * Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
> new vDSO.
>
> v18:
> * Update the ioctl-number.txt.
> * Move the driver under arch/x86.
> * Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
> * Rename the selftest as test_sgx (previously sgx-selftest).
> * In order to enable process accounting, swap EPC pages and PCMD's to a VMA
> instead of shmem.
> * Allow only to initialize and run enclaves with a subset of
> {DEBUG, MODE64BIT} set.
> * Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
> attributes e.g. PROVISIONKEY.
>
> v17:
> * Add a simple selftest.
> * Fix a null pointer dereference to section->pages when its
> allocation fails.
> * Add Sean's description of the exception handling to the documentation.
>
> v16:
> * Fixed SOB's in the commits that were a bit corrupted in v15.
> * Implemented exceptio handling properly to detect_sgx().
> * Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
> * Updated the documentation to use rst definition lists.
> * Added the missing Documentation/x86/index.rst, which has a link to
> intel_sgx.rst. Now the SGX and uapi documentation is properly generated
> with 'make htmldocs'.
> * While enumerating EPC sections, if an undefined section is found, fail
> the driver initialization instead of continuing the initialization.
> * Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
> * Remove copyright notice from arch/x86/include/asm/sgx.h.
> * Migrated from ioremap_cache() to memremap().
>
> v15:
> * Split into more digestable size patches.
> * Lots of small fixes and clean ups.
> * Signal a "plain" SIGSEGV on an EPCM violation.
>
> v14:
> * Change the comment about X86_FEATURE_SGX_LC from “SGX launch
> configuration” to “SGX launch control”.
> * Move the SGX-related CPU feature flags as part of the Linux defined
> virtual leaf 8.
> * Add SGX_ prefix to the constants defining the ENCLS leaf functions.
> * Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
> * Refine the long description for CONFIG_INTEL_SGX_CORE.
> * Do not use pr_*_ratelimited() in the driver. The use of the rate limited
> versions is legacy cruft from the prototyping phase.
> * Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
> cycles.
> * Manually prefix with “sgx:” in the core SGX code instead of redefining
> pr_fmt.
> * Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
> instead of core because it is a driver requirement.
> * Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
> default is ‘n’.
> * Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
> the SDM.
> * Allocate struct sgx_epc_page instances one at a time.
> * Use “__iomem void *” pointers for the mapped EPC memory consistently.
> * Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
> cycles.
> * Call enclave swapping operations directly from the driver instead of
> calling them .indirectly through struct sgx_epc_page_ops because indirect
> calls are not required yet as the patch set does not contain the KVM
> support.
> * Added special signal SEGV_SGXERR to notify about SGX EPCM violation
> errors.
>
> v13:
> * Always use SGX_CPUID constant instead of a hardcoded value.
> * Simplified and documented the macros and functions for ENCLS leaves.
> * Enable sgx_free_page() to free active enclave pages on demand
> in order to allow sgx_invalidate() to delete enclave pages.
> It no longer performs EREMOVE if a page is in the process of
> being reclaimed.
> * Use PM notifier per enclave so that we don't have to traverse
> the global list of active EPC pages to find enclaves.
> * Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
> * Always use ioremap() to map EPC banks as we only support 64-bit kernel.
> * Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
> to sleep.
>
> v12:
> * Split to more narrow scoped commits in order to ease the review process and
> use co-developed-by tag for co-authors of commits instead of listing them in
> the source files.
> * Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
> * Removed in-kernel LE i.e. this version of the SGX software stack only
> supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
> * Refined documentation on launching enclaves, swapping and enclave
> construction.
> * Refined sgx_arch.h to include alignment information for every struct that
> requires it and removed structs that are not needed without an LE.
> * Got rid of SGX_CPUID.
> * SGX detection now prints log messages about firmware configuration issues.
>
> v11:
> * Polished ENCLS wrappers with refined exception handling.
> * ksgxswapd was not stopped (regression in v5) in
> sgx_page_cache_teardown(), which causes a leaked kthread after driver
> deinitialization.
> * Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
> invalidated when resuming, which will cause it not function properly
> anymore.
> * Set EINITTOKEN.VALID to zero for a token that is passed when
> SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
> page.
> * Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
> around the flags field, which causes a #GP. Only flags read is readable.
> * On read access memcpy() call inside sgx_vma_access() had src and dest
> parameters in wrong order.
> * The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
> to LE even if “KASAN_SANITIZE := false” was set in the makefile.
> * Fixed a regression in the #PF handler. If a page has
> SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
> It did not, which caused weird races when trying to change other parts of
> swapping code.
> * EPC management has been refactored to a flat LRU cache and moved to
> arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
> of them. It can now swap from multiple enclaves in the same round.
> * For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
> when an enclave is already initialized or dead instead of zero.
>
> v10:
> * Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
> of the driver.
> * Unset the reserved flag from an enclave page if EDBGRD/WR fails
> (regression in v6).
> * Close the anon inode when LE is stopped (regression in v9).
> * Update the documentation with a more detailed description of SGX.
>
> v9:
> * Replaced kernel-LE IPC based on pipes with an anonymous inode.
> The driver does not require anymore new exports.
>
> v8:
> * Check that public key MSRs match the LE public key hash in the
> driver initialization when the MSRs are read-only.
> * Fix the race in VA slot allocation by checking the fullness
> immediately after succeesful allocation.
> * Fix the race in hash mrsigner calculation between the launch
> enclave and user enclaves by having a separate lock for hash
> calculation.
>
> v7:
> * Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
> when it should have been masked with ~PAGE_MASK.
> * Fixed a memory leak in sgx_ioc_enclave_create().
> * Simplified swapping code by using a pointer array for a cluster
> instead of a linked list.
> * Squeezed struct sgx_encl_page to 32 bytes.
> * Fixed deferencing of an RSA key on OpenSSL 1.1.0.
> * Modified TC's CMAC to use kernel AES-NI. Restructured the code
> a bit in order to better align with kernel conventions.
>
> v6:
> * Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
> * In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
> * Removed virtualization chapter from the documentation.
> * Changed the default filename for the signing key as signing_key.pem.
> * Reworked EPC management in a way that instead of a linked list of
> struct sgx_epc_page instances there is an array of integers that
> encodes address and bank of an EPC page (the same data as 'pa' field
> earlier). The locking has been moved to the EPC bank level instead
> of a global lock.
> * Relaxed locking requirements for EPC management. EPC pages can be
> released back to the EPC bank concurrently.
> * Cleaned up ptrace() code.
> * Refined commit messages for new architectural constants.
> * Sorted includes in every source file.
> * Sorted local variable declarations according to the line length in
> every function.
> * Style fixes based on Darren's comments to sgx_le.c.
>
> v5:
> * Described IPC between the Launch Enclave and kernel in the commit messages.
> * Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
> versions except those that exist in the imported TinyCrypt code.
> * Fixed spelling mistakes in the documentation.
> * Forgot to check the return value of sgx_drv_subsys_init().
> * Encapsulated properly page cache init and teardown.
> * Collect epc pages to a temp list in sgx_add_epc_bank
> * Removed SGX_ENCLAVE_INIT_ARCH constant.
>
> v4:
> * Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
> * Removed __exit annotation from sgx_drv_subsys_exit().
> * Fixed a leak of a backing page in sgx_process_add_page_req() in the
> case when vm_insert_pfn() fails.
> * Removed unused symbol exports for sgx_page_cache.c.
> * Updated sgx_alloc_page() to require encl parameter and documented the
> behavior (Sean Christopherson).
> * Refactored a more lean API for sgx_encl_find() and documented the behavior.
> * Moved #PF handler to sgx_fault.c.
> * Replaced subsys_system_register() with plain bus_register().
> * Retry EINIT 2nd time only if MSRs are not locked.
>
> v3:
> * Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
> * Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
> * Use unused bits in epc_page->pa to store the bank number.
> * Removed #ifdef for WQ_NONREENTRANT.
> * If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
> * Added --remove-section=.got.plt to objcopy flags in order to prevent a
> dummy .got.plt, which will cause an inconsistent size for the LE.
> * Documented sgx_encl_* functions.
> * Added remark about AES implementation used inside the LE.
> * Removed redundant sgx_sys_exit() from le/main.c.
> * Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
> * Validate miscselect in sgx_encl_create().
> * Fixed SSA frame size calculation to take the misc region into account.
> * Implemented consistent exception handling to __encls() and __encls_ret().
> * Implemented a proper device model in order to allow sysfs attributes
> and in-kernel API.
> * Cleaned up various "find enclave" implementations to the unified
> sgx_encl_find().
> * Validate that vm_pgoff is zero.
> * Discard backing pages with shmem_truncate_range() after EADD.
> * Added missing EEXTEND operations to LE signing and launch.
> * Fixed SSA size for GPRS region from 168 to 184 bytes.
> * Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
> * Check that TCS addresses are in ELRANGE and not just page aligned.
> * Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
> * Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.
>
> v2:
> * get_rand_uint32() changed the value of the pointer instead of value
> where it is pointing at.
> * Launch enclave incorrectly used sigstruct attributes-field instead of
> enclave attributes-field.
> * Removed unused struct sgx_add_page_req from sgx_ioctl.c
> * Removed unused sgx_has_sgx2.
> * Updated arch/x86/include/asm/sgx.h so that it provides stub
> implementations when sgx in not enabled.
> * Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
> * return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
> * removed unused global sgx_nr_pids
> * moved sgx_encl_release to sgx_encl.c
> * return -ERESTARTSYS instead of -EINTR in sgx_encl_init()
>
> Jarkko Sakkinen (10):
> x86/sgx: Update MAINTAINERS
> x86/sgx: Add SGX microarchitectural data structures
> x86/sgx: Add wrappers for ENCLS leaf functions
> x86/sgx: Add functions to allocate and free EPC pages
> x86/sgx: Linux Enclave Driver
> x86/sgx: Add provisioning
> x86/sgx: Add a page reclaimer
> x86/sgx: ptrace() support for the SGX driver
> selftests/x86: Add a selftest for SGX
> docs: x86/sgx: Document SGX micro architecture and kernel internals
>
> Sean Christopherson (10):
> x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
> x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
> x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
> x86/cpu/intel: Detect SGX support
> x86/sgx: Enumerate and track EPC sections
> mm: Introduce vm_ops->may_mprotect()
> x86/vdso: Add support for exception fixup in vDSO functions
> x86/fault: Add helper function to sanitize error code
> x86/traps: Attempt to fixup exceptions in vDSO before signaling
> x86/vdso: Implement a vDSO for Intel SGX enclave call
>
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> Documentation/x86/index.rst | 1 +
> Documentation/x86/sgx.rst | 206 +++++
> MAINTAINERS | 11 +
> arch/x86/Kconfig | 14 +
> arch/x86/entry/vdso/Makefile | 8 +-
> arch/x86/entry/vdso/extable.c | 46 +
> arch/x86/entry/vdso/extable.h | 29 +
> arch/x86/entry/vdso/vdso-layout.lds.S | 9 +-
> arch/x86/entry/vdso/vdso.lds.S | 1 +
> arch/x86/entry/vdso/vdso2c.h | 58 +-
> arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++
> arch/x86/include/asm/cpufeature.h | 5 +-
> arch/x86/include/asm/cpufeatures.h | 8 +-
> arch/x86/include/asm/disabled-features.h | 18 +-
> arch/x86/include/asm/enclu.h | 8 +
> arch/x86/include/asm/msr-index.h | 8 +
> arch/x86/include/asm/required-features.h | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/include/asm/vdso.h | 5 +
> arch/x86/include/uapi/asm/sgx.h | 175 ++++
> arch/x86/kernel/cpu/Makefile | 1 +
> arch/x86/kernel/cpu/common.c | 4 +
> arch/x86/kernel/cpu/feat_ctl.c | 32 +-
> arch/x86/kernel/cpu/sgx/Makefile | 6 +
> arch/x86/kernel/cpu/sgx/arch.h | 343 ++++++++
> arch/x86/kernel/cpu/sgx/driver.c | 209 +++++
> arch/x86/kernel/cpu/sgx/driver.h | 32 +
> arch/x86/kernel/cpu/sgx/encl.c | 756 +++++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 128 +++
> arch/x86/kernel/cpu/sgx/encls.h | 238 ++++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 800 ++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 280 ++++++
> arch/x86/kernel/cpu/sgx/reclaim.c | 471 +++++++++++
> arch/x86/kernel/cpu/sgx/sgx.h | 108 +++
> arch/x86/kernel/traps.c | 14 +
> arch/x86/mm/fault.c | 45 +-
> include/linux/mm.h | 2 +
> mm/mprotect.c | 14 +-
> tools/arch/x86/include/asm/cpufeatures.h | 7 +-
> tools/testing/selftests/Makefile | 1 +
> tools/testing/selftests/sgx/.gitignore | 2 +
> tools/testing/selftests/sgx/Makefile | 53 ++
> tools/testing/selftests/sgx/call.S | 54 ++
> tools/testing/selftests/sgx/defines.h | 21 +
> tools/testing/selftests/sgx/load.c | 282 ++++++
> tools/testing/selftests/sgx/main.c | 199 +++++
> tools/testing/selftests/sgx/main.h | 38 +
> tools/testing/selftests/sgx/sigstruct.c | 395 +++++++++
> tools/testing/selftests/sgx/test_encl.c | 20 +
> tools/testing/selftests/sgx/test_encl.lds | 40 +
> .../selftests/sgx/test_encl_bootstrap.S | 89 ++
> 52 files changed, 5398 insertions(+), 31 deletions(-)
> create mode 100644 Documentation/x86/sgx.rst
> create mode 100644 arch/x86/entry/vdso/extable.c
> create mode 100644 arch/x86/entry/vdso/extable.h
> create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
> create mode 100644 arch/x86/include/asm/enclu.h
> create mode 100644 arch/x86/include/uapi/asm/sgx.h
> create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
> create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
> create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/main.c
> create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
> create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
> create mode 100644 tools/testing/selftests/sgx/.gitignore
> create mode 100644 tools/testing/selftests/sgx/Makefile
> create mode 100644 tools/testing/selftests/sgx/call.S
> create mode 100644 tools/testing/selftests/sgx/defines.h
> create mode 100644 tools/testing/selftests/sgx/load.c
> create mode 100644 tools/testing/selftests/sgx/main.c
> create mode 100644 tools/testing/selftests/sgx/main.h
> create mode 100644 tools/testing/selftests/sgx/sigstruct.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.lds
> create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
>
> --
> 2.25.1
>
+cc Google folks
On Wed, Apr 22, 2020 at 12:53:07AM +0300, Jarkko Sakkinen wrote:
> Intel Software Guard eXtensions (SGX) is a set of CPU instructions that
> can be used by applications to set aside private regions of code and
> data. The code outside the SGX hosted software entity is disallowed to
> access the memory inside the enclave enforced by the CPU. We call these
> entities as enclaves.
>
> This commit implements a driver that provides an ioctl API to construct
> and run enclaves. Enclaves are constructed from pages residing in
> reserved physical memory areas. The contents of these pages can only be
> accessed when they are mapped as part of an enclave, by a hardware
> thread running inside the enclave.
>
> The starting state of an enclave consists of a fixed measured set of
> pages that are copied to the EPC during the construction process by
> using ENCLS leaf functions and Software Enclave Control Structure (SECS)
> that defines the enclave properties.
>
> Enclave are constructed by using ENCLS leaf functions ECREATE, EADD and
> EINIT. ECREATE initializes SECS, EADD copies pages from system memory to
> the EPC and EINIT check a given signed measurement and moves the enclave
> into a state ready for execution.
>
> An initialized enclave can only be accessed through special Thread Control
> Structure (TCS) pages by using ENCLU (ring-3 only) leaf EENTER. This leaf
> function converts a thread into enclave mode and continues the execution in
> the offset defined by the TCS provided to EENTER. An enclave is exited
> through syscall, exception, interrupts or by explicitly calling another
> ENCLU leaf EEXIT.
>
> The permissions, which enclave page is added will set the limit for maximum
> permissions that can be set for mmap() and mprotect(). This will
> effectively allow to build different security schemes between producers and
> consumers of enclaves. Later on we can increase granularity with LSM hooks
> for page addition (i.e. for producers) and mapping of the enclave (i.e. for
> consumers)
>
> Cc: [email protected]
> Co-developed-by: Sean Christopherson <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
> Co-developed-by: Suresh Siddha <[email protected]>
> Signed-off-by: Suresh Siddha <[email protected]>
> Tested-by: Haitao Huang <[email protected]>
> Tested-by: Jethro Beekman <[email protected]>
> Tested-by: Chunyang Hui <[email protected]>
> Tested-by: Jordan Hand <[email protected]>
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> arch/x86/include/uapi/asm/sgx.h | 66 ++
> arch/x86/kernel/cpu/sgx/Makefile | 3 +
> arch/x86/kernel/cpu/sgx/driver.c | 194 +++++
> arch/x86/kernel/cpu/sgx/driver.h | 30 +
> arch/x86/kernel/cpu/sgx/encl.c | 332 +++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 87 +++
> arch/x86/kernel/cpu/sgx/encls.h | 5 +-
> arch/x86/kernel/cpu/sgx/ioctl.c | 687 ++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 12 +-
> arch/x86/kernel/cpu/sgx/reclaim.c | 1 +
> 11 files changed, 1414 insertions(+), 4 deletions(-)
> create mode 100644 arch/x86/include/uapi/asm/sgx.h
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
> create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
>
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 2e91370dc159..1c54dd2704db 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -321,6 +321,7 @@ Code Seq# Include File Comments
> <mailto:[email protected]>
> 0xA3 90-9F linux/dtlk.h
> 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
> +0xA4 00-1F uapi/asm/sgx.h Intel SGX subsystem (a legit conflict as TEE and SGX do not co-exist)
> 0xAA 00-3F linux/uapi/linux/userfaultfd.h
> 0xAB 00-1F linux/nbd.h
> 0xAC 00-1F linux/raw.h
> diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
> new file mode 100644
> index 000000000000..5edb08ab8fd0
> --- /dev/null
> +++ b/arch/x86/include/uapi/asm/sgx.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
> +/*
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _UAPI_ASM_X86_SGX_H
> +#define _UAPI_ASM_X86_SGX_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +/**
> + * enum sgx_epage_flags - page control flags
> + * %SGX_PAGE_MEASURE: Measure the page contents with a sequence of
> + * ENCLS[EEXTEND] operations.
> + */
> +enum sgx_page_flags {
> + SGX_PAGE_MEASURE = 0x01,
> +};
> +
> +#define SGX_MAGIC 0xA4
> +
> +#define SGX_IOC_ENCLAVE_CREATE \
> + _IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
> +#define SGX_IOC_ENCLAVE_ADD_PAGES \
> + _IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
> +#define SGX_IOC_ENCLAVE_INIT \
> + _IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
> +
> +/**
> + * struct sgx_enclave_create - parameter structure for the
> + * %SGX_IOC_ENCLAVE_CREATE ioctl
> + * @src: address for the SECS page data
> + */
> +struct sgx_enclave_create {
> + __u64 src;
> +};
> +
> +/**
> + * struct sgx_enclave_add_pages - parameter structure for the
> + * %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
> + * @src: start address for the page data
> + * @offset: starting page offset
> + * @length: length of the data (multiple of the page size)
> + * @secinfo: address for the SECINFO data
> + * @flags: page control flags
> + * @count: number of bytes added (multiple of the page size)
> + */
> +struct sgx_enclave_add_pages {
> + __u64 src;
> + __u64 offset;
> + __u64 length;
> + __u64 secinfo;
> + __u64 flags;
> + __u64 count;
> +};
> +
> +/**
> + * struct sgx_enclave_init - parameter structure for the
> + * %SGX_IOC_ENCLAVE_INIT ioctl
> + * @sigstruct: address for the SIGSTRUCT data
> + */
> +struct sgx_enclave_init {
> + __u64 sigstruct;
> +};
> +
> +#endif /* _UAPI_ASM_X86_SGX_H */
> diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
> index 2dec75916a5e..f8d32da3a67a 100644
> --- a/arch/x86/kernel/cpu/sgx/Makefile
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -1,3 +1,6 @@
> obj-y += \
> + driver.o \
> + encl.o \
> + ioctl.o \
> main.o \
> reclaim.o
> diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
> new file mode 100644
> index 000000000000..b4aa7b9f8376
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.c
> @@ -0,0 +1,194 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/acpi.h>
> +#include <linux/miscdevice.h>
> +#include <linux/mman.h>
> +#include <linux/security.h>
> +#include <linux/suspend.h>
> +#include <asm/traps.h>
> +#include "driver.h"
> +#include "encl.h"
> +
> +MODULE_DESCRIPTION("Intel SGX Enclave Driver");
> +MODULE_AUTHOR("Jarkko Sakkinen <[email protected]>");
> +MODULE_LICENSE("Dual BSD/GPL");
> +
> +u64 sgx_encl_size_max_32;
> +u64 sgx_encl_size_max_64;
> +u32 sgx_misc_reserved_mask;
> +u64 sgx_attributes_reserved_mask;
> +u64 sgx_xfrm_reserved_mask = ~0x3;
> +u32 sgx_xsave_size_tbl[64];
> +
> +static int sgx_open(struct inode *inode, struct file *file)
> +{
> + struct sgx_encl *encl;
> + int ret;
> +
> + encl = kzalloc(sizeof(*encl), GFP_KERNEL);
> + if (!encl)
> + return -ENOMEM;
> +
> + atomic_set(&encl->flags, 0);
> + kref_init(&encl->refcount);
> + INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
> + mutex_init(&encl->lock);
> + INIT_LIST_HEAD(&encl->mm_list);
> + spin_lock_init(&encl->mm_lock);
> +
> + ret = init_srcu_struct(&encl->srcu);
> + if (ret) {
> + kfree(encl);
> + return ret;
> + }
> +
> + file->private_data = encl;
> +
> + return 0;
> +}
> +
> +static int sgx_release(struct inode *inode, struct file *file)
> +{
> + struct sgx_encl *encl = file->private_data;
> + struct sgx_encl_mm *encl_mm;
> +
> + for ( ; ; ) {
> + spin_lock(&encl->mm_lock);
> +
> + if (list_empty(&encl->mm_list)) {
> + encl_mm = NULL;
> + } else {
> + encl_mm = list_first_entry(&encl->mm_list,
> + struct sgx_encl_mm, list);
> + list_del_rcu(&encl_mm->list);
> + }
> +
> + spin_unlock(&encl->mm_lock);
> +
> + /* The list is empty, ready to go. */
> + if (!encl_mm)
> + break;
> +
> + synchronize_srcu(&encl->srcu);
> + mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
> + kfree(encl_mm);
> + };
> +
> + mutex_lock(&encl->lock);
> + atomic_or(SGX_ENCL_DEAD, &encl->flags);
> + mutex_unlock(&encl->lock);
> +
> + kref_put(&encl->refcount, sgx_encl_release);
> + return 0;
> +}
> +
> +#ifdef CONFIG_COMPAT
> +static long sgx_compat_ioctl(struct file *filep, unsigned int cmd,
> + unsigned long arg)
> +{
> + return sgx_ioctl(filep, cmd, arg);
> +}
> +#endif
> +
> +static int sgx_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> + struct sgx_encl *encl = file->private_data;
> + int ret;
> +
> + ret = sgx_encl_may_map(encl, vma->vm_start, vma->vm_end,
> + vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC));
> + if (ret)
> + return ret;
> +
> + ret = sgx_encl_mm_add(encl, vma->vm_mm);
> + if (ret)
> + return ret;
> +
> + vma->vm_ops = &sgx_vm_ops;
> + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
> + vma->vm_private_data = encl;
> +
> + return 0;
> +}
> +
> +static unsigned long sgx_get_unmapped_area(struct file *file,
> + unsigned long addr,
> + unsigned long len,
> + unsigned long pgoff,
> + unsigned long flags)
> +{
> + if (flags & MAP_PRIVATE)
> + return -EINVAL;
> +
> + if (flags & MAP_FIXED)
> + return addr;
> +
> + return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
> +}
> +
> +static const struct file_operations sgx_encl_fops = {
> + .owner = THIS_MODULE,
> + .open = sgx_open,
> + .release = sgx_release,
> + .unlocked_ioctl = sgx_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = sgx_compat_ioctl,
> +#endif
> + .mmap = sgx_mmap,
> + .get_unmapped_area = sgx_get_unmapped_area,
> +};
> +
> +const struct file_operations sgx_provision_fops = {
> + .owner = THIS_MODULE,
> +};
> +
> +static struct miscdevice sgx_dev_enclave = {
> + .minor = MISC_DYNAMIC_MINOR,
> + .name = "enclave",
> + .nodename = "sgx/enclave",
> + .fops = &sgx_encl_fops,
> +};
> +
> +int __init sgx_drv_init(void)
> +{
> + unsigned int eax, ebx, ecx, edx;
> + u64 attr_mask, xfrm_mask;
> + int ret;
> + int i;
> +
> + if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
> + pr_info("The public key MSRs are not writable.\n");
> + return -ENODEV;
> + }
> +
> + cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
> + sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
> + sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
> + sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
> +
> + cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
> +
> + attr_mask = (((u64)ebx) << 32) + (u64)eax;
> + sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
> +
> + if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
> + xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
> +
> + for (i = 2; i < 64; i++) {
> + cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
> + if ((1 << i) & xfrm_mask)
> + sgx_xsave_size_tbl[i] = eax + ebx;
> + }
> +
> + sgx_xfrm_reserved_mask = ~xfrm_mask;
> + }
> +
> + ret = misc_register(&sgx_dev_enclave);
> + if (ret) {
> + pr_err("Creating /dev/sgx/enclave failed with %d.\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
> new file mode 100644
> index 000000000000..e4063923115b
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +#ifndef __ARCH_SGX_DRIVER_H__
> +#define __ARCH_SGX_DRIVER_H__
> +
> +#include <crypto/hash.h>
> +#include <linux/kref.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/rwsem.h>
> +#include <linux/sched.h>
> +#include <linux/workqueue.h>
> +#include <uapi/asm/sgx.h>
> +#include "sgx.h"
> +
> +#define SGX_EINIT_SPIN_COUNT 20
> +#define SGX_EINIT_SLEEP_COUNT 50
> +#define SGX_EINIT_SLEEP_TIME 20
> +
> +extern u64 sgx_encl_size_max_32;
> +extern u64 sgx_encl_size_max_64;
> +extern u32 sgx_misc_reserved_mask;
> +extern u64 sgx_attributes_reserved_mask;
> +extern u64 sgx_xfrm_reserved_mask;
> +extern u32 sgx_xsave_size_tbl[64];
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
> +
> +int sgx_drv_init(void);
> +
> +#endif /* __ARCH_X86_SGX_DRIVER_H__ */
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> new file mode 100644
> index 000000000000..17e44bf8fa56
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -0,0 +1,332 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/lockdep.h>
> +#include <linux/mm.h>
> +#include <linux/mman.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/suspend.h>
> +#include <linux/sched/mm.h>
> +#include "arch.h"
> +#include "encl.h"
> +#include "sgx.h"
> +
> +static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
> + unsigned long addr)
> +{
> + struct sgx_encl_page *entry;
> + unsigned int flags;
> +
> + /* If process was forked, VMA is still there but vm_private_data is set
> + * to NULL.
> + */
> + if (!encl)
> + return ERR_PTR(-EFAULT);
> +
> + flags = atomic_read(&encl->flags);
> +
> + if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
> + return ERR_PTR(-EFAULT);
> +
> + entry = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT);
> + if (!entry)
> + return ERR_PTR(-EFAULT);
> +
> + /* Page is already resident in the EPC. */
> + if (entry->epc_page)
> + return entry;
> +
> + return ERR_PTR(-EFAULT);
> +}
> +
> +static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
> + struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm =
> + container_of(mn, struct sgx_encl_mm, mmu_notifier);
> + struct sgx_encl_mm *tmp = NULL;
> +
> + /*
> + * The enclave itself can remove encl_mm. Note, objects can't be moved
> + * off an RCU protected list, but deletion is ok.
> + */
> + spin_lock(&encl_mm->encl->mm_lock);
> + list_for_each_entry(tmp, &encl_mm->encl->mm_list, list) {
> + if (tmp == encl_mm) {
> + list_del_rcu(&encl_mm->list);
> + break;
> + }
> + }
> + spin_unlock(&encl_mm->encl->mm_lock);
> +
> + if (tmp == encl_mm) {
> + synchronize_srcu(&encl_mm->encl->srcu);
> + mmu_notifier_put(mn);
> + }
> +}
> +
> +static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
> +{
> + struct sgx_encl_mm *encl_mm =
> + container_of(mn, struct sgx_encl_mm, mmu_notifier);
> +
> + kfree(encl_mm);
> +}
> +
> +static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
> + .release = sgx_mmu_notifier_release,
> + .free_notifier = sgx_mmu_notifier_free,
> +};
> +
> +static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
> + struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm = NULL;
> + struct sgx_encl_mm *tmp;
> + int idx;
> +
> + idx = srcu_read_lock(&encl->srcu);
> +
> + list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
> + if (tmp->mm == mm) {
> + encl_mm = tmp;
> + break;
> + }
> + }
> +
> + srcu_read_unlock(&encl->srcu, idx);
> +
> + return encl_mm;
> +}
> +
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
> +{
> + struct sgx_encl_mm *encl_mm;
> + int ret;
> +
> + /* mm_list can be accessed only by a single thread at a time. */
> + lockdep_assert_held_write(&mm->mmap_sem);
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_DEAD)
> + return -EINVAL;
> +
> + /*
> + * mm_structs are kept on mm_list until the mm or the enclave dies,
> + * i.e. once an mm is off the list, it's gone for good, therefore it's
> + * impossible to get a false positive on @mm due to a stale mm_list.
> + */
> + if (sgx_encl_find_mm(encl, mm))
> + return 0;
> +
> + encl_mm = kzalloc(sizeof(*encl_mm), GFP_KERNEL);
> + if (!encl_mm)
> + return -ENOMEM;
> +
> + encl_mm->encl = encl;
> + encl_mm->mm = mm;
> + encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;
> +
> + ret = __mmu_notifier_register(&encl_mm->mmu_notifier, mm);
> + if (ret) {
> + kfree(encl_mm);
> + return ret;
> + }
> +
> + spin_lock(&encl->mm_lock);
> + list_add_rcu(&encl_mm->list, &encl->mm_list);
> + spin_unlock(&encl->mm_lock);
> +
> + return 0;
> +}
> +
> +static void sgx_vma_open(struct vm_area_struct *vma)
> +{
> + struct sgx_encl *encl = vma->vm_private_data;
> +
> + if (!encl)
> + return;
> +
> + if (sgx_encl_mm_add(encl, vma->vm_mm))
> + vma->vm_private_data = NULL;
> +}
> +
> +static unsigned int sgx_vma_fault(struct vm_fault *vmf)
> +{
> + unsigned long addr = (unsigned long)vmf->address;
> + struct vm_area_struct *vma = vmf->vma;
> + struct sgx_encl *encl = vma->vm_private_data;
> + struct sgx_encl_page *entry;
> + int ret = VM_FAULT_NOPAGE;
> + unsigned long pfn;
> +
> + if (!encl)
> + return VM_FAULT_SIGBUS;
> +
> + mutex_lock(&encl->lock);
> +
> + entry = sgx_encl_load_page(encl, addr);
> + if (IS_ERR(entry)) {
> + if (unlikely(PTR_ERR(entry) != -EBUSY))
> + ret = VM_FAULT_SIGBUS;
> +
> + goto out;
> + }
> +
> + if (!follow_pfn(vma, addr, &pfn))
> + goto out;
> +
> + ret = vmf_insert_pfn(vma, addr, PFN_DOWN(entry->epc_page->desc));
> + if (ret != VM_FAULT_NOPAGE) {
> + ret = VM_FAULT_SIGBUS;
> + goto out;
> + }
> +
> +out:
> + mutex_unlock(&encl->lock);
> + return ret;
> +}
> +
> +/**
> + * sgx_encl_may_map() - Check if a requested VMA mapping is allowed
> + * @encl: an enclave
> + * @start: lower bound of the address range, inclusive
> + * @end: upper bound of the address range, exclusive
> + * @vm_prot_bits: requested protections of the address range
> + *
> + * Iterate through the enclave pages contained within [@start, @end) to verify
> + * the permissions requested by @vm_prot_bits do not exceed that of any enclave
> + * page to be mapped.
> + *
> + * Return:
> + * 0 on success,
> + * -EACCES if VMA permissions exceed enclave page permissions
> + */
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> + unsigned long end, unsigned long vm_prot_bits)
> +{
> + unsigned long idx, idx_start, idx_end;
> + struct sgx_encl_page *page;
> +
> + /*
> + * Disallow RIE tasks as their VMA permissions might conflict with the
> + * enclave page permissions.
> + */
> + if (!!(current->personality & READ_IMPLIES_EXEC))
> + return -EACCES;
> +
> + idx_start = PFN_DOWN(start);
> + idx_end = PFN_DOWN(end - 1);
> +
> + for (idx = idx_start; idx <= idx_end; ++idx) {
> + mutex_lock(&encl->lock);
> + page = radix_tree_lookup(&encl->page_tree, idx);
> + mutex_unlock(&encl->lock);
> +
> + if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> + return -EACCES;
> + }
> +
> + return 0;
> +}
> +
> +static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
> + unsigned long end, unsigned long prot)
> +{
> + return sgx_encl_may_map(vma->vm_private_data, start, end,
> + calc_vm_prot_bits(prot, 0));
> +}
> +
> +const struct vm_operations_struct sgx_vm_ops = {
> + .open = sgx_vma_open,
> + .fault = sgx_vma_fault,
> + .may_mprotect = sgx_vma_mprotect,
> +};
> +
> +/**
> + * sgx_encl_find - find an enclave
> + * @mm: mm struct of the current process
> + * @addr: address in the ELRANGE
> + * @vma: the resulting VMA
> + *
> + * Find an enclave identified by the given address. Give back a VMA that is
> + * part of the enclave and located in that address. The VMA is given back if it
> + * is a proper enclave VMA even if an &sgx_encl instance does not exist yet
> + * (enclave creation has not been performed).
> + *
> + * Return:
> + * 0 on success,
> + * -EINVAL if an enclave was not found,
> + * -ENOENT if the enclave has not been created yet
> + */
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> + struct vm_area_struct **vma)
> +{
> + struct vm_area_struct *result;
> + struct sgx_encl *encl;
> +
> + result = find_vma(mm, addr);
> + if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
> + return -EINVAL;
> +
> + encl = result->vm_private_data;
> + *vma = result;
> +
> + return encl ? 0 : -ENOENT;
> +}
> +
> +/**
> + * sgx_encl_destroy() - destroy enclave resources
> + * @encl: an &sgx_encl instance
> + */
> +void sgx_encl_destroy(struct sgx_encl *encl)
> +{
> + struct sgx_encl_page *entry;
> + struct radix_tree_iter iter;
> + void **slot;
> +
> + atomic_or(SGX_ENCL_DEAD, &encl->flags);
> +
> + radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
> + entry = *slot;
> +
> + if (entry->epc_page) {
> + sgx_free_page(entry->epc_page);
> + encl->secs_child_cnt--;
> + entry->epc_page = NULL;
> + }
> +
> + radix_tree_delete(&entry->encl->page_tree,
> + PFN_DOWN(entry->desc));
> + kfree(entry);
> + }
> +
> + if (!encl->secs_child_cnt && encl->secs.epc_page) {
> + sgx_free_page(encl->secs.epc_page);
> + encl->secs.epc_page = NULL;
> + }
> +}
> +
> +/**
> + * sgx_encl_release - Destroy an enclave instance
> + * @kref: address of a kref inside &sgx_encl
> + *
> + * Used together with kref_put(). Frees all the resources associated with the
> + * enclave and the instance itself.
> + */
> +void sgx_encl_release(struct kref *ref)
> +{
> + struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
> +
> + sgx_encl_destroy(encl);
> +
> + if (encl->backing)
> + fput(encl->backing);
> +
> + WARN_ON_ONCE(!list_empty(&encl->mm_list));
> +
> + /* Detect EPC page leak's. */
> + WARN_ON_ONCE(encl->secs_child_cnt);
> + WARN_ON_ONCE(encl->secs.epc_page);
> +
> + kfree(encl);
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
> new file mode 100644
> index 000000000000..1d1bc5d590ee
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.h
> @@ -0,0 +1,87 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> +/**
> + * Copyright(c) 2016-19 Intel Corporation.
> + */
> +#ifndef _X86_ENCL_H
> +#define _X86_ENCL_H
> +
> +#include <linux/cpumask.h>
> +#include <linux/kref.h>
> +#include <linux/list.h>
> +#include <linux/mm_types.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/mutex.h>
> +#include <linux/notifier.h>
> +#include <linux/radix-tree.h>
> +#include <linux/srcu.h>
> +#include <linux/workqueue.h>
> +#include "sgx.h"
> +
> +/**
> + * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
> + * %SGX_ENCL_PAGE_ADDR_MASK: Holds the virtual address of the page.
> + *
> + * The page address for SECS is zero and is used by the subsystem to recognize
> + * the SECS page.
> + */
> +enum sgx_encl_page_desc {
> + /* Bits 11:3 are available when the page is not swapped. */
> + SGX_ENCL_PAGE_ADDR_MASK = PAGE_MASK,
> +};
> +
> +#define SGX_ENCL_PAGE_ADDR(page) \
> + ((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
> +
> +struct sgx_encl_page {
> + unsigned long desc;
> + unsigned long vm_max_prot_bits;
> + struct sgx_epc_page *epc_page;
> + struct sgx_encl *encl;
> +};
> +
> +enum sgx_encl_flags {
> + SGX_ENCL_CREATED = BIT(0),
> + SGX_ENCL_INITIALIZED = BIT(1),
> + SGX_ENCL_DEBUG = BIT(2),
> + SGX_ENCL_DEAD = BIT(3),
> + SGX_ENCL_IOCTL = BIT(4),
> +};
> +
> +struct sgx_encl_mm {
> + struct sgx_encl *encl;
> + struct mm_struct *mm;
> + struct list_head list;
> + struct mmu_notifier mmu_notifier;
> +};
> +
> +struct sgx_encl {
> + atomic_t flags;
> + u64 secs_attributes;
> + u64 allowed_attributes;
> + unsigned int page_cnt;
> + unsigned int secs_child_cnt;
> + struct mutex lock;
> + struct list_head mm_list;
> + spinlock_t mm_lock;
> + struct file *backing;
> + struct kref refcount;
> + struct srcu_struct srcu;
> + unsigned long base;
> + unsigned long size;
> + unsigned long ssaframesize;
> + struct radix_tree_root page_tree;
> + struct sgx_encl_page secs;
> + cpumask_t cpumask;
> +};
> +
> +extern const struct vm_operations_struct sgx_vm_ops;
> +
> +int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> + struct vm_area_struct **vma);
> +void sgx_encl_destroy(struct sgx_encl *encl);
> +void sgx_encl_release(struct kref *ref);
> +int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> + unsigned long end, unsigned long vm_prot_bits);
> +
> +#endif /* _X86_ENCL_H */
> diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
> index 376cdedb9a43..f716b4328614 100644
> --- a/arch/x86/kernel/cpu/sgx/encls.h
> +++ b/arch/x86/kernel/cpu/sgx/encls.h
> @@ -186,10 +186,9 @@ static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
> return __encls_2(EADD, pginfo, addr);
> }
>
> -static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
> - void *secs)
> +static inline int __einit(void *sigstruct, void *token, void *secs)
> {
> - return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
> + return __encls_ret_3(EINIT, sigstruct, secs, token);
> }
>
> static inline int __eremove(void *addr)
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> new file mode 100644
> index 000000000000..26d0425d7252
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -0,0 +1,687 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-19 Intel Corporation.
> +
> +#include <asm/mman.h>
> +#include <linux/mman.h>
> +#include <linux/delay.h>
> +#include <linux/file.h>
> +#include <linux/hashtable.h>
> +#include <linux/highmem.h>
> +#include <linux/ratelimit.h>
> +#include <linux/sched/signal.h>
> +#include <linux/shmem_fs.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
> +#include "driver.h"
> +#include "encl.h"
> +#include "encls.h"
> +
> +/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
> +static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
> +
> +static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
> +{
> + u32 size_max = PAGE_SIZE;
> + u32 size;
> + int i;
> +
> + for (i = 2; i < 64; i++) {
> + if (!((1 << i) & xfrm))
> + continue;
> +
> + size = SGX_SSA_GPRS_SIZE + sgx_xsave_size_tbl[i];
> + if (miscselect & SGX_MISC_EXINFO)
> + size += SGX_SSA_MISC_EXINFO_SIZE;
> +
> + if (size > size_max)
> + size_max = size;
> + }
> +
> + return PFN_UP(size_max);
> +}
> +
> +static int sgx_validate_secs(const struct sgx_secs *secs,
> + unsigned long ssaframesize)
> +{
> + if (secs->size < (2 * PAGE_SIZE) || !is_power_of_2(secs->size))
> + return -EINVAL;
> +
> + if (secs->base & (secs->size - 1))
> + return -EINVAL;
> +
> + if (secs->miscselect & sgx_misc_reserved_mask ||
> + secs->attributes & sgx_attributes_reserved_mask ||
> + secs->xfrm & sgx_xfrm_reserved_mask)
> + return -EINVAL;
> +
> + if (secs->attributes & SGX_ATTR_MODE64BIT) {
> + if (secs->size > sgx_encl_size_max_64)
> + return -EINVAL;
> + } else if (secs->size > sgx_encl_size_max_32)
> + return -EINVAL;
> +
> + if (!(secs->xfrm & XFEATURE_MASK_FP) ||
> + !(secs->xfrm & XFEATURE_MASK_SSE) ||
> + (((secs->xfrm >> XFEATURE_BNDREGS) & 1) !=
> + ((secs->xfrm >> XFEATURE_BNDCSR) & 1)))
> + return -EINVAL;
> +
> + if (!secs->ssa_frame_size || ssaframesize > secs->ssa_frame_size)
> + return -EINVAL;
> +
> + if (memchr_inv(secs->reserved1, 0, sizeof(secs->reserved1)) ||
> + memchr_inv(secs->reserved2, 0, sizeof(secs->reserved2)) ||
> + memchr_inv(secs->reserved3, 0, sizeof(secs->reserved3)) ||
> + memchr_inv(secs->reserved4, 0, sizeof(secs->reserved4)))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
> + unsigned long offset,
> + u64 secinfo_flags)
> +{
> + struct sgx_encl_page *encl_page;
> + unsigned long prot;
> +
> + encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
> + if (!encl_page)
> + return ERR_PTR(-ENOMEM);
> +
> + encl_page->desc = encl->base + offset;
> + encl_page->encl = encl;
> +
> + prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ) |
> + _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
> + _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
> +
> + /*
> + * TCS pages must always RW set for CPU access while the SECINFO
> + * permissions are *always* zero - the CPU ignores the user provided
> + * values and silently overwrites them with zero permissions.
> + */
> + if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
> + prot |= PROT_READ | PROT_WRITE;
> +
> + /* Calculate maximum of the VM flags for the page. */
> + encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
> +
> + return encl_page;
> +}
> +
> +static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
> +{
> + unsigned long encl_size = secs->size + PAGE_SIZE;
> + struct sgx_epc_page *secs_epc;
> + unsigned long ssaframesize;
> + struct sgx_pageinfo pginfo;
> + struct sgx_secinfo secinfo;
> + struct file *backing;
> + long ret;
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
> + return -EINVAL;
> +
> + ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
> + if (sgx_validate_secs(secs, ssaframesize)) {
> + pr_debug("invalid SECS\n");
> + return -EINVAL;
> + }
> +
> + backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
> + VM_NORESERVE);
> + if (IS_ERR(backing))
> + return PTR_ERR(backing);
> +
> + encl->backing = backing;
> +
> + secs_epc = sgx_try_alloc_page();
> + if (IS_ERR(secs_epc)) {
> + ret = PTR_ERR(secs_epc);
> + goto err_out_backing;
> + }
> +
> + encl->secs.epc_page = secs_epc;
> +
> + pginfo.addr = 0;
> + pginfo.contents = (unsigned long)secs;
> + pginfo.metadata = (unsigned long)&secinfo;
> + pginfo.secs = 0;
> + memset(&secinfo, 0, sizeof(secinfo));
> +
> + ret = __ecreate((void *)&pginfo, sgx_epc_addr(secs_epc));
> + if (ret) {
> + pr_debug("ECREATE returned %ld\n", ret);
> + goto err_out;
> + }
> +
> + if (secs->attributes & SGX_ATTR_DEBUG)
> + atomic_or(SGX_ENCL_DEBUG, &encl->flags);
> +
> + encl->secs.encl = encl;
> + encl->secs_attributes = secs->attributes;
> + encl->allowed_attributes |= SGX_ATTR_ALLOWED_MASK;
> + encl->base = secs->base;
> + encl->size = secs->size;
> + encl->ssaframesize = secs->ssa_frame_size;
> +
> + /*
> + * Set SGX_ENCL_CREATED only after the enclave is fully prepped. This
> + * allows setting and checking enclave creation without having to take
> + * encl->lock.
> + */
> + atomic_or(SGX_ENCL_CREATED, &encl->flags);
> +
> + return 0;
> +
> +err_out:
> + sgx_free_page(encl->secs.epc_page);
> + encl->secs.epc_page = NULL;
> +
> +err_out_backing:
> + fput(encl->backing);
> + encl->backing = NULL;
> +
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_create - handler for %SGX_IOC_ENCLAVE_CREATE
> + * @filep: open file to /dev/sgx
> + * @arg: userspace pointer to a struct sgx_enclave_create instance
> + *
> + * Allocate kernel data structures for a new enclave and execute ECREATE after
> + * verifying the correctness of the provided SECS.
> + *
> + * Note, enforcement of restricted and disallowed attributes is deferred until
> + * sgx_ioc_enclave_init(), only the architectural correctness of the SECS is
> + * checked by sgx_ioc_enclave_create().
> + *
> + * Return:
> + * 0 on success,
> + * -errno otherwise
> + */
> +static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_enclave_create ecreate;
> + struct page *secs_page;
> + struct sgx_secs *secs;
> + int ret;
> +
> + if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
> + return -EFAULT;
> +
> + secs_page = alloc_page(GFP_KERNEL);
> + if (!secs_page)
> + return -ENOMEM;
> +
> + secs = kmap(secs_page);
> + if (copy_from_user(secs, (void __user *)ecreate.src, sizeof(*secs))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = sgx_encl_create(encl, secs);
> +
> +out:
> + kunmap(secs_page);
> + __free_page(secs_page);
> + return ret;
> +}
> +
> +static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> +{
> + u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
> + u64 pt = secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK;
> +
> + if (pt != SGX_SECINFO_REG && pt != SGX_SECINFO_TCS)
> + return -EINVAL;
> +
> + if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
> + return -EINVAL;
> +
> + /*
> + * CPU will silently overwrite the permissions as zero, which means
> + * that we need to validate it ourselves.
> + */
> + if (pt == SGX_SECINFO_TCS && perm)
> + return -EINVAL;
> +
> + if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
> + return -EINVAL;
> +
> + if (memchr_inv(secinfo->reserved, 0, sizeof(secinfo->reserved)))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int __sgx_encl_add_page(struct sgx_encl *encl,
> + struct sgx_encl_page *encl_page,
> + struct sgx_epc_page *epc_page,
> + struct sgx_secinfo *secinfo, unsigned long src)
> +{
> + struct sgx_pageinfo pginfo;
> + struct vm_area_struct *vma;
> + struct page *src_page;
> + int ret;
> +
> + /* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
> + if (encl_page->vm_max_prot_bits & VM_EXEC) {
> + vma = find_vma(current->mm, src);
> + if (!vma)
> + return -EFAULT;
> +
> + if (!(vma->vm_flags & VM_MAYEXEC))
> + return -EACCES;
> + }
> +
> + ret = get_user_pages(src, 1, 0, &src_page, NULL);
> + if (ret < 1)
> + return ret;
> +
> + pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
> + pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
> + pginfo.metadata = (unsigned long)secinfo;
> + pginfo.contents = (unsigned long)kmap_atomic(src_page);
> +
> + ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
> +
> + kunmap_atomic((void *)pginfo.contents);
> + put_page(src_page);
> +
> + return ret ? -EIO : 0;
> +}
> +
> +static int __sgx_encl_extend(struct sgx_encl *encl,
> + struct sgx_epc_page *epc_page)
> +{
> + int ret;
> + int i;
> +
> + for (i = 0; i < 16; i++) {
> + ret = __eextend(sgx_epc_addr(encl->secs.epc_page),
> + sgx_epc_addr(epc_page) + (i * 0x100));
> + if (ret) {
> + if (encls_failed(ret))
> + ENCLS_WARN(ret, "EEXTEND");
> + return -EIO;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
> + unsigned long offset, unsigned long length,
> + struct sgx_secinfo *secinfo, unsigned long flags)
> +{
> + struct sgx_encl_page *encl_page;
> + struct sgx_epc_page *epc_page;
> + int ret;
> +
> + encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
> + if (IS_ERR(encl_page))
> + return PTR_ERR(encl_page);
> +
> + epc_page = sgx_try_alloc_page();
> + if (IS_ERR(epc_page)) {
> + kfree(encl_page);
> + return PTR_ERR(epc_page);
> + }
> +
> + if (atomic_read(&encl->flags) &
> + (SGX_ENCL_INITIALIZED | SGX_ENCL_DEAD)) {
> + ret = -EFAULT;
> + goto err_out_free;
> + }
> +
> + down_read(¤t->mm->mmap_sem);
> + mutex_lock(&encl->lock);
> +
> + /*
> + * Insert prior to EADD in case of OOM. EADD modifies MRENCLAVE, i.e.
> + * can't be gracefully unwound, while failure on EADD/EXTEND is limited
> + * to userspace errors (or kernel/hardware bugs).
> + */
> + ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
> + encl_page);
> + if (ret)
> + goto err_out_unlock;
> +
> + ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
> + src);
> + if (ret)
> + goto err_out;
> +
> + /*
> + * Complete the "add" before doing the "extend" so that the "add"
> + * isn't in a half-baked state in the extremely unlikely scenario the
> + * the enclave will be destroyed in response to EEXTEND failure.
> + */
> + encl_page->encl = encl;
> + encl_page->epc_page = epc_page;
> + encl->secs_child_cnt++;
> +
> + if (flags & SGX_PAGE_MEASURE) {
> + ret = __sgx_encl_extend(encl, epc_page);
> + if (ret)
> + goto err_out;
> + }
> +
> + mutex_unlock(&encl->lock);
> + up_read(¤t->mm->mmap_sem);
> + return ret;
> +
> +err_out:
> + radix_tree_delete(&encl_page->encl->page_tree,
> + PFN_DOWN(encl_page->desc));
> +
> +err_out_unlock:
> + mutex_unlock(&encl->lock);
> + up_read(¤t->mm->mmap_sem);
> +
> +err_out_free:
> + sgx_free_page(epc_page);
> + kfree(encl_page);
> +
> + /*
> + * Destroy enclave on ENCLS failure as this means that EPC has been
> + * invalidated.
> + */
> + if (ret == -EIO)
> + sgx_encl_destroy(encl);
> +
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
> + * @encl: pointer to an enclave instance (via ioctl() file pointer)
> + * @arg: a user pointer to a struct sgx_enclave_add_pages instance
> + *
> + * Add one or more pages to an uninitialized enclave, and optionally extend the
> + * measurement with the contents of the page. The address range of pages must
> + * be contiguous. The SECINFO and measurement mask are applied to all pages.
> + *
> + * A SECINFO for a TCS is required to always contain zero permissions because
> + * CPU silently zeros them. Allowing anything else would cause a mismatch in
> + * the measurement.
> + *
> + * mmap()'s protection bits are capped by the page permissions. For each page
> + * address, the maximum protection bits are computed with the following
> + * heuristics:
> + *
> + * 1. A regular page: PROT_R, PROT_W and PROT_X match the SECINFO permissions.
> + * 2. A TCS page: PROT_R | PROT_W.
> + *
> + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> + * within the given address range.
> + *
> + * If ENCLS opcode fails, that effectively means that EPC has been invalidated.
> + * When this happens the enclave is destroyed and -EIO is returned to the
> + * caller.
> + *
> + * Return:
> + * 0 on success,
> + * -EACCES if an executable source page is located in a noexec partition,
> + * -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails
> + * -errno otherwise
> + */
> +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_enclave_add_pages addp;
> + struct sgx_secinfo secinfo;
> + unsigned long c;
> + int ret;
> +
> + if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> + return -EINVAL;
> +
> + if (copy_from_user(&addp, arg, sizeof(addp)))
> + return -EFAULT;
> +
> + if (!IS_ALIGNED(addp.offset, PAGE_SIZE) ||
> + !IS_ALIGNED(addp.src, PAGE_SIZE))
> + return -EINVAL;
> +
> + if (!(access_ok(addp.src, PAGE_SIZE)))
> + return -EFAULT;
> +
> + if (addp.length & (PAGE_SIZE - 1))
> + return -EINVAL;
> +
> + if (addp.offset + addp.length - PAGE_SIZE >= encl->size)
> + return -EINVAL;
> +
> + if (copy_from_user(&secinfo, (void __user *)addp.secinfo,
> + sizeof(secinfo)))
> + return -EFAULT;
> +
> + if (sgx_validate_secinfo(&secinfo))
> + return -EINVAL;
> +
> + for (c = 0 ; c < addp.length; c += PAGE_SIZE) {
> + if (signal_pending(current)) {
> + ret = -EINTR;
> + break;
> + }
> +
> + if (need_resched())
> + cond_resched();
> +
> + ret = sgx_encl_add_page(encl, addp.src + c, addp.offset + c,
> + addp.length - c, &secinfo, addp.flags);
> + if (ret)
> + break;
> + }
> +
> + addp.count = c;
> +
> + if (copy_to_user(arg, &addp, sizeof(addp)))
> + return -EFAULT;
> +
> + return ret;
> +}
> +
> +static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
> + void *hash)
> +{
> + SHASH_DESC_ON_STACK(shash, tfm);
> +
> + shash->tfm = tfm;
> +
> + return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
> +}
> +
> +static int sgx_get_key_hash(const void *modulus, void *hash)
> +{
> + struct crypto_shash *tfm;
> + int ret;
> +
> + tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
> + if (IS_ERR(tfm))
> + return PTR_ERR(tfm);
> +
> + ret = __sgx_get_key_hash(tfm, modulus, hash);
> +
> + crypto_free_shash(tfm);
> + return ret;
> +}
> +
> +static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
> +{
> + u64 *cache;
> + int i;
> +
> + cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
> + for (i = 0; i < 4; i++) {
> + if (enforce || (lepubkeyhash[i] != cache[i])) {
> + wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
> + cache[i] = lepubkeyhash[i];
> + }
> + }
> +}
> +
> +static int sgx_einit(struct sgx_sigstruct *sigstruct, void *token,
> + struct sgx_epc_page *secs, u64 *lepubkeyhash)
> +{
> + int ret;
> +
> + preempt_disable();
> + sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
> + ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> + if (ret == SGX_INVALID_EINITTOKEN) {
> + sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
> + ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> + }
> + preempt_enable();
> + return ret;
> +}
> +
> +static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
> + void *token)
> +{
> + u64 mrsigner[4];
> + int ret;
> + int i;
> + int j;
> +
> + /* Check that the required attributes have been authorized. */
> + if (encl->secs_attributes & ~encl->allowed_attributes)
> + return -EACCES;
> +
> + ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&encl->lock);
> +
> + if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
> + ret = -EFAULT;
> + goto err_out;
> + }
> +
> + for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
> + for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
> + ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
> + mrsigner);
> + if (ret == SGX_UNMASKED_EVENT)
> + continue;
> + else
> + break;
> + }
> +
> + if (ret != SGX_UNMASKED_EVENT)
> + break;
> +
> + msleep_interruptible(SGX_EINIT_SLEEP_TIME);
> +
> + if (signal_pending(current)) {
> + ret = -ERESTARTSYS;
> + goto err_out;
> + }
> + }
> +
> + if (ret & ENCLS_FAULT_FLAG) {
> + if (encls_failed(ret))
> + ENCLS_WARN(ret, "EINIT");
> +
> + sgx_encl_destroy(encl);
> + ret = -EFAULT;
> + } else if (ret) {
> + pr_debug("EINIT returned %d\n", ret);
> + ret = -EPERM;
> + } else {
> + atomic_or(SGX_ENCL_INITIALIZED, &encl->flags);
> + }
> +
> +err_out:
> + mutex_unlock(&encl->lock);
> + return ret;
> +}
> +
> +/**
> + * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
> + *
> + * @filep: open file to /dev/sgx
> + * @arg: userspace pointer to a struct sgx_enclave_init instance
> + *
> + * Flush any outstanding enqueued EADD operations and perform EINIT. The
> + * Launch Enclave Public Key Hash MSRs are rewritten as necessary to match
> + * the enclave's MRSIGNER, which is caculated from the provided sigstruct.
> + *
> + * Return:
> + * 0 on success,
> + * SGX error code on EINIT failure,
> + * -errno otherwise
> + */
> +static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_sigstruct *sigstruct;
> + struct sgx_enclave_init einit;
> + struct page *initp_page;
> + void *token;
> + int ret;
> +
> + if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
> + return -EINVAL;
> +
> + if (copy_from_user(&einit, arg, sizeof(einit)))
> + return -EFAULT;
> +
> + initp_page = alloc_page(GFP_KERNEL);
> + if (!initp_page)
> + return -ENOMEM;
> +
> + sigstruct = kmap(initp_page);
> + token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
> + memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
> +
> + if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
> + sizeof(*sigstruct))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = sgx_encl_init(encl, sigstruct, token);
> +
> +out:
> + kunmap(initp_page);
> + __free_page(initp_page);
> + return ret;
> +}
> +
> +
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> +{
> + struct sgx_encl *encl = filep->private_data;
> + int ret, encl_flags;
> +
> + encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> + if (encl_flags & SGX_ENCL_IOCTL)
> + return -EBUSY;
> +
> + if (encl_flags & SGX_ENCL_DEAD)
> + return -EFAULT;
> +
> + switch (cmd) {
> + case SGX_IOC_ENCLAVE_CREATE:
> + ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_ADD_PAGES:
> + ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> + break;
> + case SGX_IOC_ENCLAVE_INIT:
> + ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> + break;
> + default:
> + ret = -ENOIOCTLCMD;
> + break;
> + }
> +
> + atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> +
> + return ret;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 60d82e7537c8..842f9abba1c0 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -8,6 +8,7 @@
> #include <linux/ratelimit.h>
> #include <linux/sched/signal.h>
> #include <linux/slab.h>
> +#include "driver.h"
> #include "encls.h"
>
> struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> @@ -193,6 +194,8 @@ static bool __init sgx_page_cache_init(void)
>
> static void __init sgx_init(void)
> {
> + int ret;
> +
> if (!boot_cpu_has(X86_FEATURE_SGX))
> return;
>
> @@ -202,10 +205,17 @@ static void __init sgx_init(void)
> if (!sgx_page_reclaimer_init())
> goto err_page_cache;
>
> + ret = sgx_drv_init();
> + if (ret)
> + goto err_kthread;
> +
> return;
>
> +err_kthread:
> + kthread_stop(ksgxswapd_tsk);
> +
> err_page_cache:
> sgx_page_cache_teardown();
> }
>
> -arch_initcall(sgx_init);
> +device_initcall(sgx_init);
> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> index 215371588a25..9e6d3e147aa2 100644
> --- a/arch/x86/kernel/cpu/sgx/reclaim.c
> +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> @@ -10,6 +10,7 @@
> #include <linux/sched/mm.h>
> #include <linux/sched/signal.h>
> #include "encls.h"
> +#include "driver.h"
>
> struct task_struct *ksgxswapd_tsk;
>
> --
> 2.25.1
>
On Fri, May 08, 2020 at 02:02:26PM -0500, Dr. Greg wrote:
> On Thu, May 07, 2020 at 02:41:30AM +0200, Thomas Gleixner wrote:
> > The diffstat of your patch is irrelevant. What's relevant is the
> > fact that it is completely unreviewed and that it creates yet
> > another user space visible ABI with a noticable lack of
> > documentation.
...
> As to lack of review, we would certainly welcome technical and API
> comments but we cannot force them.
Thomas' point isn't that your code needs to be reviewed, it's that trying
to squeeze it into the initial merge will, not might, _will_ push out the
acceptance of SGX. The same is true for other features we have lined up,
e.g. KVM and cgroup support. It's not a slight on your code, it's just
reality at this point.
> In fact, anyone who reviews the patch will see that the current driver
> creates a pointer in the ioctl call to pass downward into the hardware
> initialization routines. Our code simply replaces that pointer with
> one supplied by userspace.
Personally, I'm in favor of adding a reserved placeholder for a token so
as to avoid adding a second ioctl() in the event that something gets
upstreamed that wants the token. Ditto for a file descriptor for the
backing store in sgx_enclave_create.
But, I have contributed exactly zero ioctls to the kernel, so take that
with a big block of salt :-)
> At the very least a modular form of the driver should be considered
> that would allow alternate implementations. Sean indicated that there
> was a 'kludgy' approach that would allow an alternate modular
> implementation alongside the in-kernel driver. I believe that Andy
> has already indicated that may not be an advisable approach.
Modularizing the the driver does nothing for your use case. The "driver"
is a relatively lightweight wrapper, removing that is akin to making
/dev/sgx/enclave inaccessible, i.e. it doesn't make the EPC tracking and
core code go away. Modularizing the whole thing is flat out not an option,
as doing so is not compatible with an EPC cgroup and adds unnecessary
complexity to KVM enabling, both of which are highly desired features by
pretty much everyone that plans on using SGX.
Andy is right to caution against playing games to squish in-kernel things,
but the virtualization snafu is a completely different beast. E.g. SGX
doesn't require fiddling with CR4, won't corrupt random memory across
kexec(), doesn't block INIT, etc... And I'm not advocating long-term
shenanigans, I just wanted to point out that there are options for running
out-of-tree drivers in the short term, e.g. until proper policy controls
land upstream.
On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> Intel(R) SGX is a set of CPU instructions that can be used by applications
> to set aside private regions of code and data. The code outside the enclave
> is disallowed to access the memory inside the enclave by the CPU access
> control.
>
> There is a new hardware unit in the processor called Memory Encryption
> Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> one or many MEE regions that can hold enclave data by configuring them with
> PRMRR registers.
>
> The MEE automatically encrypts the data leaving the processor package to
> the MEE regions. The data is encrypted using a random key whose life-time
> is exactly one power cycle.
>
> The current implementation requires that the firmware sets
> IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> decide what enclaves it wants run. The implementation does not create
> any bottlenecks to support read-only MSRs later on.
>
> You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
>
> cat /proc/cpuinfo | grep sgx
Tested-by: Chunyang Hui <[email protected]>
Occlum project (https://github.com/occlum/occlum) is a libOS built on top of
Intel SGX feature. We ran Occlum tests using patch v29 on SGX hardware with
the Flexible Launch Control (FLC) feature and didn't find any problems.
As Occlum core developers, we would like these patches to be merged soon.
> v29:
> * The selftest has been moved to selftests/sgx. Because SGX is an execution
> environment of its own, it really isn't a great fit with more "standard"
> x86 tests.
>
> The RSA key is now generated on fly and the whole signing process has
> been made as part of the enclave loader instead of signing the enclave
> during the compilation time.
>
> Finally, the enclave loader loads now the test enclave directly from its
> ELF file, which means that ELF file does not need to be coverted as raw
> binary during the build process.
> * Version the mm_list instead of using on synchronize_mm() when adding new
> entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> deadlock with the page reclaimer, which could hold the lock for the old
> mm_struct.
> * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> be used to reserve the address range. Now /dev/sgx supports only opaque
> mappings to the (initialized) enclave data.
> * Make the vDSO callable directly from C by preserving RBX and taking leaf
> from RCX.
>
> v28:
> * Documented to Documentation/x86/sgx.rst how the kernel manages the
> enclave ownership.
> * Removed non-LC flow from sgx_einit().
> * Removed struct sgx_einittoken since only the size of the corresponding
> microarchitectural structure is used in the series ATM.
>
> v27:
> * Disallow RIE processes to use enclaves as there could a permission
> conflict between VMA and enclave permissions.
> * In the documentation, replace "grep /proc/cpuinfo" with
> "grep sgx /proc/cpuinfo".
>
> v26:
> * Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
> changed in v25 by mistake.
> * Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
> again for such a detailed feedback).
> * Added back the MAINTAINERS update commit, which was mistakenly removed
> in v25.
> * EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
> CPU does not allow to remove a SECS page before all of its children have
> been removed, and a child page can be in some other section than the one
> currently being processed. Thus, removed special SECS processing from
> sgx_sanitize_page() and instead put sections through it twice. In the
> 2nd round the lists should only contain SECS pages.
>
> v25:
> * Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
> fails on executing ENCLS[EADD]. The rollback path executed
> radix_tree_delete() on the same address twice when this happened.
> * Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
> a signal is pending.
> * As requested by Borislav, move the CPUID 0x12 features to their own word
> in cpufeatures.
> * Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
> was called with an uninitialized pointer when sgx_encl_get_backing()
> fails.
> * Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
> has 'groups' for setting up sysfs attributes for the device.
> * Use device_initcall instead of subsys_initcall so that misc_class is
> initialized before SGX is initialized.
> * Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
> enclave attributes that we the kernel does not allow it to set instead
> of -EINVAL.
> * Unless SGX public key MSRs are writable always deny the feature from
> Linux. Previously this was only denied from driver. How VMs should be
> supported is not really part of initial patch set, which makes this
> an obvious choice.
> * Cleaned up and refined documentation to be more approachable.
>
> v24:
> * Reclaim unmeasured and TCS pages (regression in v23).
> * Replace usages of GFP_HIGHUSER with GFP_KERNEL.
> * Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
> and use the same rollback (destroy enclave). This can happen when host
> suspends itself unknowingly to a VM running enclaves. From -EIO the user
> space can deduce what happened.
> * Have a separate @count in struct sgx_enclave_add_pages to output number
> of bytes processed instead of overwriting the input parameters for
> clarity and more importantly that the API provides means for partial
> processing (@count could be less than @length in success case).
>
> v23:
> * Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
> with %SGX_PAGE_MEASURE flag.
> * Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
> * In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
> (because of OOM) even in legit behaviour and after EBLOCK the reclaiming
> flow can be only reverted by killing the whole enclave.
> * Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
> it should have been bit 6 (Table 37-3 in the SDM).
> * Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
> error code.
>
> v22:
> * Refined bunch commit messages and added associated SDM references as
> many of them were too exhausting and some outdated.
> * Alignment checks have been removed from mmap() because it does not define the
> ELRANGE. VMAs only act as windows to the enclave. The semantics compare
> somewhat how mmap() works with regular files.
> * We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
> page aligned so that we can pass the page directly to EADD and do not have
> to do an extra copy. This was made effectively possible by removing the
> worker thread for adding pages.
> * The selftest build files have been refined throughout of various glitches
> and work properly in a cross compilation environment such as BuildRoot.
> In addition, libcalls fail the build with an assertion in the linker
> script, if they end up to the enclave binary.
> * CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
> for anything without having the driver. This could change when KVM support
> is added.
> * We require zero permissions in SECINFO for TCS pages because the CPU
> overwrites SECINFO flags with zero permissions and measures the page
> only after that. Allowing to pass TCS with non-zero permissions would
> cause mismatching measurement between the one provided in SIGSTRUCT and
> the one computed by the CPU.
> * Obviously lots of small fixes and clean ups (does make sense to
> document them all).
>
> v21:
> * Check on mmap() that the VMA does cover an area that does not have
> enclave pages. Only mapping with PROT_NONE can do that to reserve
> initial address space for an enclave.
> * Check om mmap() and mprotect() that the VMA permissions do not
> surpass the enclave permissions.
> * Remove two refcounts from vma_close(): mm_list and encl->refcount.
> Enclave refcount is only need for swapper/enclave sync and we can
> remove mm_list refcount by destroying mm_struct when the process
> is closed. By not having vm_close() the Linux MM can merge VMAs.
> * Do not naturally align MAP_FIXED address.
> * Numerous small fixes and clean ups.
> * Use SRCU for synchronizing the list of mm_struct's.
> * Move to stack based call convention in the vDSO.
>
> v20:
> * Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
> dependency as MMU notifiers are no longer used in the driver.
> * Use mm_users instead of mm_count as refcount for mm_struct as mm_count
> only protects from deleting mm_struct, not removing its contents.
> * Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
> of them. They could be in initialized state when the kernel starts
> because it might be spawned by kexec().
> * Documentation overhaul.
> * Use a device /dev/sgx/provision for delivering the provision token
> instead of securityfs.
> * Create a reference to the enclave when already when opening
> /dev/sgx/enclave. The file is then associated with this enclave only.
> mmap() can be done at free at any point and always get a reference to
> the enclave. To summarize the file now represents the enclave.
>
> v19:
> * Took 3-4 months but in some sense this was more like a rewrite of most
> of the corners of the source code. If I've forgotten to deal with some
> feedback, please don't shout me. Make a remark and I will fix it for
> the next version. Hopefully there won't be this big turnovers anymore.
> * Validate SECS attributes properly against CPUID given attributes and
> against allowed attributes. SECS attributes are the ones that are
> enforced whereas SIGSTRUCT attributes tell what is required to run
> the enclave.
> * Add KSS (Key Sharing Support) to the enclave attributes.
> * Deny MAP_PRIVATE as an enclave is always a shared memory entity.
> * Revert back to shmem backing storage so that it can be easily shared
> by multiple processes.
> * Split the recognization of an ENCLS leaf failure by using three
> functions to detect it: encsl_faulted(), encls_returned_code() and
> sgx_failed(). encls_failed() is only caused by a spurious expections that
> should never happen. Thus, it is not defined as an inline function in
> order to easily insert a kprobe to it.
> * Move low-level enclave management routines, page fault handler and page
> reclaiming routines from driver to the core. These cannot be separated
> from each other as they are heavily interdependent. The rationale is that
> the core does not call any code from the driver.
> * Allow the driver to be compiled as a module now that it no code is using
> its routines and it only uses exported symbols. Now the driver is
> essentially just a thin ioctl layer.
> * Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
> add new entries to this list as the process is forked. Each entry has
> its own refcount because they have a different life-cycle as the enclave
> does. In effect @tgid and @mm have been removed from struct sgx_encl
> and we allow forking by removing VM_DONTCOPY from vm flags.
> * Generate a cpu mask in the reclaimer from the cpu mask's of all
> mm_struct's. This will kick out the hardware threads out of the enclave
> from multiple processes. It is not a local variable because it would
> eat too much of the stack space but instead a field in struct
> sgx_encl.
> * Allow forking i.e. remove VM_DONTCOPY. I did not change the API
> because the old API scaled to the workload that Andy described. The
> codebase is now mostly API independent i.e. changing the API is a
> small task. For me the proper trigger to chanage it is a as concrete
> as possible workload that cannot be fulfilled. I hope you understand
> my thinking here. I don't want to change anything w/o proper basis
> but I'm ready to change anything if there is a proper basis. I do
> not have any kind of attachment to any particular type of API.
> * Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
> new vDSO.
>
> v18:
> * Update the ioctl-number.txt.
> * Move the driver under arch/x86.
> * Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
> * Rename the selftest as test_sgx (previously sgx-selftest).
> * In order to enable process accounting, swap EPC pages and PCMD's to a VMA
> instead of shmem.
> * Allow only to initialize and run enclaves with a subset of
> {DEBUG, MODE64BIT} set.
> * Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
> attributes e.g. PROVISIONKEY.
>
> v17:
> * Add a simple selftest.
> * Fix a null pointer dereference to section->pages when its
> allocation fails.
> * Add Sean's description of the exception handling to the documentation.
>
> v16:
> * Fixed SOB's in the commits that were a bit corrupted in v15.
> * Implemented exceptio handling properly to detect_sgx().
> * Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
> * Updated the documentation to use rst definition lists.
> * Added the missing Documentation/x86/index.rst, which has a link to
> intel_sgx.rst. Now the SGX and uapi documentation is properly generated
> with 'make htmldocs'.
> * While enumerating EPC sections, if an undefined section is found, fail
> the driver initialization instead of continuing the initialization.
> * Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
> * Remove copyright notice from arch/x86/include/asm/sgx.h.
> * Migrated from ioremap_cache() to memremap().
>
> v15:
> * Split into more digestable size patches.
> * Lots of small fixes and clean ups.
> * Signal a "plain" SIGSEGV on an EPCM violation.
>
> v14:
> * Change the comment about X86_FEATURE_SGX_LC from ???SGX launch
> configuration??? to ???SGX launch control???.
> * Move the SGX-related CPU feature flags as part of the Linux defined
> virtual leaf 8.
> * Add SGX_ prefix to the constants defining the ENCLS leaf functions.
> * Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
> * Refine the long description for CONFIG_INTEL_SGX_CORE.
> * Do not use pr_*_ratelimited() in the driver. The use of the rate limited
> versions is legacy cruft from the prototyping phase.
> * Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
> cycles.
> * Manually prefix with ???sgx:??? in the core SGX code instead of redefining
> pr_fmt.
> * Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
> instead of core because it is a driver requirement.
> * Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
> default is ???n???.
> * Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
> the SDM.
> * Allocate struct sgx_epc_page instances one at a time.
> * Use ???__iomem void *??? pointers for the mapped EPC memory consistently.
> * Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
> cycles.
> * Call enclave swapping operations directly from the driver instead of
> calling them .indirectly through struct sgx_epc_page_ops because indirect
> calls are not required yet as the patch set does not contain the KVM
> support.
> * Added special signal SEGV_SGXERR to notify about SGX EPCM violation
> errors.
>
> v13:
> * Always use SGX_CPUID constant instead of a hardcoded value.
> * Simplified and documented the macros and functions for ENCLS leaves.
> * Enable sgx_free_page() to free active enclave pages on demand
> in order to allow sgx_invalidate() to delete enclave pages.
> It no longer performs EREMOVE if a page is in the process of
> being reclaimed.
> * Use PM notifier per enclave so that we don't have to traverse
> the global list of active EPC pages to find enclaves.
> * Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
> * Always use ioremap() to map EPC banks as we only support 64-bit kernel.
> * Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
> to sleep.
>
> v12:
> * Split to more narrow scoped commits in order to ease the review process and
> use co-developed-by tag for co-authors of commits instead of listing them in
> the source files.
> * Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
> * Removed in-kernel LE i.e. this version of the SGX software stack only
> supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
> * Refined documentation on launching enclaves, swapping and enclave
> construction.
> * Refined sgx_arch.h to include alignment information for every struct that
> requires it and removed structs that are not needed without an LE.
> * Got rid of SGX_CPUID.
> * SGX detection now prints log messages about firmware configuration issues.
>
> v11:
> * Polished ENCLS wrappers with refined exception handling.
> * ksgxswapd was not stopped (regression in v5) in
> sgx_page_cache_teardown(), which causes a leaked kthread after driver
> deinitialization.
> * Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
> invalidated when resuming, which will cause it not function properly
> anymore.
> * Set EINITTOKEN.VALID to zero for a token that is passed when
> SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
> page.
> * Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
> around the flags field, which causes a #GP. Only flags read is readable.
> * On read access memcpy() call inside sgx_vma_access() had src and dest
> parameters in wrong order.
> * The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
> to LE even if ???KASAN_SANITIZE := false??? was set in the makefile.
> * Fixed a regression in the #PF handler. If a page has
> SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
> It did not, which caused weird races when trying to change other parts of
> swapping code.
> * EPC management has been refactored to a flat LRU cache and moved to
> arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
> of them. It can now swap from multiple enclaves in the same round.
> * For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
> when an enclave is already initialized or dead instead of zero.
>
> v10:
> * Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
> of the driver.
> * Unset the reserved flag from an enclave page if EDBGRD/WR fails
> (regression in v6).
> * Close the anon inode when LE is stopped (regression in v9).
> * Update the documentation with a more detailed description of SGX.
>
> v9:
> * Replaced kernel-LE IPC based on pipes with an anonymous inode.
> The driver does not require anymore new exports.
>
> v8:
> * Check that public key MSRs match the LE public key hash in the
> driver initialization when the MSRs are read-only.
> * Fix the race in VA slot allocation by checking the fullness
> immediately after succeesful allocation.
> * Fix the race in hash mrsigner calculation between the launch
> enclave and user enclaves by having a separate lock for hash
> calculation.
>
> v7:
> * Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
> when it should have been masked with ~PAGE_MASK.
> * Fixed a memory leak in sgx_ioc_enclave_create().
> * Simplified swapping code by using a pointer array for a cluster
> instead of a linked list.
> * Squeezed struct sgx_encl_page to 32 bytes.
> * Fixed deferencing of an RSA key on OpenSSL 1.1.0.
> * Modified TC's CMAC to use kernel AES-NI. Restructured the code
> a bit in order to better align with kernel conventions.
>
> v6:
> * Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
> * In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
> * Removed virtualization chapter from the documentation.
> * Changed the default filename for the signing key as signing_key.pem.
> * Reworked EPC management in a way that instead of a linked list of
> struct sgx_epc_page instances there is an array of integers that
> encodes address and bank of an EPC page (the same data as 'pa' field
> earlier). The locking has been moved to the EPC bank level instead
> of a global lock.
> * Relaxed locking requirements for EPC management. EPC pages can be
> released back to the EPC bank concurrently.
> * Cleaned up ptrace() code.
> * Refined commit messages for new architectural constants.
> * Sorted includes in every source file.
> * Sorted local variable declarations according to the line length in
> every function.
> * Style fixes based on Darren's comments to sgx_le.c.
>
> v5:
> * Described IPC between the Launch Enclave and kernel in the commit messages.
> * Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
> versions except those that exist in the imported TinyCrypt code.
> * Fixed spelling mistakes in the documentation.
> * Forgot to check the return value of sgx_drv_subsys_init().
> * Encapsulated properly page cache init and teardown.
> * Collect epc pages to a temp list in sgx_add_epc_bank
> * Removed SGX_ENCLAVE_INIT_ARCH constant.
>
> v4:
> * Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
> * Removed __exit annotation from sgx_drv_subsys_exit().
> * Fixed a leak of a backing page in sgx_process_add_page_req() in the
> case when vm_insert_pfn() fails.
> * Removed unused symbol exports for sgx_page_cache.c.
> * Updated sgx_alloc_page() to require encl parameter and documented the
> behavior (Sean Christopherson).
> * Refactored a more lean API for sgx_encl_find() and documented the behavior.
> * Moved #PF handler to sgx_fault.c.
> * Replaced subsys_system_register() with plain bus_register().
> * Retry EINIT 2nd time only if MSRs are not locked.
>
> v3:
> * Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
> * Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
> * Use unused bits in epc_page->pa to store the bank number.
> * Removed #ifdef for WQ_NONREENTRANT.
> * If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
> * Added --remove-section=.got.plt to objcopy flags in order to prevent a
> dummy .got.plt, which will cause an inconsistent size for the LE.
> * Documented sgx_encl_* functions.
> * Added remark about AES implementation used inside the LE.
> * Removed redundant sgx_sys_exit() from le/main.c.
> * Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
> * Validate miscselect in sgx_encl_create().
> * Fixed SSA frame size calculation to take the misc region into account.
> * Implemented consistent exception handling to __encls() and __encls_ret().
> * Implemented a proper device model in order to allow sysfs attributes
> and in-kernel API.
> * Cleaned up various "find enclave" implementations to the unified
> sgx_encl_find().
> * Validate that vm_pgoff is zero.
> * Discard backing pages with shmem_truncate_range() after EADD.
> * Added missing EEXTEND operations to LE signing and launch.
> * Fixed SSA size for GPRS region from 168 to 184 bytes.
> * Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
> * Check that TCS addresses are in ELRANGE and not just page aligned.
> * Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
> * Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.
>
> v2:
> * get_rand_uint32() changed the value of the pointer instead of value
> where it is pointing at.
> * Launch enclave incorrectly used sigstruct attributes-field instead of
> enclave attributes-field.
> * Removed unused struct sgx_add_page_req from sgx_ioctl.c
> * Removed unused sgx_has_sgx2.
> * Updated arch/x86/include/asm/sgx.h so that it provides stub
> implementations when sgx in not enabled.
> * Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
> * return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
> * removed unused global sgx_nr_pids
> * moved sgx_encl_release to sgx_encl.c
> * return -ERESTARTSYS instead of -EINTR in sgx_encl_init()
>
> Jarkko Sakkinen (10):
> x86/sgx: Update MAINTAINERS
> x86/sgx: Add SGX microarchitectural data structures
> x86/sgx: Add wrappers for ENCLS leaf functions
> x86/sgx: Add functions to allocate and free EPC pages
> x86/sgx: Linux Enclave Driver
> x86/sgx: Add provisioning
> x86/sgx: Add a page reclaimer
> x86/sgx: ptrace() support for the SGX driver
> selftests/x86: Add a selftest for SGX
> docs: x86/sgx: Document SGX micro architecture and kernel internals
>
> Sean Christopherson (10):
> x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
> x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
> x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
> x86/cpu/intel: Detect SGX support
> x86/sgx: Enumerate and track EPC sections
> mm: Introduce vm_ops->may_mprotect()
> x86/vdso: Add support for exception fixup in vDSO functions
> x86/fault: Add helper function to sanitize error code
> x86/traps: Attempt to fixup exceptions in vDSO before signaling
> x86/vdso: Implement a vDSO for Intel SGX enclave call
>
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> Documentation/x86/index.rst | 1 +
> Documentation/x86/sgx.rst | 206 +++++
> MAINTAINERS | 11 +
> arch/x86/Kconfig | 14 +
> arch/x86/entry/vdso/Makefile | 8 +-
> arch/x86/entry/vdso/extable.c | 46 +
> arch/x86/entry/vdso/extable.h | 29 +
> arch/x86/entry/vdso/vdso-layout.lds.S | 9 +-
> arch/x86/entry/vdso/vdso.lds.S | 1 +
> arch/x86/entry/vdso/vdso2c.h | 58 +-
> arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++
> arch/x86/include/asm/cpufeature.h | 5 +-
> arch/x86/include/asm/cpufeatures.h | 8 +-
> arch/x86/include/asm/disabled-features.h | 18 +-
> arch/x86/include/asm/enclu.h | 8 +
> arch/x86/include/asm/msr-index.h | 8 +
> arch/x86/include/asm/required-features.h | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/include/asm/vdso.h | 5 +
> arch/x86/include/uapi/asm/sgx.h | 175 ++++
> arch/x86/kernel/cpu/Makefile | 1 +
> arch/x86/kernel/cpu/common.c | 4 +
> arch/x86/kernel/cpu/feat_ctl.c | 32 +-
> arch/x86/kernel/cpu/sgx/Makefile | 6 +
> arch/x86/kernel/cpu/sgx/arch.h | 343 ++++++++
> arch/x86/kernel/cpu/sgx/driver.c | 209 +++++
> arch/x86/kernel/cpu/sgx/driver.h | 32 +
> arch/x86/kernel/cpu/sgx/encl.c | 756 +++++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 128 +++
> arch/x86/kernel/cpu/sgx/encls.h | 238 ++++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 800 ++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 280 ++++++
> arch/x86/kernel/cpu/sgx/reclaim.c | 471 +++++++++++
> arch/x86/kernel/cpu/sgx/sgx.h | 108 +++
> arch/x86/kernel/traps.c | 14 +
> arch/x86/mm/fault.c | 45 +-
> include/linux/mm.h | 2 +
> mm/mprotect.c | 14 +-
> tools/arch/x86/include/asm/cpufeatures.h | 7 +-
> tools/testing/selftests/Makefile | 1 +
> tools/testing/selftests/sgx/.gitignore | 2 +
> tools/testing/selftests/sgx/Makefile | 53 ++
> tools/testing/selftests/sgx/call.S | 54 ++
> tools/testing/selftests/sgx/defines.h | 21 +
> tools/testing/selftests/sgx/load.c | 282 ++++++
> tools/testing/selftests/sgx/main.c | 199 +++++
> tools/testing/selftests/sgx/main.h | 38 +
> tools/testing/selftests/sgx/sigstruct.c | 395 +++++++++
> tools/testing/selftests/sgx/test_encl.c | 20 +
> tools/testing/selftests/sgx/test_encl.lds | 40 +
> .../selftests/sgx/test_encl_bootstrap.S | 89 ++
> 52 files changed, 5398 insertions(+), 31 deletions(-)
> create mode 100644 Documentation/x86/sgx.rst
> create mode 100644 arch/x86/entry/vdso/extable.c
> create mode 100644 arch/x86/entry/vdso/extable.h
> create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
> create mode 100644 arch/x86/include/asm/enclu.h
> create mode 100644 arch/x86/include/uapi/asm/sgx.h
> create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
> create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
> create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
> create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
> create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
> create mode 100644 arch/x86/kernel/cpu/sgx/main.c
> create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
> create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
> create mode 100644 tools/testing/selftests/sgx/.gitignore
> create mode 100644 tools/testing/selftests/sgx/Makefile
> create mode 100644 tools/testing/selftests/sgx/call.S
> create mode 100644 tools/testing/selftests/sgx/defines.h
> create mode 100644 tools/testing/selftests/sgx/load.c
> create mode 100644 tools/testing/selftests/sgx/main.c
> create mode 100644 tools/testing/selftests/sgx/main.h
> create mode 100644 tools/testing/selftests/sgx/sigstruct.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.c
> create mode 100644 tools/testing/selftests/sgx/test_encl.lds
> create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S
>
> --
> 2.25.1
>
On Tue, May 12, 2020 at 07:55:58PM +0800, Hui, Chunyang wrote:
> > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >
> > cat /proc/cpuinfo | grep sgx
>
> Tested-by: Chunyang Hui <[email protected]>
> Occlum project (https://github.com/occlum/occlum) is a libOS built
> on top of Intel SGX feature. We ran Occlum tests using patch v29 on
> SGX hardware with the Flexible Launch Control (FLC) feature and
> didn't find any problems. As Occlum core developers, we would like
> these patches to be merged soon.
Do you use the Intel PSW or your own?
Are you using the standard ECALL interface or did the tests run with
the new VDSO entry and exception handler?
Have a good day.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Autonomously self-defensive
Enjellic Systems Development, LLC IOT platforms and edge devices.
4206 N. 19th Ave.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"I had far rather walk, as I do, in daily terror of eternity, than feel
that this was only a children's game in which all of the contestants
would get equally worthless prizes in the end."
-- T. S. Elliot
On Wed, May 06, 2020 at 02:50:48PM -0700, Sean Christopherson wrote:
> On Wed, Apr 22, 2020 at 12:53:10AM +0300, Jarkko Sakkinen wrote:
> > Add VMA callbacks for ptrace() that can be used with debug enclaves.
> > With debug enclaves data can be read and write the memory word at a time
> > by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.
> >
> > Signed-off-by: Jarkko Sakkinen <[email protected]>
> > ---
> > arch/x86/kernel/cpu/sgx/encl.c | 88 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 88 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> > index fe7dbca40bb4..0c5ea2968868 100644
> > --- a/arch/x86/kernel/cpu/sgx/encl.c
> > +++ b/arch/x86/kernel/cpu/sgx/encl.c
> > @@ -326,6 +326,7 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> > return 0;
> > }
> >
> > +
>
> Unnecessary whitespace change.
Would not update series just for this. If something else, will fix this
one.
/Jarkko
On Wed, 2020-05-06 at 17:42 -0400, Nathaniel McCallum wrote:
> Tested on Enarx. This requires a patch[0] for v29 support.
>
> Tested-by: Nathaniel McCallum <[email protected]>
Thank you. Update in my tree.
Sean, I'll fixed that whitespace issue too in my tree.
General question: maybe it would be easiest that I issue a pull request
once everyone feels that the series is ready to be pulled and stop sending
new versions of the series?
/Jarkko
On Thu, 2020-05-14 at 01:14 +0300, Jarkko Sakkinen wrote:
> On Wed, 2020-05-06 at 17:42 -0400, Nathaniel McCallum wrote:
> > Tested on Enarx. This requires a patch[0] for v29 support.
> >
> > Tested-by: Nathaniel McCallum <[email protected]>
>
> Thank you. Update in my tree.
>
> Sean, I'll fixed that whitespace issue too in my tree.
>
> General question: maybe it would be easiest that I issue a pull request
> once everyone feels that the series is ready to be pulled and stop sending
> new versions of the series?
My honest feelings about the series ATM are:
1. It is not perfect like no code never is and there are always issues.
2. Some things are very well matured, even more so than in a lot of mainline
code I've seen. I'm particularly happy how the locking code has been
converged.
3. Not worried to maintain the code in its current state. It is manageable.
/Jarkko
On Wed, 2020-05-06 at 09:39 -0700, Jordan Hand wrote:
> On 4/21/20 2:52 PM, Jarkko Sakkinen wrote:
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> >
> > There is a new hardware unit in the processor called Memory Encryption
> > Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> > one or many MEE regions that can hold enclave data by configuring them with
> > PRMRR registers.
> >
> > The MEE automatically encrypts the data leaving the processor package to
> > the MEE regions. The data is encrypted using a random key whose life-time
> > is exactly one power cycle.
> >
> > The current implementation requires that the firmware sets
> > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > decide what enclaves it wants run. The implementation does not create
> > any bottlenecks to support read-only MSRs later on.
> >
> > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >
> > cat /proc/cpuinfo | grep sgx
> >
> > v29:
> > * The selftest has been moved to selftests/sgx. Because SGX is an execution
> > environment of its own, it really isn't a great fit with more "standard"
> > x86 tests.
> >
> > The RSA key is now generated on fly and the whole signing process has
> > been made as part of the enclave loader instead of signing the enclave
> > during the compilation time.
> >
> > Finally, the enclave loader loads now the test enclave directly from its
> > ELF file, which means that ELF file does not need to be coverted as raw
> > binary during the build process.
> > * Version the mm_list instead of using on synchronize_mm() when adding new
> > entries. We hold the write lock for the mm_struct, and dup_mm() can thus
> > deadlock with the page reclaimer, which could hold the lock for the old
> > mm_struct.
> > * Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
> > be used to reserve the address range. Now /dev/sgx supports only opaque
> > mappings to the (initialized) enclave data.
> > * Make the vDSO callable directly from C by preserving RBX and taking leaf
> > from RCX.
> >
>
> Tested with the Open Enclave SDK on top of Intel PSW. Specifically built
> the Intel PSW with changes to support /dev/sgx mapping[1] new in v29.
>
> Tested-by: Jordan Hand <[email protected]>
>
> [1] https://github.com/intel/linux-sgx/pull/530
Thank you!
/Jarkko
On 2020-05-14 00:14, Jarkko Sakkinen wrote:
> General question: maybe it would be easiest that I issue a pull request
> once everyone feels that the series is ready to be pulled and stop sending
> new versions of the series?
Sounds good
--
Jethro Beekman | Fortanix
On Fri, May 08, 2020 at 12:56:35PM -0700, Sean Christopherson wrote:
Good morning, I hope the week is proceeding well for everyone.
> On Fri, May 08, 2020 at 02:02:26PM -0500, Dr. Greg wrote:
> > On Thu, May 07, 2020 at 02:41:30AM +0200, Thomas Gleixner wrote:
> > > The diffstat of your patch is irrelevant. What's relevant is the
> > > fact that it is completely unreviewed and that it creates yet
> > > another user space visible ABI with a noticable lack of
> > > documentation.
>
> ...
>
> > As to lack of review, we would certainly welcome technical and API
> > comments but we cannot force them.
> Thomas' point isn't that your code needs to be reviewed, it's that
> trying to squeeze it into the initial merge will, not might, _will_
> push out the acceptance of SGX. The same is true for other features
> we have lined up, e.g. KVM and cgroup support. It's not a slight on
> your code, it's just reality at this point.
For the record and for whatever it is worth at this point. The patch
has been available in its present form and function for around 14
months.
So there was plenty of time for its consideration and integration into
what is being prepared as the final merge candidate.
> > In fact, anyone who reviews the patch will see that the current driver
> > creates a pointer in the ioctl call to pass downward into the hardware
> > initialization routines. Our code simply replaces that pointer with
> > one supplied by userspace.
> Personally, I'm in favor of adding a reserved placeholder for a
> token so as to avoid adding a second ioctl() in the event that
> something gets upstreamed that wants the token. Ditto for a file
> descriptor for the backing store in sgx_enclave_create.
That would be a very low cost and forward looking addition.
> > At the very least a modular form of the driver should be
> > considered that would allow alternate implementations. Sean
> > indicated that there was a 'kludgy' approach that would allow an
> > alternate modular implementation alongside the in-kernel driver.
> > I believe that Andy has already indicated that may not be an
> > advisable approach.
> Modularizing the the driver does nothing for your use case. The
> "driver" is a relatively lightweight wrapper, removing that is akin
> to making /dev/sgx/enclave inaccessible, i.e. it doesn't make the
> EPC tracking and core code go away. Modularizing the whole thing is
> flat out not an option, as doing so is not compatible with an EPC
> cgroup and adds unnecessary complexity to KVM enabling, both of
> which are highly desired features by pretty much everyone that plans
> on using SGX.
All well taken technical points, but they don't speak directly to the
issue at hand. The potential security issue in all of this is access
to /dev/sgx/enclave, not the EPC tracking and core code.
Here in a nutshell is the paradox the kernel faces:
No one seems to be disputing the fact that the primary focus of this
driver will be to support the notion of 'runtime encryption' and
Confidential Computing. The whole premise of the concept and economic
predicate of the initiative is that the owner/manager of the platform
has no visibility into what is being done on the platform.
If the Linux community believes that standard platform security
controls can make qualitatively good judgements on what enclave based
execution is doing, it is effectively making the statement that the
very concept of runtime encryption and by extension Confidential
Computing is invalid.
If we accept the concept that Confidential Computing is valid then we
admit the technology provides the opportunity for unsupervised code
execution and data manipulation.
Our premise in all of this is that one page of code implementing three
linked lists is a small price to pay to provide platform owners with
the opportunity to optionally implement what is effectively 2-factor
authentication over this process.
Going forward, if we are intellectually honest, all of this suggests
that adding complexity to the driver with LSM controls makes little
sense technically. Since, by definition and economic intent, the
technology provides tools and infrastructure that allows these
controls to be evaded.
The notion that entities with adversarial intent would not try and
take advantage of this flies in the face of everything we know about
security.
> Andy is right to caution against playing games to squish in-kernel
> things, but the virtualization snafu is a completely different
> beast. E.g. SGX doesn't require fiddling with CR4, won't corrupt
> random memory across kexec(), doesn't block INIT, etc... And I'm
> not advocating long-term shenanigans, I just wanted to point out
> that there are options for running out-of-tree drivers in the short
> term, e.g. until proper policy controls land upstream.
It appears that the distributions, at least IBM/RHEL, are going to
compile this driver in and backport it as well.
What we would recommend at this point is that you and Jarkko do the
Linux community and beyond a favor and wire up a simple kernel
command-line parameter that controls the ability of the driver to be
used, ie. enables/disables access to /dev/sgx/enclave.
Distributions or others can set this command-line parameter by default
to 'disable' and avoid any possibility of the technology being used
for nefarious purposes. Since the technology now appears to be
focused only on the cloud providers they will certainly be capable of
configuring their implementations to change the default.
In essence, make the kernel's behavior secure by default.
Best wishes for a pleasant weekend to everyone.
Dr. Greg
As always,
Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
Enjellic Systems Development, LLC self-defensive IOT platforms
4206 N. 19th Ave. and edge devices.
Fargo, ND 58102
PH: 701-281-1686 EMAIL: [email protected]
------------------------------------------------------------------------------
"Intellectuals solve problems; geniuses prevent them."
-- Albert Einstein
On Tue, 2020-05-12 at 19:55 +0800, Hui, Chunyang wrote:
> On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> >
> > There is a new hardware unit in the processor called Memory Encryption
> > Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> > one or many MEE regions that can hold enclave data by configuring them with
> > PRMRR registers.
> >
> > The MEE automatically encrypts the data leaving the processor package to
> > the MEE regions. The data is encrypted using a random key whose life-time
> > is exactly one power cycle.
> >
> > The current implementation requires that the firmware sets
> > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > decide what enclaves it wants run. The implementation does not create
> > any bottlenecks to support read-only MSRs later on.
> >
> > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >
> > cat /proc/cpuinfo | grep sgx
>
> Tested-by: Chunyang Hui <[email protected]>
>
> Occlum project (https://github.com/occlum/occlum) is a libOS built on top of
> Intel SGX feature. We ran Occlum tests using patch v29 on SGX hardware with
> the Flexible Launch Control (FLC) feature and didn't find any problems.
> As Occlum core developers, we would like these patches to be merged soon.
Great, thanks adding tested by to the driver and reclaimer patch.
/Jarkko
On Thu, May 14, 2020 at 04:16:37AM -0500, Dr. Greg wrote:
> What we would recommend at this point is that you and Jarkko do the
> Linux community and beyond a favor and wire up a simple kernel
> command-line parameter that controls the ability of the driver to be
> used, ie. enables/disables access to /dev/sgx/enclave.
I'm not opposed to adding a kernel param to disable SGX. At one point
there was a proposal to extend clearcpuid to allow disabling multiple
feature bits, but it looks like that went the way of the dodo.
Note, such a param would disable SGX entirely, e.g. clear the feature bit
in /proc/cpuinfo and prevent any in-kernel SGX code from running.
On Thu, May 14, 2020 at 09:15:59AM -0700, Sean Christopherson wrote:
> I'm not opposed to adding a kernel param to disable SGX. At one point
> there was a proposal to extend clearcpuid to allow disabling multiple
> feature bits, but it looks like that went the way of the dodo.
>
> Note, such a param would disable SGX entirely, e.g. clear the feature bit
> in /proc/cpuinfo and prevent any in-kernel SGX code from running.
It is a usual practice for big features like SGX to add a
"nosgx" cmdline param to disable it in case something goes
south. We do this for all features - see all "no*" switches in
Documentation/admin-guide/kernel-parameters.txt
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Fri, May 8, 2020 at 12:08 PM Sean Christopherson
<[email protected]> wrote:
>
> Adding some Google folks to the party.
Thanks, Sean.
> On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> >
> > There is a new hardware unit in the processor called Memory Encryption
> > Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> > one or many MEE regions that can hold enclave data by configuring them with
> > PRMRR registers.
> >
> > The MEE automatically encrypts the data leaving the processor package to
> > the MEE regions. The data is encrypted using a random key whose life-time
> > is exactly one power cycle.
> >
> > The current implementation requires that the firmware sets
> > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > decide what enclaves it wants run. The implementation does not create
> > any bottlenecks to support read-only MSRs later on.
> >
> > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> >
> > cat /proc/cpuinfo | grep sgx
We applied the v29 patches to Linux 5.6.0, then tested on Xeon(R) E-2186G
with Asylo (http://asylo.dev).
Looks good. All Asylo tests pass.
Tested-by: Seth Moore <[email protected]>
Borislav Petkov <[email protected]> writes:
> On Thu, May 14, 2020 at 09:15:59AM -0700, Sean Christopherson wrote:
>> I'm not opposed to adding a kernel param to disable SGX. At one point
>> there was a proposal to extend clearcpuid to allow disabling multiple
>> feature bits, but it looks like that went the way of the dodo.
clearcpuid is a trainwreck which should have never happened.
>> Note, such a param would disable SGX entirely, e.g. clear the feature bit
>> in /proc/cpuinfo and prevent any in-kernel SGX code from running.
>
> It is a usual practice for big features like SGX to add a
> "nosgx" cmdline param to disable it in case something goes
> south. We do this for all features - see all "no*" switches in
> Documentation/admin-guide/kernel-parameters.txt
Correct.
Thanks,
tglx
Jarkko Sakkinen <[email protected]> writes:
>
> General question: maybe it would be easiest that I issue a pull request
> once everyone feels that the series is ready to be pulled and stop sending
> new versions of the series?
Might be the easiest for you, but I prefer a final series in email.
Thanks,
tglx
On Thu, 2020-05-14 at 09:15 -0700, Sean Christopherson wrote:
> On Thu, May 14, 2020 at 04:16:37AM -0500, Dr. Greg wrote:
> > What we would recommend at this point is that you and Jarkko do the
> > Linux community and beyond a favor and wire up a simple kernel
> > command-line parameter that controls the ability of the driver to be
> > used, ie. enables/disables access to /dev/sgx/enclave.
>
> I'm not opposed to adding a kernel param to disable SGX. At one point
> there was a proposal to extend clearcpuid to allow disabling multiple
> feature bits, but it looks like that went the way of the dodo.
>
> Note, such a param would disable SGX entirely, e.g. clear the feature bit
> in /proc/cpuinfo and prevent any in-kernel SGX code from running.
Greg, you are free to submit a patch for review that adds any possible
kernel command line parameter SGX and beyond. SGX support does not "wire
up" anything that would prevent reviewing such patches.
/Jarkko
On Thu, 2020-05-14 at 12:05 -0700, Seth Moore wrote:
> On Fri, May 8, 2020 at 12:08 PM Sean Christopherson
> <[email protected]> wrote:
> > Adding some Google folks to the party.
>
> Thanks, Sean.
>
> > On Wed, Apr 22, 2020 at 12:52:56AM +0300, Jarkko Sakkinen wrote:
> > > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > > to set aside private regions of code and data. The code outside the enclave
> > > is disallowed to access the memory inside the enclave by the CPU access
> > > control.
> > >
> > > There is a new hardware unit in the processor called Memory Encryption
> > > Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
> > > one or many MEE regions that can hold enclave data by configuring them with
> > > PRMRR registers.
> > >
> > > The MEE automatically encrypts the data leaving the processor package to
> > > the MEE regions. The data is encrypted using a random key whose life-time
> > > is exactly one power cycle.
> > >
> > > The current implementation requires that the firmware sets
> > > IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
> > > decide what enclaves it wants run. The implementation does not create
> > > any bottlenecks to support read-only MSRs later on.
> > >
> > > You can tell if your CPU supports SGX by looking into /proc/cpuinfo:
> > >
> > > cat /proc/cpuinfo | grep sgx
>
> We applied the v29 patches to Linux 5.6.0, then tested on Xeon(R) E-2186G
> with Asylo (http://asylo.dev).
>
> Looks good. All Asylo tests pass.
>
> Tested-by: Seth Moore <[email protected]>
Thanks.
/Jarkko
On Thu, 2020-05-14 at 21:30 +0200, Thomas Gleixner wrote:
> Jarkko Sakkinen <[email protected]> writes:
> > General question: maybe it would be easiest that I issue a pull request
> > once everyone feels that the series is ready to be pulled and stop sending
> > new versions of the series?
>
> Might be the easiest for you, but I prefer a final series in email.
>
> Thanks,
>
> tglx
For me both are just as easy or as hard :-)
Just wanted to query the preference.
/Jarkko
On Thu, 2020-05-14 at 18:20 +0200, Borislav Petkov wrote:
> On Thu, May 14, 2020 at 09:15:59AM -0700, Sean Christopherson wrote:
> > I'm not opposed to adding a kernel param to disable SGX. At one point
> > there was a proposal to extend clearcpuid to allow disabling multiple
> > feature bits, but it looks like that went the way of the dodo.
> >
> > Note, such a param would disable SGX entirely, e.g. clear the feature bit
> > in /proc/cpuinfo and prevent any in-kernel SGX code from running.
>
> It is a usual practice for big features like SGX to add a
> "nosgx" cmdline param to disable it in case something goes
> south. We do this for all features - see all "no*" switches in
> Documentation/admin-guide/kernel-parameters.txt
Uh oh, should probably address this. Should I send v31 today with a "nosgx"
patch added? Sorry for missing this one :-/
/Jarkko
On Fri, May 15, 2020 at 12:28:54PM +0300, Jarkko Sakkinen wrote:
> Uh oh, should probably address this. Should I send v31 today with a "nosgx"
> patch added? Sorry for missing this one :-/
Not the whole thing - just the one patch as a reply to your thread pls.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On Fri, 2020-05-15 at 11:42 +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 12:28:54PM +0300, Jarkko Sakkinen wrote:
> > Uh oh, should probably address this. Should I send v31 today with a "nosgx"
> > patch added? Sorry for missing this one :-/
>
> Not the whole thing - just the one patch as a reply to your thread pls.
>
> Thx.
OK, cool, thank you.
/Jarkko
On Thu, May 14, 2020 at 5:17 AM Dr. Greg <[email protected]> wrote:
>
> On Fri, May 08, 2020 at 12:56:35PM -0700, Sean Christopherson wrote:
>
> Good morning, I hope the week is proceeding well for everyone.
>
> > On Fri, May 08, 2020 at 02:02:26PM -0500, Dr. Greg wrote:
> > > On Thu, May 07, 2020 at 02:41:30AM +0200, Thomas Gleixner wrote:
> > > > The diffstat of your patch is irrelevant. What's relevant is the
> > > > fact that it is completely unreviewed and that it creates yet
> > > > another user space visible ABI with a noticable lack of
> > > > documentation.
> >
> > ...
> >
> > > As to lack of review, we would certainly welcome technical and API
> > > comments but we cannot force them.
>
> > Thomas' point isn't that your code needs to be reviewed, it's that
> > trying to squeeze it into the initial merge will, not might, _will_
> > push out the acceptance of SGX. The same is true for other features
> > we have lined up, e.g. KVM and cgroup support. It's not a slight on
> > your code, it's just reality at this point.
>
> For the record and for whatever it is worth at this point. The patch
> has been available in its present form and function for around 14
> months.
>
> So there was plenty of time for its consideration and integration into
> what is being prepared as the final merge candidate.
>
> > > In fact, anyone who reviews the patch will see that the current driver
> > > creates a pointer in the ioctl call to pass downward into the hardware
> > > initialization routines. Our code simply replaces that pointer with
> > > one supplied by userspace.
>
> > Personally, I'm in favor of adding a reserved placeholder for a
> > token so as to avoid adding a second ioctl() in the event that
> > something gets upstreamed that wants the token. Ditto for a file
> > descriptor for the backing store in sgx_enclave_create.
>
> That would be a very low cost and forward looking addition.
>
> > > At the very least a modular form of the driver should be
> > > considered that would allow alternate implementations. Sean
> > > indicated that there was a 'kludgy' approach that would allow an
> > > alternate modular implementation alongside the in-kernel driver.
> > > I believe that Andy has already indicated that may not be an
> > > advisable approach.
>
> > Modularizing the the driver does nothing for your use case. The
> > "driver" is a relatively lightweight wrapper, removing that is akin
> > to making /dev/sgx/enclave inaccessible, i.e. it doesn't make the
> > EPC tracking and core code go away. Modularizing the whole thing is
> > flat out not an option, as doing so is not compatible with an EPC
> > cgroup and adds unnecessary complexity to KVM enabling, both of
> > which are highly desired features by pretty much everyone that plans
> > on using SGX.
>
> All well taken technical points, but they don't speak directly to the
> issue at hand. The potential security issue in all of this is access
> to /dev/sgx/enclave, not the EPC tracking and core code.
>
> Here in a nutshell is the paradox the kernel faces:
>
> No one seems to be disputing the fact that the primary focus of this
> driver will be to support the notion of 'runtime encryption' and
> Confidential Computing. The whole premise of the concept and economic
> predicate of the initiative is that the owner/manager of the platform
> has no visibility into what is being done on the platform.
>
> If the Linux community believes that standard platform security
> controls can make qualitatively good judgements on what enclave based
> execution is doing, it is effectively making the statement that the
> very concept of runtime encryption and by extension Confidential
> Computing is invalid.
>
> If we accept the concept that Confidential Computing is valid then we
> admit the technology provides the opportunity for unsupervised code
> execution and data manipulation.
>
> Our premise in all of this is that one page of code implementing three
> linked lists is a small price to pay to provide platform owners with
> the opportunity to optionally implement what is effectively 2-factor
> authentication over this process.
>
> Going forward, if we are intellectually honest, all of this suggests
> that adding complexity to the driver with LSM controls makes little
> sense technically. Since, by definition and economic intent, the
> technology provides tools and infrastructure that allows these
> controls to be evaded.
>
> The notion that entities with adversarial intent would not try and
> take advantage of this flies in the face of everything we know about
> security.
>
> > Andy is right to caution against playing games to squish in-kernel
> > things, but the virtualization snafu is a completely different
> > beast. E.g. SGX doesn't require fiddling with CR4, won't corrupt
> > random memory across kexec(), doesn't block INIT, etc... And I'm
> > not advocating long-term shenanigans, I just wanted to point out
> > that there are options for running out-of-tree drivers in the short
> > term, e.g. until proper policy controls land upstream.
>
> It appears that the distributions, at least IBM/RHEL, are going to
> compile this driver in and backport it as well.
The (Red Hat sponsored) Enarx project will continue building an
unofficial, unsupported version of the Fedora kernel with the SGX
patches[0] until such time as the patches are upstream. Once upstream,
I intend to propose that the feature be enabled in the stock Fedora
kernel.
Enarx requires EDMM support as a prerequisite to being production
ready. Therefore, we are likely to continue building this custom
Fedora kernel with the latest patches until such point as EDMM support
lands upstream. This also implies that I have no current plan to
request an SGX backport to a RHEL kernel until such time as it
supports our full needs.
Disclaimer: I do not control RHEL or Fedora kernel features. None of
the above constitutes a commitment to deliver anything.
[0]: https://copr.fedorainfracloud.org/coprs/npmccallum/enarx/package/kernel/
> What we would recommend at this point is that you and Jarkko do the
> Linux community and beyond a favor and wire up a simple kernel
> command-line parameter that controls the ability of the driver to be
> used, ie. enables/disables access to /dev/sgx/enclave.
>
> Distributions or others can set this command-line parameter by default
> to 'disable' and avoid any possibility of the technology being used
> for nefarious purposes. Since the technology now appears to be
> focused only on the cloud providers they will certainly be capable of
> configuring their implementations to change the default.
>
> In essence, make the kernel's behavior secure by default.
>
> Best wishes for a pleasant weekend to everyone.
>
> Dr. Greg
>
> As always,
> Dr. Greg Wettstein, Ph.D, Worker Artisans in autonomously
> Enjellic Systems Development, LLC self-defensive IOT platforms
> 4206 N. 19th Ave. and edge devices.
> Fargo, ND 58102
> PH: 701-281-1686 EMAIL: [email protected]
> ------------------------------------------------------------------------------
> "Intellectuals solve problems; geniuses prevent them."
> -- Albert Einstein
>
Add kernel parameter to disable Intel SGX kernel support.
Tested-by: Sean Christopherson <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 2 ++
arch/x86/kernel/cpu/feat_ctl.c | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7bc83f3d9bdf..9f7202a54db6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3268,6 +3268,8 @@
nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
+ nosgx [X86-64,SGX] Disables Intel SGX kernel support.
+
nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
and disable the IO APIC. legacy for "maxcpus=0".
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index c3afcd2e4342..1837df39527f 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -101,6 +101,15 @@ static void clear_sgx_caps(void)
setup_clear_cpu_cap(X86_FEATURE_SGX2);
}
+static int __init nosgx(char *str)
+{
+ clear_sgx_caps();
+
+ return 0;
+}
+
+early_param("nosgx", nosgx);
+
void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
{
bool tboot = tboot_enabled();
--
2.25.1
On Fri, 2020-05-15 at 15:54 -0400, Nathaniel McCallum wrote:
> The (Red Hat sponsored) Enarx project will continue building an
> unofficial, unsupported version of the Fedora kernel with the SGX
> patches[0] until such time as the patches are upstream. Once upstream,
> I intend to propose that the feature be enabled in the stock Fedora
> kernel.
>
> Enarx requires EDMM support as a prerequisite to being production
> ready. Therefore, we are likely to continue building this custom
> Fedora kernel with the latest patches until such point as EDMM support
> lands upstream. This also implies that I have no current plan to
> request an SGX backport to a RHEL kernel until such time as it
> supports our full needs.
>
> Disclaimer: I do not control RHEL or Fedora kernel features. None of
> the above constitutes a commitment to deliver anything.
>
> [0]: https://copr.fedorainfracloud.org/coprs/npmccallum/enarx/package/kernel/
SGX is somewhat self-contained feature, i.e. should be easy to backport
for any recent kernel. Only the vDSO is outside of arch/x86/kernel/cpu/sgx.
/Jarkko
Hi!
> > > At the very least a modular form of the driver should be
> > > considered that would allow alternate implementations. Sean
> > > indicated that there was a 'kludgy' approach that would allow an
> > > alternate modular implementation alongside the in-kernel driver.
> > > I believe that Andy has already indicated that may not be an
> > > advisable approach.
>
> > Modularizing the the driver does nothing for your use case. The
> > "driver" is a relatively lightweight wrapper, removing that is akin
> > to making /dev/sgx/enclave inaccessible, i.e. it doesn't make the
Well... SGX is proprietary feature of Intel. I don't see any effort for standartization
so that other architectures could use it. Yet it provides userspace interface...
You clearly want distros to enable it, but that will waste memory on non-Intel systems.
That is not good.
> Here in a nutshell is the paradox the kernel faces:
>
> No one seems to be disputing the fact that the primary focus of this
> driver will be to support the notion of 'runtime encryption' and
> Confidential Computing. The whole premise of the concept and economic
> predicate of the initiative is that the owner/manager of the platform
> has no visibility into what is being done on the platform.
Well, in my eyes preventing owner of the machine from accessing all its parts is
pretty questionable.
Physics says it is impossible, many tried, and many failed. Why it should be
different this time?
> If the Linux community believes that standard platform security
> controls can make qualitatively good judgements on what enclave based
> execution is doing, it is effectively making the statement that the
> very concept of runtime encryption and by extension Confidential
> Computing is invalid.
And yes, I believe that concept of Confidential Computing is invalid.. and we
should simply not merge this support.
It provides false sense of security, and I'm afraid big companies will try to force
people to use it. "DRM, now with hardware support". "Finally advertisments you can
not skip". "Just run this piece of code on your machine to access your bank account.
Trust us!"
:-(.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
From: Pavel Machek
> Sent: 24 May 2020 22:27
..
> It provides false sense of security, and I'm afraid big companies will try to force
> people to use it. "DRM, now with hardware support". "Finally advertisments you can
> not skip". "Just run this piece of code on your machine to access your bank account.
> Trust us!"
Hey malware guys, here is somewhere you can hide your code
making it very difficult to find.
You can then use the hardware disk encryption that people think
gives them security to encrypt all the files.
Job done...
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
On Thu, May 07, 2020 at 05:25:55PM -0700, Sean Christopherson wrote:
> Ah, fudge. shmem_zero_setup() triggers shmem_acct_size() and thus
> __vm_enough_memory(). Which I should have rememered because I've stared
> at that code several times when dealing with the enclave's backing store.
> I wasn't seeing the issue because I happened to use MAP_PRIVATE.
>
> So, bad analysis, good conclusion, i.e. the kernel is still doing the
> right thing, it's just not ideal for userspace.
>
>
> Jarkko, we should update the docs and selftest to recommend and use
>
> PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS
>
> or
>
> PROT_NONE, MAP_SHARED | MAP_NORESERVE | MAP_ANONYMOUS"
>
> when carving out ELRANGE, with an explicit comment that all the normal
> rules for mapping memory still apply.
Ugh, had forgotten this.
OK, I guess this comment explains it all:
"
/*
* shmem_file_setup pre-accounts the whole fixed size of a VM object,
* for shared memory and for shared anonymous (/dev/zero) mappings
* (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
* consistent with the pre-accounting of private mappings ...
*/
static inline int shmem_acct_size(unsigned long flags, loff_t size)
"
/Jarkko
On Thu, May 28, 2020 at 02:15:18PM +0300, Jarkko Sakkinen wrote:
> On Thu, May 07, 2020 at 05:25:55PM -0700, Sean Christopherson wrote:
> > Ah, fudge. shmem_zero_setup() triggers shmem_acct_size() and thus
> > __vm_enough_memory(). Which I should have rememered because I've stared
> > at that code several times when dealing with the enclave's backing store.
> > I wasn't seeing the issue because I happened to use MAP_PRIVATE.
> >
> > So, bad analysis, good conclusion, i.e. the kernel is still doing the
> > right thing, it's just not ideal for userspace.
> >
> >
> > Jarkko, we should update the docs and selftest to recommend and use
> >
> > PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS
> >
> > or
> >
> > PROT_NONE, MAP_SHARED | MAP_NORESERVE | MAP_ANONYMOUS"
> >
> > when carving out ELRANGE, with an explicit comment that all the normal
> > rules for mapping memory still apply.
>
> Ugh, had forgotten this.
>
> OK, I guess this comment explains it all:
>
> "
> /*
> * shmem_file_setup pre-accounts the whole fixed size of a VM object,
> * for shared memory and for shared anonymous (/dev/zero) mappings
> * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
> * consistent with the pre-accounting of private mappings ...
> */
> static inline int shmem_acct_size(unsigned long flags, loff_t size)
> "
Do not agree though that any documentation should be produced but the
selftest should have correct parameters, yes. Instructions on how to
reserve a range of addresses simply does not belong to SGX documentation
because it is not SGX related in the first place. The patterns you
showed are universal.
I'll fix just the selftest for v31.
/Jarkko