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
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many of them were too exhausting and some outdated.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 (11):
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
selftests/x86: Recurse into subdirectories
selftests/x86: Add a selftest for SGX
x86/sgx: Add provisioning
x86/sgx: Add a page reclaimer
x86/sgx: ptrace() support for the SGX driver
selftests/x86: Add vDSO selftest for SGX
Sean Christopherson (13):
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 supprt
x86/sgx: Enumerate and track EPC sections
x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT]
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: Add __vdso_sgx_enter_enclave() to wrap SGX enclave
transitions
docs: x86/sgx: Document microarchitecture
docs: x86/sgx: Document kernel internals
Documentation/ioctl/ioctl-number.rst | 1 +
Documentation/x86/index.rst | 1 +
Documentation/x86/sgx/1.Architecture.rst | 431 ++++++++++
Documentation/x86/sgx/2.Kernel-internals.rst | 78 ++
Documentation/x86/sgx/index.rst | 17 +
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 | 187 +++++
arch/x86/include/asm/cpufeatures.h | 24 +-
arch/x86/include/asm/disabled-features.h | 14 +-
arch/x86/include/asm/msr-index.h | 8 +
arch/x86/include/asm/traps.h | 1 +
arch/x86/include/asm/vdso.h | 5 +
arch/x86/include/uapi/asm/sgx.h | 112 +++
arch/x86/kernel/cpu/Makefile | 1 +
arch/x86/kernel/cpu/intel.c | 41 +
arch/x86/kernel/cpu/scattered.c | 2 +
arch/x86/kernel/cpu/sgx/Makefile | 7 +
arch/x86/kernel/cpu/sgx/arch.h | 394 +++++++++
arch/x86/kernel/cpu/sgx/driver.c | 274 +++++++
arch/x86/kernel/cpu/sgx/driver.h | 34 +
arch/x86/kernel/cpu/sgx/encl.c | 750 +++++++++++++++++
arch/x86/kernel/cpu/sgx/encl.h | 127 +++
arch/x86/kernel/cpu/sgx/encls.c | 57 ++
arch/x86/kernel/cpu/sgx/encls.h | 254 ++++++
arch/x86/kernel/cpu/sgx/ioctl.c | 770 ++++++++++++++++++
arch/x86/kernel/cpu/sgx/main.c | 283 +++++++
arch/x86/kernel/cpu/sgx/reclaim.c | 464 +++++++++++
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 | 21 +-
tools/testing/selftests/x86/Makefile | 44 +
tools/testing/selftests/x86/sgx/Makefile | 47 ++
tools/testing/selftests/x86/sgx/defines.h | 39 +
tools/testing/selftests/x86/sgx/encl.c | 20 +
tools/testing/selftests/x86/sgx/encl.lds | 34 +
.../selftests/x86/sgx/encl_bootstrap.S | 94 +++
tools/testing/selftests/x86/sgx/main.c | 373 +++++++++
tools/testing/selftests/x86/sgx/sgx_call.S | 66 ++
tools/testing/selftests/x86/sgx/sgx_call.h | 14 +
tools/testing/selftests/x86/sgx/sgxsign.c | 493 +++++++++++
.../testing/selftests/x86/sgx/signing_key.pem | 39 +
51 files changed, 5944 insertions(+), 36 deletions(-)
create mode 100644 Documentation/x86/sgx/1.Architecture.rst
create mode 100644 Documentation/x86/sgx/2.Kernel-internals.rst
create mode 100644 Documentation/x86/sgx/index.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/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.c
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/x86/sgx/Makefile
create mode 100644 tools/testing/selftests/x86/sgx/defines.h
create mode 100644 tools/testing/selftests/x86/sgx/encl.c
create mode 100644 tools/testing/selftests/x86/sgx/encl.lds
create mode 100644 tools/testing/selftests/x86/sgx/encl_bootstrap.S
create mode 100644 tools/testing/selftests/x86/sgx/main.c
create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.S
create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.h
create mode 100644 tools/testing/selftests/x86/sgx/sgxsign.c
create mode 100644 tools/testing/selftests/x86/sgx/signing_key.pem
--
2.20.1
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 b25e633033c3..81472cae4024 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -171,5 +171,6 @@ 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 9ceacd1156db..b1f0060b263f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1178,6 +1178,19 @@ 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
--
2.20.1
Recurse into a list of subdirectories defined by SUBDIRS when running
x86 selftests. Override run_tests, install, emit_tests and clean
targets to implement this behaviour.
A possible alternative would be to add "x86/sgx" to TARGETS. However,
this would be problematic because detecting 64-bit build would have
to duplicated.
The implementation is derived from the makefiles of powerpc and sparc64
selftests.
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
tools/testing/selftests/x86/Makefile | 44 ++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 5d49bfec1e9a..dee6dadeba61 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -10,6 +10,8 @@ CAN_BUILD_I386 := $(shell ./check_cc.sh $(CC) trivial_32bit_program.c -m32)
CAN_BUILD_X86_64 := $(shell ./check_cc.sh $(CC) trivial_64bit_program.c)
CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) trivial_program.c -no-pie)
+SUBDIRS := sgx
+
TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
check_initial_reg_state sigreturn iopl ioperm \
protection_keys test_vdso test_vsyscall mov_ss_trap \
@@ -59,6 +61,48 @@ endif
ifeq ($(CAN_BUILD_X86_64),1)
all: all_64
+ @for DIR in $(SUBDIRS); do \
+ BUILD_TARGET=$(OUTPUT)/$$DIR; \
+ mkdir $$BUILD_TARGET -p; \
+ make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
+ done
+
+DEFAULT_RUN_TESTS := $(RUN_TESTS)
+override define RUN_TESTS
+ $(DEFAULT_RUN_TESTS)
+ @for TARGET in $(SUBDIRS); do \
+ BUILD_TARGET=$(OUTPUT)/$$TARGET; \
+ $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests; \
+ done;
+endef
+
+DEFAULT_INSTALL_RULE := $(INSTALL_RULE)
+override define INSTALL_RULE
+ $(DEFAULT_INSTALL_RULE)
+ @for TARGET in $(SUBDIRS); do \
+ BUILD_TARGET=$(OUTPUT)/$$TARGET; \
+ $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET install; \
+ done;
+endef
+
+DEFAULT_EMIT_TESTS := $(EMIT_TESTS)
+override define EMIT_TESTS
+ $(DEFAULT_EMIT_TESTS)
+ @for TARGET in $(SUBDIRS); do \
+ BUILD_TARGET=$(OUTPUT)/$$TARGET; \
+ $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests; \
+ done;
+endef
+
+DEFAULT_CLEAN := $(CLEAN)
+override define CLEAN
+ $(DEFAULT_CLEAN)
+ @for TARGET in $(SUBDIRS); do \
+ BUILD_TARGET=$(OUTPUT)/$$TARGET; \
+ $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET clean; \
+ done;
+endef
+
TEST_PROGS += $(BINARIES_64)
EXTRA_CFLAGS += -DCAN_BUILD_64
$(foreach t,$(TARGETS_C_64BIT_ALL),$(eval $(call gen-target-rule-64,$(t))))
--
2.20.1
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 given to
the enclave as arguments. Use ENCLS[EENTER] to invoke the enclave.
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
tools/testing/selftests/x86/sgx/Makefile | 47 ++
tools/testing/selftests/x86/sgx/defines.h | 39 ++
tools/testing/selftests/x86/sgx/encl.c | 20 +
tools/testing/selftests/x86/sgx/encl.lds | 34 ++
.../selftests/x86/sgx/encl_bootstrap.S | 94 ++++
tools/testing/selftests/x86/sgx/main.c | 241 +++++++++
tools/testing/selftests/x86/sgx/sgx_call.S | 23 +
tools/testing/selftests/x86/sgx/sgx_call.h | 11 +
tools/testing/selftests/x86/sgx/sgxsign.c | 493 ++++++++++++++++++
.../testing/selftests/x86/sgx/signing_key.pem | 39 ++
10 files changed, 1041 insertions(+)
create mode 100644 tools/testing/selftests/x86/sgx/Makefile
create mode 100644 tools/testing/selftests/x86/sgx/defines.h
create mode 100644 tools/testing/selftests/x86/sgx/encl.c
create mode 100644 tools/testing/selftests/x86/sgx/encl.lds
create mode 100644 tools/testing/selftests/x86/sgx/encl_bootstrap.S
create mode 100644 tools/testing/selftests/x86/sgx/main.c
create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.S
create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.h
create mode 100644 tools/testing/selftests/x86/sgx/sgxsign.c
create mode 100644 tools/testing/selftests/x86/sgx/signing_key.pem
diff --git a/tools/testing/selftests/x86/sgx/Makefile b/tools/testing/selftests/x86/sgx/Makefile
new file mode 100644
index 000000000000..a09ef5f965dc
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/Makefile
@@ -0,0 +1,47 @@
+top_srcdir = ../../../../..
+
+include ../../lib.mk
+
+ifndef OBJCOPY
+OBJCOPY := $(CROSS_COMPILE)objcopy
+endif
+
+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)/encl.bin $(OUTPUT)/encl.ss
+
+all: $(TEST_CUSTOM_PROGS)
+
+$(OUTPUT)/test_sgx: $(OUTPUT)/main.o $(OUTPUT)/sgx_call.o
+ $(CC) $(HOST_CFLAGS) -o $@ $^
+
+$(OUTPUT)/main.o: main.c
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/sgx_call.o: sgx_call.S
+ $(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/encl.bin: $(OUTPUT)/encl.elf $(OUTPUT)/sgxsign
+ $(OBJCOPY) -O binary $< $@
+
+$(OUTPUT)/encl.elf: encl.lds encl.c encl_bootstrap.S
+ $(CC) $(ENCL_CFLAGS) -T $^ -o $@
+
+$(OUTPUT)/encl.ss: $(OUTPUT)/encl.bin
+ $(OUTPUT)/sgxsign signing_key.pem $(OUTPUT)/encl.bin $(OUTPUT)/encl.ss
+
+$(OUTPUT)/sgxsign: sgxsign.c
+ $(CC) -o $@ $< -lcrypto
+
+EXTRA_CLEAN := \
+ $(OUTPUT)/encl.bin \
+ $(OUTPUT)/encl.elf \
+ $(OUTPUT)/encl.ss \
+ $(OUTPUT)/sgx_call.o \
+ $(OUTPUT)/sgxsign \
+ $(OUTPUT)/test_sgx \
+ $(OUTPUT)/test_sgx.o \
+
+.PHONY: clean
diff --git a/tools/testing/selftests/x86/sgx/defines.h b/tools/testing/selftests/x86/sgx/defines.h
new file mode 100644
index 000000000000..1e67f2f29f42
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/defines.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef DEFINES_H
+#define DEFINES_H
+
+#include <stdint.h>
+
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+#define __aligned(x) __attribute__((__aligned__(x)))
+#define __packed __attribute__((packed))
+
+/* Derived from asm-generic/bitsperlong.h. */
+#if __x86_64__
+#define BITS_PER_LONG 64
+#else
+#define BITS_PER_LONG 32
+#endif
+#define BITS_PER_LONG_LONG 64
+
+/* Taken from linux/bits.h. */
+#define BIT(nr) (1UL << (nr))
+#define BIT_ULL(nr) (1ULL << (nr))
+#define GENMASK(h, l) \
+ (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
+#define GENMASK_ULL(h, l) \
+ (((~0ULL) - (1ULL << (l)) + 1) & \
+ (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
+
+#include "../../../../../arch/x86/kernel/cpu/sgx/arch.h"
+#include "../../../../../arch/x86/include/uapi/asm/sgx.h"
+
+#endif /* DEFINES_H */
diff --git a/tools/testing/selftests/x86/sgx/encl.c b/tools/testing/selftests/x86/sgx/encl.c
new file mode 100644
index 000000000000..ede915399742
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/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/x86/sgx/encl.lds b/tools/testing/selftests/x86/sgx/encl.lds
new file mode 100644
index 000000000000..9a56d3064104
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/encl.lds
@@ -0,0 +1,34 @@
+OUTPUT_FORMAT(elf64-x86-64)
+
+SECTIONS
+{
+ . = 0;
+ .tcs : {
+ *(.tcs*)
+ }
+
+ . = ALIGN(4096);
+ .text : {
+ *(.text*)
+ *(.rodata*)
+ }
+
+ . = ALIGN(4096);
+ .data : {
+ *(.data*)
+ }
+
+ /DISCARD/ : {
+ *(.data*)
+ *(.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/x86/sgx/encl_bootstrap.S b/tools/testing/selftests/x86/sgx/encl_bootstrap.S
new file mode 100644
index 000000000000..d07f970ccdf9
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/encl_bootstrap.S
@@ -0,0 +1,94 @@
+/* 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", "a"
+ .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
+
+ .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
+
+ # Restore XSAVE registers to a synthetic state.
+ mov $0xFFFFFFFF, %rax
+ mov $0xFFFFFFFF, %rdx
+ lea (xsave_area)(%rbx), %rdi
+ fxrstor (%rdi)
+
+ # Clear GPRs.
+ xor %rcx, %rcx
+ xor %rdx, %rdx
+ xor %rdi, %rdi
+ xor %rsi, %rsi
+ xor %r8, %r8
+ xor %r9, %r9
+ xor %r10, %r10
+ xor %r11, %r11
+ xor %r12, %r12
+ xor %r13, %r13
+ xor %r14, %r14
+ xor %r15, %r15
+
+ # 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
+
+xsave_area:
+ .fill 1, 4, 0x037F # FCW
+ .fill 5, 4, 0
+ .fill 1, 4, 0x1F80 # MXCSR
+ .fill 1, 4, 0xFFFF # MXCSR_MASK
+ .fill 123, 4, 0
+ .fill 1, 4, 0x80000000 # XCOMP_BV[63] = 1, compaction mode
+ .fill 12, 4, 0
+
+ .balign 4096
+ .space 8192
+encl_stack:
diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c
new file mode 100644
index 000000000000..a1a9e75099c2
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/main.c
@@ -0,0 +1,241 @@
+// 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 "../../../../../arch/x86/kernel/cpu/sgx/arch.h"
+#include "../../../../../arch/x86/include/uapi/asm/sgx.h"
+#include "sgx_call.h"
+
+#define PAGE_SIZE 4096
+
+static const uint64_t MAGIC = 0x1122334455667788ULL;
+
+static bool encl_create(int dev_fd, unsigned long bin_size,
+ struct sgx_secs *secs)
+{
+ struct sgx_enclave_create ioc;
+ void *area;
+ int rc;
+
+ memset(secs, 0, sizeof(*secs));
+ secs->ssa_frame_size = 1;
+ secs->attributes = SGX_ATTR_MODE64BIT;
+ secs->xfrm = 3;
+
+ for (secs->size = 4096; secs->size < bin_size; )
+ secs->size <<= 1;
+
+ area = mmap(NULL, secs->size * 2, PROT_NONE, MAP_SHARED, dev_fd, 0);
+ if (area == MAP_FAILED) {
+ perror("mmap");
+ return false;
+ }
+
+ secs->base = ((uint64_t)area + secs->size - 1) & ~(secs->size - 1);
+
+ munmap(area, secs->base - (uint64_t)area);
+ munmap((void *)(secs->base + secs->size),
+ (uint64_t)area + secs->size - secs->base);
+
+ ioc.src = (unsigned long)secs;
+ rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_CREATE, &ioc);
+ if (rc) {
+ fprintf(stderr, "ECREATE failed rc=%d, err=%d.\n", rc, errno);
+ munmap((void *)secs->base, secs->size);
+ return false;
+ }
+
+ return true;
+}
+
+static bool encl_add_pages(int dev_fd, unsigned long offset, void *data,
+ unsigned long length, uint64_t flags)
+{
+ struct sgx_enclave_add_pages ioc;
+ struct sgx_secinfo secinfo;
+ int rc;
+
+ memset(&secinfo, 0, sizeof(secinfo));
+ secinfo.flags = flags;
+
+ ioc.src = (uint64_t)data;
+ ioc.offset = offset;
+ ioc.length = length;
+ ioc.secinfo = (unsigned long)&secinfo;
+ ioc.flags = SGX_PAGE_MEASURE;
+
+ rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_ADD_PAGES, &ioc);
+ if (rc) {
+ fprintf(stderr, "EADD failed rc=%d.\n", rc);
+ return false;
+ }
+
+ return true;
+}
+
+#define SGX_REG_PAGE_FLAGS \
+ (SGX_SECINFO_REG | SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X)
+
+static bool encl_build(struct sgx_secs *secs, void *bin,
+ unsigned long bin_size, struct sgx_sigstruct *sigstruct)
+{
+ struct sgx_enclave_init ioc;
+ void *addr;
+ int dev_fd;
+ int rc;
+
+ dev_fd = open("/dev/sgx/enclave", O_RDWR);
+ if (dev_fd < 0) {
+ fprintf(stderr, "Unable to open /dev/sgx\n");
+ return false;
+ }
+
+ if (!encl_create(dev_fd, bin_size, secs))
+ goto out_dev_fd;
+
+ encl_add_pages(dev_fd, 0, bin, PAGE_SIZE, SGX_SECINFO_TCS);
+ encl_add_pages(dev_fd, PAGE_SIZE, bin + PAGE_SIZE,
+ bin_size - PAGE_SIZE, SGX_REG_PAGE_FLAGS);
+
+ ioc.sigstruct = (uint64_t)sigstruct;
+ rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_INIT, &ioc);
+ if (rc) {
+ printf("EINIT failed rc=%d\n", rc);
+ goto out_map;
+ }
+
+ addr = mmap((void *)secs->base, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_FIXED, dev_fd, 0);
+ if (addr == MAP_FAILED) {
+ fprintf(stderr, "mmap() failed on TCS, errno=%d.\n", errno);
+ return false;
+ }
+
+ addr = mmap((void *)(secs->base + PAGE_SIZE), bin_size - PAGE_SIZE,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_SHARED | MAP_FIXED, dev_fd, 0);
+ if (addr == MAP_FAILED) {
+ fprintf(stderr, "mmap() failed, errno=%d.\n", errno);
+ return false;
+ }
+
+ close(dev_fd);
+ return true;
+out_map:
+ munmap((void *)secs->base, secs->size);
+out_dev_fd:
+ close(dev_fd);
+ return false;
+}
+
+bool get_file_size(const char *path, off_t *bin_size)
+{
+ struct stat sb;
+ int ret;
+
+ ret = stat(path, &sb);
+ if (ret) {
+ perror("stat");
+ return false;
+ }
+
+ if (!sb.st_size || sb.st_size & 0xfff) {
+ fprintf(stderr, "Invalid blob size %lu\n", sb.st_size);
+ return false;
+ }
+
+ *bin_size = sb.st_size;
+ return true;
+}
+
+bool encl_data_map(const char *path, void **bin, off_t *bin_size)
+{
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1) {
+ fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno);
+ return false;
+ }
+
+ if (!get_file_size(path, bin_size))
+ goto err_out;
+
+ *bin = mmap(NULL, *bin_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (*bin == MAP_FAILED) {
+ fprintf(stderr, "mmap() %s failed, errno=%d.\n", path, errno);
+ goto err_out;
+ }
+
+ close(fd);
+ return true;
+
+err_out:
+ close(fd);
+ return false;
+}
+
+bool load_sigstruct(const char *path, void *sigstruct)
+{
+ int fd;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1) {
+ fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno);
+ return false;
+ }
+
+ if (read(fd, sigstruct, sizeof(struct sgx_sigstruct)) !=
+ sizeof(struct sgx_sigstruct)) {
+ fprintf(stderr, "read() %s failed, errno=%d.\n", path, errno);
+ close(fd);
+ return false;
+ }
+
+ close(fd);
+ return true;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+ struct sgx_sigstruct sigstruct;
+ struct sgx_secs secs;
+ uint64_t result = 0;
+ off_t bin_size;
+ void *bin;
+
+ if (!encl_data_map("encl.bin", &bin, &bin_size))
+ exit(1);
+
+ if (!load_sigstruct("encl.ss", &sigstruct))
+ exit(1);
+
+ if (!encl_build(&secs, bin, bin_size, &sigstruct))
+ exit(1);
+
+ printf("Input: 0x%lx\n", MAGIC);
+
+ sgx_call_eenter((void *)&MAGIC, &result, (void *)secs.base);
+ if (result != MAGIC) {
+ fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC);
+ exit(1);
+ }
+
+ printf("Output: 0x%lx\n", result);
+
+ exit(0);
+}
diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S
new file mode 100644
index 000000000000..ca4c7893f9d9
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/sgx_call.S
@@ -0,0 +1,23 @@
+/* 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_eenter
+sgx_call_eenter:
+ push %rbx
+ mov $0x02, %rax
+ mov %rdx, %rbx
+ lea sgx_async_exit(%rip), %rcx
+sgx_async_exit:
+ ENCLU
+ pop %rbx
+ ret
diff --git a/tools/testing/selftests/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h
new file mode 100644
index 000000000000..bf72068ada23
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/sgx_call.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef SGX_CALL_H
+#define SGX_CALL_H
+
+void sgx_call_eenter(void *rdi, void *rsi, void *entry);
+
+#endif /* SGX_CALL_H */
diff --git a/tools/testing/selftests/x86/sgx/sgxsign.c b/tools/testing/selftests/x86/sgx/sgxsign.c
new file mode 100644
index 000000000000..3d9007af40c9
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/sgxsign.c
@@ -0,0 +1,493 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#define _GNU_SOURCE
+#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"
+
+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 void exit_usage(const char *program)
+{
+ fprintf(stderr,
+ "Usage: %s/sign-le <key> <enclave> <sigstruct>\n", program);
+ exit(1);
+}
+
+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 *load_sign_key(const char *path)
+{
+ FILE *f;
+ RSA *key;
+
+ f = fopen(path, "rb");
+ if (!f) {
+ fprintf(stderr, "Unable to open %s\n", path);
+ return NULL;
+ }
+ key = RSA_new();
+ if (!PEM_read_RSAPrivateKey(f, &key, NULL, NULL))
+ return NULL;
+ fclose(f);
+
+ if (BN_num_bytes(get_modulus(key)) != SGX_MODULUS_SIZE) {
+ fprintf(stderr, "Invalid key size %d\n",
+ BN_num_bytes(get_modulus(key)));
+ RSA_free(key);
+ return NULL;
+ }
+
+ return key;
+}
+
+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, 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;
+}
+
+/**
+ * measure_encl - measure enclave
+ * @path: path to the enclave
+ * @mrenclave: measurement
+ *
+ * Calculates MRENCLAVE. Assumes that the very first page is a TCS page and
+ * following pages are regular pages. Does not measure the contents of the
+ * enclave as the signing tool is used at the moment only for the launch
+ * enclave, which is pass-through (everything gets a token).
+ */
+static bool measure_encl(const char *path, uint8_t *mrenclave)
+{
+ FILE *file;
+ struct stat sb;
+ EVP_MD_CTX *ctx;
+ uint64_t flags;
+ uint64_t offset;
+ uint8_t data[0x1000];
+ int rc;
+
+ ctx = EVP_MD_CTX_create();
+ if (!ctx)
+ return false;
+
+ file = fopen(path, "rb");
+ if (!file) {
+ perror("fopen");
+ EVP_MD_CTX_destroy(ctx);
+ return false;
+ }
+
+ rc = stat(path, &sb);
+ if (rc) {
+ perror("stat");
+ goto out;
+ }
+
+ if (!sb.st_size || sb.st_size & 0xfff) {
+ fprintf(stderr, "Invalid blob size %lu\n", sb.st_size);
+ goto out;
+ }
+
+ if (!mrenclave_ecreate(ctx, sb.st_size))
+ goto out;
+
+ for (offset = 0; offset < sb.st_size; offset += 0x1000) {
+ if (!offset)
+ flags = SGX_SECINFO_TCS;
+ else
+ flags = SGX_SECINFO_REG | SGX_SECINFO_R |
+ SGX_SECINFO_W | SGX_SECINFO_X;
+
+ if (!mrenclave_eadd(ctx, offset, flags))
+ goto out;
+
+ rc = fread(data, 1, 0x1000, file);
+ if (!rc)
+ break;
+ if (rc < 0x1000)
+ goto out;
+
+ if (!mrenclave_eextend(ctx, offset, data))
+ goto out;
+ }
+
+ if (!mrenclave_commit(ctx, mrenclave))
+ goto out;
+
+ fclose(file);
+ EVP_MD_CTX_destroy(ctx);
+ return true;
+out:
+ fclose(file);
+ EVP_MD_CTX_destroy(ctx);
+ return false;
+}
+
+/**
+ * sign_encl - sign enclave
+ * @sigstruct: pointer to SIGSTRUCT
+ * @key: 3072-bit RSA key
+ * @signature: byte array for the signature
+ *
+ * Calculates EMSA-PKCSv1.5 signature for the given SIGSTRUCT. The result is
+ * stored in big-endian format so that it can be further passed to OpenSSL
+ * libcrypto functions.
+ */
+static bool sign_encl(const struct sgx_sigstruct *sigstruct, RSA *key,
+ uint8_t *signature)
+{
+ struct sgx_sigstruct_payload payload;
+ unsigned int siglen;
+ uint8_t digest[SHA256_DIGEST_LENGTH];
+ bool ret;
+
+ memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header));
+ memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body));
+
+ SHA256((unsigned char *)&payload, sizeof(payload), digest);
+
+ ret = RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH, signature,
+ &siglen, key);
+
+ return ret;
+}
+
+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;
+}
+
+static bool save_sigstruct(const struct sgx_sigstruct *sigstruct,
+ const char *path)
+{
+ FILE *f = fopen(path, "wb");
+
+ if (!f) {
+ fprintf(stderr, "Unable to open %s\n", path);
+ return false;
+ }
+
+ fwrite(sigstruct, sizeof(*sigstruct), 1, f);
+ fclose(f);
+ return true;
+}
+
+int main(int argc, char **argv)
+{
+ uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
+ uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
+ struct sgx_sigstruct ss;
+ const char *program;
+ int opt;
+ RSA *sign_key;
+
+ memset(&ss, 0, sizeof(ss));
+ ss.header.header1[0] = header1[0];
+ ss.header.header1[1] = header1[1];
+ ss.header.header2[0] = header2[0];
+ ss.header.header2[1] = header2[1];
+ ss.exponent = 3;
+
+#ifndef CONFIG_EINITTOKENKEY
+ ss.body.attributes = SGX_ATTR_MODE64BIT;
+#else
+ ss.body.attributes = SGX_ATTR_MODE64BIT | SGX_ATTR_EINITTOKENKEY;
+#endif
+ ss.body.xfrm = 3,
+
+ program = argv[0];
+
+ do {
+ opt = getopt(argc, argv, "");
+ switch (opt) {
+ case -1:
+ break;
+ default:
+ exit_usage(program);
+ }
+ } while (opt != -1);
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc < 3)
+ exit_usage(program);
+
+ /* sanity check only */
+ if (check_crypto_errors())
+ exit(1);
+
+ sign_key = load_sign_key(argv[0]);
+ if (!sign_key)
+ goto out;
+
+ BN_bn2bin(get_modulus(sign_key), ss.modulus);
+
+ if (!measure_encl(argv[1], ss.body.mrenclave))
+ goto out;
+
+ if (!sign_encl(&ss, sign_key, ss.signature))
+ goto out;
+
+ if (!calc_q1q2(ss.signature, ss.modulus, ss.q1, ss.q2))
+ goto out;
+
+ /* convert to little endian */
+ reverse_bytes(ss.signature, SGX_MODULUS_SIZE);
+ reverse_bytes(ss.modulus, SGX_MODULUS_SIZE);
+ reverse_bytes(ss.q1, SGX_MODULUS_SIZE);
+ reverse_bytes(ss.q2, SGX_MODULUS_SIZE);
+
+ if (!save_sigstruct(&ss, argv[2]))
+ goto out;
+ exit(0);
+out:
+ check_crypto_errors();
+ exit(1);
+}
diff --git a/tools/testing/selftests/x86/sgx/signing_key.pem b/tools/testing/selftests/x86/sgx/signing_key.pem
new file mode 100644
index 000000000000..d76f21f19187
--- /dev/null
+++ b/tools/testing/selftests/x86/sgx/signing_key.pem
@@ -0,0 +1,39 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
--
2.20.1
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 312f954c5c07..22186d89042a 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -320,6 +320,7 @@ 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)
{
@@ -327,10 +328,97 @@ 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,
};
/**
--
2.20.1
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 4bb0f8447112..9f06a3441f10 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -61,6 +61,7 @@
#include <asm/mpx.h>
#include <asm/vm86.h>
#include <asm/umip.h>
+#include <asm/vdso.h>
#ifdef CONFIG_X86_64
#include <asm/x86_init.h>
@@ -210,6 +211,9 @@ 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;
}
/*
@@ -557,6 +561,9 @@ do_general_protection(struct pt_regs *regs, long error_code)
return;
}
+ if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0))
+ return;
+
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = X86_TRAP_GP;
@@ -771,6 +778,10 @@ 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.
@@ -851,6 +862,9 @@ 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 0e0842e941eb..105252776172 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -29,6 +29,7 @@
#include <asm/efi.h> /* efi_recover_from_page_fault()*/
#include <asm/desc.h> /* store_idt(), ... */
#include <asm/cpu_entry_area.h> /* exception stack */
+#include <asm/vdso.h> /* fixup_vdso_exception() */
#define CREATE_TRACE_POINTS
#include <asm/trace/exceptions.h>
@@ -901,6 +902,10 @@ __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);
@@ -1018,6 +1023,9 @@ 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
--
2.20.1
From: Sean Christopherson <[email protected]>
Intel Software Guard Extensions (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.
Skipping over a great deal of gory architecture details[1], SGX was
designed in such a way that the host process can utilize a library to
build, launch and run an enclave. This is roughly analogous to how
e.g. libc implementations are used by most applications so that the
application can focus on its business logic.
The big gotcha is that because enclaves can generate *and* handle
exceptions, any SGX library must be prepared to handle nearly any
exception at any time (well, any time a thread is executing in an
enclave). In Linux, this means the SGX library must register a
signal handler in order to intercept relevant exceptions and forward
them to the enclave (or in some cases, take action on behalf of the
enclave). Unfortunately, Linux's signal mechanism doesn't mesh well
with libraries, e.g. signal handlers are process wide, are difficult
to chain, etc... 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.
In comes vDSO to save the day. Now that vDSO can fixup exceptions,
add a function, __vdso_sgx_enter_enclave(), to wrap enclave transitions
and intercept any exceptions that occur when running the enclave.
__vdso_sgx_enter_enclave() does NOT adhere to the x86-64 ABI and instead
uses a custom calling convention. The primary motivation is to avoid
issues that arise due to asynchronous enclave exits. The x86-64 ABI
requires that EFLAGS.DF, MXCSR and FCW be preserved by the callee, and
unfortunately for the vDSO, the aformentioned registers/bits are not
restored after an asynchronous exit, e.g. EFLAGS.DF is in an unknown
state while MXCSR and FCW are reset to their init values. So the vDSO
cannot simply pass the buck by requiring enclaves to adhere to the
x86-64 ABI. That leaves three somewhat reasonable options:
1) Save/restore non-volatile GPRs, MXCSR and FCW, and clear EFLAGS.DF
+ 100% compliant with the x86-64 ABI
+ Callable from any code
+ Minimal documentation required
- Restoring MXCSR/FCW is likely unnecessary 99% of the time
- Slow
2) Save/restore non-volatile GPRs and clear EFLAGS.DF
+ Mostly compliant with the x86-64 ABI
+ Callable from any code that doesn't use SIMD registers
- Need to document deviations from x86-64 ABI, i.e. MXCSR and FCW
3) Require the caller to save/restore everything.
+ Fast
+ Userspace can pass all GPRs to the enclave (minus EAX, RBX and RCX)
- Custom ABI
- For all intents and purposes must be called from an assembly wrapper
__vdso_sgx_enter_enclave() implements option (3). The custom ABI is
mostly a documentation issue, and even that is offset by the fact that
being more similar to hardware's ENCLU[EENTER/ERESUME] ABI reduces the
amount of documentation needed for the vDSO, e.g. options (2) and (3)
would need to document which registers are marshalled to/from enclaves.
Requiring an assembly wrapper imparts minimal pain on userspace as SGX
libraries and/or applications need a healthy chunk of assembly, e.g. in
the enclave, regardless of the vDSO's implementation.
Note, the C-like pseudocode describing the assembly routine is wrapped
in a non-existent macro instead of in a comment to trick kernel-doc into
auto-parsing the documentation and function prototype. This is a double
win as the pseudocode is intended to aid kernel developers, not userland
enclave developers.
[1] Documentation/x86/sgx/1.Architecture.rst
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]>
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 | 187 +++++++++++++++++++++++
arch/x86/include/uapi/asm/sgx.h | 37 +++++
4 files changed, 227 insertions(+)
create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 111228445add..53ab19dae6e1 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
@@ -92,6 +93,7 @@ CFLAGS_REMOVE_vclock_gettime.o = -pg
CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
CFLAGS_REMOVE_vgetcpu.o = -pg
CFLAGS_REMOVE_vvar.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..c6ca6e6031b6
--- /dev/null
+++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S
@@ -0,0 +1,187 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+#include <asm/errno.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"
+
+/**
+ * __vdso_sgx_enter_enclave() - Enter an SGX enclave
+ * @leaf: ENCLU leaf, must be EENTER or ERESUME
+ * @tcs: TCS, must be non-NULL
+ * @e: Optional struct sgx_enclave_exception instance
+ * @handler: Optional enclave exit handler
+ *
+ * **Important!** __vdso_sgx_enter_enclave() is **NOT** compliant with the
+ * x86-64 ABI, i.e. cannot be called from standard C code.
+ *
+ * Input ABI:
+ * @leaf %eax
+ * @tcs 8(%rsp)
+ * @e 0x10(%rsp)
+ * @handler 0x18(%rsp)
+ *
+ * Output ABI:
+ * @ret %eax
+ *
+ * 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 userspace exit handler is responsible for unwinding the stack, e.g. to
+ * pop @e, u_rsp and @tcs, prior to returning to __vdso_sgx_enter_enclave().
+ * The exit handler may also transfer control, e.g. via longjmp() or a 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
+ */
+#ifdef SGX_KERNEL_DOC
+/* C-style function prototype to coerce kernel-doc into parsing the comment. */
+int __vdso_sgx_enter_enclave(int leaf, void *tcs,
+ struct sgx_enclave_exception *e,
+ sgx_enclave_exit_handler_t handler);
+#endif
+ENTRY(__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
+
+.Lenter_enclave:
+ /* EENTER <= leaf <= ERESUME */
+ cmp $0x2, %eax
+ jb .Linvalid_leaf
+ cmp $0x3, %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:
+ 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 in %rbx (non-volatile register). */
+ mov %rsp, %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
+
+ /* Restore %rsp to its post-exit value. */
+ mov %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)
+
+ENDPROC(__vdso_sgx_enter_enclave)
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index e7b20f1e41b3..88644b6ad849 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -72,4 +72,41 @@ 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);
+
#endif /* _UAPI_ASM_X86_SGX_H */
--
2.20.1
From: Sean Christopherson <[email protected]>
Document some of the more tricky parts of the kernel implementation
internals.
Cc: [email protected]
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/x86/sgx/2.Kernel-internals.rst | 78 ++++++++++++++++++++
Documentation/x86/sgx/index.rst | 1 +
2 files changed, 79 insertions(+)
create mode 100644 Documentation/x86/sgx/2.Kernel-internals.rst
diff --git a/Documentation/x86/sgx/2.Kernel-internals.rst b/Documentation/x86/sgx/2.Kernel-internals.rst
new file mode 100644
index 000000000000..7bfd5cb19b8e
--- /dev/null
+++ b/Documentation/x86/sgx/2.Kernel-internals.rst
@@ -0,0 +1,78 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================
+Kernel Internals
+================
+
+CPU configuration
+=================
+
+Because SGX has an ever evolving and expanding feature set, it's possible for
+a BIOS or VMM to configure a system in such a way that not all CPUs are equal,
+e.g. where Launch Control is only enabled on a subset of CPUs. Linux does
+*not* support such a heterogeneous system configuration, nor does it even
+attempt to play nice in the face of a misconfigured system. With the exception
+of Launch Control's hash MSRs, which can vary per CPU, Linux assumes that all
+CPUs have a configuration that is identical to the boot CPU.
+
+EPC management
+==============
+
+Because the kernel can't arbitrarily read EPC memory or share RO backing pages
+between enclaves, traditional memory models such as CoW and fork() do not work
+with enclaves. In other words, the architectural rules of EPC force it to be
+treated as MAP_SHARED at all times.
+
+The inability to employ traditional memory models also means that EPC memory
+must be isolated from normal memory pools, e.g. attempting to use EPC memory
+for normal mappings would result in faults and/or perceived data corruption.
+Furthermore, EPC is not enumerated as normal memory, e.g. BIOS enumerates
+EPC as reserved memory in the e820 tables, or not at all. As a result, EPC
+memory is directly managed by the SGX subsystem, e.g. SGX employs VM_PFNMAP to
+manually insert/zap/swap page table entries, and exposes EPC to userspace via
+a well known device, /dev/sgx/enclave.
+
+The net effect is that all enclave VMAs must be MAP_SHARED and are backed by
+a single file, /dev/sgx/enclave.
+
+EPC oversubscription
+====================
+
+SGX allows to have larger enclaves the than amount of available EPC by providing
+a subset of leaf instructions for swapping EPC pages to the system memory. The
+details of these instructions are discussed in the architecture document. Due to
+the unique requirements for swapping EPC pages, and because EPC pages do not
+have associated page structures, management of the EPC is not handled by the
+standard memory subsystem.
+
+SGX directly handles swapping of EPC pages, including a thread to initiate the
+reclaiming process and a rudimentary LRU mechanism. When the amount of free EPC
+pages goes below a low watermark the swapping thread starts reclaiming pages.
+The pages that have not been recently accessed (i.e. do not have the A bit set)
+are selected as victim pages. Each enclave holds an shmem file as a backing
+storage for reclaimed pages.
+
+Launch Control
+==============
+
+The current kernel implementation supports only writable MSRs. The launch is
+performed by setting the MSRs to the hash of the public key modulus of the
+enclave signer and a token with the valid bit set to zero.
+
+If the MSRs were read-only, the platform would need to provide a launch enclave
+(LE), which would be signed with the key matching the MSRs. The LE creates
+cryptographic tokens for other enclaves that they can pass together with their
+signature to the ENCLS(EINIT) opcode, which is used to initialize enclaves.
+
+Provisioning
+============
+
+The use of provisioning must be controlled because it allows to get access to
+the provisioning keys to attest to a remote party that the software is running
+inside a legitimate enclave. This could be used by a malware network to ensure
+that its nodes are running inside legitimate enclaves.
+
+The driver introduces a special device file /dev/sgx/provision and a special
+ioctl SGX_IOC_ENCLAVE_SET_ATTRIBUTE to accomplish this. A file descriptor
+pointing to /dev/sgx/provision is passed to ioctl from which kernel authorizes
+the PROVISION_KEY attribute to the enclave.
diff --git a/Documentation/x86/sgx/index.rst b/Documentation/x86/sgx/index.rst
index c5dfef62e612..5d660e83d984 100644
--- a/Documentation/x86/sgx/index.rst
+++ b/Documentation/x86/sgx/index.rst
@@ -14,3 +14,4 @@ potentially malicious.
:maxdepth: 1
1.Architecture
+ 2.Kernel-internals
--
2.20.1
Expand the selftest by invoking the enclave by using
__vdso_sgx_enter_enclave() in addition to direct ENCLS[EENTER].
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
tools/testing/selftests/x86/sgx/main.c | 132 +++++++++++++++++++++
tools/testing/selftests/x86/sgx/sgx_call.S | 43 +++++++
tools/testing/selftests/x86/sgx/sgx_call.h | 3 +
3 files changed, 178 insertions(+)
diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c
index a1a9e75099c2..df6846098f6f 100644
--- a/tools/testing/selftests/x86/sgx/main.c
+++ b/tools/testing/selftests/x86/sgx/main.c
@@ -23,6 +23,109 @@
#define PAGE_SIZE 4096
static const uint64_t MAGIC = 0x1122334455667788ULL;
+void *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;
+}
static bool encl_create(int dev_fd, unsigned long bin_size,
struct sgx_secs *secs)
@@ -212,10 +315,14 @@ bool load_sigstruct(const char *path, void *sigstruct)
int main(int argc, char *argv[], char *envp[])
{
+ struct sgx_enclave_exception exception;
struct sgx_sigstruct sigstruct;
+ struct vdso_symtab symtab;
+ Elf64_Sym *eenter_sym;
struct sgx_secs secs;
uint64_t result = 0;
off_t bin_size;
+ void *addr;
void *bin;
if (!encl_data_map("encl.bin", &bin, &bin_size))
@@ -237,5 +344,30 @@ int main(int argc, char *argv[], char *envp[])
printf("Output: 0x%lx\n", result);
+ memset(&exception, 0, sizeof(exception));
+
+ addr = vdso_get_base_addr(envp);
+ if (!addr)
+ exit(1);
+
+ if (!vdso_get_symtab(addr, &symtab))
+ exit(1);
+
+ eenter_sym = vdso_symtab_get(&symtab, "__vdso_sgx_enter_enclave");
+ if (!eenter_sym)
+ exit(1);
+ eenter = addr + eenter_sym->st_value;
+
+ printf("Input: 0x%lx\n", MAGIC);
+
+ sgx_call_vdso((void *)&MAGIC, &result, 0, NULL, NULL, NULL,
+ (void *)secs.base, &exception, NULL);
+ if (result != MAGIC) {
+ fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC);
+ exit(1);
+ }
+
+ printf("Output: 0x%lx\n", result);
+
exit(0);
}
diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S
index ca4c7893f9d9..e71f44f7a995 100644
--- a/tools/testing/selftests/x86/sgx/sgx_call.S
+++ b/tools/testing/selftests/x86/sgx/sgx_call.S
@@ -21,3 +21,46 @@ sgx_async_exit:
ENCLU
pop %rbx
ret
+
+ .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
+ mov $2, %eax
+ 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/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h
index bf72068ada23..a4072c5ecce7 100644
--- a/tools/testing/selftests/x86/sgx/sgx_call.h
+++ b/tools/testing/selftests/x86/sgx/sgx_call.h
@@ -8,4 +8,7 @@
void sgx_call_eenter(void *rdi, void *rsi, void *entry);
+int sgx_call_vdso(void *rdi, void *rsi, long rdx, void *rcx, void *r8, void *r9,
+ void *tcs, struct sgx_enclave_exception *ei, void *cb);
+
#endif /* SGX_CALL_H */
--
2.20.1
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 b1f0060b263f..0e0842e941eb 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -681,6 +681,18 @@ 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)
{
@@ -737,6 +749,8 @@ 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. */
@@ -885,13 +899,7 @@ __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);
@@ -1008,6 +1016,8 @@ 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
--
2.20.1
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 0154674cbad3..08a67272ed14 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8512,6 +8512,17 @@ 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]
--
2.20.1
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/cpufeatures.h | 23 +++++++++++++++++------
arch/x86/include/asm/disabled-features.h | 14 ++++++++++++--
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kernel/cpu/scattered.c | 2 ++
tools/arch/x86/include/asm/cpufeatures.h | 21 +++++++++++++++------
5 files changed, 47 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 0652d3eed9bd..0872fec45534 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -221,12 +221,22 @@
#define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* "" L1TF workaround PTE inversion */
#define X86_FEATURE_IBRS_ENHANCED ( 7*32+30) /* Enhanced IBRS */
-/* Virtualization flags: Linux defined, word 8 */
-#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
-#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
-#define X86_FEATURE_FLEXPRIORITY ( 8*32+ 2) /* Intel FlexPriority */
-#define X86_FEATURE_EPT ( 8*32+ 3) /* Intel Extended Page Table */
-#define X86_FEATURE_VPID ( 8*32+ 4) /* Intel Virtual Processor ID */
+/*
+ * Scattered Intel features: Linux defined, word 8.
+ *
+ * Note that the bit location of the SGX features is meaningful as KVM expects
+ * the Linux defined bit to match the Intel defined bit, e.g. X86_FEATURE_SGX1
+ * must remain at bit 0, SGX2 at bit 1, etc...
+ */
+#define X86_FEATURE_SGX1 ( 8*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2 ( 8*32+ 1) /* SGX2 leaf functions */
+/* Bits [0:7] are reserved for SGX */
+
+#define X86_FEATURE_TPR_SHADOW ( 8*32+ 8) /* Intel TPR Shadow */
+#define X86_FEATURE_VNMI ( 8*32+ 9) /* Intel Virtual NMI */
+#define X86_FEATURE_FLEXPRIORITY ( 8*32+10) /* Intel FlexPriority */
+#define X86_FEATURE_EPT ( 8*32+11) /* Intel Extended Page Table */
+#define X86_FEATURE_VPID ( 8*32+12) /* Intel Virtual Processor ID */
#define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer VMMCALL to VMCALL */
#define X86_FEATURE_XENPV ( 8*32+16) /* "" Xen paravirtual guest */
@@ -237,6 +247,7 @@
/* 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 */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index a5ea841cc6d2..926f9dc4d75a 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -34,12 +34,16 @@
# 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))
+# 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
@@ -62,6 +66,12 @@
# define DISABLE_PTI (1 << (X86_FEATURE_PTI & 31))
#endif
+#ifdef CONFIG_INTEL_SGX
+# define DISABLE_SGX_CORE 0
+#else
+# define DISABLE_SGX_CORE (1 << (X86_FEATURE_SGX & 31))
+#endif
+
/*
* Make sure to add features to the correct mask
*/
@@ -73,8 +83,8 @@
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
#define DISABLED_MASK7 (DISABLE_PTI)
-#define DISABLED_MASK8 0
-#define DISABLED_MASK9 (DISABLE_MPX|DISABLE_SMAP)
+#define DISABLED_MASK8 (DISABLE_SGX1|DISABLE_SGX2)
+#define DISABLED_MASK9 (DISABLE_MPX|DISABLE_SMAP|DISABLE_SGX_CORE)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 0
#define DISABLED_MASK12 0
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 20ce682a2540..975a957a791a 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -551,6 +551,7 @@
#define FEATURE_CONTROL_LOCKED (1<<0)
#define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
#define FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX (1<<2)
+#define FEATURE_CONTROL_SGX_ENABLE (1<<18)
#define FEATURE_CONTROL_LMCE (1<<20)
#define MSR_IA32_APICBASE 0x0000001b
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index adf9b71386ef..9aea45c0b494 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -35,6 +35,8 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_CDP_L3, CPUID_ECX, 2, 0x00000010, 1 },
{ X86_FEATURE_CDP_L2, CPUID_ECX, 2, 0x00000010, 2 },
{ X86_FEATURE_MBA, CPUID_EBX, 3, 0x00000010, 0 },
+ { X86_FEATURE_SGX1, CPUID_EAX, 0, 0x00000012, 0 },
+ { X86_FEATURE_SGX2, CPUID_EAX, 1, 0x00000012, 0 },
{ X86_FEATURE_HW_PSTATE, CPUID_EDX, 7, 0x80000007, 0 },
{ X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index 0652d3eed9bd..ed691ada4244 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -221,12 +221,21 @@
#define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* "" L1TF workaround PTE inversion */
#define X86_FEATURE_IBRS_ENHANCED ( 7*32+30) /* Enhanced IBRS */
-/* Virtualization flags: Linux defined, word 8 */
-#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
-#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
-#define X86_FEATURE_FLEXPRIORITY ( 8*32+ 2) /* Intel FlexPriority */
-#define X86_FEATURE_EPT ( 8*32+ 3) /* Intel Extended Page Table */
-#define X86_FEATURE_VPID ( 8*32+ 4) /* Intel Virtual Processor ID */
+/*
+ * Scattered Intel features: Linux defined, word 8.
+ *
+ * Note that the bit numbers of the SGX features are meaningful as KVM expects
+ * the Linux defined bit to match the Intel defined bit, e.g. X86_FEATURE_SGX1
+ * must remain at bit 0, SGX2 at bit 1, etc...
+ */
+#define X86_FEATURE_SGX1 ( 8*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2 ( 8*32+ 1) /* SGX2 leaf functions */
+
+#define X86_FEATURE_TPR_SHADOW ( 8*32+ 8) /* Intel TPR Shadow */
+#define X86_FEATURE_VNMI ( 8*32+ 9) /* Intel Virtual NMI */
+#define X86_FEATURE_FLEXPRIORITY ( 8*32+10) /* Intel FlexPriority */
+#define X86_FEATURE_EPT ( 8*32+11) /* Intel Extended Page Table */
+#define X86_FEATURE_VPID ( 8*32+12) /* Intel Virtual Processor ID */
#define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer VMMCALL to VMCALL */
#define X86_FEATURE_XENPV ( 8*32+16) /* "" Xen paravirtual guest */
--
2.20.1
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 0872fec45534..71ccc14511f9 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -358,6 +358,7 @@
#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 975a957a791a..7dadfcfe6afd 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -551,6 +551,7 @@
#define FEATURE_CONTROL_LOCKED (1<<0)
#define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
#define FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX (1<<2)
+#define FEATURE_CONTROL_SGX_LE_WR (1<<17)
#define FEATURE_CONTROL_SGX_ENABLE (1<<18)
#define FEATURE_CONTROL_LMCE (1<<20)
@@ -564,6 +565,12 @@
#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
--
2.20.1
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 | 394 +++++++++++++++++++++++++++++++++
1 file changed, 394 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..7a5d24b4d1bb
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/arch.h
@@ -0,0 +1,394 @@
+/* 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/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 182
+#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_EINITTOKEN_RESERVED1_SIZE 11
+#define SGX_EINITTOKEN_RESERVED2_SIZE 32
+#define SGX_EINITTOKEN_RESERVED3_SIZE 32
+#define SGX_EINITTOKEN_RESERVED4_SIZE 24
+
+/**
+ * struct sgx_einittoken - a token permitting to launch an enclave
+ * @valid: one if valid and zero if invalid
+ * @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
+ * @le_cpusvn: a value that reflects the SGX implementation
+ * running in in the CPU
+ * @le_isvprodid: a user-defined value that is used in key
+ * derivation
+ * @le_isvsvn: a user-defined value that is used in key
+ * derivation
+ * @le_keyed_miscselect: LE's miscselect masked with the token keys
+ * miscselect
+ * @le_keyed_attributes: LE's attributes masked with the token keys
+ * attributes
+ * @le_keyed_xfrm: LE's XFRM masked with the token keys xfrm
+ * @salt: random salt for wear-out protection
+ * @mac: CMAC over the preceding fields
+ *
+ * An enclave with EINITTOKENKEY attribute can access a key with the same name
+ * by using ENCLS(EGETKEY) and use this to sign cryptographic tokens that can
+ * be passed to ENCLS(EINIT) to permit the launch of other enclaves. This is
+ * the only viable way to launch enclaves if IA32_SGXLEPUBKEYHASHn MSRs are
+ * locked assuming that there is a Launch Enclave (LE) available that can be
+ * used for generating these tokens.
+ */
+struct sgx_einittoken {
+ u32 valid;
+ u32 reserved1[SGX_EINITTOKEN_RESERVED1_SIZE];
+ u64 attributes;
+ u64 xfrm;
+ u8 mrenclave[32];
+ u8 reserved2[SGX_EINITTOKEN_RESERVED2_SIZE];
+ u8 mrsigner[32];
+ u8 reserved3[SGX_EINITTOKEN_RESERVED3_SIZE];
+ u8 le_cpusvn[16];
+ u16 le_isvprodid;
+ u16 le_isvsvn;
+ u8 reserved4[SGX_EINITTOKEN_RESERVED4_SIZE];
+ u32 le_keyed_miscselect;
+ u64 le_keyed_attributes;
+ u64 le_keyed_xfrm;
+ u8 salt[32];
+ u8 mac[16];
+} __packed __aligned(512);
+
+#endif /* _ASM_X86_SGX_ARCH_H */
--
2.20.1
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 | 251 ++++++++++++++++++++++++++++++++
1 file changed, 251 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..d6381e4f6eb2
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -0,0 +1,251 @@
+/* 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 - ENCLS leaf function type
+ * %ECREATE: Create an uninitialized enclave.
+ * %EADD: Add a page to an uninitialized enclave.
+ * %EINIT: Change enclave to initialized state.
+ * %EREMOVE: Remove a page from an enclave.
+ * %EDBGRD: Read a word from an enclave.
+ * %EDBGWR: Write a word to an enclave.
+ * %EEXTEND: Measure 256 bytes of an added page.
+ * %ELDU: Load a reclaimed page in unblocked state.
+ * %EBLOCK: Change page state to blocked, which means that hardware threads
+ * cannot access it and create new TLB entries to it.
+ * %EPA: Create a Version Array (VA) page used to store the version
+ * numbers for 512 reclaimed EPC pages.
+ * %EWB: Reclaim a page to the regular memory.
+ * %ETRACK: Start a new shoot down sequence. Used to together with EBLOCK to
+ * make sure that a page is safe to swap.
+ */
+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(_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 =
+ boot_cpu_has(X86_FEATURE_SGX2) ? X86_TRAP_PF : X86_TRAP_GP;
+ bool fault = ret & ENCLS_FAULT_FLAG;
+
+ return (fault && ENCLS_TRAPNR(ret) != epcm_trapnr) || (!fault && 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 */
--
2.20.1
From: Sean Christopherson <[email protected]>
When the CPU supports SGX, check that the BIOS has enabled SGX and SGX1
opcodes are available. Otherwise, all the SGX related capabilities.
In addition, clear X86_FEATURE_SGX_LC also in the case when the launch
enclave are read-only. This way the feature bit reflects the level that
Linux supports the launch control.
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.
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/intel.c | 41 +++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index c2fdc00df163..89a71367716c 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -624,6 +624,42 @@ static void detect_tme(struct cpuinfo_x86 *c)
c->x86_phys_bits -= keyid_bits;
}
+static void __maybe_unused detect_sgx(struct cpuinfo_x86 *c)
+{
+ unsigned long long fc;
+
+ rdmsrl(MSR_IA32_FEATURE_CONTROL, fc);
+ if (!(fc & FEATURE_CONTROL_LOCKED)) {
+ pr_err_once("sgx: The feature control MSR is not locked\n");
+ goto err_unsupported;
+ }
+
+ if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) {
+ pr_err_once("sgx: SGX is not enabled in IA32_FEATURE_CONTROL MSR\n");
+ goto err_unsupported;
+ }
+
+ if (!cpu_has(c, X86_FEATURE_SGX1)) {
+ pr_err_once("sgx: SGX1 instruction set is not supported\n");
+ goto err_unsupported;
+ }
+
+ if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) {
+ pr_info_once("sgx: The launch control MSRs are not writable\n");
+ goto err_msrs_rdonly;
+ }
+
+ return;
+
+err_unsupported:
+ setup_clear_cpu_cap(X86_FEATURE_SGX);
+ setup_clear_cpu_cap(X86_FEATURE_SGX1);
+ setup_clear_cpu_cap(X86_FEATURE_SGX2);
+
+err_msrs_rdonly:
+ setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
+}
+
static void init_cpuid_fault(struct cpuinfo_x86 *c)
{
u64 msr;
@@ -761,6 +797,11 @@ static void init_intel(struct cpuinfo_x86 *c)
if (cpu_has(c, X86_FEATURE_TME))
detect_tme(c);
+#ifdef CONFIG_INTEL_SGX
+ if (cpu_has(c, X86_FEATURE_SGX))
+ detect_sgx(c);
+#endif
+
init_intel_misc_features(c);
}
--
2.20.1
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 | 154 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/reclaim.c | 87 +++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 70 ++++++++++++++
6 files changed, 329 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 d6e1faa28c58..8f2faadc447e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1940,6 +1940,20 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
If unsure, say y.
+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 d7a1e5a9331c..97deac5108df 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -45,6 +45,7 @@ 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..f8ba10516eaf
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -0,0 +1,154 @@
+// 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;
+
+ BUILD_BUG_ON(SGX_MAX_EPC_SECTIONS > (SGX_EPC_SECTION_MASK + 1));
+
+ for (i = 0; i < (SGX_MAX_EPC_SECTIONS + 1); 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 sub-leaf type: %u\n", type);
+ break;
+ }
+
+ if (i == SGX_MAX_EPC_SECTIONS) {
+ pr_warn("More than %d EPC sections\n",
+ SGX_MAX_EPC_SECTIONS);
+ 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 memory for the 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..f071158d34f6
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -0,0 +1,87 @@
+// 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;
+
+/*
+ * Reset all pages to uninitialized state. Pages could be in initialized on
+ * kmemexec.
+ */
+static void sgx_sanitize_section(struct sgx_epc_section *section)
+{
+ struct sgx_epc_page *page, *tmp;
+ 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();
+ }
+
+ list_for_each_entry_safe(page, tmp, &secs_list, list) {
+ if (kthread_should_stop())
+ return;
+
+ ret = __eremove(sgx_epc_addr(page));
+ if (!WARN_ON_ONCE(ret)) {
+ spin_lock(§ion->lock);
+ list_move(&page->list, §ion->page_list);
+ spin_unlock(§ion->lock);
+ } else {
+ list_del(&page->list);
+ kfree(page);
+ }
+
+ cond_resched();
+ }
+}
+
+static int ksgxswapd(void *p)
+{
+ int i;
+
+ set_freezable();
+
+ for (i = 0; i < sgx_nr_epc_sections; i++)
+ sgx_sanitize_section(&sgx_epc_sections[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..9d8036f997b1
--- /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;
+};
+
+#define SGX_MAX_EPC_SECTIONS 8
+
+extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
+
+/**
+ * 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 */
+};
+
+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 */
--
2.20.1
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 cc292273e6ba..cd1122d4d51d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -469,6 +469,8 @@ 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 7967825f6d33..80717e9ca217 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;
--
2.20.1
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]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/ioctl/ioctl-number.rst | 1 +
arch/x86/include/uapi/asm/sgx.h | 64 +++
arch/x86/kernel/cpu/sgx/Makefile | 3 +
arch/x86/kernel/cpu/sgx/driver.c | 252 ++++++++++
arch/x86/kernel/cpu/sgx/driver.h | 32 ++
arch/x86/kernel/cpu/sgx/encl.c | 329 ++++++++++++++
arch/x86/kernel/cpu/sgx/encl.h | 87 ++++
arch/x86/kernel/cpu/sgx/ioctl.c | 656 +++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/main.c | 10 +
arch/x86/kernel/cpu/sgx/reclaim.c | 1 +
10 files changed, 1435 insertions(+)
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/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst
index bef79cd4c6b4..f9f3ea9606fc 100644
--- a/Documentation/ioctl/ioctl-number.rst
+++ b/Documentation/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..e0f79ebdfd8a
--- /dev/null
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -0,0 +1,64 @@
+/* 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
+ */
+struct sgx_enclave_add_pages {
+ __u64 src;
+ __u64 offset;
+ __u64 length;
+ __u64 secinfo;
+ __u64 flags;
+};
+
+/**
+ * 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 874492d9e3bd..3ddcdabab081 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -1,4 +1,7 @@
obj-y += \
+ driver.o \
+ encl.o \
encls.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..c724dcccf2e2
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/acpi.h>
+#include <linux/cdev.h>
+#include <linux/mman.h>
+#include <linux/platform_device.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");
+
+struct workqueue_struct *sgx_encl_wq;
+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,
+};
+
+static struct bus_type sgx_bus_type = {
+ .name = "sgx",
+};
+
+static struct device sgx_encl_dev;
+static struct cdev sgx_encl_cdev;
+static dev_t sgx_devt;
+
+static void sgx_dev_release(struct device *dev)
+{
+}
+
+static __init int sgx_dev_init(const char *name, struct device *dev,
+ struct cdev *cdev,
+ const struct file_operations *fops, int minor)
+{
+ int ret;
+
+ device_initialize(dev);
+
+ dev->bus = &sgx_bus_type;
+ dev->devt = MKDEV(MAJOR(sgx_devt), minor);
+ dev->release = sgx_dev_release;
+
+ ret = dev_set_name(dev, name);
+ if (ret) {
+ put_device(dev);
+ return ret;
+ }
+
+ cdev_init(cdev, fops);
+ cdev->owner = THIS_MODULE;
+ return 0;
+}
+
+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;
+ }
+
+ ret = bus_register(&sgx_bus_type);
+ if (ret)
+ return ret;
+
+ ret = alloc_chrdev_region(&sgx_devt, 0, SGX_DRV_NR_DEVICES, "sgx");
+ if (ret < 0)
+ goto err_bus;
+
+ 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 = sgx_dev_init("sgx/enclave", &sgx_encl_dev, &sgx_encl_cdev,
+ &sgx_encl_fops, 0);
+ if (ret)
+ goto err_chrdev_region;
+
+ sgx_encl_wq = alloc_workqueue("sgx-encl-wq",
+ WQ_UNBOUND | WQ_FREEZABLE, 1);
+ if (!sgx_encl_wq) {
+ ret = -ENOMEM;
+ goto err_encl_dev;
+ }
+
+ ret = cdev_device_add(&sgx_encl_cdev, &sgx_encl_dev);
+ if (ret)
+ goto err_encl_wq;
+
+ return 0;
+
+err_encl_wq:
+ destroy_workqueue(sgx_encl_wq);
+
+err_encl_dev:
+ put_device(&sgx_encl_dev);
+
+err_chrdev_region:
+ unregister_chrdev_region(sgx_devt, SGX_DRV_NR_DEVICES);
+
+err_bus:
+ bus_unregister(&sgx_bus_type);
+
+ return ret;
+}
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
new file mode 100644
index 000000000000..e95c6e86c0c6
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -0,0 +1,32 @@
+/* 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_DRV_NR_DEVICES 2
+#define SGX_EINIT_SPIN_COUNT 20
+#define SGX_EINIT_SLEEP_COUNT 50
+#define SGX_EINIT_SLEEP_TIME 20
+
+extern struct workqueue_struct *sgx_encl_wq;
+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..cd2b8dbb0eca
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -0,0 +1,329 @@
+// 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;
+
+ 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);
+
+ synchronize_srcu(&encl->srcu);
+
+ 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. Page addresses that do not have an associated enclave
+ * page are interpreted to zero permissions.
+ *
+ * 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;
+
+ /* PROT_NONE always succeeds. */
+ if (!vm_prot_bits)
+ return 0;
+
+ 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/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
new file mode 100644
index 000000000000..691efac24ed7
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -0,0 +1,656 @@
+// 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"
+
+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_HIGHUSER);
+ 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 ? -EFAULT : 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 -EFAULT;
+ }
+ }
+
+ return 0;
+}
+
+static int sgx_encl_add_page(struct sgx_encl *encl,
+ struct sgx_enclave_add_pages *addp,
+ struct sgx_secinfo *secinfo)
+{
+ struct sgx_encl_page *encl_page;
+ struct sgx_epc_page *epc_page;
+ int ret;
+
+ encl_page = sgx_encl_page_alloc(encl, addp->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,
+ addp->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 (addp->flags & SGX_PAGE_MEASURE) {
+ ret = __sgx_encl_extend(encl, epc_page);
+ if (ret)
+ sgx_encl_destroy(encl);
+ }
+
+ 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);
+
+ 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 (EADD) one or more pages to an uninitialized enclave, and optionally
+ * extend (EEXTEND) the measurement with the contents of the page. The range of
+ * pages must be virtually contiguous. The SECINFO and measurement mask are
+ * applied to all pages, i.e. pages with different properties must be added in
+ * separate calls.
+ *
+ * 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.
+ * 3. No page: PROT_NONE.
+ *
+ * mmap() is not allowed to surpass the minimum of the maximum protection bits
+ * within the given address range.
+ *
+ * As stated above, a non-existent page is interpreted as a page with no
+ * permissions. In effect, this allows mmap() with PROT_NONE to be used to seek
+ * an address range for the enclave that can be then populated into SECS.
+ *
+ * @arg->addr, @arg->src and @arg->length are adjusted to reflect the
+ * remaining pages that need to be added to the enclave, e.g. userspace can
+ * re-invoke SGX_IOC_ENCLAVE_ADD_PAGES using the same struct in response to an
+ * ERESTARTSYS error.
+ *
+ * Return:
+ * 0 on success,
+ * -EINVAL if any input param or the SECINFO contains invalid data,
+ * -EACCES if an executable source page is located in a noexec partition,
+ * -ENOMEM if any memory allocation, including EPC, fails,
+ * -ERESTARTSYS if a pending signal is recognized
+ */
+static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
+{
+ struct sgx_enclave_add_pages addp;
+ struct sgx_secinfo secinfo;
+ 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 ( ; addp.length > 0; addp.length -= PAGE_SIZE) {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ if (need_resched())
+ cond_resched();
+
+ ret = sgx_encl_add_page(encl, &addp, &secinfo);
+ if (ret)
+ break;
+
+ addp.offset += PAGE_SIZE;
+ addp.src += PAGE_SIZE;
+ }
+
+ 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 int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
+ struct sgx_einittoken *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 -EINVAL;
+
+ 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_einittoken *einittoken;
+ struct sgx_sigstruct *sigstruct;
+ struct sgx_enclave_init einit;
+ struct page *initp_page;
+ 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_HIGHUSER);
+ if (!initp_page)
+ return -ENOMEM;
+
+ sigstruct = kmap(initp_page);
+ einittoken = (struct sgx_einittoken *)
+ ((unsigned long)sigstruct + PAGE_SIZE / 2);
+ memset(einittoken, 0, sizeof(*einittoken));
+
+ if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
+ sizeof(*sigstruct))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = sgx_encl_init(encl, sigstruct, einittoken);
+
+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 6a37df61ae32..36a295a0272b 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];
@@ -196,6 +197,8 @@ static bool __init sgx_page_cache_init(void)
static void __init sgx_init(void)
{
+ int ret;
+
if (!boot_cpu_has(X86_FEATURE_SGX))
return;
@@ -205,8 +208,15 @@ 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();
}
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index f071158d34f6..bdb42f4326aa 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;
--
2.20.1
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 | 23 +++++++++++++++-
arch/x86/kernel/cpu/sgx/driver.h | 2 ++
arch/x86/kernel/cpu/sgx/ioctl.c | 47 ++++++++++++++++++++++++++++++++
4 files changed, 82 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index e0f79ebdfd8a..e7b20f1e41b3 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
@@ -61,4 +63,13 @@ 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 c724dcccf2e2..4d996463b213 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -141,12 +141,18 @@ static const struct file_operations sgx_encl_fops = {
.get_unmapped_area = sgx_get_unmapped_area,
};
+const struct file_operations sgx_provision_fops = {
+ .owner = THIS_MODULE,
+};
+
static struct bus_type sgx_bus_type = {
.name = "sgx",
};
static struct device sgx_encl_dev;
static struct cdev sgx_encl_cdev;
+static struct device sgx_provision_dev;
+static struct cdev sgx_provision_cdev;
static dev_t sgx_devt;
static void sgx_dev_release(struct device *dev)
@@ -223,22 +229,37 @@ int __init sgx_drv_init(void)
if (ret)
goto err_chrdev_region;
+ ret = sgx_dev_init("sgx/provision", &sgx_provision_dev,
+ &sgx_provision_cdev, &sgx_provision_fops, 1);
+ if (ret)
+ goto err_encl_dev;
+
sgx_encl_wq = alloc_workqueue("sgx-encl-wq",
WQ_UNBOUND | WQ_FREEZABLE, 1);
if (!sgx_encl_wq) {
ret = -ENOMEM;
- goto err_encl_dev;
+ goto err_provision_dev;
}
ret = cdev_device_add(&sgx_encl_cdev, &sgx_encl_dev);
if (ret)
goto err_encl_wq;
+ ret = cdev_device_add(&sgx_provision_cdev, &sgx_provision_dev);
+ if (ret)
+ goto err_encl_cdev;
+
return 0;
+err_encl_cdev:
+ cdev_device_del(&sgx_encl_cdev, &sgx_encl_dev);
+
err_encl_wq:
destroy_workqueue(sgx_encl_wq);
+err_provision_dev:
+ put_device(&sgx_provision_dev);
+
err_encl_dev:
put_device(&sgx_encl_dev);
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
index e95c6e86c0c6..2f13886522a8 100644
--- a/arch/x86/kernel/cpu/sgx/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -25,6 +25,8 @@ 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 691efac24ed7..e71618cef90c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -622,6 +622,50 @@ 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)
{
@@ -645,6 +689,9 @@ 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;
--
2.20.1
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 0f2154106d01..111228445add 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
@@ -122,8 +122,8 @@ $(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 93c6dc7812d0..8ef849064501 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -63,11 +63,18 @@ 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 230474e2ddb5..745300a05f25 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 */
@@ -44,6 +46,9 @@ 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 */
--
2.20.1
From: Sean Christopherson <[email protected]>
Document microarchitectural features of Intel SGX relevant to the
kernel.
Cc: [email protected]
Signed-off-by: Sean Christopherson <[email protected]>
Co-developed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
Documentation/x86/index.rst | 1 +
Documentation/x86/sgx/1.Architecture.rst | 431 +++++++++++++++++++++++
Documentation/x86/sgx/index.rst | 16 +
3 files changed, 448 insertions(+)
create mode 100644 Documentation/x86/sgx/1.Architecture.rst
create mode 100644 Documentation/x86/sgx/index.rst
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
index af64c4bb4447..f3f3ba45de35 100644
--- a/Documentation/x86/index.rst
+++ b/Documentation/x86/index.rst
@@ -30,3 +30,4 @@ x86-specific Documentation
usb-legacy-support
i386/index
x86_64/index
+ sgx/index
diff --git a/Documentation/x86/sgx/1.Architecture.rst b/Documentation/x86/sgx/1.Architecture.rst
new file mode 100644
index 000000000000..a4de6c610231
--- /dev/null
+++ b/Documentation/x86/sgx/1.Architecture.rst
@@ -0,0 +1,431 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+Architecture
+============
+
+Introduction
+============
+
+SGX is a set of instructions and mechanisms that enable ring 3 applications to
+set aside private regions of code and data for the purpose of establishing and
+running enclaves. An enclave is a secure entity whose private memory can only
+be accessed by code running within the enclave. Accesses from outside the
+enclave, including software running at a higher privilege level and other
+enclaves, are disallowed by hardware.
+
+SGX also provides for local and remote attestation. `Attestation`_ allows an
+enclave to attest its identity, that it has not been tampered with, that it is
+running on a genuine platform with Intel SGX enabled, and the security
+properties of the platform on which it is running.
+
+You can determine if your CPU supports SGX by querying ``/proc/cpuinfo``:
+
+ ``cat /proc/cpuinfo | grep sgx``
+
+
+Enclave Page Cache
+==================
+
+SGX utilizes an Enclave Page Cache (EPC) to store pages that are associated
+with an enclave. The EPC is secure storage whose exact physical implementation
+is micro-architecture specific (see `EPC Implemenations`_). Similar to normal
+system memory, the EPC is managed by privileged software using conventional
+paging mechanisms, e.g. the kernel can grant/deny access to EPC memory by
+manipulating a process' page tables, and can swap pages in/out of the EPC in
+order to oversubscribe the EPC.
+
+Unlikely regular memory, hardware prevents arbitrary insertion, eviction,
+deletion, access, etc... to/from the EPC. Software must instead use dedicated
+`SGX instructions`_ to operate on the EPC, which enables the processor to
+provide SGX's security guarantees by enforcing various restrictions and
+behaviors, e.g. limits concurrent accesses to EPC pages and ensures proper TLB
+flushing when moving pages in/out of the EPC.
+
+Accesses to EPC pages are allowed if and only if the access is classified as an
+"enclave access". There are two categories of allowed enclave accesses: direct
+and indirect. Direct enclave accesses are generated if and only the processor
+is executing in Enclave Mode (see `Enclave execution`_). Indirect enclave
+accesses are generated by various ENCL{S,U,V} functions, many of which can be
+executed outside of Enclave Mode.
+
+Non-enclave accesses to the EPC result in undefined behavior. Conversely,
+enclave accesses to non-EPC memory result in a page fault (#PF)[1]_. Page
+faults due to invalid enclave accesses set the PF_SGX flag (bit 15) in the page
+fault error code[2]_.
+
+Although all EPC implementations will undoubtedly encrypt the EPC itself, all
+all EPC code/data is stored unencrypted in the processor's caches. I.e. SGX
+relies on the aforementioned mechanisms to protect an enclave's secrets while
+they are resident in the cache.
+
+Note, EPC pages are always 4KB sized and aligned. Software can map EPC using
+using large pages, but the processor always operates on a 4KB granularity when
+working with EPC pages.
+
+
+SGX instructions
+================
+
+SGX introduces three new instructions, ENCLS, ENCLU and ENCLV, for Supervisor,
+User and Virtualization respectively. ENCL{S,U,V} are umbrella instructions,
+using a single opcode as the front end to a variety of SGX functions. The leaf
+function to execute is specified via %eax, with %rbx, %rcx and %rdx optionally
+used for leaf-specific purposes.
+
+Note that supervisor software, i.e. the kernel, creates and manages enclaves,
+but only user-level software can execute/enter an enclave.
+
+ENCLS Leafs
+-----------
+
+ - ECREATE: create an enclave
+ - EADD: add page to an uninitialized enclave
+ - EAUG: add page to an initialized enclave
+ - EEXTEND: extended the measurement of an (uninitialized) enclave
+ - EINIT: verify and initialize enclave
+ - EDBG{RD,WR}: read/write from/to a debug enclave’s memory
+ - EMODPR: restrict an EPC page’s permissions
+ - EMODT: modify an EPC page’s type
+ - EBLOCK: mark a page as blocked in EPCM
+ - ETRACK{C}: activate blocking tracing
+ - EWB: write back page from EPC to regular memory
+ - ELD{B,U}{C}: load page in {un}blocked state from system memory to EPC
+ - EPA: add version array (use to track evicted EPC pages)
+ - EREMOVE: remove a page from EPC
+ - ERDINFO: retrieve info about an EPC page from EPCM
+
+ENCLU Leafs
+-----------
+ - EENTER: enter an enclave
+ - ERESUME: resume execution of an interrupted enclave
+ - EEXIT: exit an enclave
+ - EGETKEY: retrieve a cryptographic key from the processor
+ - EREPORT: generate a cryptographic report describing an enclave
+ - EMODPE: extend an EPC page's permissions
+ - EACCEPT: accept changes to an EPC page
+ - EACCEPTCOPY: copy an existing EPC page to an uninitialized EPC page
+
+ENCLV Leafs
+-----------
+ - E{DEC,INC}VIRTCHILD: {dec,inc}rement SECS virtual refcount
+ - ESETCONTEXT: set SECS’ context pointer
+
+
+EPC page types
+==============
+
+All pages in the EPC have an explicit page type identifying the type of page.
+The type of page affects the page's accessibility, concurrency requirements,
+lifecycle, etc...
+
+SGX Enclave Control Structure (SECS)
+ An enclave is defined and referenced by an SGX Enclave Control Structure.
+ When creating an enclave (via ECREATE), software provides a source SECS for
+ the enclave, which is copied into a target EPC page. The source SECS
+ contains security and measurement information, as well as attributes and
+ properties of the enclave. Once the SECS is copied into the EPC, it's used
+ by the processor to store enclave metadata, e.g. the number of EPC pages
+ associated with the enclave, and is no longer directly accessible by
+ software.
+
+Regular (REG)
+ Regular EPC pages contain the code and data of an enclave. Code and data
+ pages can be added to an uninitialized enclave (prior to EINIT) via EADD.
+ Post EINIT, pages can be added to an enclave via EAUG. Pages added via
+ EAUG must be explicitly accepted by the enclave via EACCEPT or EACCEPTCOPY.
+
+Thread Control Structure (TCS)
+ Thread Control Structure pages define the entry points to an enclave and
+ track the execution state of an enclave thread. A TCS can only be used by
+ a single logical CPU at any given time, but otherwise has no attachment to
+ any particular logical CPU. Like regular pages, TCS pages are added to
+ enclaves via EADD and EINIT.
+
+Version Array (VA)
+ Version Array pages contain 512 slots, each of which can contain a version
+ number for a page evicted from the EPC. A version number is a unique 8-byte
+ value that is fed into the MAC computation used to verify the contents of an
+ evicted page when reloading said page into the EPC. VA pages are the only
+ page type not directly associated with an enclave, and are allocated in the
+ EPC via EPA. Note that VA pages can also be evicted from the EPC, but
+ doing so requires another VA page/slot to hold the version number of the VA
+ page being evicted.
+
+Trim (TRIM)
+ The Trim page type indicates that a page has been trimmed from the enclave’s
+ address space and is no longer accessible to enclave software, i.e. is about
+ to be removed from the enclave (via EREMOVE). Removing pages from a running
+ enclaves requires the enclave to explicit accept the removal (via EACCEPT).
+ The intermediate Trim type allows software to batch deallocation operations
+ to improve efficiency, e.g. minimize transitions between userspace, enclave
+ and kernel.
+
+
+Enclave Page Cache Map
+======================
+
+The processor tracks EPC pages via the Enclave Page Cache Map (EPCM). The EPCM
+is a processor-managed structure that enforces access restrictions to EPC pages
+in addition to the software-managed page tables. The EPCM contains one entry
+per EPC page, and although the details are implementation specific, all
+implementations contain the following architectural information:
+
+ - The status of EPC page with respect to validity and accessibility.
+ - An SECS identifier of the enclave to which the page belongs.
+ - The type of page: regular, SECS, TCS, VA or TRIM
+ - The linear address through which the enclave is allowed to access the page.
+ - The specified read/write/execute permissions on that page.
+
+Access violations, e.g. insufficient permissions or incorrect linear address,
+detected via the EPCM result in a page fault (#PF)[1]_ exception being signaled
+by the processor. Page faults due to EPCM violations set the PF_SGX flag
+(bit 15) in the page fault error code[2]_.
+
+The EPCM is consulted if and only if walking the software-managed page tables,
+i.e. the kernel's page tables, succeeds. I.e. the effective permissions for an
+EPC page are a logical AND of the kernel's page tables and the corresponding
+EPCM entry. This allows the kernel to make its page tables more restrictive
+without triggering an EPCM violation, e.g. it may mark an entry as not-present
+prior to evicting a page from the EPC.
+
+**IMPORTANT** 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. Most processors are expected
+to implement the EPC{M} as a subset of system DRAM that is encrypted with an
+ephemeral key, i.e. a key that is randomly generated at processor reset. As a
+result of using an ephemeral key, the contents of the EPC{M} are lost when the
+processor is powered down as part of an S3 transition or when a virtual machine
+is live migrated to a new physical system.
+
+
+Enclave initialization
+======================
+
+Because software cannot directly access the EPC except when executing in an
+enclave, an enclave must be built using ENCLS functions (ECREATE and EADD) as
+opposed to simply copying the enclave from the filesystem to memory. Once an
+enclave is built, it must be initialized (via EINIT) before userspace can enter
+the enclave and begin `Enclave execution`_.
+
+During the enclave build process, two "measurements", i.e. SHA-256 hashes, are
+taken of the enclave: MRENCLAVE and MRSIGNER. MRENCLAVE measures the enclave's
+contents, e.g. code/data explicitly added to the measurement (via EEXTEND), as
+well as metadata from the enclave's build process, e.g. pages offsets (relative
+to the enclave's base) and page permissions of all pages added to the enclave
+(via EADD). MRENCLAVE is initialized by ECREATE and finalized by EINIT.
+MRSIGNER is simply the SHA-256 hash of the public key used to sign the enclave.
+
+EINIT accepts two parameters in addition to the SECS of the target enclave: an
+Enclave Signature Struct (SIGSTRUCT) and an EINIT token (EINITTOKEN).
+SIGSTRUCT is a structure created and signed by the enclave's developer. Among
+other fields, SIGSTRUCT contains the expected MRENCLAVE of the enclave and the
+MRSIGNER of the enclave. SIGSTRUCT's MRENCLAVE is used by the processor to
+verify that the enclave was properly built (at runtime), and its SIGSTRUCT is
+copied to the SECS upon successful EINIT. EINITTOKEN is an optional parameter
+that is consumed as part of `Launch Control`_.
+
+
+Enclave execution
+=================
+
+Enclaves execute in a bespoke sub-mode of ring 3, appropriately named Enclave
+Mode. Enclave Mode changes behavior in key ways to support SGX's security
+guarantees and to reduce the probability of unintentional disclosure of
+sensitive data.
+
+A notable cornerstone of Enclave Mode is the Enclave Linear Range (ELRANGE).
+An enclave is associated with one, and only one, contiguous linear address
+range, its ELRANGE. The ELRANGE is specified via the SIZE and BASEADDR fields
+in the SECS (provided to ECREATE). The processor queries the active enclave's
+ELRANGE to differentiate enclave and non-enclave accesses, i.e. accesses that
+originate in Enclave Mode *and* whose linear address falls within ELRANGE are
+considered (direct) enclave accesses. Note, the processor also generates
+(indirect) enclave accesses when executing ENCL* instructions, which may occur
+outside of Enclave Mode, e.g. when copying the SECS to its target EPC page
+during ECREATE.
+
+Enclave Mode changes include, but are not limited to:
+
+ - Permits direct software access to EPC pages owned by the enclave
+ - Ensures enclave accesses map to the EPC (EPCM violation, i.e. #PF w/ PF_SGX)
+ - Prevents executing code outside the enclave's ELRANGE (#GP fault)
+ - Changes the behavior of exceptions/events
+ - Causes many instructions to become illegal, i.e. generate an exception
+ - Supresses all instruction breakpoints*
+ - Suppresses data breakpoints within enclave's ELRANGE*
+
+ * For non-debug enclaves.
+
+Transitions to/from Enclave Mode have semantics that are a lovely blend of
+SYSCALL, SYSRET and VM-Exit. In normal execution, entering and exiting Enclave
+Mode can only be done through EENTER and EEXIT respectively. EENTER+EEXIT is
+analogous to SYSCALL+SYSRET, e.g. EENTER/SYSCALL load RCX with the next RIP and
+EEXIT/SYSRET load RIP from R{B,C}X, and EENTER can only jump to a predefined
+location controlled by the enclave/kernel.
+
+But when an exception, interrupt, VM-Exit, etc... occurs, enclave transitions
+behave more like VM-Exit and VMRESUME. To maintain the black box nature of the
+enclave, the processor automatically switches register context when any of the
+aforementioned events occur (the SDM refers to such events as Enclave Exiting
+Events (EEE)).
+
+To handle an EEE, the processor performs an Asynchronous Enclave Exits (AEX).
+Note, although exceptions and traps are synchronous from a processor execution
+perspective, the are asynchronous from the enclave's perspective as the enclave
+is not provided an opportunity to save/fuzz state prior to exiting the enclave.
+On an AEX, the processor exits the enclave to a predefined %rip called the
+Asynchronous Exiting Pointer (AEP). The AEP is specified at enclave entry (via
+EENTER/ERESUME) and saved into the associated TCS, similar to how a hypervisor
+specifies the VM-Exit target (via VMCS.HOST_RIP at VMLAUNCH/VMRESUME), i.e. the
+the AEP is an exit location controlled by the enclave's untrusted runtime.
+
+On an AEX, the processor fully exits the enclave prior to vectoring the event,
+i.e. from the event handler's perspective the event occurred at the AEP. Thus,
+IRET/RSM/VMRESUME (from the event handler) returns control to the enclave's
+untrusted runtime, which can take appropriate action, e.g. immediately ERESUME
+the enclave on interrupts, forward expected exceptions to the enclave, restart
+the enclave on fatal exceptions, and so on and so forth.
+
+To preserve the enclave's state across AEX events, the processor automatically
+saves architectural into a State Save Area (SSA). Because SGX supports nested
+AEX events, e.g. the untrusted runtime can re-EENTER the enclave after an AEX,
+which can in turn trigger an AEX, the TCS holds a pointer to a stack of SSA
+frames (as opposed to a single SSA), an index to the current SSA frame and the
+total number of available frames. When an AEX occurs, the processor saves the
+architectural state into the TCS's current SSA frame. The untrusted runtime
+can then pop the last SSA frame (off the TCS's stack) via ERESUME, i.e. restart
+the enclave after the AEX is handled.
+
+
+Launch Control
+==============
+
+SGX provides a set of controls, referred to as Launch Control, that governs the
+initialization of enclaves. The processor internally stores a SHA-256 hash of
+a 3072-bit RSA public key, i.e. a MRSIGNER, often referred to as the "LE pubkey
+hash". The LE pubkey hash is used during EINIT to prevent launching an enclave
+without proper authorization. In order for EINIT to succeed, the enclave's
+MRSIGNER (from SIGSTRUCT) *or* the MRSIGNER of the enclave's EINITTOKEN must
+match the LE pubkey hash.
+
+An EINITTOKEN can only be created by a so called Launch Enclave (LE). A LE is
+an enclave with SECS.ATTRIBUTES.EINITTOKEN_KEY=1, which grants it access to the
+EINITTOKEN_KEY (retrieved via EGETKEY). EINITTOKENs provide a ready-built
+mechanism for userspace to bless enclaves without requiring additional kernel
+infrastructure.
+
+Processors that support SGX Launch Control Configuration, enumerated by the
+SGX_LC flag (bit 30 in CPUID 0x7.0x0.ECX), expose the LE pubkey hash as a set
+of four MSRs, aptly named IA32_SGXLEPUBKEYHASH[0-3]. The reset value of the
+MSRs is an internally defined (Intel) key (processors that don't support
+SGX_LC also use an internally defined key, it's just not exposed to software).
+
+While the IA32_SGXLEPUBKEYHASH MSRs are readable on any platform that supports
+SGX_LC, the MSRs are only writable if the IA32_FEATURE_CONTROL is locked with
+bit 17 ("SGX Launch Control Enable" per the SDM, or more accurately "SGX LE
+pubkey hash writable") set to '1'. Note, the MSRs are also writable prior to
+`SGX activation`_.
+
+Note, while "Launch Control Configuration" is the official feature name used by
+the Intel SDM, other documentation may use the term "Flexible Launch Control",
+or even simply "Launch Control". Colloquially, the vast majority of usage of
+the term "Launch Control" is synonymous with "Launch Control Configuration".
+
+
+EPC oversubscription
+====================
+
+SGX supports the concept of EPC oversubscription. Analogous to swapping system
+DRAM to disk, enclave pages can be swapped from the EPC to memory, and later
+reloaded from memory to the EPC. But because the kernel is untrusted, swapping
+pages in/out of the EPC has specialized requirements:
+
+ - The kernel cannot directly access EPC memory, i.e. cannot copy data to/from
+ the EPC.
+ - The kernel must "prove" to hardware that there are no valid TLB entries for
+ said page prior to eviction (a stale TLB entry would allow an attacker to
+ bypass SGX access controls).
+ - When loading a page back into the EPC, hardware must be able to verify
+ the integrity and freshness of the data.
+ - When loading an enclave page, e.g. regular and TCS pages, hardware must be
+ able to associate the page with an SECS, i.e. refcount an enclaves pages.
+
+To satisfy the above requirements, the CPU provides dedicated ENCLS functions
+to support paging data in/out of the EPC:
+
+ - EBLOCK: Mark a page as blocked in the EPC Map (EPCM). Attempting to access
+ a blocked page that misses the TLB will fault.
+ - ETRACK: Activate TLB tracking. Hardware verifies that all translations for
+ pages marked as "blocked" have been flushed from the TLB.
+ - EPA: Add Version Array page to the EPC (see `EPC page types`_)
+ - EWB: Write back a page from EPC to memory, e.g. RAM. Software must
+ supply a VA slot, memory to hold the Paging Crypto Metadata (PCMD) of the
+ page and obviously backing for the evicted page.
+ - ELD*: Load a page in {un}blocked state from memory to EPC.
+
+Swapped EPC pages are {de,en}crypted on their way in/out of the EPC, e.g. EWB
+encrypts and ELDU decrypts. The version number (stored in a VA page) and PCMD
+structure associated with an evicted EPC page seal a page (prevent undetected
+modification) and ensure its freshness (prevent rollback to a stale version of
+the page) while the page resides in unprotected storage, e.g. memory or disk.
+
+
+Attestation
+===========
+
+SGX provides mechanisms that allow software to implement what Intel refers to
+as Local Attestation (used by enclaves running on a the same physical platform
+to securely identify one another) and Remote Attestation (a process by which an
+enclave attests itself to a remote entity in order to gain the trust of said
+entity).
+
+The details of Local Attestation and Remote Attestation are far beyond the
+scope of this document. Please see Intel's Software Developer's Manual and/or
+use your search engine of choice to learn more about SGX's attestation
+capabilities.
+
+
+EPC Implemenations
+==================
+
+PRM with MEE
+--------------
+
+Initial hardware support for SGX implements the EPC by reserving a chunk of
+system DRAM, referred to as Processor Reserved Memory (PRM). A percentage of
+PRM is consumed by the processor to implement the EPCM, with the remainder of
+PRM being exposed to software as the EPC. PRM is configured by firmware via
+dedicated PRM Range Registers (PRMRRs). The PRMRRs are locked which are locked as part of SGX activation, i.e.
+resizing the PRM, and thus EPC, requires rebooting the system.
+
+An autonomous hardware unit called the Memory Encryption Engine (MEE) protects
+the confidentiality, integrity, and freshness of the PRM, e.g. {de,en}crypts
+data as it is read/written from/to DRAM to provide confidentiality.
+
+
+SGX activation
+==============
+
+Before SGX can be fully enabled, e.g. via FEATURE_CONTROL, the platform must
+undergo explicit SGX activation. SGX activation is a mechanism by which the
+processor verifies and locks the platform configuration set by pre-boot
+firmware, e.g. to ensure it satisfies SGX's security requirements. Before
+SGX is activated (and its configuration locked), firmware can modify the
+PRMRRs, e.g. to set the base/size of the PRM and thus EPC, and can also write
+the SGX_LEPUBKEYHASH MSRs. Notably, the latter allows pre-boot firmware to
+lock the SGX_LEPUBKEYHASH MSRs to a non-Intel value by writing the MSRs and
+locking MSR_IA32_FEATURE_CONTROL without setting the "SGX LE pubkey hash
+writable" flag, i.e. making the SGX_LEPUBKEYHASH MSRs readonly.
+
+
+Footnotes
+=========
+
+.. [1] All processors that do not support the SGX2 ISA take an errata and
+ signal #GP(0) instead of #PF(PF_SGX) when vectoring EPCM violations and
+ faults due to enclave-accesses to non-EPC memory.
+
+.. [2] Note that despite being vectored as a #PF, a #PF with PF_SGX has nothing
+ to do with conventional paging.
+
diff --git a/Documentation/x86/sgx/index.rst b/Documentation/x86/sgx/index.rst
new file mode 100644
index 000000000000..c5dfef62e612
--- /dev/null
+++ b/Documentation/x86/sgx/index.rst
@@ -0,0 +1,16 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+Software Guard Extensions
+=========================
+
+Intel(R) SGX is a set of architectural extensions that enables applications to
+establish secure containers, a.k.a. enclaves. SGX enclaves provide security
+guarantees such as integrity and confidentiality, even when running on a system
+where privileged software, e.g. kernel, hypervisor, etc... is untrusted and
+potentially malicious.
+
+.. toctree::
+ :maxdepth: 1
+
+ 1.Architecture
--
2.20.1
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 f8ba10516eaf..6a37df61ae32 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 9d8036f997b1..a6d734a70362 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 */
--
2.20.1
From: Sean Christopherson <[email protected]>
Enclaves are SGX hosted measured and signed software entities. ENCLS[EINIT]
leaf function checks that the enclave has a legit signed measurement and
transforms the enclave to the state ready for execution. The signed
measurement is provided by the caller in the form of SIGSTRUCT data
structure [1].
Wrap ENCLS[EINIT] into sgx_einit(). Set MSR_IA32_SGXLEPUBKEYHASH* MSRs to
match the public key contained in the SIGSTRUCT [2]. This sets Linux to
enforce a policy where the provided public key is as long as the signed
measurement matches the enclave contents in memory.
Add a per-cpu cache to avoid unnecessary reads and write to the MSRs
as they are expensive operations.
[1] Intel SDM: 37.1.3 ENCLAVE SIGNATURE STRUCTURE (SIGSTRUCT)
[2] 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/kernel/cpu/sgx/Makefile | 1 +
arch/x86/kernel/cpu/sgx/encls.c | 57 ++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/encls.h | 3 ++
3 files changed, 61 insertions(+)
create mode 100644 arch/x86/kernel/cpu/sgx/encls.c
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
index 2dec75916a5e..874492d9e3bd 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -1,3 +1,4 @@
obj-y += \
+ encls.o \
main.o \
reclaim.o
diff --git a/arch/x86/kernel/cpu/sgx/encls.c b/arch/x86/kernel/cpu/sgx/encls.c
new file mode 100644
index 000000000000..44291062967a
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encls.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-19 Intel Corporation.
+
+#include <asm/cpufeature.h>
+#include <asm/traps.h>
+#include "encls.h"
+#include "sgx.h"
+
+/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
+static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
+
+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];
+ }
+ }
+}
+
+/**
+ * sgx_einit - initialize an enclave
+ * @sigstruct: a pointer a SIGSTRUCT
+ * @token: a pointer an EINITTOKEN (optional)
+ * @secs: a pointer a SECS
+ * @lepubkeyhash: the desired value for IA32_SGXLEPUBKEYHASHx MSRs
+ *
+ * Execute ENCLS[EINIT], writing the IA32_SGXLEPUBKEYHASHx MSRs according
+ * to @lepubkeyhash (if possible and necessary).
+ *
+ * Return:
+ * 0 on success,
+ * -errno or SGX error on failure
+ */
+int sgx_einit(struct sgx_sigstruct *sigstruct, struct sgx_einittoken *token,
+ struct sgx_epc_page *secs, u64 *lepubkeyhash)
+{
+ int ret;
+
+ if (!boot_cpu_has(X86_FEATURE_SGX_LC))
+ return __einit(sigstruct, token, sgx_epc_addr(secs));
+
+ 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;
+}
diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
index d6381e4f6eb2..af94bbfe4cf6 100644
--- a/arch/x86/kernel/cpu/sgx/encls.h
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -248,4 +248,7 @@ static inline int __ewb(struct sgx_pageinfo *pginfo, void *addr,
return __encls_ret_3(EWB, pginfo, addr, va);
}
+int sgx_einit(struct sgx_sigstruct *sigstruct, struct sgx_einittoken *token,
+ struct sgx_epc_page *secs, u64 *lepubkeyhash);
+
#endif /* _X86_ENCLS_H */
--
2.20.1
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 | 337 +++++++++++++++++++++++++-
arch/x86/kernel/cpu/sgx/encl.h | 40 ++++
arch/x86/kernel/cpu/sgx/ioctl.c | 77 +++++-
arch/x86/kernel/cpu/sgx/main.c | 61 ++++-
arch/x86/kernel/cpu/sgx/reclaim.c | 376 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 35 +++
7 files changed, 919 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index 4d996463b213..4bbbef479293 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -34,6 +34,7 @@ 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 cd2b8dbb0eca..312f954c5c07 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,
@@ -180,6 +272,8 @@ 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;
@@ -277,6 +371,7 @@ 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;
@@ -287,6 +382,13 @@ 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;
@@ -301,6 +403,19 @@ 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);
+ }
}
/**
@@ -327,3 +442,221 @@ 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..44b353aa8866 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;
};
@@ -69,11 +80,20 @@ struct sgx_encl {
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 +104,24 @@ 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 e71618cef90c..5b82670bb79a 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -16,6 +16,43 @@
#include "encl.h"
#include "encls.h"
+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;
@@ -111,6 +148,7 @@ 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;
@@ -120,20 +158,29 @@ 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;
@@ -180,6 +227,9 @@ 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;
}
@@ -316,13 +366,14 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
{
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, addp->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);
@@ -334,9 +385,22 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
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
@@ -365,6 +429,8 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
ret = __sgx_encl_extend(encl, epc_page);
if (ret)
sgx_encl_destroy(encl);
+ else
+ sgx_mark_page_reclaimable(encl_page->epc_page);
}
mutex_unlock(&encl->lock);
@@ -376,6 +442,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
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 36a295a0272b..8b2440bac26b 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 bdb42f4326aa..21fbfe2ed9c4 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);
/*
* Reset all pages to uninitialized state. Pages could be in initialized on
@@ -71,6 +75,20 @@ static int ksgxswapd(void *p)
for (i = 0; i < sgx_nr_epc_sections; i++)
sgx_sanitize_section(&sgx_epc_sections[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;
}
@@ -86,3 +104,361 @@ 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;
+ struct sgx_encl_mm *encl_mm;
+ struct vm_area_struct *vma;
+ int idx, ret;
+
+ 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);
+
+ 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_encl *encl, struct sgx_epc_page *epc_page,
+ struct sgx_va_page *va_page, unsigned int va_offset,
+ 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),
+ sgx_epc_addr(va_page->epc_page) + va_offset);
+
+ 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;
+
+ 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;
+ 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);
+ if (sgx_va_page_full(va_page))
+ list_move_tail(&va_page->list, &encl->va_pages);
+
+ ret = __sgx_encl_ewb(encl, epc_page, va_page, va_offset, 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(encl, epc_page, va_page, va_offset,
+ 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(encl, epc_page, va_page,
+ va_offset, 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));
+ WARN(ret, "EREMOVE returned %d\n", ret);
+ } 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) {
+ 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);
+ }
+ }
+
+ 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 a6d734a70362..461749db0f0b 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;
@@ -44,9 +46,14 @@ extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
* 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 */
--
2.20.1
On Mon, Oct 28, 2019 at 11:03:12PM +0200, Jarkko Sakkinen wrote:
> +/**
> + * 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 (EADD) one or more pages to an uninitialized enclave, and optionally
> + * extend (EEXTEND) the measurement with the contents of the page. The range of
> + * pages must be virtually contiguous. The SECINFO and measurement mask are
> + * applied to all pages, i.e. pages with different properties must be added in
> + * separate calls.
> + *
> + * 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.
> + * 3. No page: PROT_NONE.
> + *
> + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> + * within the given address range.
> + *
> + * As stated above, a non-existent page is interpreted as a page with no
> + * permissions. In effect, this allows mmap() with PROT_NONE to be used to seek
> + * an address range for the enclave that can be then populated into SECS.
> + *
> + * @arg->addr, @arg->src and @arg->length are adjusted to reflect the
> + * remaining pages that need to be added to the enclave, e.g. userspace can
> + * re-invoke SGX_IOC_ENCLAVE_ADD_PAGES using the same struct in response to an
> + * ERESTARTSYS error.
> + *
> + * Return:
> + * 0 on success,
> + * -EINVAL if any input param or the SECINFO contains invalid data,
> + * -EACCES if an executable source page is located in a noexec partition,
> + * -ENOMEM if any memory allocation, including EPC, fails,
> + * -ERESTARTSYS if a pending signal is recognized
> + */
> +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
This should return the number of pages processed instead of zero on
success. Kernel needs to be able to cap the amount it will process.
/Jarkko
On Tue, Oct 29, 2019 at 11:29:20AM +0200, Jarkko Sakkinen wrote:
> On Mon, Oct 28, 2019 at 11:03:12PM +0200, Jarkko Sakkinen wrote:
> > +/**
> > + * 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 (EADD) one or more pages to an uninitialized enclave, and optionally
> > + * extend (EEXTEND) the measurement with the contents of the page. The range of
> > + * pages must be virtually contiguous. The SECINFO and measurement mask are
> > + * applied to all pages, i.e. pages with different properties must be added in
> > + * separate calls.
> > + *
> > + * 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.
> > + * 3. No page: PROT_NONE.
> > + *
> > + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> > + * within the given address range.
> > + *
> > + * As stated above, a non-existent page is interpreted as a page with no
> > + * permissions. In effect, this allows mmap() with PROT_NONE to be used to seek
> > + * an address range for the enclave that can be then populated into SECS.
> > + *
> > + * @arg->addr, @arg->src and @arg->length are adjusted to reflect the
> > + * remaining pages that need to be added to the enclave, e.g. userspace can
> > + * re-invoke SGX_IOC_ENCLAVE_ADD_PAGES using the same struct in response to an
> > + * ERESTARTSYS error.
> > + *
> > + * Return:
> > + * 0 on success,
> > + * -EINVAL if any input param or the SECINFO contains invalid data,
> > + * -EACCES if an executable source page is located in a noexec partition,
> > + * -ENOMEM if any memory allocation, including EPC, fails,
> > + * -ERESTARTSYS if a pending signal is recognized
> > + */
> > +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
>
> This should return the number of pages processed instead of zero on
> success. Kernel needs to be able to cap the amount it will process.
Why? The number of pages processed is effectively returned via the params
on any error, e.g. wouldn't it be more appropriate to return -ERESTARTSYS?
And I don't see any reason to add an arbitrary cap on the number of pages,
e.g. SGX plays nice with the scheduler and signals, and restricting the
number of EPC pages available to a process via cgroups (returning -ENOMEM)
is a better solution for managing EPC.
On 10/28/19 5:03 PM, 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)
Where do things stand wrt to ensuring that SGX cannot be used to
introduce executable mappings that were never authorized by the LSM (or
never measured by IMA)?
>
> 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]>
> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> Documentation/ioctl/ioctl-number.rst | 1 +
> arch/x86/include/uapi/asm/sgx.h | 64 +++
> arch/x86/kernel/cpu/sgx/Makefile | 3 +
> arch/x86/kernel/cpu/sgx/driver.c | 252 ++++++++++
> arch/x86/kernel/cpu/sgx/driver.h | 32 ++
> arch/x86/kernel/cpu/sgx/encl.c | 329 ++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 87 ++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 656 +++++++++++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 10 +
> arch/x86/kernel/cpu/sgx/reclaim.c | 1 +
> 10 files changed, 1435 insertions(+)
> 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/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst
> index bef79cd4c6b4..f9f3ea9606fc 100644
> --- a/Documentation/ioctl/ioctl-number.rst
> +++ b/Documentation/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..e0f79ebdfd8a
> --- /dev/null
> +++ b/arch/x86/include/uapi/asm/sgx.h
> @@ -0,0 +1,64 @@
> +/* 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
> + */
> +struct sgx_enclave_add_pages {
> + __u64 src;
> + __u64 offset;
> + __u64 length;
> + __u64 secinfo;
> + __u64 flags;
> +};
> +
> +/**
> + * 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 874492d9e3bd..3ddcdabab081 100644
> --- a/arch/x86/kernel/cpu/sgx/Makefile
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -1,4 +1,7 @@
> obj-y += \
> + driver.o \
> + encl.o \
> encls.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..c724dcccf2e2
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.c
> @@ -0,0 +1,252 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-18 Intel Corporation.
> +
> +#include <linux/acpi.h>
> +#include <linux/cdev.h>
> +#include <linux/mman.h>
> +#include <linux/platform_device.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");
> +
> +struct workqueue_struct *sgx_encl_wq;
> +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,
> +};
> +
> +static struct bus_type sgx_bus_type = {
> + .name = "sgx",
> +};
> +
> +static struct device sgx_encl_dev;
> +static struct cdev sgx_encl_cdev;
> +static dev_t sgx_devt;
> +
> +static void sgx_dev_release(struct device *dev)
> +{
> +}
> +
> +static __init int sgx_dev_init(const char *name, struct device *dev,
> + struct cdev *cdev,
> + const struct file_operations *fops, int minor)
> +{
> + int ret;
> +
> + device_initialize(dev);
> +
> + dev->bus = &sgx_bus_type;
> + dev->devt = MKDEV(MAJOR(sgx_devt), minor);
> + dev->release = sgx_dev_release;
> +
> + ret = dev_set_name(dev, name);
> + if (ret) {
> + put_device(dev);
> + return ret;
> + }
> +
> + cdev_init(cdev, fops);
> + cdev->owner = THIS_MODULE;
> + return 0;
> +}
> +
> +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;
> + }
> +
> + ret = bus_register(&sgx_bus_type);
> + if (ret)
> + return ret;
> +
> + ret = alloc_chrdev_region(&sgx_devt, 0, SGX_DRV_NR_DEVICES, "sgx");
> + if (ret < 0)
> + goto err_bus;
> +
> + 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 = sgx_dev_init("sgx/enclave", &sgx_encl_dev, &sgx_encl_cdev,
> + &sgx_encl_fops, 0);
> + if (ret)
> + goto err_chrdev_region;
> +
> + sgx_encl_wq = alloc_workqueue("sgx-encl-wq",
> + WQ_UNBOUND | WQ_FREEZABLE, 1);
> + if (!sgx_encl_wq) {
> + ret = -ENOMEM;
> + goto err_encl_dev;
> + }
> +
> + ret = cdev_device_add(&sgx_encl_cdev, &sgx_encl_dev);
> + if (ret)
> + goto err_encl_wq;
> +
> + return 0;
> +
> +err_encl_wq:
> + destroy_workqueue(sgx_encl_wq);
> +
> +err_encl_dev:
> + put_device(&sgx_encl_dev);
> +
> +err_chrdev_region:
> + unregister_chrdev_region(sgx_devt, SGX_DRV_NR_DEVICES);
> +
> +err_bus:
> + bus_unregister(&sgx_bus_type);
> +
> + return ret;
> +}
> diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
> new file mode 100644
> index 000000000000..e95c6e86c0c6
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/driver.h
> @@ -0,0 +1,32 @@
> +/* 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_DRV_NR_DEVICES 2
> +#define SGX_EINIT_SPIN_COUNT 20
> +#define SGX_EINIT_SLEEP_COUNT 50
> +#define SGX_EINIT_SLEEP_TIME 20
> +
> +extern struct workqueue_struct *sgx_encl_wq;
> +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..cd2b8dbb0eca
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -0,0 +1,329 @@
> +// 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;
> +
> + 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);
> +
> + synchronize_srcu(&encl->srcu);
> +
> + 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. Page addresses that do not have an associated enclave
> + * page are interpreted to zero permissions.
> + *
> + * 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;
> +
> + /* PROT_NONE always succeeds. */
> + if (!vm_prot_bits)
> + return 0;
> +
> + 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/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> new file mode 100644
> index 000000000000..691efac24ed7
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -0,0 +1,656 @@
> +// 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"
> +
> +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_HIGHUSER);
> + 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 ? -EFAULT : 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 -EFAULT;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int sgx_encl_add_page(struct sgx_encl *encl,
> + struct sgx_enclave_add_pages *addp,
> + struct sgx_secinfo *secinfo)
> +{
> + struct sgx_encl_page *encl_page;
> + struct sgx_epc_page *epc_page;
> + int ret;
> +
> + encl_page = sgx_encl_page_alloc(encl, addp->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,
> + addp->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 (addp->flags & SGX_PAGE_MEASURE) {
> + ret = __sgx_encl_extend(encl, epc_page);
> + if (ret)
> + sgx_encl_destroy(encl);
> + }
> +
> + 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);
> +
> + 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 (EADD) one or more pages to an uninitialized enclave, and optionally
> + * extend (EEXTEND) the measurement with the contents of the page. The range of
> + * pages must be virtually contiguous. The SECINFO and measurement mask are
> + * applied to all pages, i.e. pages with different properties must be added in
> + * separate calls.
> + *
> + * 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.
> + * 3. No page: PROT_NONE.
> + *
> + * mmap() is not allowed to surpass the minimum of the maximum protection bits
> + * within the given address range.
> + *
> + * As stated above, a non-existent page is interpreted as a page with no
> + * permissions. In effect, this allows mmap() with PROT_NONE to be used to seek
> + * an address range for the enclave that can be then populated into SECS.
> + *
> + * @arg->addr, @arg->src and @arg->length are adjusted to reflect the
> + * remaining pages that need to be added to the enclave, e.g. userspace can
> + * re-invoke SGX_IOC_ENCLAVE_ADD_PAGES using the same struct in response to an
> + * ERESTARTSYS error.
> + *
> + * Return:
> + * 0 on success,
> + * -EINVAL if any input param or the SECINFO contains invalid data,
> + * -EACCES if an executable source page is located in a noexec partition,
> + * -ENOMEM if any memory allocation, including EPC, fails,
> + * -ERESTARTSYS if a pending signal is recognized
> + */
> +static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
> +{
> + struct sgx_enclave_add_pages addp;
> + struct sgx_secinfo secinfo;
> + 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 ( ; addp.length > 0; addp.length -= PAGE_SIZE) {
> + if (signal_pending(current)) {
> + ret = -ERESTARTSYS;
> + break;
> + }
> +
> + if (need_resched())
> + cond_resched();
> +
> + ret = sgx_encl_add_page(encl, &addp, &secinfo);
> + if (ret)
> + break;
> +
> + addp.offset += PAGE_SIZE;
> + addp.src += PAGE_SIZE;
> + }
> +
> + 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 int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
> + struct sgx_einittoken *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 -EINVAL;
> +
> + 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_einittoken *einittoken;
> + struct sgx_sigstruct *sigstruct;
> + struct sgx_enclave_init einit;
> + struct page *initp_page;
> + 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_HIGHUSER);
> + if (!initp_page)
> + return -ENOMEM;
> +
> + sigstruct = kmap(initp_page);
> + einittoken = (struct sgx_einittoken *)
> + ((unsigned long)sigstruct + PAGE_SIZE / 2);
> + memset(einittoken, 0, sizeof(*einittoken));
> +
> + if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
> + sizeof(*sigstruct))) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = sgx_encl_init(encl, sigstruct, einittoken);
> +
> +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 6a37df61ae32..36a295a0272b 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];
> @@ -196,6 +197,8 @@ static bool __init sgx_page_cache_init(void)
>
> static void __init sgx_init(void)
> {
> + int ret;
> +
> if (!boot_cpu_has(X86_FEATURE_SGX))
> return;
>
> @@ -205,8 +208,15 @@ 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();
> }
> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> index f071158d34f6..bdb42f4326aa 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;
>
>
On Wed, Oct 30, 2019 at 02:30:45AM -0700, Sean Christopherson wrote:
> Why? The number of pages processed is effectively returned via the params
> on any error, e.g. wouldn't it be more appropriate to return -ERESTARTSYS?
> And I don't see any reason to add an arbitrary cap on the number of pages,
> e.g. SGX plays nice with the scheduler and signals, and restricting the
> number of EPC pages available to a process via cgroups (returning -ENOMEM)
> is a better solution for managing EPC.
Returning -ENOMEM does not tell you from which page to retry.
/Jarkko
On Wed, Oct 30, 2019 at 09:45:05AM -0400, Stephen Smalley wrote:
> On 10/28/19 5:03 PM, 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)
>
> Where do things stand wrt to ensuring that SGX cannot be used to introduce
> executable mappings that were never authorized by the LSM (or never measured
> by IMA)?
This was the latest discussion about that subject:
https://lore.kernel.org/linux-sgx/CALCETrWDLX68Vi4=9Dicq9ATmJ5mv36bzrc02heNYaHaBeWumQ@mail.gmail.com/
/Jarkko
On 10/31/19 5:17 PM, Jarkko Sakkinen wrote:
> On Wed, Oct 30, 2019 at 09:45:05AM -0400, Stephen Smalley wrote:
>> On 10/28/19 5:03 PM, 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)
>>
>> Where do things stand wrt to ensuring that SGX cannot be used to introduce
>> executable mappings that were never authorized by the LSM (or never measured
>> by IMA)?
>
> This was the latest discussion about that subject:
>
> https://lore.kernel.org/linux-sgx/CALCETrWDLX68Vi4=9Dicq9ATmJ5mv36bzrc02heNYaHaBeWumQ@mail.gmail.com/
So, IIUC, that means that merging the driver will create a regression
with respect to LSM control over executable mappings that will only be
rectified at some future point in time if/when someone submits LSM hooks
or calls to existing hooks to restore such control. That doesn't seem
like a good idea. Why can't you include at least that basic level of
control now? It is one thing to defer finer grained control or
SGX-specific access controls to the future - that I can understand. But
introducing a regression in the existing controls is not really ok.
On 11/1/19 9:16 AM, Stephen Smalley wrote:
> On 10/31/19 5:17 PM, Jarkko Sakkinen wrote:
>> On Wed, Oct 30, 2019 at 09:45:05AM -0400, Stephen Smalley wrote:
>>> On 10/28/19 5:03 PM, 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)
>>>
>>> Where do things stand wrt to ensuring that SGX cannot be used to
>>> introduce
>>> executable mappings that were never authorized by the LSM (or never
>>> measured
>>> by IMA)?
>>
>> This was the latest discussion about that subject:
>>
>> https://lore.kernel.org/linux-sgx/CALCETrWDLX68Vi4=9Dicq9ATmJ5mv36bzrc02heNYaHaBeWumQ@mail.gmail.com/
>>
>
> So, IIUC, that means that merging the driver will create a regression
> with respect to LSM control over executable mappings that will only be
> rectified at some future point in time if/when someone submits LSM hooks
> or calls to existing hooks to restore such control. That doesn't seem
> like a good idea. Why can't you include at least that basic level of
> control now? It is one thing to defer finer grained control or
> SGX-specific access controls to the future - that I can understand. But
> introducing a regression in the existing controls is not really ok.
Unless you are arguing that the existing checks on mmap/mprotect of
/dev/sgx/enclave are a coarse-grained approximation (effectively
requiring WX to the file or execmem for any user of SGX).
On Fri, Nov 01, 2019 at 09:28:17AM -0400, Stephen Smalley wrote:
> On 11/1/19 9:16 AM, Stephen Smalley wrote:
> >So, IIUC, that means that merging the driver will create a regression with
> >respect to LSM control over executable mappings that will only be
> >rectified at some future point in time if/when someone submits LSM hooks
> >or calls to existing hooks to restore such control.? That doesn't seem
> >like a good idea.? Why can't you include at least that basic level of
> >control now?? It is one thing to defer finer grained control or
> >SGX-specific access controls to the future - that I can understand.? But
> >introducing a regression in the existing controls is not really ok.
>
> Unless you are arguing that the existing checks on mmap/mprotect of
> /dev/sgx/enclave are a coarse-grained approximation (effectively requiring
> WX to the file or execmem for any user of SGX).
Yes, that's the argument as running any enclave will require RWX access to
/dev/sgx/enclave. EXECMEM won't trigger for SGX users as /dev/sgx/enclave
must be MAP_SHARED and it's a non-private file (not backed by anonymous
inode, in case I got the file terminology wrong).
On 11/1/19 11:32 AM, Sean Christopherson wrote:
> On Fri, Nov 01, 2019 at 09:28:17AM -0400, Stephen Smalley wrote:
>> On 11/1/19 9:16 AM, Stephen Smalley wrote:
>>> So, IIUC, that means that merging the driver will create a regression with
>>> respect to LSM control over executable mappings that will only be
>>> rectified at some future point in time if/when someone submits LSM hooks
>>> or calls to existing hooks to restore such control. That doesn't seem
>>> like a good idea. Why can't you include at least that basic level of
>>> control now? It is one thing to defer finer grained control or
>>> SGX-specific access controls to the future - that I can understand. But
>>> introducing a regression in the existing controls is not really ok.
>>
>> Unless you are arguing that the existing checks on mmap/mprotect of
>> /dev/sgx/enclave are a coarse-grained approximation (effectively requiring
>> WX to the file or execmem for any user of SGX).
>
> Yes, that's the argument as running any enclave will require RWX access to
> /dev/sgx/enclave. EXECMEM won't trigger for SGX users as /dev/sgx/enclave
> must be MAP_SHARED and it's a non-private file (not backed by anonymous
> inode, in case I got the file terminology wrong).
Ok, so for SELinux's purposes, one will need to allow :file { open ioctl
map read write execute } to whatever type is ultimately assigned to
/dev/sgx/enclave in order to use SGX.
On Thu, Oct 31, 2019 at 11:12:52PM +0200, Jarkko Sakkinen wrote:
> On Wed, Oct 30, 2019 at 02:30:45AM -0700, Sean Christopherson wrote:
> > Why? The number of pages processed is effectively returned via the params
> > on any error, e.g. wouldn't it be more appropriate to return -ERESTARTSYS?
> > And I don't see any reason to add an arbitrary cap on the number of pages,
> > e.g. SGX plays nice with the scheduler and signals, and restricting the
> > number of EPC pages available to a process via cgroups (returning -ENOMEM)
> > is a better solution for managing EPC.
>
> Returning -ENOMEM does not tell you from which page to retry.
API should be robust enough to be able to cap the amount of data
processed with or without cgroups like send(), recv(), read() and
write() are and the call pattern for it must be a loop not a single shot
call for any megalomaniac length.
I'll add @count to address this. This output field will contain the
number of bytes actually written instead of overwriting input
parameters, which is a bad practice in anyway.
We don't need to actually cap to anything but API must be able to
support such scenario. Caller must be prepared to deal with the
situation where the return value is zero but @count < @length.
/Jarkko
On Fri, Nov 01, 2019 at 01:16:59PM -0400, Stephen Smalley wrote:
> On 11/1/19 11:32 AM, Sean Christopherson wrote:
> > On Fri, Nov 01, 2019 at 09:28:17AM -0400, Stephen Smalley wrote:
> > > On 11/1/19 9:16 AM, Stephen Smalley wrote:
> > > > So, IIUC, that means that merging the driver will create a regression with
> > > > respect to LSM control over executable mappings that will only be
> > > > rectified at some future point in time if/when someone submits LSM hooks
> > > > or calls to existing hooks to restore such control.? That doesn't seem
> > > > like a good idea.? Why can't you include at least that basic level of
> > > > control now?? It is one thing to defer finer grained control or
> > > > SGX-specific access controls to the future - that I can understand.? But
> > > > introducing a regression in the existing controls is not really ok.
> > >
> > > Unless you are arguing that the existing checks on mmap/mprotect of
> > > /dev/sgx/enclave are a coarse-grained approximation (effectively requiring
> > > WX to the file or execmem for any user of SGX).
> >
> > Yes, that's the argument as running any enclave will require RWX access to
> > /dev/sgx/enclave. EXECMEM won't trigger for SGX users as /dev/sgx/enclave
> > must be MAP_SHARED and it's a non-private file (not backed by anonymous
> > inode, in case I got the file terminology wrong).
>
> Ok, so for SELinux's purposes, one will need to allow :file { open ioctl map
> read write execute } to whatever type is ultimately assigned to
> /dev/sgx/enclave in order to use SGX.
AFAIK yes.
/Jarkko
On Tue, Nov 05, 2019 at 01:11:22PM +0200, Jarkko Sakkinen wrote:
> I'll add @count to address this. This output field will contain the
> number of bytes actually written instead of overwriting input
> parameters, which is a bad practice in anyway.
>
> We don't need to actually cap to anything but API must be able to
> support such scenario. Caller must be prepared to deal with the
> situation where the return value is zero but @count < @length.
I summarized here my reasoning on @count:
https://lore.kernel.org/linux-sgx/[email protected]/
/Jarkko
The Enarx (https://enarx.io) project is eager to see these patches
merged. We have tested them on the hardware we have available to us
and haven't noticed any problems.
On Mon, Oct 28, 2019 at 5:03 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
>
> 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 (11):
> 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
> selftests/x86: Recurse into subdirectories
> selftests/x86: Add a selftest for SGX
> x86/sgx: Add provisioning
> x86/sgx: Add a page reclaimer
> x86/sgx: ptrace() support for the SGX driver
> selftests/x86: Add vDSO selftest for SGX
>
> Sean Christopherson (13):
> 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 supprt
> x86/sgx: Enumerate and track EPC sections
> x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT]
> 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: Add __vdso_sgx_enter_enclave() to wrap SGX enclave
> transitions
> docs: x86/sgx: Document microarchitecture
> docs: x86/sgx: Document kernel internals
>
> Documentation/ioctl/ioctl-number.rst | 1 +
> Documentation/x86/index.rst | 1 +
> Documentation/x86/sgx/1.Architecture.rst | 431 ++++++++++
> Documentation/x86/sgx/2.Kernel-internals.rst | 78 ++
> Documentation/x86/sgx/index.rst | 17 +
> 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 | 187 +++++
> arch/x86/include/asm/cpufeatures.h | 24 +-
> arch/x86/include/asm/disabled-features.h | 14 +-
> arch/x86/include/asm/msr-index.h | 8 +
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/include/asm/vdso.h | 5 +
> arch/x86/include/uapi/asm/sgx.h | 112 +++
> arch/x86/kernel/cpu/Makefile | 1 +
> arch/x86/kernel/cpu/intel.c | 41 +
> arch/x86/kernel/cpu/scattered.c | 2 +
> arch/x86/kernel/cpu/sgx/Makefile | 7 +
> arch/x86/kernel/cpu/sgx/arch.h | 394 +++++++++
> arch/x86/kernel/cpu/sgx/driver.c | 274 +++++++
> arch/x86/kernel/cpu/sgx/driver.h | 34 +
> arch/x86/kernel/cpu/sgx/encl.c | 750 +++++++++++++++++
> arch/x86/kernel/cpu/sgx/encl.h | 127 +++
> arch/x86/kernel/cpu/sgx/encls.c | 57 ++
> arch/x86/kernel/cpu/sgx/encls.h | 254 ++++++
> arch/x86/kernel/cpu/sgx/ioctl.c | 770 ++++++++++++++++++
> arch/x86/kernel/cpu/sgx/main.c | 283 +++++++
> arch/x86/kernel/cpu/sgx/reclaim.c | 464 +++++++++++
> 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 | 21 +-
> tools/testing/selftests/x86/Makefile | 44 +
> tools/testing/selftests/x86/sgx/Makefile | 47 ++
> tools/testing/selftests/x86/sgx/defines.h | 39 +
> tools/testing/selftests/x86/sgx/encl.c | 20 +
> tools/testing/selftests/x86/sgx/encl.lds | 34 +
> .../selftests/x86/sgx/encl_bootstrap.S | 94 +++
> tools/testing/selftests/x86/sgx/main.c | 373 +++++++++
> tools/testing/selftests/x86/sgx/sgx_call.S | 66 ++
> tools/testing/selftests/x86/sgx/sgx_call.h | 14 +
> tools/testing/selftests/x86/sgx/sgxsign.c | 493 +++++++++++
> .../testing/selftests/x86/sgx/signing_key.pem | 39 +
> 51 files changed, 5944 insertions(+), 36 deletions(-)
> create mode 100644 Documentation/x86/sgx/1.Architecture.rst
> create mode 100644 Documentation/x86/sgx/2.Kernel-internals.rst
> create mode 100644 Documentation/x86/sgx/index.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/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.c
> 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/x86/sgx/Makefile
> create mode 100644 tools/testing/selftests/x86/sgx/defines.h
> create mode 100644 tools/testing/selftests/x86/sgx/encl.c
> create mode 100644 tools/testing/selftests/x86/sgx/encl.lds
> create mode 100644 tools/testing/selftests/x86/sgx/encl_bootstrap.S
> create mode 100644 tools/testing/selftests/x86/sgx/main.c
> create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.S
> create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.h
> create mode 100644 tools/testing/selftests/x86/sgx/sgxsign.c
> create mode 100644 tools/testing/selftests/x86/sgx/signing_key.pem
>
> --
> 2.20.1
>
On Thu, Nov 21, 2019 at 10:08:24AM -0500, Nathaniel McCallum wrote:
> The Enarx (https://enarx.io) project is eager to see these patches
> merged. We have tested them on the hardware we have available to us
> and haven't noticed any problems.
There was one regression in reclaimer code in v23. I'm also making a
small API change to v24 i.e. have @count for number of bytes processed
in ADD_PAGES ioctl.
Is it possible to test this in v24 once it is available and potentially
give tested-by to the driver patch if it works for you?
/Jarkko
On Mon, Oct 28, 2019 at 11:03:12PM +0200, Jarkko Sakkinen wrote:
> +static struct device sgx_encl_dev;
Ugh, really? After 23 versions of this patchset no one saw this?
> +static struct cdev sgx_encl_cdev;
> +static dev_t sgx_devt;
> +
> +static void sgx_dev_release(struct device *dev)
> +{
> +}
The old kernel documentation used to say I was allowed to make fun of
people who did this, but that was removed as it really wasn't that nice.
But I'm seriously reconsidering that at the moment.
No, this is NOT OK!
Think about what you are doing here, and why you feel that it is ok to
work around a kernel message that was added there explicitly to help you
do things the right way. I didn't add it just because I felt like it, I
was trying to give you a chance to not get the use of this api
incorrect.
That failed :(
Ugh, not ok. Seriously, not ok...
> +static __init int sgx_dev_init(const char *name, struct device *dev,
> + struct cdev *cdev,
> + const struct file_operations *fops, int minor)
> +{
> + int ret;
> +
> + device_initialize(dev);
Why do you even need a struct device in the first place?
> +
> + dev->bus = &sgx_bus_type;
> + dev->devt = MKDEV(MAJOR(sgx_devt), minor);
> + dev->release = sgx_dev_release;
> +
> + ret = dev_set_name(dev, name);
> + if (ret) {
> + put_device(dev);
> + return ret;
> + }
> +
> + cdev_init(cdev, fops);
Why a whole cdev?
Why not use a misc device? YOu only have 2 devices right? Why not 2
misc devices then? That saves the use of a whole major number and makes
your code a _LOT_ simpler.
> + ret = bus_register(&sgx_bus_type);
I'm afraid to look at this bus code.
Instead I'm going to ask, why do you need a bus at all? What drivers do
you have for this bus?
ugh I don't know why I looked at this code, but it's not ok as-is and
anyone who reviewed the driver model interaction needs to rethink
things...
greg k-h
On Thu, Nov 28, 2019 at 07:24:50PM +0100, Greg KH wrote:
> On Mon, Oct 28, 2019 at 11:03:12PM +0200, Jarkko Sakkinen wrote:
> > +static struct device sgx_encl_dev;
>
> Ugh, really? After 23 versions of this patchset no one saw this?
Nobody has really given feedback on the device model. This is the
first review on that and thanks for taking your time. Previously
feeback has been mainly on the ioctl API and file management.
> > +static dev_t sgx_devt;
> > +
> > +static void sgx_dev_release(struct device *dev)
> > +{
> > +}
>
> The old kernel documentation used to say I was allowed to make fun of
> people who did this, but that was removed as it really wasn't that nice.
>
> But I'm seriously reconsidering that at the moment.
>
> No, this is NOT OK!
>
> Think about what you are doing here, and why you feel that it is ok to
> work around a kernel message that was added there explicitly to help you
> do things the right way. I didn't add it just because I felt like it, I
> was trying to give you a chance to not get the use of this api
> incorrect.
>
> That failed :(
>
> Ugh, not ok. Seriously, not ok...
It used to delete a context structure called sgx_dev_ctx. This structure
was removed in v20. I've failed to notice this when the code was refactored
for v20.
> Why a whole cdev?
>
> Why not use a misc device? YOu only have 2 devices right? Why not 2
> misc devices then? That saves the use of a whole major number and makes
> your code a _LOT_ simpler.
The downside would be that if we ever want to add sysfs attributes, that
could not be done synchronously with the device creation.
/Jarkko
On Fri, Dec 06, 2019 at 10:38:07PM +0200, Jarkko Sakkinen wrote:
> > Why a whole cdev?
> >
> > Why not use a misc device? YOu only have 2 devices right? Why not 2
> > misc devices then? That saves the use of a whole major number and makes
> > your code a _LOT_ simpler.
>
> The downside would be that if we ever want to add sysfs attributes, that
> could not be done synchronously with the device creation.
That is what the groups member of struct misc_device is for.
greg k-h
On Sat, Dec 07, 2019 at 09:09:39AM +0100, Greg KH wrote:
> On Fri, Dec 06, 2019 at 10:38:07PM +0200, Jarkko Sakkinen wrote:
> > > Why a whole cdev?
> > >
> > > Why not use a misc device? YOu only have 2 devices right? Why not 2
> > > misc devices then? That saves the use of a whole major number and makes
> > > your code a _LOT_ simpler.
> >
> > The downside would be that if we ever want to add sysfs attributes, that
> > could not be done synchronously with the device creation.
>
> That is what the groups member of struct misc_device is for.
OK, cool, then there is no problem changing to misc.
I haven't seen misc drivers (not that I've looked through every single
of them so I suppose there are such) to use it and somehow have been
blind to seeing it that it si there.
Thanks again for the feedback. I'll fix this for the next patch set
version.
/Jarkko
On Mon, Dec 09, 2019 at 09:57:19PM +0200, Jarkko Sakkinen wrote:
> On Sat, Dec 07, 2019 at 09:09:39AM +0100, Greg KH wrote:
> > On Fri, Dec 06, 2019 at 10:38:07PM +0200, Jarkko Sakkinen wrote:
> > > > Why a whole cdev?
> > > >
> > > > Why not use a misc device? YOu only have 2 devices right? Why not 2
> > > > misc devices then? That saves the use of a whole major number and makes
> > > > your code a _LOT_ simpler.
> > >
> > > The downside would be that if we ever want to add sysfs attributes, that
> > > could not be done synchronously with the device creation.
> >
> > That is what the groups member of struct misc_device is for.
>
> OK, cool, then there is no problem changing to misc.
>
> I haven't seen misc drivers (not that I've looked through every single
> of them so I suppose there are such) to use it and somehow have been
> blind to seeing it that it si there.
>
> Thanks again for the feedback. I'll fix this for the next patch set
> version.
Back in 2014 we bumped with the TPM driver to this issue with sysfs
attributes and converted the driver to have its own class to get around
the issue.
The feature came into misc in 2015 [*]. When I sent the first versions
of the patch set in 2017 I was not aware of this change (should have
checked tho). Agree that the bus was not a great choice but I just
used what I thought I had available.
[*] bd735995308b553cc3c7f6a975aa284b270c7e2c
/Jarkko