This patchset provides the changes required for
the AppArmor security module to stack safely with any other.
There are additional changes required for SELinux and Smack
to coexist. These are primarily in the networking code and
will be addressed after these changes are upstream.
v38: Rebase to 6.0-rc7
- Discard the implementation of /proc/self/attr/context
- Discard the implementation of /proc/self/attr/display_lsm
- Implement a system call lsm_self_attr() which provides
a complete list of LSM process attributes.
- Implement a system call lsm_module_list() which provides
a list of the security modules active on the system.
- Implement a pair of prctl() options PR_LSM_ATTR_SET
and PR_LSM_ATTR_GET. These are used to control the LSM
that provides the values in /proc/.../attr entries.
- Make more of the infrastructure data changes early in the
patch set in support of the new system calls.
- Add a user interface header uapi/linux/lsm.h which contains
the format of data provided by lsm_self_attr() and the
integer LSM identifier values.
v37: Rebase to 5.19-rc3
- Audit changes should be complete, all comments have been
addressed.
- Address indexing an empty array for the case where no
built in security modules require data in struct lsmblob.
- Fix a few checkpatch complaints.
v36: Rebase to 5.19-rc1
- Yet another rework of the audit changes. Rearranging how the
timestamp is managed allows auxiliary records to be generated
correctly with a minimum of fuss.
- In the end no LSM interface scaffolding remains. Secids have
been replaced with lsmblob structures in all cases, including
IMA and NetLabel.
v35: Rebase to 5.18-rc2
- Address the case where CONFIG_SECURITY is enabled but
no security modules that use secid slots are included.
The resulting blob.secid[0] instances, although never
present in a call path, raised concerns.
- Address the case in interface_lsm where the BPF module
returns -EINVAL, resulting in a failed setting of the
value that would be otherwise allowed.
v34: Rebase to 5.18-rc1
- Incorporate feedback on the audit generation.
v33:
- Rework the supplimental audit record generation once more,
this time taking pseudo-code provided by Paul Moore as a
basis. The resulting code is considerably simpler and fits
better with the existing code flow.
v32: Rebase to 5.17-rc2
- Incorporate additional feedback from v30.
v31: Rebase to 5.16-rc4
- Incorporate feedback from Paul Moore on the audit
component changes.
v30: Rebase to 5.16-rc1
- Replace the integrity sub-system reuse of the audit
subsystem event matching functions with IMA specific
functions. This is done because audit needs to maintain
information about multiple security modules in audit
rules while IMA to restricts the information to a single
security module.
- The binder hooks have been changed and are no longer
called with sufficient information to identify the
interface_lsm. Pass that information in the binder
message, and use that in the compatibility decision.
- Refactor the audit changes.
v29: Rebase to 5.15-rc1
- Rework the supplimental audit record generation. Attach
a list of supplimental data to the audit_buffer and
generate the auxiliary records as needed on event end.
This should be usable for other auxiliary data, such as
container IDs. There is other ongoing audit work that
will require integration with this.
v28: Rebase to 5.14-rc2
- Provide IMA rules bounds checking (patch 04)
- Quote contexts in MAC_TASK_CONTEXTS and MAC_OBJ_CONTEXTS
audit records because of AppArmor's use of '=' in context
values. (patch 22,23)
v27: Fixes for landlock (patch 02)
- Rework the subject audit record generation. This version is
simpler and reflects feedback from Paul Moore. (patch 22)
v26: Rebase to 5.13-rc1
- Include the landlock security module.
- Accomodate change from security_task_getsecid() to
security_task_getsecid_obj() and security_task_getsecid_subj().
v25: Rebase to 5.12-rc2
Incorporate feedback from v24
- The IMA team suggested improvements to the integrity rule
processing.
v24: Rebase to 5.11-rc1
Incorporate feedback from v23
- Address the IMA team's concerns about "label collisions".
A label collision occurs when there is ambiguity about
which of multiple LSMs is being targeted in the definition
of an integrity check rule. A system with Smack and
AppArmor would be unable to distinguish which LSM is
important to an integrity rule referrencing the label
"unconfined" as that label is meaningful to both.
Provide a boot option to specify which LSM will be used in
IMA rules when multiple LSMs are present. (patch 04)
Pull LSM "slot" identification from later audit patches in
in support of this (patch 03).
- Pick up a few audit events that need to include supplimental
subject context records that had been missed in the
previous version.
v23: Rebase to 5.10-rc4
Incorporate feedback from v22
- Change /proc/*/attr/display to /proc/*/attr/interface_lsm to
make the purpose clearer. (patch 0012)
- Include ABI documentation. (patch 0012, 0022)
- Introduce LSM documentation updates with the patches where
the interfaces are added rather than at the end. (patch 0012, 0022)
Include more maintainers and mail lists in To: and Cc: directives.
v22: Rebase to 5.10-rc1
v21: Rebase to 5.9-rc4
Incorporate feedback from v20
- Further revert UDS SO_PEERSEC to use scaffolding around
the interfaces that use lsmblobs and store only a single
secid. The possibility of multiple security modules
requiring data here is still a future problem.
- Incorporate Richard Guy Briggs' non-syscall auxiliary
records patch (patch 0019-0021) in place of my "supplimental"
records implementation. [I'm not sure I've given proper
attestation. I will correct as appropriate]
v20: Rebase to 5.9-rc1
Change the BPF security module to use the lsmblob data. (patch 0002)
Repair length logic in subject label processing (patch 0015)
Handle -EINVAL from the empty BPF setprocattr hook (patch 0020)
Correct length processing in append_ctx() (patch 0022)
v19: Rebase to 5.8-rc6
Incorporate feedback from v18
- Revert UDS SO_PEERSEC implementation to use lsmblobs
directly, rather than allocating as needed. The correct
treatment of out-of-memory conditions in the later case
is difficult to define. (patch 0005)
- Use a size_t in append_ctx() (patch 0021)
- Fix a memory leak when creating compound contexts. (patch 0021)
Fix build error when CONFIG_SECURITY isn't set (patch 0013)
Fix build error when CONFIG_SECURITY isn't set (patch 0020)
Fix build error when CONFIG_SECURITY isn't set (patch 0021)
v18: Rebase to 5.8-rc3
Incorporate feedback from v17
- Null pointer checking in UDS (patch 0005)
Match changes in IMA code (patch 0012)
Fix the behavior of LSM context supplimental audit
records so that there's always exactly one when it's
appropriate for there to be one. This is a substantial
change that requires extention of the audit_context beyond
syscall events. (patch 0020)
v17: Rebase to 5.7-rc4
v16: Rebase to 5.6
Incorporate feedback from v15 - Thanks Stephen, Mimi and Paul
- Generally improve commit messages WRT scaffolding
- Comment ima_lsm_isset() (patch 0002)
- Some question may remain on IMA warning (patch 0002)
- Mark lsm_slot as __lsm_ro_after_init not __init_data (patch 0002)
- Change name of lsmblob variable in ima_match_rules() (patch 0003)
- Instead of putting a struct lsmblob into the unix_skb_parms
structure put a pointer to an allocated instance. There is
currently only space for 5 u32's in unix_skb_parms and it is
likely to get even tighter. Fortunately, the lifecycle
management of the allocated lsmblob is simple. (patch 0005)
- Dropped Acks due to the above change (patch 0005)
- Improved commentary on secmark labeling scaffolding. (patch 0006)
- Reduced secmark related labeling scaffolding. (patch 0006)
- Replace use of the zeroth entry of an lsmblob in scaffolding
with a function lsmblob_value() to hopefully make it less
obscure. (patch 0006)
- Convert security_secmark_relabel_packet to use lsmblob as
this reduces much of the most contentious scaffolding. (patch 0006)
- Dropped Acks due to the above change (patch 0006)
- Added BUILD_BUG_ON() for CIPSO tag 6. (patch 0018)
- Reworked audit subject information. Instead of adding fields in
the middle of existing records add a new record to the event. When
a separate record is required use subj="?". (patch 0020)
- Dropped Acks due to the above change (patch 0020)
- Reworked audit object information. Instead of adding fields in
the middle of existing records add a new record to the event. When
a separate record is required use obj="?". (patch 0021)
- Dropped Acks due to the above change (patch 0021)
- Enhanced documentation (patch 0022)
- Removed unnecessary error code check in security_getprocattr()
(patch 0021)
v15: Rebase to 5.6-rc1
- Revise IMA data use (patch 0002)
Incorporate feedback from v14
- Fix lockdown module registration naming (patch 0002)
- Revise how /proc/self/attr/context is gathered. (patch 0022)
- Revise access modes on /proc/self/attr/context. (patch 0022)
- Revise documentation on LSM external interfaces. (patch 0022)
v14: Rebase to 5.5-rc5
Incorporate feedback from v13
- Use an array of audit rules (patch 0002)
- Significant change, removed Acks (patch 0002)
- Remove unneeded include (patch 0013)
- Use context.len correctly (patch 0015)
- Reorder code to be more sensible (patch 0016)
- Drop SO_PEERCONTEXT as it's not needed yet (patch 0023)
v13: Rebase to 5.5-rc2
Incorporate feedback from v12
- Print lsmblob size with %z (Patch 0002)
- Convert lockdown LSM initialization. (Patch 0002)
- Restore error check in nft_secmark_compute_secid (Patch 0006)
- Correct blob scaffolding in ima_must_appraise() (Patch 0009)
- Make security_setprocattr() clearer (Patch 0013)
- Use lsm_task_display more widely (Patch 0013)
- Use passed size in lsmcontext_init() (Patch 0014)
- Don't add a smack_release_secctx() hook (Patch 0014)
- Don't print warning in security_release_secctx() (Patch 0014)
- Don't duplicate the label in nfs4_label_init_security() (Patch 0016)
- Remove reviewed-by as code has significant change (Patch 0016)
- Send the entire lsmblob for Tag 6 (Patch 0019)
- Fix description of socket_getpeersec_stream parameters (Patch 0023)
- Retain LSMBLOB_FIRST. What was I thinking? (Patch 0023)
- Add compound context to LSM documentation (Patch 0023)
v12: Rebase to 5.5-rc1
Fixed a couple of incorrect contractions in the text.
v11: Rebase to 5.4-rc6
Incorporate feedback from v10
- Disambiguate reading /proc/.../attr/display by restricting
all use of the interface to the current process.
- Fix a merge error in AppArmor's display attribute check
v10: Ask the security modules if the display can be changed.
v9: There is no version 9
v8: Incorporate feedback from v7
- Minor clean-up in display value management
- refactor "compound" context creation to use a common
append_ctx() function.
v7: Incorporate feedback from v6
- Make setting the display a privileged operation. The
availability of compound contexts reduces the need for
setting the display.
v6: Incorporate feedback from v5
- Add subj_<lsm>= and obj_<lsm>= fields to audit records
- Add /proc/.../attr/context to get the full context in
lsmname\0value\0... format as suggested by Simon McVittie
- Add SO_PEERCONTEXT for getsockopt() to get the full context
in the same format, also suggested by Simon McVittie.
- Add /sys/kernel/security/lsm_display_default to provide
the display default value.
v5: Incorporate feedback from v4
- Initialize the lsmcontext in security_secid_to_secctx()
- Clear the lsmcontext in all security_release_secctx() cases
- Don't use the "display" on strictly internal context
interfaces.
- The SELinux binder hooks check for cases where the context
"display" isn't compatible with SELinux.
v4: Incorporate feedback from v3
- Mark new lsm_<blob>_alloc functions static
- Replace the lsm and slot fields of the security_hook_list
with a pointer to a LSM allocated lsm_id structure. The
LSM identifies if it needs a slot explicitly. Use the
lsm_id rather than make security_add_hooks return the
slot value.
- Validate slot values used in security.c
- Reworked the "display" process attribute handling so that
it works right and doesn't use goofy list processing.
- fix display value check in dentry_init_security
- Replace audit_log of secids with '?' instead of deleting
the audit log
v3: Incorporate feedback from v2
- Make lsmblob parameter and variable names more
meaningful, changing "le" and "l" to "blob".
- Improve consistency of constant naming.
- Do more sanity checking during LSM initialization.
- Be a bit clearer about what is temporary scaffolding.
- Rather than clutter security_getpeersec_dgram with
otherwise unnecessary checks remove the apparmor
stub, which does nothing useful.
Patch 01 changes the LSM registration interface to pass a
structure lsm_id containing the name of the module instead of
just the LSM name itself.
Patch 02 introduces uapi/linux/lsm.h and numeric LSM identifiers.
The numeric ID is added to the lsm_id structure.
Patch 03 Adds the information about which process attributes are
supported by each LSM to the lsm_id structure.
Patch 04 introduces a table of LSM attribute data.
Patch 05 changes security_[gs]etprocattr() to use the LSM ID rather
than the LSM name.
Patch 06 implements the lsm_self_attr() system call.
Patch 07 separates the audit rule processing from the
integrity rule processing. They were never really the
same, but void pointers could hide that. The changes
following use the rule pointers differently in audit
and IMA, so keeping the code common is not a good idea.
Patch 08 moves management of the sock security blob
from the individual modules to the infrastructure.
Patches 09-10 introduce a structure "lsmblob" that will gradually
replace the "secid" as a shorthand for security module information.
At this point lsmblob contains an array of u32 secids, one "slot"
for each of the security modules compiled into the kernel that
used secids. A "slot" is allocated when a security module requests
one.
Patch 11 provides mechanism for the IMA subsystem to identify
explicitly which LSM is subject to IMA policy. This includes
a boot option for specifying the default and an additional option
in IMA rules "lsm=".
Patches 12-19 change LSM interfaces to use the lsmblob instead
of secids. It is important that the lsmblob be a fixed size entity
that does not have to be allocated. Several of the places
where it is used would have performance and/or locking
issues with dynamic allocation.
Patch 20 provides a mechanism for a process to identify which
security module's hooks should be used when displaying or
converting a security context string. A new prctl() options
PR_LSM_ATTR_[GS]ET get and set which security module to show.
Setting the value requires that all modules using the /proc
interfaces allow the transition. The interface LSM of other
processess can be neither read nor written.
Patch 21 Starts the process of changing how a security
context is represented. Since it is possible for a
security context to have been generated by more than one
security module it is now necessary to note which module
created a security context so that the correct "release"
hook can be called. There are several places where the
module that created a security context cannot be inferred.
This is achieved by introducing a "lsmcontext" structure
which contains the context string, its length and the
"slot" number of the security module that created it.
The security_release_secctx() interface is changed,
replacing the (string,len) pointer pair with a lsmcontext
pointer.
Patches 22-25 convert the security interfaces from
(string,len) pointer pairs to a lsmcontext pointer.
The slot number identifying the creating module is
added by the infrastructure. Where the security context
is stored for extended periods the data type is changed.
Patch 26 converts the Netlabel code to save lsmblob structures
instead of secids. This is not strictly necessary as there can
only be one security module that uses Netlabel at this point.
Using a lsmblob is much cleaner, as the interfaces that use the
data have all been converted.
Patch 27 adds checks to the binder hooks which verify
that both ends of a transaction use the same interface LSM.
Patch 28 adds a parameter to security_secid_to_secctx()
that indicates which of the security modules should be used
to provide the context.
Patches 29-33 update the audit system to better handle auxiliary
records. This requires rearranging the timestamp and serial number
handling. The skb pointer used to collect audit data is replaced
by a list of skb pointers.
Patch 34 adds a supplimental audit record for subject
LSM data when there are multiple security modules with such data.
The AUDIT_MAC_TASK_CONTEXTS record is used in conjuction with a
"subj=?" field to identify the subject data. The
AUDIT_MAC_TASK_CONTEXTS record identifies the security module
with the data: subj_selinux=xyz_t subj_apparmor=abc.
An example of the MAC_TASK_CONTEXTS (1420) record is:
type=UNKNOWN[1420]
msg=audit(1600880931.832:113)
subj_apparmor==unconfined
subj_smack=_
Patch 35 adds a supplimental audit record for object
LSM data when there are multiple security modules with such data.
The AUDIT_MAC_OBJ_CONTEXTS record is used in conjuction The
with a "obj=?" field to identify the object data.
The AUDIT_MAC_OBJ_CONTEXTS record identifies the security module
with the data: obj_selinux="xyz_t obj_apparmor="abc". While
AUDIT_MAC_TASK_CONTEXTS records will always contain an entry
for each possible security modules, AUDIT_MAC_OBJ_CONTEXTS
records will only contain entries for security modules for
which the object in question has data.
An example of the MAC_OBJ_CONTEXTS (1421) record is:
type=UNKNOWN[1421]
msg=audit(1601152467.009:1050):
obj_selinux=unconfined_u:object_r:user_home_t:s0
Patches 36-37 clean out scaffolding code.
With all interference on the AppArmor hooks removed,
Patch 38 removes the exclusive bit from AppArmor. An unnecessary
stub hook was also removed.
Patch 39 adds a system call lsm_module_list() that provides a set
of integer LSM ID values describing what is active on the system.
The Ubuntu project is using an earlier version of this patchset in
their distribution to enable stacking for containers.
Performance measurements to date have the change within the "noise".
The sockperf and dbench results are on the order of 0.2% to 0.8%
difference, with better performance being as common as worse. The
benchmarks were run with AppArmor and Smack on Ubuntu.
https://github.com/cschaufler/lsm-stacking.git#stack-6.0-rc7-38
Casey Schaufler (39):
LSM: Identify modules by more than name
LSM: Add an LSM identifier for external use
LSM: Identify the process attributes for each module
LSM: Maintain a table of LSM attribute data
proc: Use lsmids instead of lsm names for attrs
LSM: lsm_self_attr syscall for LSM self attributes
integrity: disassociate ima_filter_rule from security_audit_rule
LSM: Infrastructure management of the sock security
LSM: Add the lsmblob data structure.
LSM: provide lsm name and id slot mappings
IMA: avoid label collisions with stacked LSMs
LSM: Use lsmblob in security_audit_rule_match
LSM: Use lsmblob in security_kernel_act_as
LSM: Use lsmblob in security_secctx_to_secid
LSM: Use lsmblob in security_secid_to_secctx
LSM: Use lsmblob in security_ipc_getsecid
LSM: Use lsmblob in security_current_getsecid
LSM: Use lsmblob in security_inode_getsecid
LSM: Use lsmblob in security_cred_getsecid
LSM: Specify which LSM to display
LSM: Ensure the correct LSM context releaser
LSM: Use lsmcontext in security_secid_to_secctx
LSM: Use lsmcontext in security_inode_getsecctx
Use lsmcontext in security_dentry_init_security
LSM: security_secid_to_secctx in netlink netfilter
NET: Store LSM netlabel data in a lsmblob
binder: Pass LSM identifier for confirmation
LSM: security_secid_to_secctx module selection
Audit: Keep multiple LSM data in audit_names
Audit: Create audit_stamp structure
LSM: Add a function to report multiple LSMs
Audit: Allow multiple records in an audit_buffer
Audit: Add record for multiple task security contexts
audit: multiple subject lsm values for netlabel
Audit: Add record for multiple object contexts
netlabel: Use a struct lsmblob in audit data
LSM: Removed scaffolding function lsmcontext_init
AppArmor: Remove the exclusive flag
LSM: Create lsm_module_list system call
Documentation/ABI/testing/ima_policy | 8 +-
arch/x86/entry/syscalls/syscall_64.tbl | 2 +
drivers/android/binder.c | 47 ++-
drivers/android/binder_internal.h | 1 +
fs/ceph/super.h | 3 +-
fs/ceph/xattr.c | 15 +-
fs/fuse/dir.c | 35 +-
fs/nfs/dir.c | 2 +-
fs/nfs/inode.c | 17 +-
fs/nfs/internal.h | 8 +-
fs/nfs/nfs4proc.c | 14 +-
fs/nfs/nfs4xdr.c | 22 +-
fs/nfsd/nfs4xdr.c | 20 +-
fs/proc/base.c | 29 +-
fs/proc/internal.h | 2 +-
include/linux/audit.h | 21 +-
include/linux/cred.h | 3 +-
include/linux/lsm_hooks.h | 15 +-
include/linux/nfs4.h | 8 +-
include/linux/nfs_fs.h | 2 +-
include/linux/security.h | 292 +++++++++++--
include/linux/syscalls.h | 2 +
include/net/netlabel.h | 10 +-
include/net/scm.h | 15 +-
include/uapi/asm-generic/unistd.h | 8 +-
include/uapi/linux/audit.h | 2 +
include/uapi/linux/lsm.h | 67 +++
include/uapi/linux/prctl.h | 4 +
kernel/audit.c | 261 +++++++++---
kernel/audit.h | 18 +-
kernel/auditfilter.c | 29 +-
kernel/auditsc.c | 160 +++----
kernel/cred.c | 12 +-
kernel/sys_ni.c | 4 +
net/ipv4/cipso_ipv4.c | 26 +-
net/ipv4/ip_sockglue.c | 12 +-
net/netfilter/nf_conntrack_netlink.c | 24 +-
net/netfilter/nf_conntrack_standalone.c | 11 +-
net/netfilter/nfnetlink_queue.c | 38 +-
net/netfilter/nft_meta.c | 10 +-
net/netfilter/xt_SECMARK.c | 7 +-
net/netlabel/netlabel_kapi.c | 6 +-
net/netlabel/netlabel_unlabeled.c | 98 +++--
net/netlabel/netlabel_unlabeled.h | 2 +-
net/netlabel/netlabel_user.c | 10 +-
net/netlabel/netlabel_user.h | 2 +-
security/Makefile | 1 +
security/apparmor/include/apparmor.h | 3 +-
security/apparmor/include/net.h | 6 +-
security/apparmor/lsm.c | 110 ++---
security/apparmor/net.c | 2 +-
security/bpf/hooks.c | 14 +-
security/commoncap.c | 9 +-
security/integrity/ima/ima.h | 32 +-
security/integrity/ima/ima_api.c | 6 +-
security/integrity/ima/ima_appraise.c | 11 +-
security/integrity/ima/ima_main.c | 62 +--
security/integrity/ima/ima_policy.c | 92 +++-
security/landlock/cred.c | 2 +-
security/landlock/fs.c | 2 +-
security/landlock/ptrace.c | 2 +-
security/landlock/setup.c | 7 +
security/landlock/setup.h | 1 +
security/loadpin/loadpin.c | 10 +-
security/lockdown/lockdown.c | 9 +-
security/lsm_syscalls.c | 206 +++++++++
security/safesetid/lsm.c | 10 +-
security/security.c | 539 +++++++++++++++++++++---
security/selinux/hooks.c | 115 +++--
security/selinux/include/classmap.h | 3 +-
security/selinux/include/objsec.h | 5 +
security/selinux/include/security.h | 1 +
security/selinux/netlabel.c | 25 +-
security/selinux/ss/services.c | 4 +-
security/smack/smack.h | 6 +
security/smack/smack_access.c | 2 +-
security/smack/smack_lsm.c | 85 ++--
security/smack/smack_netfilter.c | 4 +-
security/smack/smackfs.c | 12 +-
security/tomoyo/tomoyo.c | 10 +-
security/yama/yama_lsm.c | 9 +-
81 files changed, 2063 insertions(+), 758 deletions(-)
create mode 100644 include/uapi/linux/lsm.h
create mode 100644 security/lsm_syscalls.c
--
2.37.3
Create a system call lsm_self_attr() to provide the security
module maintained attributes of the current process. Historically
these attributes have been exposed to user space via entries in
procfs under /proc/self/attr.
Attributes are provided as a collection of lsm_ctx structures
which are placed into a user supplied buffer. Each structure
identifys the security module providing the attribute, which
of the possible attributes is provided, the size of the
attribute, and finally the attribute value. The format of the
attribute value is defined by the security module, but will
always be \0 terminated. The ctx_len value will be larger than
strlen(ctx).
------------------------------
| unsigned int id |
------------------------------
| unsigned int flags |
------------------------------
| __kernel_size_t ctx_len |
------------------------------
| unsigned char ctx[ctx_len] |
------------------------------
| unsigned int id |
------------------------------
| unsigned int flags |
------------------------------
| __kernel_size_t ctx_len |
------------------------------
| unsigned char ctx[ctx_len] |
------------------------------
Signed-off-by: Casey Schaufler <[email protected]>
---
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
include/linux/syscalls.h | 1 +
include/uapi/asm-generic/unistd.h | 5 +-
include/uapi/linux/lsm.h | 21 ++++
kernel/sys_ni.c | 3 +
security/Makefile | 1 +
security/lsm_syscalls.c | 156 +++++++++++++++++++++++++
7 files changed, 187 insertions(+), 1 deletion(-)
create mode 100644 security/lsm_syscalls.c
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index c84d12608cd2..56d5c5202fd0 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -372,6 +372,7 @@
448 common process_mrelease sys_process_mrelease
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
+451 common lsm_self_attr sys_lsm_self_attr
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a34b0f9a9972..7f87ef8be546 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1056,6 +1056,7 @@ asmlinkage long sys_memfd_secret(unsigned int flags);
asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long len,
unsigned long home_node,
unsigned long flags);
+asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 45fa180cc56a..aa66718e1b48 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -886,8 +886,11 @@ __SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
+#define __NR_lsm_self_attr 451
+__SYSCALL(__NR_lsm_self_attr, sys_lsm_self_attr)
+
#undef __NR_syscalls
-#define __NR_syscalls 451
+#define __NR_syscalls 452
/*
* 32 bit systems traditionally used different
diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
index 4bb692b84a28..5acd791f82a9 100644
--- a/include/uapi/linux/lsm.h
+++ b/include/uapi/linux/lsm.h
@@ -9,6 +9,27 @@
#ifndef _UAPI_LINUX_LSM_H
#define _UAPI_LINUX_LSM_H
+#include <linux/types.h>
+#include <linux/unistd.h>
+
+/**
+ * struct lsm_ctx - LSM context
+ * @id: the LSM id number, see LSM_ID_XXX
+ * @flags: context specifier and LSM specific flags
+ * @ctx_len: the size of @ctx
+ * @ctx: the LSM context, a nul terminated string
+ *
+ * @ctx in a nul terminated string.
+ * (strlen(@ctx) < @ctx_len) is always true.
+ * (strlen(@ctx) == @ctx_len + 1) is not guaranteed.
+ */
+struct lsm_ctx {
+ unsigned int id;
+ unsigned int flags;
+ __kernel_size_t ctx_len;
+ unsigned char ctx[];
+};
+
/*
* ID values to identify security modules.
* A system may use more than one security module.
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 860b2dcf3ac4..0fdb0341251d 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -262,6 +262,9 @@ COND_SYSCALL_COMPAT(recvmsg);
/* mm/nommu.c, also with MMU */
COND_SYSCALL(mremap);
+/* security/lsm_syscalls.c */
+COND_SYSCALL(lsm_self_attr);
+
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
COND_SYSCALL(request_key);
diff --git a/security/Makefile b/security/Makefile
index 18121f8f85cd..59f238490665 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_KEYS) += keys/
# always enable default capabilities
obj-y += commoncap.o
+obj-$(CONFIG_SECURITY) += lsm_syscalls.o
obj-$(CONFIG_MMU) += min_addr.o
# Object file lists
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
new file mode 100644
index 000000000000..da0fab7065e2
--- /dev/null
+++ b/security/lsm_syscalls.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * System calls implementing the Linux Security Module API.
+ *
+ * Copyright (C) 2022 Casey Schaufler <[email protected]>
+ * Copyright (C) Intel Corporation
+ */
+
+#include <asm/current.h>
+#include <linux/compiler_types.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/security.h>
+#include <linux/stddef.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/lsm_hooks.h>
+#include <uapi/linux/lsm.h>
+
+struct feature_map {
+ char *name;
+ int feature;
+};
+
+static const struct feature_map lsm_attr_names[] = {
+ { .name = "current", .feature = LSM_ATTR_CURRENT, },
+ { .name = "exec", .feature = LSM_ATTR_EXEC, },
+ { .name = "fscreate", .feature = LSM_ATTR_FSCREATE, },
+ { .name = "keycreate", .feature = LSM_ATTR_KEYCREATE, },
+ { .name = "prev", .feature = LSM_ATTR_PREV, },
+ { .name = "sockcreate", .feature = LSM_ATTR_SOCKCREATE, },
+};
+
+/**
+ * lsm_self_attr - Return current task's security module attributes
+ * @ctx: the LSM contexts
+ * @size: size of @ctx, updated on return
+ * @flags: reserved for future use, must be zero
+ *
+ * Returns the calling task's LSM contexts. On success this
+ * function returns the number of @ctx array elements. This value
+ * may be zero if there are no LSM contexts assigned. If @size is
+ * insufficient to contain the return data -E2BIG is returned and
+ * @size is set to the minimum required size. In all other cases
+ * a negative value indicating the error is returned.
+ */
+SYSCALL_DEFINE3(lsm_self_attr,
+ struct lsm_ctx __user *, ctx,
+ size_t __user *, size,
+ int, flags)
+{
+ struct lsm_ctx *final = NULL;
+ struct lsm_ctx *interum;
+ struct lsm_ctx *ip;
+ void *curr;
+ char **interum_ctx;
+ char *cp;
+ size_t total_size = 0;
+ int count = 0;
+ int attr;
+ int len;
+ int rc = 0;
+ int i;
+
+ interum = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
+ sizeof(*interum), GFP_KERNEL);
+ if (interum == NULL)
+ return -ENOMEM;
+ ip = interum;
+
+ interum_ctx = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
+ sizeof(*interum_ctx), GFP_KERNEL);
+ if (interum_ctx == NULL) {
+ kfree(interum);
+ return -ENOMEM;
+ }
+
+ for (attr = 0; attr < ARRAY_SIZE(lsm_attr_names); attr++) {
+ for (i = 0; i < lsm_id; i++) {
+ if ((lsm_idlist[i]->features &
+ lsm_attr_names[attr].feature) == 0)
+ continue;
+
+ len = security_getprocattr(current, lsm_idlist[i]->id,
+ lsm_attr_names[attr].name,
+ &cp);
+ if (len <= 0)
+ continue;
+
+ ip->id = lsm_idlist[i]->id;
+ ip->flags = lsm_attr_names[attr].feature;
+ /* space for terminating \0 is allocated below */
+ ip->ctx_len = len + 1;
+ interum_ctx[count] = cp;
+ /*
+ * Security modules have been inconsistent about
+ * including the \0 terminator in the size. The
+ * context len has been adjusted to ensure there
+ * is one.
+ * At least one security module adds a \n at the
+ * end of a context to make it look nicer. Change
+ * that to a \0 so that user space doesn't have to
+ * work around it. Because of this meddling it is
+ * safe to assume that lsm_ctx.name is terminated
+ * and that strlen(lsm_ctx.name) < lsm.ctx_len.
+ */
+ total_size += sizeof(*interum) + ip->ctx_len;
+ cp = strnchr(cp, len, '\n');
+ if (cp != NULL)
+ *cp = '\0';
+ ip++;
+ count++;
+ }
+ }
+
+ if (count == 0)
+ goto free_out;
+
+ final = kzalloc(total_size, GFP_KERNEL);
+ if (final == NULL) {
+ rc = -ENOMEM;
+ goto free_out;
+ }
+
+ curr = final;
+ ip = interum;
+ for (i = 0; i < count; i++) {
+ memcpy(curr, ip, sizeof(*interum));
+ curr += sizeof(*interum);
+ memcpy(curr, interum_ctx[i], ip->ctx_len);
+ curr += ip->ctx_len;
+ ip++;
+ }
+
+ if (get_user(len, size)) {
+ rc = -EFAULT;
+ goto free_out;
+ }
+ if (total_size > len) {
+ rc = -ERANGE;
+ goto free_out;
+ }
+ if (copy_to_user(ctx, final, total_size) != 0 ||
+ put_user(total_size, size) != 0)
+ rc = -EFAULT;
+ else
+ rc = count;
+
+free_out:
+ for (i = 0; i < count; i++)
+ kfree(interum_ctx[i]);
+ kfree(interum_ctx);
+ kfree(interum);
+ kfree(final);
+ return rc;
+}
--
2.37.3
Create a new audit record AUDIT_MAC_OBJ_CONTEXTS.
An example of the MAC_OBJ_CONTEXTS (1421) record is:
type=MAC_OBJ_CONTEXTS[1421]
msg=audit(1601152467.009:1050):
obj_selinux=unconfined_u:object_r:user_home_t:s0
When an audit event includes a AUDIT_MAC_OBJ_CONTEXTS record
the "obj=" field in other records in the event will be "obj=?".
An AUDIT_MAC_OBJ_CONTEXTS record is supplied when the system has
multiple security modules that may make access decisions based
on an object security context.
Signed-off-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
---
include/linux/audit.h | 5 +++
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 49 ++++++++++++++++++++++-
kernel/auditsc.c | 79 ++++++++++++--------------------------
4 files changed, 78 insertions(+), 56 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 87ba6fe7f1a2..ce3f034e0c04 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -188,6 +188,8 @@ extern void audit_log_path_denied(int type,
const char *operation);
extern void audit_log_lost(const char *message);
+extern void audit_log_object_context(struct audit_buffer *ab,
+ struct lsmblob *blob);
extern int audit_log_subject_context(struct audit_buffer *ab,
struct lsmblob *blob);
extern int audit_log_task_context(struct audit_buffer *ab);
@@ -250,6 +252,9 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
{ }
static inline void audit_log_path_denied(int type, const char *operation)
{ }
+static inline void audit_log_object_context(struct audit_buffer *ab,
+ struct lsmblob *blob)
+{ }
static inline int audit_log_subject_context(struct audit_buffer *ab,
struct lsmblob *blob)
{
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 7a5966b46f38..e5fae08982ca 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -144,6 +144,7 @@
#define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */
#define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */
#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */
+#define AUDIT_MAC_OBJ_CONTEXTS 1421 /* Multiple LSM objext contexts */
#define AUDIT_FIRST_KERN_ANOM_MSG 1700
#define AUDIT_LAST_KERN_ANOM_MSG 1799
diff --git a/kernel/audit.c b/kernel/audit.c
index a611130f83cb..a1679bac7944 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1107,7 +1107,6 @@ static int is_audit_feature_set(int i)
return af.features & AUDIT_FEATURE_TO_MASK(i);
}
-
static int audit_get_feature(struct sk_buff *skb)
{
u32 seq;
@@ -2288,6 +2287,54 @@ int audit_log_task_context(struct audit_buffer *ab)
}
EXPORT_SYMBOL(audit_log_task_context);
+void audit_log_object_context(struct audit_buffer *ab, struct lsmblob *blob)
+{
+ int i;
+ int error;
+ struct lsmcontext context;
+
+ if (!lsm_multiple_contexts()) {
+ error = security_secid_to_secctx(blob, &context, LSMBLOB_FIRST);
+ if (error) {
+ if (error != -EINVAL)
+ goto error_path;
+ return;
+ }
+ audit_log_format(ab, " obj=%s", context.context);
+ security_release_secctx(&context);
+ } else {
+ audit_log_format(ab, " obj=?");
+ error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS);
+ if (error)
+ goto error_path;
+
+ for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+ if (blob->secid[i] == 0)
+ continue;
+ error = security_secid_to_secctx(blob, &context, i);
+ if (error) {
+ audit_log_format(ab, "%sobj_%s=?",
+ i ? " " : "",
+ lsm_slot_to_name(i));
+ if (error != -EINVAL)
+ audit_panic("error in audit_log_object_context");
+ } else {
+ audit_log_format(ab, "%sobj_%s=%s",
+ i ? " " : "",
+ lsm_slot_to_name(i),
+ context.context);
+ security_release_secctx(&context);
+ }
+ }
+
+ audit_buffer_aux_end(ab);
+ }
+ return;
+
+error_path:
+ audit_panic("error in audit_log_object_context");
+}
+
void audit_log_d_path_exe(struct audit_buffer *ab,
struct mm_struct *mm)
{
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index bc0621282a9a..f62605d994fa 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1089,36 +1089,25 @@ static inline void audit_free_context(struct audit_context *context)
kfree(context);
}
-static int audit_log_pid_context(struct audit_context *context, pid_t pid,
- kuid_t auid, kuid_t uid,
- unsigned int sessionid,
- struct lsmblob *blob, char *comm)
+static void audit_log_pid_context(struct audit_context *context, pid_t pid,
+ kuid_t auid, kuid_t uid,
+ unsigned int sessionid,
+ struct lsmblob *blob, char *comm)
{
struct audit_buffer *ab;
- struct lsmcontext lsmctx;
- int rc = 0;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
if (!ab)
- return rc;
+ return;
audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
from_kuid(&init_user_ns, auid),
from_kuid(&init_user_ns, uid), sessionid);
- if (lsmblob_is_set(blob)) {
- if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
- audit_log_format(ab, " obj=(none)");
- rc = 1;
- } else {
- audit_log_format(ab, " obj=%s", lsmctx.context);
- security_release_secctx(&lsmctx);
- }
- }
+ if (lsmblob_is_set(blob))
+ audit_log_object_context(ab, blob);
audit_log_format(ab, " ocomm=");
audit_log_untrustedstring(ab, comm);
audit_log_end(ab);
-
- return rc;
}
static void audit_log_execve_info(struct audit_context *context,
@@ -1395,18 +1384,10 @@ static void show_special(struct audit_context *context, int *call_panic)
from_kgid(&init_user_ns, context->ipc.gid),
context->ipc.mode);
if (osid) {
- struct lsmcontext lsmcxt;
struct lsmblob blob;
lsmblob_init(&blob, osid);
- if (security_secid_to_secctx(&blob, &lsmcxt,
- LSMBLOB_FIRST)) {
- audit_log_format(ab, " osid=%u", osid);
- *call_panic = 1;
- } else {
- audit_log_format(ab, " obj=%s", lsmcxt.context);
- security_release_secctx(&lsmcxt);
- }
+ audit_log_object_context(ab, &blob);
}
if (context->ipc.has_perm) {
audit_log_end(ab);
@@ -1563,19 +1544,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
from_kgid(&init_user_ns, n->gid),
MAJOR(n->rdev),
MINOR(n->rdev));
- if (lsmblob_is_set(&n->lsmblob)) {
- struct lsmcontext lsmctx;
-
- if (security_secid_to_secctx(&n->lsmblob, &lsmctx,
- LSMBLOB_FIRST)) {
- audit_log_format(ab, " osid=?");
- if (call_panic)
- *call_panic = 2;
- } else {
- audit_log_format(ab, " obj=%s", lsmctx.context);
- security_release_secctx(&lsmctx);
- }
- }
+ if (lsmblob_is_set(&n->lsmblob))
+ audit_log_object_context(ab, &n->lsmblob);
/* log the audit_names record type */
switch (n->type) {
@@ -1780,21 +1750,20 @@ static void audit_log_exit(void)
struct audit_aux_data_pids *axs = (void *)aux;
for (i = 0; i < axs->pid_count; i++)
- if (audit_log_pid_context(context, axs->target_pid[i],
- axs->target_auid[i],
- axs->target_uid[i],
- axs->target_sessionid[i],
- &axs->target_lsm[i],
- axs->target_comm[i]))
- call_panic = 1;
- }
-
- if (context->target_pid &&
- audit_log_pid_context(context, context->target_pid,
- context->target_auid, context->target_uid,
- context->target_sessionid,
- &context->target_lsm, context->target_comm))
- call_panic = 1;
+ audit_log_pid_context(context, axs->target_pid[i],
+ axs->target_auid[i],
+ axs->target_uid[i],
+ axs->target_sessionid[i],
+ &axs->target_lsm[i],
+ axs->target_comm[i]);
+ }
+
+ if (context->target_pid)
+ audit_log_pid_context(context, context->target_pid,
+ context->target_auid, context->target_uid,
+ context->target_sessionid,
+ &context->target_lsm,
+ context->target_comm);
if (context->pwd.dentry && context->pwd.mnt) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
--
2.37.3
With the inclusion of the interface LSM process attribute
mechanism AppArmor no longer needs to be treated as an
"exclusive" security module. Remove the flag that indicates
it is exclusive. Remove the stub getpeersec_dgram AppArmor
hook as it has no effect in the single LSM case and
interferes in the multiple LSM case.
Acked-by: Stephen Smalley <[email protected]>
Acked-by: John Johansen <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>
---
security/apparmor/lsm.c | 20 +-------------------
1 file changed, 1 insertion(+), 19 deletions(-)
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index f47134da6723..284f74ba9af7 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1168,22 +1168,6 @@ static int apparmor_socket_getpeersec_stream(struct socket *sock,
return error;
}
-/**
- * apparmor_socket_getpeersec_dgram - get security label of packet
- * @sock: the peer socket
- * @skb: packet data
- * @secid: pointer to where to put the secid of the packet
- *
- * Sets the netlabel socket state on sk from parent
- */
-static int apparmor_socket_getpeersec_dgram(struct socket *sock,
- struct sk_buff *skb, u32 *secid)
-
-{
- /* TODO: requires secid support */
- return -ENOPROTOOPT;
-}
-
/**
* apparmor_sock_graft - Initialize newly created socket
* @sk: child sock
@@ -1290,8 +1274,6 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
#endif
LSM_HOOK_INIT(socket_getpeersec_stream,
apparmor_socket_getpeersec_stream),
- LSM_HOOK_INIT(socket_getpeersec_dgram,
- apparmor_socket_getpeersec_dgram),
LSM_HOOK_INIT(sock_graft, apparmor_sock_graft),
#ifdef CONFIG_NETWORK_SECMARK
LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request),
@@ -1954,7 +1936,7 @@ static int __init apparmor_init(void)
DEFINE_LSM(apparmor) = {
.name = "apparmor",
- .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
+ .flags = LSM_FLAG_LEGACY_MAJOR,
.enabled = &apparmor_enabled,
.blobs = &apparmor_blob_sizes,
.init = apparmor_init,
--
2.37.3
Create a new audit record AUDIT_MAC_TASK_CONTEXTS.
An example of the MAC_TASK_CONTEXTS (1420) record is:
type=MAC_TASK_CONTEXTS[1420]
msg=audit(1600880931.832:113)
subj_apparmor=unconfined
subj_smack=_
When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record
the "subj=" field in other records in the event will be "subj=?".
An AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has
multiple security modules that may make access decisions based
on a subject security context.
Acked-by: Paul Moore <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>
---
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 42 +++++++++++++++++++++++++++++++-------
2 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 7c1dc818b1d5..7a5966b46f38 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -143,6 +143,7 @@
#define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */
#define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */
#define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */
#define AUDIT_FIRST_KERN_ANOM_MSG 1700
#define AUDIT_LAST_KERN_ANOM_MSG 1799
diff --git a/kernel/audit.c b/kernel/audit.c
index ef6b2d38e38d..fb182f7e9d18 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2228,6 +2228,7 @@ static void audit_buffer_aux_end(struct audit_buffer *ab)
int audit_log_task_context(struct audit_buffer *ab)
{
+ int i;
int error;
struct lsmblob blob;
struct lsmcontext context;
@@ -2236,16 +2237,43 @@ int audit_log_task_context(struct audit_buffer *ab)
if (!lsmblob_is_set(&blob))
return 0;
- error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST);
-
- if (error) {
- if (error != -EINVAL)
+ if (!lsm_multiple_contexts()) {
+ error = security_secid_to_secctx(&blob, &context,
+ LSMBLOB_FIRST);
+ if (error) {
+ if (error != -EINVAL)
+ goto error_path;
+ return 0;
+ }
+ audit_log_format(ab, " subj=%s", context.context);
+ security_release_secctx(&context);
+ } else {
+ /* Multiple LSMs provide contexts. Include an aux record. */
+ audit_log_format(ab, " subj=?");
+ error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS);
+ if (error)
goto error_path;
- return 0;
+ for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+ if (blob.secid[i] == 0)
+ continue;
+ error = security_secid_to_secctx(&blob, &context, i);
+ if (error) {
+ audit_log_format(ab, "%ssubj_%s=?",
+ i ? " " : "",
+ lsm_slot_to_name(i));
+ if (error != -EINVAL)
+ audit_panic("error in audit_log_task_context");
+ } else {
+ audit_log_format(ab, "%ssubj_%s=%s",
+ i ? " " : "",
+ lsm_slot_to_name(i),
+ context.context);
+ security_release_secctx(&context);
+ }
+ }
+ audit_buffer_aux_end(ab);
}
- audit_log_format(ab, " subj=%s", context.context);
- security_release_secctx(&context);
return 0;
error_path:
--
2.37.3
Add a new boolean function lsm_multiple_contexts() to
identify when multiple security modules provide security
context strings.
Signed-off-by: Casey Schaufler <[email protected]>
Acked-by: Paul Moore <[email protected]>
Reviewed-by: John Johansen <[email protected]>
---
include/linux/security.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/linux/security.h b/include/linux/security.h
index 170b303e9122..c190b9189287 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -262,6 +262,15 @@ static inline const char *lsm_slot_to_name(int slot)
}
#endif
+static inline bool lsm_multiple_contexts(void)
+{
+#ifdef CONFIG_SECURITY
+ return lsm_slot_to_name(1) != NULL;
+#else
+ return false;
+#endif
+}
+
/**
* lsmblob_value - find the first non-zero value in an lsmblob structure.
* @blob: Pointer to the data
--
2.37.3
Refactor audit_log_task_context(), creating a new
audit_log_subject_context(). This is used in netlabel auditing
to provide multiple subject security contexts as necessary.
Acked-by: Paul Moore <[email protected]>
Signed-off-by: Casey Schaufler <[email protected]>
---
include/linux/audit.h | 7 +++++++
kernel/audit.c | 26 ++++++++++++++++----------
net/netlabel/netlabel_user.c | 7 +------
3 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index edb919722448..87ba6fe7f1a2 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -188,6 +188,8 @@ extern void audit_log_path_denied(int type,
const char *operation);
extern void audit_log_lost(const char *message);
+extern int audit_log_subject_context(struct audit_buffer *ab,
+ struct lsmblob *blob);
extern int audit_log_task_context(struct audit_buffer *ab);
extern void audit_log_task_info(struct audit_buffer *ab);
@@ -248,6 +250,11 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
{ }
static inline void audit_log_path_denied(int type, const char *operation)
{ }
+static inline int audit_log_subject_context(struct audit_buffer *ab,
+ struct lsmblob *blob)
+{
+ return 0;
+}
static inline int audit_log_task_context(struct audit_buffer *ab)
{
return 0;
diff --git a/kernel/audit.c b/kernel/audit.c
index fb182f7e9d18..a611130f83cb 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2226,20 +2226,17 @@ static void audit_buffer_aux_end(struct audit_buffer *ab)
ab->skb = skb_peek(&ab->skb_list);
}
-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_subject_context(struct audit_buffer *ab, struct lsmblob *blob)
{
int i;
int error;
- struct lsmblob blob;
struct lsmcontext context;
- security_current_getsecid_subj(&blob);
- if (!lsmblob_is_set(&blob))
+ if (!lsmblob_is_set(blob))
return 0;
if (!lsm_multiple_contexts()) {
- error = security_secid_to_secctx(&blob, &context,
- LSMBLOB_FIRST);
+ error = security_secid_to_secctx(blob, &context, LSMBLOB_FIRST);
if (error) {
if (error != -EINVAL)
goto error_path;
@@ -2254,15 +2251,15 @@ int audit_log_task_context(struct audit_buffer *ab)
if (error)
goto error_path;
for (i = 0; i < LSMBLOB_ENTRIES; i++) {
- if (blob.secid[i] == 0)
+ if (blob->secid[i] == 0)
continue;
- error = security_secid_to_secctx(&blob, &context, i);
+ error = security_secid_to_secctx(blob, &context, i);
if (error) {
audit_log_format(ab, "%ssubj_%s=?",
i ? " " : "",
lsm_slot_to_name(i));
if (error != -EINVAL)
- audit_panic("error in audit_log_task_context");
+ audit_panic("error in audit_log_subject_context");
} else {
audit_log_format(ab, "%ssubj_%s=%s",
i ? " " : "",
@@ -2277,9 +2274,18 @@ int audit_log_task_context(struct audit_buffer *ab)
return 0;
error_path:
- audit_panic("error in audit_log_task_context");
+ audit_panic("error in audit_log_subject_context");
return error;
}
+EXPORT_SYMBOL(audit_log_subject_context);
+
+int audit_log_task_context(struct audit_buffer *ab)
+{
+ struct lsmblob blob;
+
+ security_current_getsecid_subj(&blob);
+ return audit_log_subject_context(ab, &blob);
+}
EXPORT_SYMBOL(audit_log_task_context);
void audit_log_d_path_exe(struct audit_buffer *ab,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 1941877fd16f..42812bdfc31a 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,7 +84,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
struct netlbl_audit *audit_info)
{
struct audit_buffer *audit_buf;
- struct lsmcontext context;
struct lsmblob blob;
if (audit_enabled == AUDIT_OFF)
@@ -99,11 +98,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
audit_info->sessionid);
lsmblob_init(&blob, audit_info->secid);
- if (audit_info->secid != 0 &&
- security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST) == 0) {
- audit_log_format(audit_buf, " subj=%s", context.context);
- security_release_secctx(&context);
- }
+ audit_log_subject_context(audit_buf, &blob);
return audit_buf;
}
--
2.37.3
Create a system call to report the list of Linux Security Modules
that are active on the system. The list is provided as an array
of LSM ID numbers.
Signed-off-by: Casey Schaufler <[email protected]>
---
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
include/linux/syscalls.h | 1 +
include/uapi/asm-generic/unistd.h | 5 ++-
kernel/sys_ni.c | 1 +
security/lsm_syscalls.c | 50 ++++++++++++++++++++++++++
5 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 56d5c5202fd0..40b35e7069a7 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -373,6 +373,7 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common lsm_self_attr sys_lsm_self_attr
+452 common lsm_module_list sys_lsm_module_list
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7f87ef8be546..e2e2a9e93e8c 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1057,6 +1057,7 @@ asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long l
unsigned long home_node,
unsigned long flags);
asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
+asmlinkage long sys_lsm_module_list(unsigned int *ids, size_t *size, int flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index aa66718e1b48..090617a9a53a 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -889,8 +889,11 @@ __SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
#define __NR_lsm_self_attr 451
__SYSCALL(__NR_lsm_self_attr, sys_lsm_self_attr)
+#define __NR_lsm_module_list 452
+__SYSCALL(__NR_lsm_module_list, sys_lsm_module_list)
+
#undef __NR_syscalls
-#define __NR_syscalls 452
+#define __NR_syscalls 453
/*
* 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 0fdb0341251d..bde9e74a3473 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -264,6 +264,7 @@ COND_SYSCALL(mremap);
/* security/lsm_syscalls.c */
COND_SYSCALL(lsm_self_attr);
+COND_SYSCALL(lsm_module_list);
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index da0fab7065e2..41d9ef945ede 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -154,3 +154,53 @@ SYSCALL_DEFINE3(lsm_self_attr,
kfree(final);
return rc;
}
+
+/**
+ * lsm_module_list - Return a list of the active security modules
+ * @ids: the LSM module ids
+ * @size: size of @ids, updated on return
+ * @flags: reserved for future use, must be zero
+ *
+ * Returns a list of the active LSM ids. On success this function
+ * returns the number of @ids array elements. This value may be zero
+ * if there are no LSMs active. If @size is insufficient to contain
+ * the return data -E2BIG is returned and @size is set to the minimum
+ * required size. In all other cases a negative value indicating the
+ * error is returned.
+ */
+SYSCALL_DEFINE3(lsm_module_list,
+ unsigned int __user *, ids,
+ size_t __user *, size,
+ int, flags)
+{
+ unsigned int *interum;
+ size_t total_size = lsm_id * sizeof(*interum);
+ size_t usize;
+ int rc;
+ int i;
+
+ if (get_user(usize, size))
+ return -EFAULT;
+
+ if (usize < total_size) {
+ if (put_user(total_size, size) != 0)
+ return -EFAULT;
+ return -E2BIG;
+ }
+
+ interum = kzalloc(total_size, GFP_KERNEL);
+ if (interum == NULL)
+ return -ENOMEM;
+
+ for (i = 0; i < lsm_id; i++)
+ interum[i] = lsm_idlist[i]->id;
+
+ if (copy_to_user(ids, interum, total_size) != 0 ||
+ put_user(total_size, size) != 0)
+ rc = -EFAULT;
+ else
+ rc = lsm_id;
+
+ kfree(interum);
+ return rc;
+}
--
2.37.3
Hi Casey,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc7]
[cannot apply to pcmoore-audit/next pcmoore-selinux/next zohar-integrity/next-integrity next-20220927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 46452d3786a82bd732ba73fb308ae5cbe4e1e591
config: m68k-allyesconfig
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/e614eb870ca4cc351e1847e79041960feb9604dc
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
git checkout e614eb870ca4cc351e1847e79041960feb9604dc
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash kernel/sched/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
In file included from include/linux/syscalls_api.h:1,
from kernel/sched/core.c:13:
>> include/linux/syscalls.h:1059:42: warning: 'struct lsm_ctx' declared inside parameter list will not be visible outside of this definition or declaration
1059 | asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
| ^~~~~~~
--
In file included from include/linux/syscalls_api.h:1,
from kernel/sched/sched.h:61,
from kernel/sched/fair.c:54:
>> include/linux/syscalls.h:1059:42: warning: 'struct lsm_ctx' declared inside parameter list will not be visible outside of this definition or declaration
1059 | asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
| ^~~~~~~
kernel/sched/fair.c:672:5: warning: no previous prototype for 'sched_update_scaling' [-Wmissing-prototypes]
672 | int sched_update_scaling(void)
| ^~~~~~~~~~~~~~~~~~~~
vim +1059 include/linux/syscalls.h
903
904 /* mm/, CONFIG_MMU only */
905 asmlinkage long sys_swapon(const char __user *specialfile, int swap_flags);
906 asmlinkage long sys_swapoff(const char __user *specialfile);
907 asmlinkage long sys_mprotect(unsigned long start, size_t len,
908 unsigned long prot);
909 asmlinkage long sys_msync(unsigned long start, size_t len, int flags);
910 asmlinkage long sys_mlock(unsigned long start, size_t len);
911 asmlinkage long sys_munlock(unsigned long start, size_t len);
912 asmlinkage long sys_mlockall(int flags);
913 asmlinkage long sys_munlockall(void);
914 asmlinkage long sys_mincore(unsigned long start, size_t len,
915 unsigned char __user * vec);
916 asmlinkage long sys_madvise(unsigned long start, size_t len, int behavior);
917 asmlinkage long sys_process_madvise(int pidfd, const struct iovec __user *vec,
918 size_t vlen, int behavior, unsigned int flags);
919 asmlinkage long sys_process_mrelease(int pidfd, unsigned int flags);
920 asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
921 unsigned long prot, unsigned long pgoff,
922 unsigned long flags);
923 asmlinkage long sys_mbind(unsigned long start, unsigned long len,
924 unsigned long mode,
925 const unsigned long __user *nmask,
926 unsigned long maxnode,
927 unsigned flags);
928 asmlinkage long sys_get_mempolicy(int __user *policy,
929 unsigned long __user *nmask,
930 unsigned long maxnode,
931 unsigned long addr, unsigned long flags);
932 asmlinkage long sys_set_mempolicy(int mode, const unsigned long __user *nmask,
933 unsigned long maxnode);
934 asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
935 const unsigned long __user *from,
936 const unsigned long __user *to);
937 asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
938 const void __user * __user *pages,
939 const int __user *nodes,
940 int __user *status,
941 int flags);
942
943 asmlinkage long sys_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
944 siginfo_t __user *uinfo);
945 asmlinkage long sys_perf_event_open(
946 struct perf_event_attr __user *attr_uptr,
947 pid_t pid, int cpu, int group_fd, unsigned long flags);
948 asmlinkage long sys_accept4(int, struct sockaddr __user *, int __user *, int);
949 asmlinkage long sys_recvmmsg(int fd, struct mmsghdr __user *msg,
950 unsigned int vlen, unsigned flags,
951 struct __kernel_timespec __user *timeout);
952 asmlinkage long sys_recvmmsg_time32(int fd, struct mmsghdr __user *msg,
953 unsigned int vlen, unsigned flags,
954 struct old_timespec32 __user *timeout);
955
956 asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
957 int options, struct rusage __user *ru);
958 asmlinkage long sys_prlimit64(pid_t pid, unsigned int resource,
959 const struct rlimit64 __user *new_rlim,
960 struct rlimit64 __user *old_rlim);
961 asmlinkage long sys_fanotify_init(unsigned int flags, unsigned int event_f_flags);
962 asmlinkage long sys_fanotify_mark(int fanotify_fd, unsigned int flags,
963 u64 mask, int fd,
964 const char __user *pathname);
965 asmlinkage long sys_name_to_handle_at(int dfd, const char __user *name,
966 struct file_handle __user *handle,
967 int __user *mnt_id, int flag);
968 asmlinkage long sys_open_by_handle_at(int mountdirfd,
969 struct file_handle __user *handle,
970 int flags);
971 asmlinkage long sys_clock_adjtime(clockid_t which_clock,
972 struct __kernel_timex __user *tx);
973 asmlinkage long sys_clock_adjtime32(clockid_t which_clock,
974 struct old_timex32 __user *tx);
975 asmlinkage long sys_syncfs(int fd);
976 asmlinkage long sys_setns(int fd, int nstype);
977 asmlinkage long sys_pidfd_open(pid_t pid, unsigned int flags);
978 asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg,
979 unsigned int vlen, unsigned flags);
980 asmlinkage long sys_process_vm_readv(pid_t pid,
981 const struct iovec __user *lvec,
982 unsigned long liovcnt,
983 const struct iovec __user *rvec,
984 unsigned long riovcnt,
985 unsigned long flags);
986 asmlinkage long sys_process_vm_writev(pid_t pid,
987 const struct iovec __user *lvec,
988 unsigned long liovcnt,
989 const struct iovec __user *rvec,
990 unsigned long riovcnt,
991 unsigned long flags);
992 asmlinkage long sys_kcmp(pid_t pid1, pid_t pid2, int type,
993 unsigned long idx1, unsigned long idx2);
994 asmlinkage long sys_finit_module(int fd, const char __user *uargs, int flags);
995 asmlinkage long sys_sched_setattr(pid_t pid,
996 struct sched_attr __user *attr,
997 unsigned int flags);
998 asmlinkage long sys_sched_getattr(pid_t pid,
999 struct sched_attr __user *attr,
1000 unsigned int size,
1001 unsigned int flags);
1002 asmlinkage long sys_renameat2(int olddfd, const char __user *oldname,
1003 int newdfd, const char __user *newname,
1004 unsigned int flags);
1005 asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
1006 void __user *uargs);
1007 asmlinkage long sys_getrandom(char __user *buf, size_t count,
1008 unsigned int flags);
1009 asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
1010 asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
1011 asmlinkage long sys_execveat(int dfd, const char __user *filename,
1012 const char __user *const __user *argv,
1013 const char __user *const __user *envp, int flags);
1014 asmlinkage long sys_userfaultfd(int flags);
1015 asmlinkage long sys_membarrier(int cmd, unsigned int flags, int cpu_id);
1016 asmlinkage long sys_mlock2(unsigned long start, size_t len, int flags);
1017 asmlinkage long sys_copy_file_range(int fd_in, loff_t __user *off_in,
1018 int fd_out, loff_t __user *off_out,
1019 size_t len, unsigned int flags);
1020 asmlinkage long sys_preadv2(unsigned long fd, const struct iovec __user *vec,
1021 unsigned long vlen, unsigned long pos_l, unsigned long pos_h,
1022 rwf_t flags);
1023 asmlinkage long sys_pwritev2(unsigned long fd, const struct iovec __user *vec,
1024 unsigned long vlen, unsigned long pos_l, unsigned long pos_h,
1025 rwf_t flags);
1026 asmlinkage long sys_pkey_mprotect(unsigned long start, size_t len,
1027 unsigned long prot, int pkey);
1028 asmlinkage long sys_pkey_alloc(unsigned long flags, unsigned long init_val);
1029 asmlinkage long sys_pkey_free(int pkey);
1030 asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
1031 unsigned mask, struct statx __user *buffer);
1032 asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
1033 int flags, uint32_t sig);
1034 asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags);
1035 asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
1036 int to_dfd, const char __user *to_path,
1037 unsigned int ms_flags);
1038 asmlinkage long sys_mount_setattr(int dfd, const char __user *path,
1039 unsigned int flags,
1040 struct mount_attr __user *uattr, size_t usize);
1041 asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
1042 asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key,
1043 const void __user *value, int aux);
1044 asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
1045 asmlinkage long sys_fspick(int dfd, const char __user *path, unsigned int flags);
1046 asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
1047 siginfo_t __user *info,
1048 unsigned int flags);
1049 asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
1050 asmlinkage long sys_landlock_create_ruleset(const struct landlock_ruleset_attr __user *attr,
1051 size_t size, __u32 flags);
1052 asmlinkage long sys_landlock_add_rule(int ruleset_fd, enum landlock_rule_type rule_type,
1053 const void __user *rule_attr, __u32 flags);
1054 asmlinkage long sys_landlock_restrict_self(int ruleset_fd, __u32 flags);
1055 asmlinkage long sys_memfd_secret(unsigned int flags);
1056 asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long len,
1057 unsigned long home_node,
1058 unsigned long flags);
> 1059 asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
1060
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Casey,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc7]
[cannot apply to pcmoore-audit/next pcmoore-selinux/next zohar-integrity/next-integrity next-20220927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 46452d3786a82bd732ba73fb308ae5cbe4e1e591
config: s390-defconfig
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/e614eb870ca4cc351e1847e79041960feb9604dc
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
git checkout e614eb870ca4cc351e1847e79041960feb9604dc
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> security/lsm_syscalls.c:51: warning: expecting prototype for lsm_self_attr(). Prototype was for sys_lsm_self_attr() instead
vim +51 security/lsm_syscalls.c
33
34 /**
35 * lsm_self_attr - Return current task's security module attributes
36 * @ctx: the LSM contexts
37 * @size: size of @ctx, updated on return
38 * @flags: reserved for future use, must be zero
39 *
40 * Returns the calling task's LSM contexts. On success this
41 * function returns the number of @ctx array elements. This value
42 * may be zero if there are no LSM contexts assigned. If @size is
43 * insufficient to contain the return data -E2BIG is returned and
44 * @size is set to the minimum required size. In all other cases
45 * a negative value indicating the error is returned.
46 */
47 SYSCALL_DEFINE3(lsm_self_attr,
48 struct lsm_ctx __user *, ctx,
49 size_t __user *, size,
50 int, flags)
> 51 {
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Casey,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc7]
[cannot apply to pcmoore-audit/next pcmoore-selinux/next zohar-integrity/next-integrity next-20220927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 46452d3786a82bd732ba73fb308ae5cbe4e1e591
config: s390-defconfig
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/6f957bc7939d85848cbe2a2a1c1007e344629ae0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Casey-Schaufler/LSM-Identify-modules-by-more-than-name/20220928-045406
git checkout 6f957bc7939d85848cbe2a2a1c1007e344629ae0
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
security/lsm_syscalls.c:51: warning: expecting prototype for lsm_self_attr(). Prototype was for sys_lsm_self_attr() instead
>> security/lsm_syscalls.c:175: warning: expecting prototype for lsm_module_list(). Prototype was for sys_lsm_module_list() instead
vim +175 security/lsm_syscalls.c
33
34 /**
35 * lsm_self_attr - Return current task's security module attributes
36 * @ctx: the LSM contexts
37 * @size: size of @ctx, updated on return
38 * @flags: reserved for future use, must be zero
39 *
40 * Returns the calling task's LSM contexts. On success this
41 * function returns the number of @ctx array elements. This value
42 * may be zero if there are no LSM contexts assigned. If @size is
43 * insufficient to contain the return data -E2BIG is returned and
44 * @size is set to the minimum required size. In all other cases
45 * a negative value indicating the error is returned.
46 */
47 SYSCALL_DEFINE3(lsm_self_attr,
48 struct lsm_ctx __user *, ctx,
49 size_t __user *, size,
50 int, flags)
> 51 {
52 struct lsm_ctx *final = NULL;
53 struct lsm_ctx *interum;
54 struct lsm_ctx *ip;
55 void *curr;
56 char **interum_ctx;
57 char *cp;
58 size_t total_size = 0;
59 int count = 0;
60 int attr;
61 int len;
62 int rc = 0;
63 int i;
64
65 interum = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
66 sizeof(*interum), GFP_KERNEL);
67 if (interum == NULL)
68 return -ENOMEM;
69 ip = interum;
70
71 interum_ctx = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
72 sizeof(*interum_ctx), GFP_KERNEL);
73 if (interum_ctx == NULL) {
74 kfree(interum);
75 return -ENOMEM;
76 }
77
78 for (attr = 0; attr < ARRAY_SIZE(lsm_attr_names); attr++) {
79 for (i = 0; i < lsm_id; i++) {
80 if ((lsm_idlist[i]->features &
81 lsm_attr_names[attr].feature) == 0)
82 continue;
83
84 len = security_getprocattr(current, lsm_idlist[i]->id,
85 lsm_attr_names[attr].name,
86 &cp);
87 if (len <= 0)
88 continue;
89
90 ip->id = lsm_idlist[i]->id;
91 ip->flags = lsm_attr_names[attr].feature;
92 /* space for terminating \0 is allocated below */
93 ip->ctx_len = len + 1;
94 interum_ctx[count] = cp;
95 /*
96 * Security modules have been inconsistent about
97 * including the \0 terminator in the size. The
98 * context len has been adjusted to ensure there
99 * is one.
100 * At least one security module adds a \n at the
101 * end of a context to make it look nicer. Change
102 * that to a \0 so that user space doesn't have to
103 * work around it. Because of this meddling it is
104 * safe to assume that lsm_ctx.name is terminated
105 * and that strlen(lsm_ctx.name) < lsm.ctx_len.
106 */
107 total_size += sizeof(*interum) + ip->ctx_len;
108 cp = strnchr(cp, len, '\n');
109 if (cp != NULL)
110 *cp = '\0';
111 ip++;
112 count++;
113 }
114 }
115
116 if (count == 0)
117 goto free_out;
118
119 final = kzalloc(total_size, GFP_KERNEL);
120 if (final == NULL) {
121 rc = -ENOMEM;
122 goto free_out;
123 }
124
125 curr = final;
126 ip = interum;
127 for (i = 0; i < count; i++) {
128 memcpy(curr, ip, sizeof(*interum));
129 curr += sizeof(*interum);
130 memcpy(curr, interum_ctx[i], ip->ctx_len);
131 curr += ip->ctx_len;
132 ip++;
133 }
134
135 if (get_user(len, size)) {
136 rc = -EFAULT;
137 goto free_out;
138 }
139 if (total_size > len) {
140 rc = -ERANGE;
141 goto free_out;
142 }
143 if (copy_to_user(ctx, final, total_size) != 0 ||
144 put_user(total_size, size) != 0)
145 rc = -EFAULT;
146 else
147 rc = count;
148
149 free_out:
150 for (i = 0; i < count; i++)
151 kfree(interum_ctx[i]);
152 kfree(interum_ctx);
153 kfree(interum);
154 kfree(final);
155 return rc;
156 }
157
158 /**
159 * lsm_module_list - Return a list of the active security modules
160 * @ids: the LSM module ids
161 * @size: size of @ids, updated on return
162 * @flags: reserved for future use, must be zero
163 *
164 * Returns a list of the active LSM ids. On success this function
165 * returns the number of @ids array elements. This value may be zero
166 * if there are no LSMs active. If @size is insufficient to contain
167 * the return data -E2BIG is returned and @size is set to the minimum
168 * required size. In all other cases a negative value indicating the
169 * error is returned.
170 */
171 SYSCALL_DEFINE3(lsm_module_list,
172 unsigned int __user *, ids,
173 size_t __user *, size,
174 int, flags)
> 175 {
--
0-DAY CI Kernel Test Service
https://01.org/lkp
At least [email protected] should be in Cc for new syscalls.
You need a dedicated patch to wire this syscall with all architectures.
It will help a lot dealing with merge conflicts because of other new
syscalls. You can take a look at the Landlock syscall implementations:
https://git.kernel.org/c/torvalds/a49f4f81cb48925e8d7cbd9e59068f516e984144
About the name, I'd suggest using a verb, something like lsm_get_self_attr.
On 27/09/2022 21:53, Casey Schaufler wrote:
> Create a system call lsm_self_attr() to provide the security
> module maintained attributes of the current process. Historically
> these attributes have been exposed to user space via entries in
> procfs under /proc/self/attr.
I think this paragraph is not enough to justify a new syscall. We should
highlight what is not possible (or difficult) to do with the filesystem:
e.g.
- usable in a sandbox which may not have access to the filesystem (but
is that a good thing here?);
- clearly defined ABI/format;
- …?
What is the goal of this syscall? How will it be used? By who?
>
> Attributes are provided as a collection of lsm_ctx structures
> which are placed into a user supplied buffer. Each structure
> identifys the security module providing the attribute, which
"identifies"
> of the possible attributes is provided, the size of the
> attribute, and finally the attribute value. The format of the
> attribute value is defined by the security module, but will
> always be \0 terminated. The ctx_len value will be larger than
> strlen(ctx).
>
> ------------------------------
> | unsigned int id |
> ------------------------------
> | unsigned int flags |
> ------------------------------
> | __kernel_size_t ctx_len |
> ------------------------------
> | unsigned char ctx[ctx_len] |
> ------------------------------
> | unsigned int id |
> ------------------------------
> | unsigned int flags |
> ------------------------------
> | __kernel_size_t ctx_len |
> ------------------------------
> | unsigned char ctx[ctx_len] |
> ------------------------------
>
> Signed-off-by: Casey Schaufler <[email protected]>
> ---
> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
> include/linux/syscalls.h | 1 +
> include/uapi/asm-generic/unistd.h | 5 +-
> include/uapi/linux/lsm.h | 21 ++++
> kernel/sys_ni.c | 3 +
> security/Makefile | 1 +
> security/lsm_syscalls.c | 156 +++++++++++++++++++++++++
> 7 files changed, 187 insertions(+), 1 deletion(-)
> create mode 100644 security/lsm_syscalls.c
>
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index c84d12608cd2..56d5c5202fd0 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -372,6 +372,7 @@
> 448 common process_mrelease sys_process_mrelease
> 449 common futex_waitv sys_futex_waitv
> 450 common set_mempolicy_home_node sys_set_mempolicy_home_node
> +451 common lsm_self_attr sys_lsm_self_attr
>
> #
> # Due to a historical design error, certain syscalls are numbered differently
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index a34b0f9a9972..7f87ef8be546 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1056,6 +1056,7 @@ asmlinkage long sys_memfd_secret(unsigned int flags);
> asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long len,
> unsigned long home_node,
> unsigned long flags);
> +asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
>
> /*
> * Architecture-specific system calls
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index 45fa180cc56a..aa66718e1b48 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -886,8 +886,11 @@ __SYSCALL(__NR_futex_waitv, sys_futex_waitv)
> #define __NR_set_mempolicy_home_node 450
> __SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
>
> +#define __NR_lsm_self_attr 451
> +__SYSCALL(__NR_lsm_self_attr, sys_lsm_self_attr)
> +
> #undef __NR_syscalls
> -#define __NR_syscalls 451
> +#define __NR_syscalls 452
This need to move to a dedicated "wire syscall" patch.
>
> /*
> * 32 bit systems traditionally used different
> diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
> index 4bb692b84a28..5acd791f82a9 100644
> --- a/include/uapi/linux/lsm.h
> +++ b/include/uapi/linux/lsm.h
> @@ -9,6 +9,27 @@
> #ifndef _UAPI_LINUX_LSM_H
> #define _UAPI_LINUX_LSM_H
>
> +#include <linux/types.h>
> +#include <linux/unistd.h>
> +
> +/**
> + * struct lsm_ctx - LSM context
> + * @id: the LSM id number, see LSM_ID_XXX
> + * @flags: context specifier and LSM specific flags
> + * @ctx_len: the size of @ctx
> + * @ctx: the LSM context, a nul terminated string
> + *
> + * @ctx in a nul terminated string.
"NULL-terminated"?
> + * (strlen(@ctx) < @ctx_len) is always true.
> + * (strlen(@ctx) == @ctx_len + 1) is not guaranteed.
> + */
> +struct lsm_ctx {
> + unsigned int id;
I suggest using __u32 instead of unsigned int.
> + unsigned int flags;
What could be the use case for these flags?
> + __kernel_size_t ctx_len;
> + unsigned char ctx[];
> +};
To avoid holes in this struct, you might want to use
__attribute__((packed)).
> +
> /*
> * ID values to identify security modules.
> * A system may use more than one security module.
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index 860b2dcf3ac4..0fdb0341251d 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -262,6 +262,9 @@ COND_SYSCALL_COMPAT(recvmsg);
> /* mm/nommu.c, also with MMU */
> COND_SYSCALL(mremap);
>
> +/* security/lsm_syscalls.c */
> +COND_SYSCALL(lsm_self_attr);
> +
> /* security/keys/keyctl.c */
> COND_SYSCALL(add_key);
> COND_SYSCALL(request_key);
> diff --git a/security/Makefile b/security/Makefile
> index 18121f8f85cd..59f238490665 100644
> --- a/security/Makefile
> +++ b/security/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_KEYS) += keys/
>
> # always enable default capabilities
> obj-y += commoncap.o
> +obj-$(CONFIG_SECURITY) += lsm_syscalls.o
> obj-$(CONFIG_MMU) += min_addr.o
>
> # Object file lists
> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
> new file mode 100644
> index 000000000000..da0fab7065e2
> --- /dev/null
> +++ b/security/lsm_syscalls.c
> @@ -0,0 +1,156 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * System calls implementing the Linux Security Module API.
> + *
> + * Copyright (C) 2022 Casey Schaufler <[email protected]>
> + * Copyright (C) Intel Corporation
> + */
> +
> +#include <asm/current.h>
> +#include <linux/compiler_types.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/security.h>
> +#include <linux/stddef.h>
> +#include <linux/syscalls.h>
> +#include <linux/types.h>
> +#include <linux/lsm_hooks.h>
> +#include <uapi/linux/lsm.h>
> +
> +struct feature_map {
> + char *name;
> + int feature;
> +};
> +
> +static const struct feature_map lsm_attr_names[] = {
> + { .name = "current", .feature = LSM_ATTR_CURRENT, },
> + { .name = "exec", .feature = LSM_ATTR_EXEC, },
> + { .name = "fscreate", .feature = LSM_ATTR_FSCREATE, },
> + { .name = "keycreate", .feature = LSM_ATTR_KEYCREATE, },
> + { .name = "prev", .feature = LSM_ATTR_PREV, },
> + { .name = "sockcreate", .feature = LSM_ATTR_SOCKCREATE, },
> +};
> +
> +/**
> + * lsm_self_attr - Return current task's security module attributes
> + * @ctx: the LSM contexts
> + * @size: size of @ctx, updated on return
> + * @flags: reserved for future use, must be zero
> + *
> + * Returns the calling task's LSM contexts. On success this
> + * function returns the number of @ctx array elements. This value
> + * may be zero if there are no LSM contexts assigned.
> If @size is
> + * insufficient to contain the return data -E2BIG is returned and
> + * @size is set to the minimum required size.
I'd prefer @size to not be a pointer but a value, and then only be read
to get the context size.
Because lazy userspace only reading the top
If the ctx buffer is not big enough,
> In all other cases
> + * a negative value indicating the error is returned.
lsm_module_list() already returns the enabled LSM IDs. It would be much
simpler to only returns the properties of a specified LSM.
The syscall could then look like this:
lsm_get_self_attr(__u32 lsm_id, char *attr, size_t size, __u32 flags)
> + */
> +SYSCALL_DEFINE3(lsm_self_attr,
> + struct lsm_ctx __user *, ctx,
> + size_t __user *, size,
> + int, flags)
> +{
> + struct lsm_ctx *final = NULL;
> + struct lsm_ctx *interum;
> + struct lsm_ctx *ip;
> + void *curr;
> + char **interum_ctx;
> + char *cp;
> + size_t total_size = 0;
> + int count = 0;
> + int attr;
> + int len;
> + int rc = 0;
> + int i;
> +
> + interum = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
> + sizeof(*interum), GFP_KERNEL);
> + if (interum == NULL)
> + return -ENOMEM;
> + ip = interum;
> +
> + interum_ctx = kzalloc(ARRAY_SIZE(lsm_attr_names) * lsm_id *
> + sizeof(*interum_ctx), GFP_KERNEL);
> + if (interum_ctx == NULL) {
> + kfree(interum);
> + return -ENOMEM;
> + }
> +
> + for (attr = 0; attr < ARRAY_SIZE(lsm_attr_names); attr++) {
> + for (i = 0; i < lsm_id; i++) {
> + if ((lsm_idlist[i]->features &
> + lsm_attr_names[attr].feature) == 0)
> + continue;
> +
> + len = security_getprocattr(current, lsm_idlist[i]->id,
> + lsm_attr_names[attr].name,
> + &cp);
> + if (len <= 0)
> + continue;
> +
> + ip->id = lsm_idlist[i]->id;
> + ip->flags = lsm_attr_names[attr].feature;
> + /* space for terminating \0 is allocated below */
> + ip->ctx_len = len + 1;
> + interum_ctx[count] = cp;
> + /*
> + * Security modules have been inconsistent about
> + * including the \0 terminator in the size. The
> + * context len has been adjusted to ensure there
> + * is one.
> + * At least one security module adds a \n at the
> + * end of a context to make it look nicer. Change
> + * that to a \0 so that user space doesn't have to
> + * work around it. Because of this meddling it is
> + * safe to assume that lsm_ctx.name is terminated
> + * and that strlen(lsm_ctx.name) < lsm.ctx_len.
> + */
> + total_size += sizeof(*interum) + ip->ctx_len;
> + cp = strnchr(cp, len, '\n');
> + if (cp != NULL)
> + *cp = '\0';
> + ip++;
> + count++;
> + }
> + }
> +
> + if (count == 0)
> + goto free_out;
> +
> + final = kzalloc(total_size, GFP_KERNEL);
> + if (final == NULL) {
> + rc = -ENOMEM;
> + goto free_out;
> + }
> +
> + curr = final;
> + ip = interum;
> + for (i = 0; i < count; i++) {
> + memcpy(curr, ip, sizeof(*interum));
> + curr += sizeof(*interum);
> + memcpy(curr, interum_ctx[i], ip->ctx_len);
> + curr += ip->ctx_len;
> + ip++;
> + }
> +
> + if (get_user(len, size)) {
> + rc = -EFAULT;
> + goto free_out;
> + }
> + if (total_size > len) {
> + rc = -ERANGE;
> + goto free_out;
> + }
> + if (copy_to_user(ctx, final, total_size) != 0 ||
> + put_user(total_size, size) != 0)
> + rc = -EFAULT;
> + else
> + rc = count;
> +
> +free_out:
> + for (i = 0; i < count; i++)
> + kfree(interum_ctx[i]);
> + kfree(interum_ctx);
> + kfree(interum);
> + kfree(final);
> + return rc;
> +}
On 27/09/2022 22:31, Casey Schaufler wrote:
> Create a system call to report the list of Linux Security Modules
> that are active on the system. The list is provided as an array
> of LSM ID numbers.
With lsm_self_attr(), this would look like a dir/file structure.
Would it be useful for user space to list all the currently used LSMs
instead of only retrieving information about a known (list of) LSM?
What is the use case for this syscall?
>
> Signed-off-by: Casey Schaufler <[email protected]>
> ---
> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
> include/linux/syscalls.h | 1 +
> include/uapi/asm-generic/unistd.h | 5 ++-
> kernel/sys_ni.c | 1 +
> security/lsm_syscalls.c | 50 ++++++++++++++++++++++++++
> 5 files changed, 57 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index 56d5c5202fd0..40b35e7069a7 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -373,6 +373,7 @@
> 449 common futex_waitv sys_futex_waitv
> 450 common set_mempolicy_home_node sys_set_mempolicy_home_node
> 451 common lsm_self_attr sys_lsm_self_attr
> +452 common lsm_module_list sys_lsm_module_list
As for the other syscall, this should also be in the same dedicated
"wire syscalls" patch.
>
> #
> # Due to a historical design error, certain syscalls are numbered differently
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 7f87ef8be546..e2e2a9e93e8c 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1057,6 +1057,7 @@ asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long l
> unsigned long home_node,
> unsigned long flags);
> asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t *size, int flags);
> +asmlinkage long sys_lsm_module_list(unsigned int *ids, size_t *size, int flags);
>
> /*
> * Architecture-specific system calls
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index aa66718e1b48..090617a9a53a 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -889,8 +889,11 @@ __SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
> #define __NR_lsm_self_attr 451
> __SYSCALL(__NR_lsm_self_attr, sys_lsm_self_attr)
>
> +#define __NR_lsm_module_list 452
> +__SYSCALL(__NR_lsm_module_list, sys_lsm_module_list)
> +
> #undef __NR_syscalls
> -#define __NR_syscalls 452
> +#define __NR_syscalls 453
Same here.
>
> /*
> * 32 bit systems traditionally used different
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index 0fdb0341251d..bde9e74a3473 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -264,6 +264,7 @@ COND_SYSCALL(mremap);
>
> /* security/lsm_syscalls.c */
> COND_SYSCALL(lsm_self_attr);
> +COND_SYSCALL(lsm_module_list);
>
> /* security/keys/keyctl.c */
> COND_SYSCALL(add_key);
> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
> index da0fab7065e2..41d9ef945ede 100644
> --- a/security/lsm_syscalls.c
> +++ b/security/lsm_syscalls.c
> @@ -154,3 +154,53 @@ SYSCALL_DEFINE3(lsm_self_attr,
> kfree(final);
> return rc;
> }
> +
> +/**
> + * lsm_module_list - Return a list of the active security modules
> + * @ids: the LSM module ids
> + * @size: size of @ids, updated on return
> + * @flags: reserved for future use, must be zero
> + *
> + * Returns a list of the active LSM ids. On success this function
> + * returns the number of @ids array elements. This value may be zero
> + * if there are no LSMs active. If @size is insufficient to contain
> + * the return data -E2BIG is returned and @size is set to the minimum
> + * required size. In all other cases a negative value indicating the
> + * error is returned.
> + */
> +SYSCALL_DEFINE3(lsm_module_list,
> + unsigned int __user *, ids,
> + size_t __user *, size,
> + int, flags)
> +{
> + unsigned int *interum;
> + size_t total_size = lsm_id * sizeof(*interum);
> + size_t usize;
> + int rc;
> + int i;
> +
> + if (get_user(usize, size))
> + return -EFAULT;
> +
> + if (usize < total_size) {
> + if (put_user(total_size, size) != 0)
> + return -EFAULT;
> + return -E2BIG;
> + }
> +
> + interum = kzalloc(total_size, GFP_KERNEL);
> + if (interum == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < lsm_id; i++)
> + interum[i] = lsm_idlist[i]->id;
> +
> + if (copy_to_user(ids, interum, total_size) != 0 ||
> + put_user(total_size, size) != 0)
> + rc = -EFAULT;
> + else
> + rc = lsm_id;
> +
> + kfree(interum);
> + return rc;
> +}
On Tue, Sep 27, 2022 at 01:31:55PM -0700, Casey Schaufler wrote:
> +SYSCALL_DEFINE3(lsm_module_list,
> + unsigned int __user *, ids,
> + size_t __user *, size,
> + int, flags)
Please make this unsigned int.
> +{
> + unsigned int *interum;
> + size_t total_size = lsm_id * sizeof(*interum);
> + size_t usize;
> + int rc;
> + int i;
Please test that flags == 0 so it can be used in the future:
if (flags)
return -EINVAL;
> +
> + if (get_user(usize, size))
> + return -EFAULT;
> +
> + if (usize < total_size) {
> + if (put_user(total_size, size) != 0)
> + return -EFAULT;
> + return -E2BIG;
> + }
> +
> + interum = kzalloc(total_size, GFP_KERNEL);
> + if (interum == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < lsm_id; i++)
> + interum[i] = lsm_idlist[i]->id;
> +
> + if (copy_to_user(ids, interum, total_size) != 0 ||
> + put_user(total_size, size) != 0)
> + rc = -EFAULT;
No need to repeat this, if it is written first.
> + else
> + rc = lsm_id;
> +
> + kfree(interum);
> + return rc;
No need for the alloc/free. Here's what I would imagine for the whole
thing:
if (flags)
return -EINVAL;
if (get_user(usize, size))
return -EFAULT;
if (put_user(total_size, size) != 0)
return -EFAULT;
if (usize < total_size)
return -E2BIG;
for (i = 0; i < lsm_id; i++)
if (put_user(lsm_idlist[i]->id, id++))
return -EFAULT;
return lsm_id;
--
Kees Cook
On 10/20/2022 8:44 AM, Paul Moore wrote:
> On Tue, Sep 27, 2022 at 3:57 PM Casey Schaufler <[email protected]> wrote:
>> Create a system call lsm_self_attr() to provide the security
>> module maintained attributes of the current process. Historically
>> these attributes have been exposed to user space via entries in
>> procfs under /proc/self/attr.
> Hi Casey,
>
> I had hoped to get to review these patches earlier this week, I know
> you are very anxious to see something happen here, but unfortunately
> that didn't work out and I'm now in a position of limited network
> access and time for a bit. I will do my best to at least comment on
> the new syscall related additions, but thankfully you've already
> started to get some good comments from others so I'm hopeful that will
> help you keep moving forward.
Thanks. I just got back to work myself. Hopefully the comments will prove
useful. I'm just getting to them.
> One comment I did want to make, and it's important: please separate
> the LSM syscall patches from the LSM stacking patches. While the
> stacking patches will obviously be dependent on the syscall patches,
> the syscall patches should not be dependent on stacking. However, the
> LSM syscall patches must be designed from the start to support
> multiple, simultaneous LSMs.
OK. I will refactor into two patch sets. The first will be the syscalls
for getting the LSM attributes and the second will be the stacking changes.
The prctl() I proposed to set the "display" LSM will be in the second, as
it makes no sense to have without anything to change. I have not to date
included the SO_PEERCONTEXT that would be required for complete stacking.
Would you like to see that included in the syscall patches?
> Thanks.
Thank you.
On Tue, Sep 27, 2022 at 3:57 PM Casey Schaufler <[email protected]> wrote:
>
> Create a system call lsm_self_attr() to provide the security
> module maintained attributes of the current process. Historically
> these attributes have been exposed to user space via entries in
> procfs under /proc/self/attr.
Hi Casey,
I had hoped to get to review these patches earlier this week, I know
you are very anxious to see something happen here, but unfortunately
that didn't work out and I'm now in a position of limited network
access and time for a bit. I will do my best to at least comment on
the new syscall related additions, but thankfully you've already
started to get some good comments from others so I'm hopeful that will
help you keep moving forward.
One comment I did want to make, and it's important: please separate
the LSM syscall patches from the LSM stacking patches. While the
stacking patches will obviously be dependent on the syscall patches,
the syscall patches should not be dependent on stacking. However, the
LSM syscall patches must be designed from the start to support
multiple, simultaneous LSMs.
Thanks.
--
paul-moore.com
On 10/12/2022 2:19 PM, Mickaël Salaün wrote:
>
> On 27/09/2022 22:31, Casey Schaufler wrote:
>> Create a system call to report the list of Linux Security Modules
>> that are active on the system. The list is provided as an array
>> of LSM ID numbers.
>
> With lsm_self_attr(), this would look like a dir/file structure.
I'm not sure I understand what you mean by this. I think you're suggesting
that lsm_module_list() shows the list of possibilities and lsm_self_attr()
shows the data. That's roughly correct. Note that many security modules
will never provide any data in lsm_self_attr(), and that others will
only provide it when it has been explicitly set.
>
> Would it be useful for user space to list all the currently used LSMs
> instead of only retrieving information about a known (list of) LSM?
I believe so. User space tends to lag behind kernel features. ps(1) can report
the "current" value for any LSM without knowing which module supplied the value
today by using the /proc/self/attr/current interface. id(1) could do the same
were it not unnecessarily coded to be SELinux specific. lsm_module_list(2), like
the existing /sys/kernel/security/lsm interface, allows an application to know
if it should address the modules it knows about. It also provides the LSM order,
which could be significant to systemd, dbus, auditd or other sophisticated system
services.
> What is the use case for this syscall?
1. Identify if a specific LSM is in the list.
Used by ps(1) to format the -Z output correctly
Used by systemd(1) to determine which service start options to support
Used by dbus to identify what policy to enforce at runtime
2. Identify the order of LSMs in the list.
Will AppArmor data show up in /proc/self/attr/current, or will Smack data?
>
>
>>
>> Signed-off-by: Casey Schaufler <[email protected]>
>> ---
>> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
>> include/linux/syscalls.h | 1 +
>> include/uapi/asm-generic/unistd.h | 5 ++-
>> kernel/sys_ni.c | 1 +
>> security/lsm_syscalls.c | 50 ++++++++++++++++++++++++++
>> 5 files changed, 57 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl
>> b/arch/x86/entry/syscalls/syscall_64.tbl
>> index 56d5c5202fd0..40b35e7069a7 100644
>> --- a/arch/x86/entry/syscalls/syscall_64.tbl
>> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
>> @@ -373,6 +373,7 @@
>> 449 common futex_waitv sys_futex_waitv
>> 450 common set_mempolicy_home_node
>> sys_set_mempolicy_home_node
>> 451 common lsm_self_attr sys_lsm_self_attr
>> +452 common lsm_module_list sys_lsm_module_list
>
> As for the other syscall, this should also be in the same dedicated
> "wire syscalls" patch.
>
>
>> #
>> # Due to a historical design error, certain syscalls are numbered
>> differently
>> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
>> index 7f87ef8be546..e2e2a9e93e8c 100644
>> --- a/include/linux/syscalls.h
>> +++ b/include/linux/syscalls.h
>> @@ -1057,6 +1057,7 @@ asmlinkage long
>> sys_set_mempolicy_home_node(unsigned long start, unsigned long l
>> unsigned long home_node,
>> unsigned long flags);
>> asmlinkage long sys_lsm_self_attr(struct lsm_ctx *ctx, size_t
>> *size, int flags);
>> +asmlinkage long sys_lsm_module_list(unsigned int *ids, size_t *size,
>> int flags);
>> /*
>> * Architecture-specific system calls
>> diff --git a/include/uapi/asm-generic/unistd.h
>> b/include/uapi/asm-generic/unistd.h
>> index aa66718e1b48..090617a9a53a 100644
>> --- a/include/uapi/asm-generic/unistd.h
>> +++ b/include/uapi/asm-generic/unistd.h
>> @@ -889,8 +889,11 @@ __SYSCALL(__NR_set_mempolicy_home_node,
>> sys_set_mempolicy_home_node)
>> #define __NR_lsm_self_attr 451
>> __SYSCALL(__NR_lsm_self_attr, sys_lsm_self_attr)
>> +#define __NR_lsm_module_list 452
>> +__SYSCALL(__NR_lsm_module_list, sys_lsm_module_list)
>> +
>> #undef __NR_syscalls
>> -#define __NR_syscalls 452
>> +#define __NR_syscalls 453
>
> Same here.
>
>
>> /*
>> * 32 bit systems traditionally used different
>> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
>> index 0fdb0341251d..bde9e74a3473 100644
>> --- a/kernel/sys_ni.c
>> +++ b/kernel/sys_ni.c
>> @@ -264,6 +264,7 @@ COND_SYSCALL(mremap);
>> /* security/lsm_syscalls.c */
>> COND_SYSCALL(lsm_self_attr);
>> +COND_SYSCALL(lsm_module_list);
>> /* security/keys/keyctl.c */
>> COND_SYSCALL(add_key);
>> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
>> index da0fab7065e2..41d9ef945ede 100644
>> --- a/security/lsm_syscalls.c
>> +++ b/security/lsm_syscalls.c
>> @@ -154,3 +154,53 @@ SYSCALL_DEFINE3(lsm_self_attr,
>> kfree(final);
>> return rc;
>> }
>> +
>> +/**
>> + * lsm_module_list - Return a list of the active security modules
>> + * @ids: the LSM module ids
>> + * @size: size of @ids, updated on return
>> + * @flags: reserved for future use, must be zero
>> + *
>> + * Returns a list of the active LSM ids. On success this function
>> + * returns the number of @ids array elements. This value may be zero
>> + * if there are no LSMs active. If @size is insufficient to contain
>> + * the return data -E2BIG is returned and @size is set to the minimum
>> + * required size. In all other cases a negative value indicating the
>> + * error is returned.
>> + */
>> +SYSCALL_DEFINE3(lsm_module_list,
>> + unsigned int __user *, ids,
>> + size_t __user *, size,
>> + int, flags)
>> +{
>> + unsigned int *interum;
>> + size_t total_size = lsm_id * sizeof(*interum);
>> + size_t usize;
>> + int rc;
>> + int i;
>> +
>> + if (get_user(usize, size))
>> + return -EFAULT;
>> +
>> + if (usize < total_size) {
>> + if (put_user(total_size, size) != 0)
>> + return -EFAULT;
>> + return -E2BIG;
>> + }
>> +
>> + interum = kzalloc(total_size, GFP_KERNEL);
>> + if (interum == NULL)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < lsm_id; i++)
>> + interum[i] = lsm_idlist[i]->id;
>> +
>> + if (copy_to_user(ids, interum, total_size) != 0 ||
>> + put_user(total_size, size) != 0)
>> + rc = -EFAULT;
>> + else
>> + rc = lsm_id;
>> +
>> + kfree(interum);
>> + return rc;
>> +}
On 10/12/2022 3:04 PM, Kees Cook wrote:
> On Tue, Sep 27, 2022 at 01:31:55PM -0700, Casey Schaufler wrote:
>> +SYSCALL_DEFINE3(lsm_module_list,
>> + unsigned int __user *, ids,
>> + size_t __user *, size,
>> + int, flags)
> Please make this unsigned int.
Sure.
>> +{
>> + unsigned int *interum;
>> + size_t total_size = lsm_id * sizeof(*interum);
>> + size_t usize;
>> + int rc;
>> + int i;
> Please test that flags == 0 so it can be used in the future:
>
> if (flags)
> return -EINVAL;
Yup.
>> +
>> + if (get_user(usize, size))
>> + return -EFAULT;
>> +
>> + if (usize < total_size) {
>> + if (put_user(total_size, size) != 0)
>> + return -EFAULT;
>> + return -E2BIG;
>> + }
>> +
>> + interum = kzalloc(total_size, GFP_KERNEL);
>> + if (interum == NULL)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < lsm_id; i++)
>> + interum[i] = lsm_idlist[i]->id;
>> +
>> + if (copy_to_user(ids, interum, total_size) != 0 ||
>> + put_user(total_size, size) != 0)
>> + rc = -EFAULT;
> No need to repeat this, if it is written first.
>
>> + else
>> + rc = lsm_id;
>> +
>> + kfree(interum);
>> + return rc;
> No need for the alloc/free. Here's what I would imagine for the whole
> thing:
A better approach. Thank you.
>
> if (flags)
> return -EINVAL;
>
> if (get_user(usize, size))
> return -EFAULT;
>
> if (put_user(total_size, size) != 0)
> return -EFAULT;
>
> if (usize < total_size)
> return -E2BIG;
>
> for (i = 0; i < lsm_id; i++)
> if (put_user(lsm_idlist[i]->id, id++))
> return -EFAULT;
>
> return lsm_id;
>