[PATCH v38 00/39] LSM: Module stacking for AppArmor
by Casey Schaufler
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
1 year, 8 months
- 7
- 67
LSM stacking in next for 6.1?
by Casey Schaufler
I would like very much to get v38 or v39 of the LSM stacking for Apparmor
patch set in the LSM next branch for 6.1. The audit changes have polished
up nicely and I believe that all comments on the integrity code have been
addressed. The interface_lsm mechanism has been beaten to a frothy peak.
There are serious binder changes, but I think they address issues beyond
the needs of stacking. Changes outside these areas are pretty well limited
to LSM interface improvements.
2 years
- 7
- 73
[PATCH 0/3] improve audit syscall-exit latency
by Ankur Arora
This series attempts to reduce syscall-exit latency in the audit path,
especially for cases where there are a lot of audit exit rules.
>From profiling, audit_filter_syscall() takes the largest chunk of time,
specifically in this list-walk while processing the AUDIT_FILTER_EXIT
list:
list = &audit_filter_list[AUDIT_FILTER_EXIT];
list_for_each_entry_rcu(e, list, list) {
if (audit_in_mask(&e->rule, ctx->major) &&
audit_filter_rules(tsk, &e->rule, ctx, NULL,
&state, false, x)) {
rcu_read_unlock();
ctx->current_state = state;
return state;
}
}
(Note that almost identical logic exists in audit_filter_uring(),
audit_filter_inode_name().)
Comparing baseline performance with audit=0/audit=1 with a user-space
getpid() loop (executes 10^7 times.) For audit=1, this uses an
audit-rule set where the audit_filter_syscall() loop iterates over
42 AUDIT_FILTER_EXIT rules which, for getpid(), calls audit_filter_rules()
for 5 of them (we use this set of rules in production.)
Test system:
Server: ORACLE SERVER X8-2L
CPU: Intel Skylakex (6:85:6)
Microcode: 0x400320a
# v6.0.0-rc5.baseline, audit=0
Performance counter stats for 'bin/getpid' (3 runs):
734.10 msec task-clock # 0.999 CPUs utilized ( +- 0.03% )
1 context-switches # 1.361 /sec ( +- 66.67% )
0 cpu-migrations # 0.000 /sec
53 page-faults # 72.152 /sec ( +- 0.63% )
2,838,869,156 cycles # 3.865 GHz ( +- 0.01% ) (62.40%)
4,174,224,305 instructions # 1.47 insn per cycle ( +- 0.01% ) (74.93%)
890,798,133 branches # 1.213 G/sec ( +- 0.01% ) (74.93%)
5,015,118 branch-misses # 0.56% of all branches ( +- 0.05% ) (74.93%)
1,231,150,558 L1-dcache-loads # 1.676 G/sec ( +- 0.01% ) (74.94%)
418,297 L1-dcache-load-misses # 0.03% of all L1-dcache accesses ( +- 0.68% ) (75.07%)
3,937 LLC-loads # 5.360 K/sec ( +- 3.76% ) (50.13%)
510 LLC-load-misses # 13.39% of all LL-cache accesses ( +- 79.89% ) (50.00%)
0.735018 +- 0.000275 seconds time elapsed ( +- 0.04% )
# v6.0.0-rc5.baseline, audit=1
Performance counter stats for 'bin/getpid' (3 runs):
2,158.81 msec task-clock # 0.998 CPUs utilized ( +- 0.13% )
2 context-switches # 0.925 /sec ( +- 28.87% )
0 cpu-migrations # 0.000 /sec
52 page-faults # 24.056 /sec ( +- 0.64% )
8,364,119,898 cycles # 3.869 GHz ( +- 0.11% ) (62.48%)
19,996,521,678 instructions # 2.39 insn per cycle ( +- 0.01% ) (74.98%)
4,302,068,252 branches # 1.990 G/sec ( +- 0.00% ) (74.98%)
15,135,694 branch-misses # 0.35% of all branches ( +- 0.16% ) (74.99%)
4,714,694,841 L1-dcache-loads # 2.181 G/sec ( +- 0.01% ) (74.99%)
66,407,857 L1-dcache-load-misses # 1.41% of all L1-dcache accesses ( +- 1.50% ) (75.01%)
6,785 LLC-loads # 3.139 K/sec ( +- 12.49% ) (50.03%)
3,235 LLC-load-misses # 41.29% of all LL-cache accesses ( +- 6.08% ) (50.01%)
2.16213 +- 0.00288 seconds time elapsed ( +- 0.13% )
perf stat numbers for each getpid() iteration:
baseline baseline
audit=0 audit=1
cycles 283 836
instructions 417 1999
IPC 1.47 2.39
branches 89 430
branch-misses 0.50 1.51
L1-loads 123 471
L1-load-misses ~0 ~6.6*
* the L1-load-misses are largely stable for runs across a single
boot, but vary across boots due to vagaries of the SLAB allocator.
baseline audit=1 spends a significant amount of time executing in audit
code and incurs a new branch-miss and a few new L1-load-misses. Also
note that computed audit-only IPC is 2.86 so the baseline is not
ill-performant code.
Patches
==
Patch 1 "audit: cache ctx->major in audit_filter_syscall()", caches
ctx->major in a local variable. This gets rid of a persistent entry
from L1-dcache (audit_context::major) that had similar alignment
constraints as a potentially busy cache-set (audit_entry::list) and
allows some of the error checking in audit_in_mask() to be hoisted out
of the loop.
Patch 2: "audit: annotate branch direction for audit_in_mask()", so
the compiler can pessimize the call to audit_filter_rules().
Patch 3, "audit: unify audit_filter_{uring(),inode_name(),syscall()}"
centralizes this logic in a common function.
with these changes:
Performance counter stats for 'bin/getpid' (3 runs):
1,750.21 msec task-clock # 0.994 CPUs utilized ( +- 0.45% )
3 context-switches # 1.705 /sec ( +- 11.11% )
0 cpu-migrations # 0.000 /sec
52 page-faults # 29.548 /sec ( +- 0.64% )
6,770,976,590 cycles # 3.848 GHz ( +- 0.40% ) (27.74%)
16,588,372,024 instructions # 2.44 insn per cycle ( +- 0.03% ) (33.34%)
4,322,555,829 branches # 2.456 G/sec ( +- 0.02% ) (33.40%)
2,803,286 branch-misses # 0.06% of all branches ( +- 26.45% ) (33.46%)
4,449,426,336 L1-dcache-loads # 2.528 G/sec ( +- 0.01% ) (27.71%)
63,612,108 L1-dcache-load-misses # 1.43% of all L1-dcache accesses ( +- 0.50% ) (27.71%)
6,123 LLC-loads # 3.479 K/sec ( +- 8.68% ) (27.71%)
1,890 LLC-load-misses # 26.69% of all LL-cache accesses ( +- 46.99% ) (27.71%)
1.76033 +- 0.00791 seconds time elapsed ( +- 0.45% )
And, overall getpid() latency numbers (aggregated over 12 boots for each):
Min Mean Median Max pstdev
(ns) (ns) (ns) (ns)
baseline 201.30 216.14 216.22 228.46 (+- 1.45%)
patch1 196.63 207.86 206.60 230.98 (+- 3.92%)
patch1-2 173.11 182.51 179.65 202.09 (+- 4.34%)
patch1-3 162.11 175.26 173.71 190.56 (+- 4.33%)
This gives a reasonable speedup. My testing was on Intel Skylake, but I
suspect this should translate to other archs as well (especially on less
wide architectures.)
Please review.
Thanks
Ankur
Ankur Arora (3):
audit: cache ctx->major in audit_filter_syscall()
audit: annotate branch direction for audit_in_mask()
audit: unify audit_filter_{uring(),inode_name(),syscall()}
kernel/auditsc.c | 86 +++++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 41 deletions(-)
--
2.31.1
2 years
- 3
- 19
[PATCH RFC] LSM: lsm_self_attr system call to get security module attributes
by Casey Schaufler
This is probably a tin-man proposal for the first in a series of
system calls dealing with Linux security module data. It is based
on suggestions by Paul Moore, however the flaws in design and
implementation are all mine.
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
identifies the security module providing the attribute, which
of the possible attributes is provided, the size of the
attribute, and finally the attribute value as a nul terminated
string.
An LSM ID table is introduced to map IDs to security modules.
Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com>
--
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 | 67 +++++++++++++
kernel/sys_ni.c | 3 +
security/Makefile | 2 +-
security/lsm_syscalls.c | 166 +++++++++++++++++++++++++++++++++
7 files changed, 243 insertions(+), 2 deletions(-)
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
new file mode 100644
index 000000000000..ec7bb1a7b943
--- /dev/null
+++ b/include/uapi/linux/lsm.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Linus Security Modules (LSM) - User space API
+ *
+ * Copyright (C) 2022 Casey Schaufler <casey(a)schaufler-ca.com>
+ * Copyright (C) Intel Corporation
+ */
+
+#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.
+ *
+ * LSM_ID_XXX values 32 and below are reserved for future use
+ */
+#define LSM_ID_SELINUX 33
+#define LSM_ID_SMACK 34
+#define LSM_ID_TOMOYO 35
+#define LSM_ID_IMA 36
+#define LSM_ID_APPARMOR 37
+#define LSM_ID_YAMA 38
+#define LSM_ID_LOADPIN 39
+#define LSM_ID_SAFESETID 40
+#define LSM_ID_LOCKDOWN 41
+#define LSM_ID_BPF 42
+#define LSM_ID_LANDLOCK 43
+
+/*
+ * Flag values.
+ *
+ * LSM_ATTR_XXX values identify the /proc/.../attr entry that the
+ * context represents. Not all security modules provide all of these
+ * values. Some security modules provide none of them.
+ */
+/* clang-format off */
+#define LSM_ATTR_CURRENT (1UL << 0)
+#define LSM_ATTR_EXEC (1UL << 1)
+#define LSM_ATTR_FSCREATE (1UL << 2)
+#define LSM_ATTR_KEYCREATE (1UL << 3)
+#define LSM_ATTR_PREV (1UL << 4)
+#define LSM_ATTR_SOCKCREATE (1UL << 5)
+/* clang-format on */
+
+#endif /* _UAPI_LINUX_LSM_H */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index a492f159624f..c579ffc50454 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_attr_self);
+
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
COND_SYSCALL(request_key);
diff --git a/security/Makefile b/security/Makefile
index 18121f8f85cd..409c47a25fcf 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -6,7 +6,7 @@
obj-$(CONFIG_KEYS) += keys/
# always enable default capabilities
-obj-y += commoncap.o
+obj-y += commoncap.o lsm_syscalls.o
obj-$(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..fba8aeea1a10
--- /dev/null
+++ b/security/lsm_syscalls.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * System calls implementing the Linux Security Module API.
+ *
+ * Copyright (C) 2022 Casey Schaufler <casey(a)schaufler-ca.com>
+ * 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 <uapi/linux/lsm.h>
+
+struct id_map {
+ char *name;
+ int id;
+};
+
+static const struct id_map lsm_attr_names[] = {
+ { "current", LSM_ATTR_CURRENT, },
+ { "exec", LSM_ATTR_EXEC, },
+ { "fscreate", LSM_ATTR_FSCREATE, },
+ { "keycreate", LSM_ATTR_KEYCREATE, },
+ { "prev", LSM_ATTR_PREV, },
+ { "sockcreate", LSM_ATTR_SOCKCREATE, },
+};
+
+static const struct id_map lsm_names[] = {
+ { "selinux", LSM_ID_SELINUX, },
+ { "smack", LSM_ID_SMACK, },
+ { "tomoyo", LSM_ID_TOMOYO, },
+ { "ima", LSM_ID_IMA, },
+ { "apparmor", LSM_ID_APPARMOR, },
+ { "yama", LSM_ID_YAMA, },
+ { "loadpin", LSM_ID_LOADPIN, },
+ { "safesetid", LSM_ID_SAFESETID, },
+ { "lockdown", LSM_ID_LOCKDOWN, },
+ { "bpf", LSM_ID_BPF, },
+ { "landlock", LSM_ID_LANDLOCK, },
+};
+
+/**
+ * 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 lsm;
+ int len;
+ int rc = 0;
+ int i;
+
+ interum = kzalloc(ARRAY_SIZE(lsm_attr_names) * ARRAY_SIZE(lsm_names) *
+ sizeof(*interum), GFP_KERNEL);
+ if (interum == NULL)
+ return -ENOMEM;
+ ip = interum;
+
+ interum_ctx = kzalloc(ARRAY_SIZE(lsm_attr_names) *
+ ARRAY_SIZE(lsm_names) * sizeof(*interum_ctx),
+ GFP_KERNEL);
+ if (interum_ctx == NULL) {
+ kfree(interum);
+ return -ENOMEM;
+ }
+
+ for (attr = 0; attr < ARRAY_SIZE(lsm_attr_names); attr++) {
+ for (lsm = 0; lsm < ARRAY_SIZE(lsm_names); lsm++) {
+ len = security_getprocattr(current,
+ lsm_names[lsm].name,
+ lsm_attr_names[attr].name,
+ &cp);
+ if (len <= 0)
+ continue;
+
+ ip->id = lsm_names[lsm].id;
+ ip->flags = lsm_attr_names[attr].id;
+ ip->ctx_len = len;
+ interum_ctx[count] = cp;
+ /*
+ * Security modules have been inconsistent about
+ * including the \0 terminator in the size. Add
+ * space for it from an abundance of caution.
+ * 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 does'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) + len + 1;
+ 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 += interum[i].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 years, 1 month
- 2
- 2
Query regarding the lib audit-userspace
by Manojkiran Eda
Hi team,
I was working on leveraging the libaudit shared library to generate audit events from a user space daemon. I have been using the audit_open as well as audit_log_acct_message() API’s to send message to the kernel audit subsystem. From the man pages I understand that every message to the kernel audit subsystem would get an ACK back. Now my question is does the daemon[single threaded] consuming this libaudit for sending events using audit_log_acct_message() API be blocked until it gets an ACK back from the kernel ?
If yes , is there a way to not have the application blocked during this period ?
Thanks,
Manoj
2 years, 1 month
- 3
- 3
[PATCH RFC] LSM: Specify which LSM to display
by Casey Schaufler
Create two new prctl() options PR_LSM_ATTR_SET and PR_LSM_ATTR_GET
which change and report the Interface LSM respectively.
The LSM ID number of an active LSM that supplies hooks for
human readable data may be passed in the arg2 value with the
PR_LSM_ATTR_SET option. The PR_LSM_ATT_GET option returns the
LSM ID currently in use. At this point there can only be one LSM
capable of display active. A helper function lsm_task_ilsm() is
provided to get the interface lsm slot for a task_struct.
Security modules that wish to restrict this action may provide
a task_prctl hook to do so. Each such security module is
responsible for defining its policy.
AppArmor hook initially provided by John Johansen
<john.johansen(a)canonical.com>. SELinux hook initially provided by
Stephen Smalley <stephen.smalley.work(a)gmail.com>
Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com>
---
include/linux/security.h | 17 ++++
include/uapi/linux/prctl.h | 4 +
security/apparmor/include/apparmor.h | 3 +-
security/apparmor/lsm.c | 42 +++++++++
security/security.c | 126 +++++++++++++++++++++++----
security/selinux/hooks.c | 21 +++++
security/selinux/include/classmap.h | 3 +-
7 files changed, 197 insertions(+), 19 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 5140dfec76d5..28f8895203be 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -240,6 +240,23 @@ static inline u32 lsmblob_first(const struct lsmblob *blob)
#endif
}
+/**
+ * lsm_task_ilsm - the "interface_lsm" for this task
+ * @task: The task to report on
+ *
+ * Returns the task's interface LSM slot.
+ */
+static inline int lsm_task_ilsm(struct task_struct *task)
+{
+#ifdef CONFIG_SECURITY
+ int *ilsm = task->security;
+
+ if (ilsm)
+ return *ilsm;
+#endif
+ return LSMBLOB_INVALID;
+}
+
/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
int cap, unsigned int opts);
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index a5e06dcbba13..531c6e8d2d18 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -281,6 +281,10 @@ struct prctl_mm_map {
# define PR_SME_VL_LEN_MASK 0xffff
# define PR_SME_VL_INHERIT (1 << 17) /* inherit across exec */
+/* Set/get the active security module for /proc/self/attr */
+#define PR_LSM_ATTR_SET 65 /* Set the display LSM ID */
+#define PR_LSM_ATTR_GET 66 /* Get the display LSM ID */
+
#define PR_SET_VMA 0x53564d41
# define PR_SET_VMA_ANON_NAME 0
diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
index 9c3fc36a0702..c9e08102c96f 100644
--- a/security/apparmor/include/apparmor.h
+++ b/security/apparmor/include/apparmor.h
@@ -28,8 +28,9 @@
#define AA_CLASS_SIGNAL 10
#define AA_CLASS_NET 14
#define AA_CLASS_LABEL 16
+#define AA_CLASS_DISPLAY_LSM 17
-#define AA_CLASS_LAST AA_CLASS_LABEL
+#define AA_CLASS_LAST AA_CLASS_DISPLAY_LSM
/* Control parameters settable through module/boot flags */
extern enum audit_mode aa_g_audit;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index eccba6667458..183004c864ac 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -15,6 +15,7 @@
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/ptrace.h>
+#include <linux/prctl.h>
#include <linux/ctype.h>
#include <linux/sysctl.h>
#include <linux/audit.h>
@@ -642,6 +643,46 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
return error;
}
+
+static int profile_interface_lsm(struct aa_profile *profile,
+ struct common_audit_data *sa)
+{
+ struct aa_perms perms = { };
+ unsigned int state;
+
+ state = PROFILE_MEDIATES(profile, AA_CLASS_DISPLAY_LSM);
+ if (state) {
+ aa_compute_perms(profile->policy.dfa, state, &perms);
+ aa_apply_modes_to_perms(profile, &perms);
+ aad(sa)->label = &profile->label;
+
+ return aa_check_perms(profile, &perms, AA_MAY_WRITE, sa, NULL);
+ }
+
+ return 0;
+}
+
+static int apparmor_task_prctl(int option, unsigned long arg2,
+ unsigned long arg3, unsigned long arg4,
+ unsigned long arg5)
+{
+ struct aa_profile *profile;
+ struct aa_label *label;
+ int error;
+ DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETPROCATTR);
+
+ if (option != PR_LSM_ATTR_SET)
+ return 0;
+
+ /* LSM infrastructure does actual setting of interface_lsm if allowed */
+ aad(&sa)->info = "set interface lsm";
+ label = begin_current_label_crit_section();
+ error = fn_for_each_confined(label, profile,
+ profile_interface_lsm(profile, &sa));
+ end_current_label_crit_section(label);
+ return error;
+}
+
static int apparmor_setprocattr(const char *name, void *value,
size_t size)
{
@@ -1195,6 +1236,7 @@ static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
+ LSM_HOOK_INIT(task_prctl, apparmor_task_prctl),
LSM_HOOK_INIT(capget, apparmor_capget),
LSM_HOOK_INIT(capable, apparmor_capable),
diff --git a/security/security.c b/security/security.c
index ca3b1216e5f6..b29145de891f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -28,6 +28,7 @@
#include <linux/backing-dev.h>
#include <linux/string.h>
#include <linux/msg.h>
+#include <linux/prctl.h>
#include <net/flow.h>
#include <net/sock.h>
@@ -80,7 +81,16 @@ static struct kmem_cache *lsm_file_cache;
static struct kmem_cache *lsm_inode_cache;
char *lsm_names;
-static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
+
+/*
+ * The task blob includes the "interface_lsm" slot used for
+ * chosing which module presents contexts.
+ * Using a long to avoid potential alignment issues with
+ * module assigned task blobs.
+ */
+static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
+ .lbs_task = sizeof(long),
+};
/* Boot-time LSM user choice */
static __initdata const char *chosen_lsm_order;
@@ -673,6 +683,8 @@ int lsm_inode_alloc(struct inode *inode)
*/
static int lsm_task_alloc(struct task_struct *task)
{
+ int *ilsm;
+
if (blob_sizes.lbs_task == 0) {
task->security = NULL;
return 0;
@@ -681,6 +693,15 @@ static int lsm_task_alloc(struct task_struct *task)
task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
if (task->security == NULL)
return -ENOMEM;
+
+ /*
+ * The start of the task blob contains the "interface" LSM slot number.
+ * Start with it set to the invalid slot number, indicating that the
+ * default first registered LSM be displayed.
+ */
+ ilsm = task->security;
+ *ilsm = LSMBLOB_INVALID;
+
return 0;
}
@@ -1747,14 +1768,26 @@ int security_file_open(struct file *file)
int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
{
+ int *oilsm = current->security;
+ int *nilsm;
int rc = lsm_task_alloc(task);
- if (rc)
+ if (unlikely(rc))
return rc;
+
rc = call_int_hook(task_alloc, 0, task, clone_flags);
- if (unlikely(rc))
+ if (unlikely(rc)) {
security_task_free(task);
- return rc;
+ return rc;
+ }
+
+ if (oilsm) {
+ nilsm = task->security;
+ if (nilsm)
+ *nilsm = *oilsm;
+ }
+
+ return 0;
}
void security_task_free(struct task_struct *task)
@@ -2013,10 +2046,15 @@ int security_task_kill(struct task_struct *p, struct kernel_siginfo *info,
int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
+ int *ilsm = current->security;
int thisrc;
+ int slot;
int rc = LSM_RET_DEFAULT(task_prctl);
struct security_hook_list *hp;
+ if (lsm_slot == 0)
+ return -EINVAL;
+
hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) {
thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5);
if (thisrc != LSM_RET_DEFAULT(task_prctl)) {
@@ -2025,6 +2063,25 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
break;
}
}
+
+ switch (option) {
+ case PR_LSM_ATTR_SET:
+ if (rc && rc != LSM_RET_DEFAULT(task_prctl))
+ return rc;
+ for (slot = 0; slot < lsm_slot; slot++)
+ if (lsm_slotlist[slot]->id == arg2) {
+ *ilsm = lsm_slotlist[slot]->slot;
+ return 0;
+ }
+ return -EINVAL;
+ case PR_LSM_ATTR_GET:
+ if (rc && rc != LSM_RET_DEFAULT(task_prctl))
+ return rc;
+ if (*ilsm != LSMBLOB_INVALID)
+ return lsm_slotlist[*ilsm]->id;
+ return lsm_slotlist[0]->id;
+ }
+
return rc;
}
@@ -2191,23 +2248,45 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
char **value)
{
struct security_hook_list *hp;
+ int ilsm = lsm_task_ilsm(current);
hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
continue;
+ if (lsm == NULL && ilsm != LSMBLOB_INVALID &&
+ ilsm != hp->lsmid->slot)
+ continue;
return hp->hook.getprocattr(p, name, value);
}
return LSM_RET_DEFAULT(getprocattr);
}
+/**
+ * security_setprocattr - Set process attributes via /proc
+ * @lsm: name of module involved, or NULL
+ * @name: name of the attribute
+ * @value: value to set the attribute to
+ * @size: size of the value
+ *
+ * Set the process attribute for the specified security module
+ * to the specified value. Note that this can only be used to set
+ * the process attributes for the current, or "self" process.
+ * The /proc code has already done this check.
+ *
+ * Returns 0 on success, an appropriate code otherwise.
+ */
int security_setprocattr(const char *lsm, const char *name, void *value,
size_t size)
{
struct security_hook_list *hp;
+ int *ilsm = current->security;
hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
continue;
+ if (lsm == NULL && *ilsm != LSMBLOB_INVALID &&
+ *ilsm != hp->lsmid->slot)
+ continue;
return hp->hook.setprocattr(name, value, size);
}
return LSM_RET_DEFAULT(setprocattr);
@@ -2227,15 +2306,15 @@ EXPORT_SYMBOL(security_ismaclabel);
int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
{
struct security_hook_list *hp;
- int rc;
+ int ilsm = lsm_task_ilsm(current);
hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
continue;
- rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
- secdata, seclen);
- if (rc != LSM_RET_DEFAULT(secid_to_secctx))
- return rc;
+ if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+ return hp->hook.secid_to_secctx(
+ blob->secid[hp->lsmid->slot],
+ secdata, seclen);
}
return LSM_RET_DEFAULT(secid_to_secctx);
@@ -2246,16 +2325,15 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
struct lsmblob *blob)
{
struct security_hook_list *hp;
- int rc;
+ int ilsm = lsm_task_ilsm(current);
lsmblob_init(blob, 0);
hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
continue;
- rc = hp->hook.secctx_to_secid(secdata, seclen,
- &blob->secid[hp->lsmid->slot]);
- if (rc != 0)
- return rc;
+ if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+ return hp->hook.secctx_to_secid(secdata, seclen,
+ &blob->secid[hp->lsmid->slot]);
}
return 0;
}
@@ -2263,7 +2341,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
void security_release_secctx(char *secdata, u32 seclen)
{
- call_void_hook(release_secctx, secdata, seclen);
+ struct security_hook_list *hp;
+ int ilsm = lsm_task_ilsm(current);
+
+ hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
+ if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
+ hp->hook.release_secctx(secdata, seclen);
+ return;
+ }
}
EXPORT_SYMBOL(security_release_secctx);
@@ -2404,8 +2489,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
int __user *optlen, unsigned len)
{
- return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
- optval, optlen, len);
+ int ilsm = lsm_task_ilsm(current);
+ struct security_hook_list *hp;
+
+ hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
+ list)
+ if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+ return hp->hook.socket_getpeersec_stream(sock, optval,
+ optlen, len);
+ return -ENOPROTOOPT;
}
int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f03b98b35ef4..56ad1fd62df7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -92,6 +92,7 @@
#include <linux/fsnotify.h>
#include <linux/fanotify.h>
#include <linux/io_uring.h>
+#include <linux/prctl.h>
#include <uapi/linux/lsm.h>
#include "avc.h"
@@ -6373,6 +6374,24 @@ static int selinux_getprocattr(struct task_struct *p,
return error;
}
+static int selinux_task_prctl(int option, unsigned long arg2,
+ unsigned long arg3, unsigned long arg4,
+ unsigned long arg5)
+{
+ u32 mysid = current_sid();
+
+ if (option != PR_LSM_ATTR_SET)
+ return -ENOSYS;
+
+ /*
+ * For setting interface_lsm, we only perform a permission check;
+ * the actual update to the interface_lsm value is handled by the
+ * LSM framework.
+ */
+ return avc_has_perm(&selinux_state, mysid, mysid, SECCLASS_PROCESS2,
+ PROCESS2__SETINTERFACE_LSM, NULL);
+}
+
static int selinux_setprocattr(const char *name, void *value, size_t size)
{
struct task_security_struct *tsec;
@@ -6384,6 +6403,7 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
/*
* Basic control over ability to set these attributes at all.
*/
+
if (!strcmp(name, "exec"))
error = avc_has_perm(&selinux_state,
mysid, mysid, SECCLASS_PROCESS,
@@ -7038,6 +7058,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_access_check, selinux_ptrace_access_check),
LSM_HOOK_INIT(ptrace_traceme, selinux_ptrace_traceme),
+ LSM_HOOK_INIT(task_prctl, selinux_task_prctl),
LSM_HOOK_INIT(capget, selinux_capget),
LSM_HOOK_INIT(capset, selinux_capset),
LSM_HOOK_INIT(capable, selinux_capable),
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 1c2f41ff4e55..6b8569347bc0 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -53,7 +53,8 @@ const struct security_class_mapping secclass_map[] = {
"execmem", "execstack", "execheap", "setkeycreate",
"setsockcreate", "getrlimit", NULL } },
{ "process2",
- { "nnp_transition", "nosuid_transition", NULL } },
+ { "nnp_transition", "nosuid_transition", "setinterface_lsm",
+ NULL } },
{ "system",
{ "ipc_info", "syslog_read", "syslog_mod",
"syslog_console", "module_request", "module_load", NULL } },
--
2.36.1
2 years, 1 month
- 1
- 0
[PATCH v4 0/4] fanotify: Allow user space to pass back additional audit info
by Richard Guy Briggs
The Fanotify API can be used for access control by requesting permission
event notification. The user space tooling that uses it may have a
complicated policy that inherently contains additional context for the
decision. If this information were available in the audit trail, policy
writers can close the loop on debugging policy. Also, if this additional
information were available, it would enable the creation of tools that
can suggest changes to the policy similar to how audit2allow can help
refine labeled security.
This patchset defines a new flag (FAN_INFO) and new extensions that
define additional information which are appended after the response
structure returned from user space on a permission event. The appended
information is organized with headers containing a type and size that
can be delegated to interested subsystems. One new information type is
defined for audit rule number.
A newer kernel will work with an older userspace and an older kernel
will behave as expected and reject a newer userspace, leaving it up to
the newer userspace to test appropriately and adapt as necessary.
The audit function was updated to log the additional information in the
AUDIT_FANOTIFY record. The following is an example of the new record
format:
type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3F
changelog:
v1:
- first version by Steve Grubb <sgrubb(a)redhat.com>
Link: https://lore.kernel.org/r/2042449.irdbgypaU6@x2
v2:
- enhancements suggested by Jan Kara <jack(a)suse.cz>
- 1/3 change %d to %u in pr_debug
- 2/3 change response from __u32 to __u16
- mod struct fanotify_response and fanotify_perm_event add extra_info_type, extra_info_buf
- extra_info_buf size max FANOTIFY_MAX_RESPONSE_EXTRA_LEN, add struct fanotify_response_audit_rule
- extend debug statements
- remove unneeded macros
- [internal] change interface to finish_permission_event() and process_access_response()
- 3/3 update format of extra information
- [internal] change interface to audit_fanotify()
- change ctx_type= to fan_type=
Link: https://lore.kernel.org/r/cover.1651174324.git.rgb@redhat.com
v3:
- 1/3 switch {,__}audit_fanotify() from uint to u32
- 2/3 re-add fanotify_get_response switch case FAN_DENY: to avoid unnecessary churn
- add FAN_EXTRA flag to indicate more info and break with old kernel
- change response from u16 to u32 to avoid endian issues
- change extra_info_buf to union
- move low-cost fd check earlier
- change FAN_RESPONSE_INFO_AUDIT_NONE to FAN_RESPONSE_INFO_NONE
- switch to u32 for internal and __u32 for uapi
Link: https://lore.kernel.org/r/cover.1652724390.git.rgb@redhat.com
v4:
- scrap FAN_INVALID_RESPONSE_MASK in favour of original to catch invalid response == 0
- introduce FANOTIFY_RESPONSE_* macros
- uapi: remove union
- keep original struct fanotify_response, add fan_info infra starting with audit reason
- uapi add struct fanotify_response_info_header{type/pad/len} and struct fanotify_response_info_audit_rule{hdr/rule}
- rename fan_ctx= to fan_info=, FAN_EXTRA to FAN_INFO
- change event struct from type/buf to len/buf
- enable multiple info extensions in one message
- hex encode fan_info in __audit_fanotify()
- record type FANOTIFY extended to "type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=3F"
Link: https://lore.kernel.org/r/cover.1659981772.git.rgb@redhat.com
Richard Guy Briggs (4):
fanotify: Ensure consistent variable type for response
fanotify: define struct members to hold response decision context
fanotify,audit: Allow audit to use the full permission event response
fanotify,audit: deliver fan_info as a hex-encoded string
fs/notify/fanotify/fanotify.c | 13 +++-
fs/notify/fanotify/fanotify.h | 4 +-
fs/notify/fanotify/fanotify_user.c | 106 ++++++++++++++++++++++-------
include/linux/audit.h | 9 +--
include/linux/fanotify.h | 5 ++
include/uapi/linux/fanotify.h | 27 +++++++-
kernel/auditsc.c | 45 +++++++++++-
7 files changed, 174 insertions(+), 35 deletions(-)
--
2.27.0
2 years, 1 month
- 8
- 43
[PATCH -next] audit: remove selinux_audit_rule_update() declaration
by Xiu Jianfeng
selinux_audit_rule_update() has been renamed to audit_update_lsm_rules()
since commit d7a96f3a1ae2 ("Audit: internally use the new LSM audit
hooks"), so remove it.
Signed-off-by: Xiu Jianfeng <xiujianfeng(a)huawei.com>
---
kernel/audit.h | 2 --
1 file changed, 2 deletions(-)
diff --git a/kernel/audit.h b/kernel/audit.h
index d6eb7b59c791..c57b008b9914 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -245,8 +245,6 @@ struct audit_netlink_list {
int audit_send_list_thread(void *_dest);
-extern int selinux_audit_rule_update(void);
-
extern struct mutex audit_filter_mutex;
extern int audit_del_rule(struct audit_entry *entry);
extern void audit_free_rule_rcu(struct rcu_head *head);
--
2.17.1
2 years, 1 month
- 2
- 1
- ← Newer
- 1
- Older →