Recognizing that the audit context is an internal audit value, use an
access function to retrieve the audit context pointer for the task
rather than reaching directly into the task struct to get it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: merge fuzz in auditsc.c and selinuxfs.c, checkpatch.pl fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"We didn't have anything to send for v4.16, but we're back with a
little more than usual for v4.17.
Eleven patches in total, most fall into the small fix category, but
there are three non-trivial changes worth calling out:
- the audit entry filter is being removed after deprecating it for
quite a while (years of no one really using it because it turns out
to be not very practical)
- created our own version of "__mutex_owner()" because the locking
folks were upset we were using theirs
- improved our handling of kernel command line parameters to make
them more forgiving
- we fixed auditing of symlink operations
Everything passes the audit-testsuite and as of a few minutes ago it
merges well with your tree"
* tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: add refused symlink to audit_names
audit: remove path param from link denied function
audit: link denied should not directly generate PATH record
audit: make ANOM_LINK obey audit_enabled and audit_dummy_context
audit: do not panic on invalid boot parameter
audit: track the owner of the command mutex ourselves
audit: return on memory error to avoid null pointer dereference
audit: bail before bug check if audit disabled
audit: deprecate the AUDIT_FILTER_ENTRY filter
audit: session ID should not set arch quick field pointer
audit: update bugtracker and source URIs
In commit 45b578fe4c
("audit: link denied should not directly generate PATH record")
the need for the struct path *link parameter was removed.
Remove the now useless struct path argument.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Audit link denied events generate duplicate PATH records which disagree
in different ways from symlink and hardlink denials.
audit_log_link_denied() should not directly generate PATH records.
See: https://github.com/linux-audit/audit-kernel/issues/21
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
If you pass in an invalid audit boot parameter value, e.g. "audit=off",
the kernel panics very early in boot before the regular console is
initialized. Unless you have earlyprintk enabled, there is no
indication of what the problem is on the console.
Convert the panic() calls to pr_err(), and leave auditing enabled if an
invalid parameter value was passed in.
Modify the parameter to also accept "on" or "off" as valid values, and
update the documentation accordingly.
Signed-off-by: Greg Edwards <gedwards@ddn.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Evidently the __mutex_owner() function was never intended for use
outside the core mutex code, so build a thing locking wrapper around
the mutex code which allows us to track the mutex owner.
One, arguably positive, side effect is that this allows us to hide
the audit_cmd_mutex inside of kernel/audit.c behind the lock/unlock
functions.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
If there is a memory allocation error when trying to change an audit
kernel feature value, the ignored allocation error will trigger a NULL
pointer dereference oops on subsequent use of that pointer. Return
instead.
Passes audit-testsuite.
See: https://github.com/linux-audit/audit-kernel/issues/76
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: not necessary (other funcs check for NULL), but a good practice]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Since the Linux Audit project has transitioned completely over to
github, update the MAINTAINERS file and the primary audit source file to
reflect that reality.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The function audit_log_secctx() is unused in the upstream kernel.
All it does is wrap another function that doesn't need wrapping.
It claims to give you the SELinux context, but that is not true if
you are using a different security module.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use audit_set_enabled() to enable auditing during early boot. This
obviously won't emit an audit change record, but it will work anyway
and should help prevent in future problems by consolidating the
enable/disable code in one function.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
We were treating it as a boolean, let's make it a boolean to help
avoid future mistakes.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The simple_strtol() function is deprecated, use kstrtol() instead.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
We can't initialize the audit subsystem until after the network layer
is initialized (core_initcall), but do it soon after.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Prior to this patch we enabled audit in audit_init(), which is too
late for PID 1 as the standard initcalls are run after the PID 1 task
is forked. This means that we never allocate an audit_context (see
audit_alloc()) for PID 1 and therefore miss a lot of audit events
generated by PID 1.
This patch enables audit as early as possible to help ensure that when
PID 1 is forked it can allocate an audit_context if required.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Commit 2115bb250f ("audit: Use timespec64 to represent audit timestamps")
noted that audit timestamps were not y2038 safe and used a 64-bit
timestamp. In itself, this makes sense but the conversion was from
CURRENT_TIME to ktime_get_real_ts64() which is a heavier call to record
an accurate timestamp which is required in some, but not all, cases. The
impact is that when auditd is running without any rules that all syscalls
have higher overhead. This is visible in the sysbench-thread benchmark as
a 11.5% performance hit. That benchmark is dumb as rocks but it's also
visible in redis as an 8-10% hit on all operations which is of greater
concern. It is somewhat stupid of audit to track syscalls without any
rules related to syscalls but that is how it behaves.
The overhead can be directly measured with perf comparing 4.9 with 4.12
4.9
7.76% sysbench [kernel.vmlinux] [k] __schedule
7.62% sysbench [kernel.vmlinux] [k] _raw_spin_lock
7.37% sysbench libpthread-2.22.so [.] __lll_lock_elision
7.29% sysbench [kernel.vmlinux] [.] syscall_return_via_sysret
6.59% sysbench [kernel.vmlinux] [k] native_sched_clock
5.21% sysbench libc-2.22.so [.] __sched_yield
4.38% sysbench [kernel.vmlinux] [k] entry_SYSCALL_64
4.28% sysbench [kernel.vmlinux] [k] do_syscall_64
3.49% sysbench libpthread-2.22.so [.] __lll_unlock_elision
3.13% sysbench [kernel.vmlinux] [k] __audit_syscall_exit
2.87% sysbench [kernel.vmlinux] [k] update_curr
2.73% sysbench [kernel.vmlinux] [k] pick_next_task_fair
2.31% sysbench [kernel.vmlinux] [k] syscall_trace_enter
2.20% sysbench [kernel.vmlinux] [k] __audit_syscall_entry
.....
0.00% swapper [kernel.vmlinux] [k] read_tsc
4.12
7.84% sysbench [kernel.vmlinux] [k] __schedule
7.05% sysbench [kernel.vmlinux] [k] _raw_spin_lock
6.57% sysbench libpthread-2.22.so [.] __lll_lock_elision
6.50% sysbench [kernel.vmlinux] [.] syscall_return_via_sysret
5.95% sysbench [kernel.vmlinux] [k] read_tsc
5.71% sysbench [kernel.vmlinux] [k] native_sched_clock
4.78% sysbench libc-2.22.so [.] __sched_yield
4.30% sysbench [kernel.vmlinux] [k] entry_SYSCALL_64
3.94% sysbench [kernel.vmlinux] [k] do_syscall_64
3.37% sysbench libpthread-2.22.so [.] __lll_unlock_elision
3.32% sysbench [kernel.vmlinux] [k] __audit_syscall_exit
2.91% sysbench [kernel.vmlinux] [k] __getnstimeofday64
Note the additional overhead from read_tsc which goes from 0% to 5.95%.
This is on a single-socket E3-1230 but similar overheads have been measured
on an older machine which the patch also eliminates.
The patch in question has no explanation as to why a fully-accurate timestamp
is required and is likely an oversight. Using a coarser, but monotically
increasing, timestamp the overhead can be eliminated. While it can be
worked around by configuring or disabling audit, it's tricky enough to
detect that a kernel fix is justified. With this patch, we see the following;
sysbenchthread
4.9.0 4.12.0 4.12.0
vanilla vanilla coarse-v1r1
Amean 1 1.49 ( 0.00%) 1.66 ( -11.42%) 1.51 ( -1.34%)
Amean 3 1.48 ( 0.00%) 1.65 ( -11.45%) 1.50 ( -0.96%)
Amean 5 1.49 ( 0.00%) 1.67 ( -12.31%) 1.51 ( -1.83%)
Amean 7 1.49 ( 0.00%) 1.66 ( -11.72%) 1.50 ( -0.67%)
Amean 12 1.48 ( 0.00%) 1.65 ( -11.57%) 1.52 ( -2.89%)
Amean 16 1.49 ( 0.00%) 1.65 ( -11.13%) 1.51 ( -1.73%)
The benchmark is reporting the time required for different thread counts to
lock/unlock a private mutex which, while dense, demonstrates the syscall
overhead. This is showing that 4.12 took a 11-12% hit but the overhead is
almost eliminated by the patch. While the variance is not reported here,
it's well within the noise with the patch applied.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit fix from Paul Moore:
"A small audit fix, just a single line, to plug a memory leak in some
audit error handling code"
* 'stable-4.13' of git://git.infradead.org/users/pcmoore/audit:
audit: fix memleak in auditd_send_unicast_skb.
Pull audit updates from Paul Moore:
"Things are relatively quiet on the audit front for v4.13, just five
patches for a total diffstat of 102 lines.
There are two patches from Richard to consistently record the POSIX
capabilities and add the ambient capability information as well.
I also chipped in two patches to fix a race condition with the auditd
tracking code and ensure we don't skip sending any records to the
audit multicast group.
Finally a single style fix that I accepted because I must have been in
a good mood that day.
Everything passes our test suite, and should be relatively harmless,
please merge for v4.13"
* 'stable-4.13' of git://git.infradead.org/users/pcmoore/audit:
audit: make sure we never skip the multicast broadcast
audit: fix a race condition with the auditd tracking code
audit: style fix
audit: add ambient capabilities to CAPSET and BPRM_FCAPS records
audit: unswing cap_* fields in PATH records
When the auditd connection is reset, either intentionally or due to
a failure, any records that were in the main backlog queue would not
be sent in a multicast broadcast. This patch fixes this problem by
not flushing the main backlog queue on a connection reset, the main
kauditd_thread() will take care of that normally.
Resolves: https://github.com/linux-audit/audit-kernel/issues/41
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Originally reported by Adam and Dusty, it appears we have a small
race window in kauditd_thread(), as documented in the Fedora BZ:
* https://bugzilla.redhat.com/show_bug.cgi?id=1459326#c35
"This issue is partly due to the read-copy nature of RCU, and
partly due to how we sync the auditd_connection state across
kauditd_thread and the audit control channel. The kauditd_thread
thread is always running so it can service the record queues and
emit the multicast messages, if it happens to be just past the
"main_queue" label, but before the "if (sk == NULL || ...)"
if-statement which calls auditd_reset() when the new auditd
connection is registered it could end up resetting the auditd
connection, regardless of if it is valid or not. This is a rather
small window and the variable nature of multi-core scheduling
explains why this is proving rather difficult to reproduce."
The fix is to have functions only call auditd_reset() when they
believe that the kernel/auditd connection is still valid, e.g.
non-NULL, and to have these callers pass their local copy of the
auditd_connection pointer to auditd_reset() where it can be compared
with the current connection state before resetting. If the caller
has a stale state tracking pointer then the reset is ignored.
We also make a small change to kauditd_thread() so that if the
kernel/auditd connection is dead we skip the retry queue and send the
records straight to the hold queue. This is necessary as we used to
rely on auditd_reset() to occasionally purge the retry queue but we
are going to be calling the reset function much less now and we want
to make sure the retry queue doesn't grow unbounded.
Reported-by: Adam Williamson <awilliam@redhat.com>
Reported-by: Dusty Mabe <dustymabe@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
