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>
The cap_* fields swing in and out of PATH records.
If no capabilities are set, the cap_* fields are completely missing and when
one of the cap_fi or cap_fp values is empty, that field is omitted.
Original:
type=PATH msg=audit(04/20/2017 12:17:11.222:193) : item=1 name=/lib64/ld-linux-x86-64.so.2 inode=787694 dev=08:03 mode=file,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:ld_so_t:s0 nametype=NORMAL
type=PATH msg=audit(04/20/2017 12:17:11.222:193) : item=0 name=/home/sleep inode=1319469 dev=08:03 mode=file,suid,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:bin_t:s0 nametype=NORMAL cap_fp=sys_admin cap_fe=1 cap_fver=2
Normalize the PATH record by always printing all 4 cap_* fields.
Fixed:
type=PATH msg=audit(04/20/2017 13:01:31.679:201) : item=1 name=/lib64/ld-linux-x86-64.so.2 inode=787694 dev=08:03 mode=file,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:ld_so_t:s0 nametype=NORMAL cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
type=PATH msg=audit(04/20/2017 13:01:31.679:201) : item=0 name=/home/sleep inode=1319469 dev=08:03 mode=file,suid,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:bin_t:s0 nametype=NORMAL cap_fp=sys_admin cap_fi=none cap_fe=1 cap_fver=2
See: https://github.com/linux-audit/audit-kernel/issues/42
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"Fourteen audit patches for v4.12 that span the full range of fixes,
new features, and internal cleanups.
We have a patches to move to 64-bit timestamps, convert refcounts from
atomic_t to refcount_t, track PIDs using the pid struct instead of
pid_t, convert our own private audit buffer cache to a standard
kmem_cache, log kernel module names when they are unloaded, and
normalize the NETFILTER_PKT to make the userspace folks happier.
From a fixes perspective, the most important is likely the auditd
connection tracking RCU fix; it was a rather brain dead bug that I'll
take the blame for, but thankfully it didn't seem to affect many
people (only one report).
I think the patch subject lines and commit descriptions do a pretty
good job of explaining the details and why the changes are important
so I'll point you there instead of duplicating it here; as usual, if
you have any questions you know where to find us.
We also manage to take out more code than we put in this time, that
always makes me happy :)"
* 'stable-4.12' of git://git.infradead.org/users/pcmoore/audit:
audit: fix the RCU locking for the auditd_connection structure
audit: use kmem_cache to manage the audit_buffer cache
audit: Use timespec64 to represent audit timestamps
audit: store the auditd PID as a pid struct instead of pid_t
audit: kernel generated netlink traffic should have a portid of 0
audit: combine audit_receive() and audit_receive_skb()
audit: convert audit_watch.count from atomic_t to refcount_t
audit: convert audit_tree.count from atomic_t to refcount_t
audit: normalize NETFILTER_PKT
netfilter: use consistent ipv4 network offset in xt_AUDIT
audit: log module name on delete_module
audit: remove unnecessary semicolon in audit_watch_handle_event()
audit: remove unnecessary semicolon in audit_mark_handle_event()
audit: remove unnecessary semicolon in audit_field_valid()
Cong Wang correctly pointed out that the RCU read locking of the
auditd_connection struct was wrong, this patch correct this by
adopting a more traditional, and correct RCU locking model.
This patch is heavily based on an earlier prototype by Cong Wang.
Cc: <stable@vger.kernel.org> # 4.11.x-
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The audit subsystem implemented its own buffer cache mechanism which
is a bit silly these days when we could use the kmem_cache construct.
Some credit is due to Florian Westphal for originally proposing that
we remove the audit cache implementation in favor of simple
kmalloc()/kfree() calls, but I would rather have a dedicated slab
cache to ease debugging and future stats/performance work.
Cc: Florian Westphal <fw@strlen.de>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
struct timespec is not y2038 safe.
Audit timestamps are recorded in string format into
an audit buffer for a given context.
These mark the entry timestamps for the syscalls.
Use y2038 safe struct timespec64 to represent the times.
The log strings can handle this transition as strings can
hold upto 1024 characters.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This is arguably the right thing to do, and will make it easier when
we start supporting multiple audit daemons in different namespaces.
Signed-off-by: Paul Moore <paul@paul-moore.com>
We were setting the portid incorrectly in the netlink message headers,
fix that to always be 0 (nlmsg_pid = 0).
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
There is no reason to have both of these functions, combine the two.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Conflicts were simply overlapping changes. In the net/ipv4/route.c
case the code had simply moved around a little bit and the same fix
was made in both 'net' and 'net-next'.
In the net/sched/sch_generic.c case a fix in 'net' happened at
the same time that a new argument was added to qdisc_hash_add().
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.
Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The retry queue is intended to provide a temporary buffer in the case
of transient errors when communicating with auditd, it is not meant
as a long life queue, that functionality is provided by the hold
queue.
This patch fixes a problem identified by Seth where the retry queue
could grow uncontrollably if an auditd instance did not connect to
the kernel to drain the queues. This commit fixes this by doing the
following:
* Make sure we always call auditd_reset() if we decide the connection
with audit is really dead. There were some cases in
kauditd_hold_skb() where we did not reset the connection, this patch
relocates the reset calls to kauditd_thread() so all the error
conditions are caught and the connection reset. As a side effect,
this means we could move auditd_reset() and get rid of the forward
definition at the top of kernel/audit.c.
* We never checked the status of the auditd connection when
processing the main audit queue which meant that the retry queue
could grow unchecked. This patch adds a call to auditd_reset()
after the main queue has been processed if auditd is not connected,
the auditd_reset() call will make sure the retry and hold queues are
correctly managed/flushed so that the retry queue remains reasonable.
Cc: <stable@vger.kernel.org> # 4.10.x-: 5b52330bbf
Reported-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
What started as a rather straightforward race condition reported by
Dmitry using the syzkaller fuzzer ended up revealing some major
problems with how the audit subsystem managed its netlink sockets and
its connection with the userspace audit daemon. Fixing this properly
had quite the cascading effect and what we are left with is this rather
large and complicated patch. My initial goal was to try and decompose
this patch into multiple smaller patches, but the way these changes
are intertwined makes it difficult to split these changes into
meaningful pieces that don't break or somehow make things worse for
the intermediate states.
The patch makes a number of changes, but the most significant are
highlighted below:
* The auditd tracking variables, e.g. audit_sock, are now gone and
replaced by a RCU/spin_lock protected variable auditd_conn which is
a structure containing all of the auditd tracking information.
* We no longer track the auditd sock directly, instead we track it
via the network namespace in which it resides and we use the audit
socket associated with that namespace. In spirit, this is what the
code was trying to do prior to this patch (at least I think that is
what the original authors intended), but it was done rather poorly
and added a layer of obfuscation that only masked the underlying
problems.
* Big backlog queue cleanup, again. In v4.10 we made some pretty big
changes to how the audit backlog queues work, here we haven't changed
the queue design so much as cleaned up the implementation. Brought
about by the locking changes, we've simplified kauditd_thread() quite
a bit by consolidating the queue handling into a new helper function,
kauditd_send_queue(), which allows us to eliminate a lot of very
similar code and makes the looping logic in kauditd_thread() clearer.
* All netlink messages sent to auditd are now sent via
auditd_send_unicast_skb(). Other than just making sense, this makes
the lock handling easier.
* Change the audit_log_start() sleep behavior so that we never sleep
on auditd events (unchanged) or if the caller is holding the
audit_cmd_mutex (changed). Previously we didn't sleep if the caller
was auditd or if the message type fell between a certain range; the
type check was a poor effort of doing what the cmd_mutex check now
does. Richard Guy Briggs originally proposed not sleeping the
cmd_mutex owner several years ago but his patch wasn't acceptable
at the time. At least the idea lives on here.
* A problem with the lost record counter has been resolved. Steve
Grubb and I both happened to notice this problem and according to
some quick testing by Steve, this problem goes back quite some time.
It's largely a harmless problem, although it may have left some
careful sysadmins quite puzzled.
Cc: <stable@vger.kernel.org> # 4.10.x-
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"The audit changes for v4.11 are relatively small compared to what we
did for v4.10, both in terms of size and impact.
- two patches from Steve tweak the formatting for some of the audit
records to make them more consistent with other audit records.
- three patches from Richard record the name of a module on module
load, fix the logging of sockaddr information when using
socketcall() on 32-bit systems, and add the ability to reset
audit's lost record counter.
- my lone patch just fixes an annoying style nit that I was reminded
about by one of Richard's patches.
All these patches pass our test suite"
* 'stable-4.11' of git://git.infradead.org/users/pcmoore/audit:
audit: remove unnecessary curly braces from switch/case statements
audit: log module name on init_module
audit: log 32-bit socketcalls
audit: add feature audit_lost reset
audit: Make AUDIT_ANOM_ABEND event normalized
audit: Make AUDIT_KERNEL event conform to the specification
Add a method to reset the audit_lost value.
An AUDIT_SET message with the AUDIT_STATUS_LOST flag set by itself
will return a positive value repesenting the current audit_lost value
and reset the counter to zero. If AUDIT_STATUS_LOST is not the
only flag set, the reset command will be ignored. The value sent with
the command is ignored. The return value will be the +ve lost value at
reset time.
An AUDIT_CONFIG_CHANGE message will be queued to the listening audit
daemon. The message will be a standard CONFIG_CHANGE message with the
fields "lost=0" and "old=" with the latter containing the value of
audit_lost at reset time.
See: https://github.com/linux-audit/audit-kernel/issues/3
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull more vfs updates from Al Viro:
"In this pile:
- autofs-namespace series
- dedupe stuff
- more struct path constification"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
ocfs2: implement the VFS clone_range, copy_range, and dedupe_range features
ocfs2: charge quota for reflinked blocks
ocfs2: fix bad pointer cast
ocfs2: always unlock when completing dio writes
ocfs2: don't eat io errors during _dio_end_io_write
ocfs2: budget for extent tree splits when adding refcount flag
ocfs2: prohibit refcounted swapfiles
ocfs2: add newlines to some error messages
ocfs2: convert inode refcount test to a helper
simple_write_end(): don't zero in short copy into uptodate
exofs: don't mess with simple_write_{begin,end}
9p: saner ->write_end() on failing copy into non-uptodate page
fix gfs2_stuffed_write_end() on short copies
fix ceph_write_end()
nfs_write_end(): fix handling of short copies
vfs: refactor clone/dedupe_file_range common functions
fs: try to clone files first in vfs_copy_file_range
vfs: misc struct path constification
namespace.c: constify struct path passed to a bunch of primitives
quota: constify struct path in quota_on
...
Pull audit updates from Paul Moore:
"After the small number of patches for v4.9, we've got a much bigger
pile for v4.10.
The bulk of these patches involve a rework of the audit backlog queue
to enable us to move the netlink multicasting out of the task/thread
that generates the audit record and into the kernel thread that emits
the record (just like we do for the audit unicast to auditd).
While we were playing with the backlog queue(s) we fixed a number of
other little problems with the code, and from all the testing so far
things look to be in much better shape now. Doing this also allowed us
to re-enable disabling IRQs for some netns operations ("netns: avoid
disabling irq for netns id").
The remaining patches fix some small problems that are well documented
in the commit descriptions, as well as adding session ID filtering
support"
* 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit:
audit: use proper refcount locking on audit_sock
netns: avoid disabling irq for netns id
audit: don't ever sleep on a command record/message
audit: handle a clean auditd shutdown with grace
audit: wake up kauditd_thread after auditd registers
audit: rework audit_log_start()
audit: rework the audit queue handling
audit: rename the queues and kauditd related functions
audit: queue netlink multicast sends just like we do for unicast sends
audit: fixup audit_init()
audit: move kaudit thread start from auditd registration to kaudit init (#2)
audit: add support for session ID user filter
audit: fix formatting of AUDIT_CONFIG_CHANGE events
audit: skip sessionid sentinel value when auto-incrementing
audit: tame initialization warning len_abuf in audit_log_execve_info
audit: less stack usage for /proc/*/loginuid
The AUDIT_KERNEL event is not following name=value format. This causes
some information to get lost. The event has been reformatted to follow
the convention. Additionally the audit_enabled value was added for
troubleshooting purposes. The following is an example of the new event:
type=KERNEL audit(1480621249.833:1): state=initialized
audit_enabled=0 res=1
Signed-off-by: Steve Grubb <sgrubb@redhat.com>
[PM: commit tweaks to make checkpatch.pl happy]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Resetting audit_sock appears to be racy.
audit_sock was being copied and dereferenced without using a refcount on
the source sock.
Bump the refcount on the underlying sock when we store a refrence in
audit_sock and release it when we reset audit_sock. audit_sock
modification needs the audit_cmd_mutex.
See: https://lkml.org/lkml/2016/11/26/232
Thanks to Eric Dumazet <edumazet@google.com> and Cong Wang
<xiyou.wangcong@gmail.com> on ideas how to fix it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
[PM: fixed the comment block text formatting for auditd_reset()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Sleeping on a command record/message in audit_log_start() could slow
something, e.g. auditd, from doing something important, e.g. clean
shutdown, which could present problems on a heavily loaded system.
This patch allows tasks to bypass any queue restrictions if they are
logging a command record/message.
Signed-off-by: Paul Moore <paul@paul-moore.com>
When auditd stops cleanly it sets 'auditd_pid' to 0 with an
AUDIT_SET message, in this case we should reset our backlog
queues via the auditd_reset() function. This patch also adds
a 'auditd_pid' check to the top of kauditd_send_unicast_skb()
so we can fail quicker.
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch was suggested by Richard Briggs back in 2015, see the link
to the mail archive below. Unfortunately, that patch is no longer
even remotely valid due to other changes to the code.
* https://www.redhat.com/archives/linux-audit/2015-October/msg00075.html
Suggested-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The backlog queue handling in audit_log_start() is a little odd with
some questionable design decisions, this patch attempts to rectify
this with the following changes:
* Never make auditd wait, ignore any backlog limits as we need auditd
awake so it can drain the backlog queue.
* When we hit a backlog limit and start dropping records, don't wake
all the tasks sleeping on the backlog, that's silly. Instead, let
kauditd_thread() take care of waking everyone once it has had a chance
to drain the backlog queue.
* Don't keep a global backlog timeout countdown, make it per-task. A
per-task timer means we won't have all the sleeping tasks waking at
the same time and hammering on an already stressed backlog queue.
Signed-off-by: Paul Moore <paul@paul-moore.com>
The audit record backlog queue has always been a bit of a mess, and
the moving the multicast send into kauditd_thread() from
audit_log_end() only makes things worse. This patch attempts to fix
the backlog queue with a better design that should hold up better
under load and have less of a performance impact at syscall
invocation time.
While it looks like there is a log going on in this patch, the main
change is the move from a single backlog queue to three queues:
* A queue for holding records generated from audit_log_end() that
haven't been consumed by kauditd_thread() (audit_queue).
* A queue for holding records that have been sent via multicast but
had a temporary failure when sending via unicast and need a resend
(audit_retry_queue).
* A queue for holding records that haven't been sent via unicast
because no one is listening (audit_hold_queue).
Special care is taken in this patch to ensure that the proper
record ordering is preserved, e.g. we send everything in the hold
queue first, then the retry queue, and finally the main queue.
Signed-off-by: Paul Moore <paul@paul-moore.com>
The audit queue names can be shortened and the record sending
helpers associated with the kauditd task could be named better, do
these small cleanups now to make life easier once we start reworking
the queues and kauditd code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Sending audit netlink multicast messages is bad for all the same
reasons that sending audit netlink unicast messages is bad, so this
patch reworks things so that we don't do the multicast send in
audit_log_end(), we do it from the dedicated kauditd_thread thread just
as we do for unicast messages.
See the GitHub issues below for more information/history:
* https://github.com/linux-audit/audit-kernel/issues/23
* https://github.com/linux-audit/audit-kernel/issues/22
Signed-off-by: Paul Moore <paul@paul-moore.com>
Make sure everything is initialized before we start the kauditd_thread
and don't emit the "initialized" record until everything is finished.
We also panic with a descriptive message if we can't start the
kauditd_thread.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Richard made this change some time ago but Eric backed it out because
the rest of the supporting code wasn't ready. In order to move the
netlink multicast send to kauditd_thread we need to ensure the
kauditd_thread is always running, so restore commit 6ff5e459 ("audit:
move kaudit thread start from auditd registration to kaudit init").
Signed-off-by: Richard Guy Briggs <rbriggs@redhat.com>
[PM: brought forward and merged based on Richard's old patch]
Signed-off-by: Paul Moore <paul@paul-moore.com>
netlink kernel socket is protected by refcount, not RCU.
Its rcv path is neither protected by RCU. So the synchronize_net()
is just pointless.
Cc: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make struct pernet_operations::id unsigned.
There are 2 reasons to do so:
1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.
2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.
"int" being used as an array index needs to be sign-extended
to 64-bit before being used.
void f(long *p, int i)
{
g(p[i]);
}
roughly translates to
movsx rsi, esi
mov rdi, [rsi+...]
call g
MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.
Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:
static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}
And this function is used a lot, so those sign extensions add up.
Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]
However, overall balance is in negative direction:
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull audit updates from Paul Moore:
"Another relatively small pull request for v4.9 with just two patches.
The patch from Richard updates the list of features we support and
report back to userspace; this should have been sent earlier with the
rest of the v4.8 patches but it got lost in my inbox.
The second patch fixes a problem reported by our Android friends where
we weren't very consistent in recording PIDs"
* 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit:
audit: add exclude filter extension to feature bitmap
audit: consistently record PIDs with task_tgid_nr()
Unfortunately we record PIDs in audit records using a variety of
methods despite the correct way being the use of task_tgid_nr().
This patch converts all of these callers, except for the case of
AUDIT_SET in audit_receive_msg() (see the comment in the code).
Reported-by: Jeff Vander Stoep <jeffv@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"Six audit patches for 4.8.
There are a couple of style and minor whitespace tweaks for the logs,
as well as a minor fixup to catch errors on user filter rules, however
the major improvements are a fix to the s390 syscall argument masking
code (reviewed by the nice s390 folks), some consolidation around the
exclude filtering (less code, always a win), and a double-fetch fix
for recording the execve arguments"
* 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit:
audit: fix a double fetch in audit_log_single_execve_arg()
audit: fix whitespace in CWD record
audit: add fields to exclude filter by reusing user filter
s390: ensure that syscall arguments are properly masked on s390
audit: fix some horrible switch statement style crimes
audit: fixup: log on errors from filter user rules
Pull audit fixes from Paul Moore:
"Two small patches to fix audit problems in 4.7-rcX: the first fixes a
potential kref leak, the second removes some header file noise.
The first is an important bug fix that really should go in before 4.7
is released, the second is not critical, but falls into the very-nice-
to-have category so I'm including in the pull request.
Both patches are straightforward, self-contained, and pass our
testsuite without problem"
* 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit:
audit: move audit_get_tty to reduce scope and kabi changes
audit: move calcs after alloc and check when logging set loginuid
The only users of audit_get_tty and audit_put_tty are internal to
audit, so move it out of include/linux/audit.h to kernel.h and create
a proper function rather than inlining it. This also reduces kABI
changes.
Suggested-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: line wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
RFE: add additional fields for use in audit filter exclude rules
https://github.com/linux-audit/audit-kernel/issues/5
Re-factor and combine audit_filter_type() with audit_filter_user() to
use audit_filter_user_rules() to enable the exclude filter to
additionally filter on PID, UID, GID, AUID, LOGINUID_SET, SUBJ_*.
The process of combining the similar audit_filter_user() and
audit_filter_type() functions, required inverting the meaning and
including the ALWAYS action of the latter.
Include audit_filter_user_rules() into audit_filter(), removing
unneeded logic in the process.
Keep the check to quit early if the list is empty.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: checkpatch.pl fixes - whitespace damage, wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"Four small audit patches for 4.7.
Two are simple cleanups around the audit thread management code, one
adds a tty field to AUDIT_LOGIN events, and the final patch makes
tty_name() usable regardless of CONFIG_TTY.
Nothing controversial, and it all passes our regression test"
* 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit:
tty: provide tty_name() even without CONFIG_TTY
audit: add tty field to LOGIN event
audit: we don't need to __set_current_state(TASK_RUNNING)
audit: cleanup prune_tree_thread
The tty field was missing from AUDIT_LOGIN events.
Refactor code to create a new function audit_get_tty(), using it to
replace the call in audit_log_task_info() and to add it to
audit_log_set_loginuid(). Lock and bump the kref to protect it, adding
audit_put_tty() alias to decrement it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Remove the calls to __set_current_state() to mark the task as running
and do some related cleanup in wait_for_auditd() to limit the amount
of work we do when we aren't going to reschedule the current task.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull audit updates from Paul Moore:
"A small set of patches for audit this time; just three in total and
one is a spelling fix.
The two patches with actual content are designed to help prevent new
instances of auditd from displacing an existing, functioning auditd
and to generate a log of the attempt. Not to worry, dead/stuck auditd
instances can still be replaced by a new instance without problem.
Nothing controversial, and everything passes our regression suite"
* 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit:
audit: Fix typo in comment
audit: log failed attempts to change audit_pid configuration
audit: stop an old auditd being starved out by a new auditd
The audit_tty and audit_tty_log_passwd fields are actually bool
values, so merge into single memory location to access atomically.
NB: audit log operations may still occur after tty audit is disabled
which is consistent with the existing functionality
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_audit_push() and tty_audit_push_current() perform identical
tasks; eliminate the tty_audit_push() implementation and the
tty_audit_push_current() name.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Failed attempts to change the audit_pid configuration are not presently
logged. One case is an attempt to starve an old auditd by starting up
a new auditd when the old one is still alive and active. The other
case is an attempt to orphan a new auditd when an old auditd shuts
down.
Log both as AUDIT_CONFIG_CHANGE messages with failure result.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
