The fanotify interface allows user space daemons to make access
control decisions. Under common criteria requirements, we need to
optionally record decisions based on policy. This patch adds a bit mask,
FAN_AUDIT, that a user space daemon can 'or' into the response decision
which will tell the kernel that it made a decision and record it.

It would be used something like this in user space code:

  response.response = FAN_DENY | FAN_AUDIT;
  write(fd, &response, sizeof(struct fanotify_response));

When the syscall ends, the audit system will record the decision as a
AUDIT_FANOTIFY auxiliary record to denote that the reason this event
occurred is the result of an access control decision from fanotify
rather than DAC or MAC policy.

A sample event looks like this:

type=PATH msg=audit(1504310584.332:290): item=0 name="./evil-ls"
inode=1319561 dev=fc:03 mode=0100755 ouid=1000 ogid=1000 rdev=00:00
obj=unconfined_u:object_r:user_home_t:s0 nametype=NORMAL
type=CWD msg=audit(1504310584.332:290): cwd="/home/sgrubb"
type=SYSCALL msg=audit(1504310584.332:290): arch=c000003e syscall=2
success=no exit=-1 a0=32cb3fca90 a1=0 a2=43 a3=8 items=1 ppid=901
pid=959 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000
fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="bash"
exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t:
s0-s0:c0.c1023 key=(null)
type=FANOTIFY msg=audit(1504310584.332:290): resp=2

Prior to using the audit flag, the developer needs to call
fanotify_init or'ing in FAN_ENABLE_AUDIT to ensure that the kernel
supports auditing. The calling process must also have the CAP_AUDIT_WRITE
capability.
Signed-off-by: Nsgrubb <sgrubb@redhat.com>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Update the function comments to match the code.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Commit 2115bb25 ("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: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NDeepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

struct timespec is not y2038 safe. Replace
all uses of timespec by y2038 safe struct timespec64.

Even though timespec is used here to represent timeouts,
replace these with timespec64 so that it facilitates
in verification by creating a y2038 safe kernel image
that is free of timespec.

The syscall interfaces themselves are not changed as part
of the patch. They will be part of a different series.
Signed-off-by: NDeepa Dinamani <deepa.kernel@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: NRichard Guy Briggs <rgb@redhat.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Capabilities were augmented to include ambient capabilities in v4.3
commit 58319057 ("capabilities: ambient capabilities").

Add ambient capabilities to the audit BPRM_FCAPS and CAPSET records.

The record contains fields "old_pp", "old_pi", "old_pe", "new_pp",
"new_pi", "new_pe" so in keeping with the previous record
normalizations, change the "new_*" variants to simply drop the "new_"
prefix.

A sample of the replaced BPRM_FCAPS record:
RAW: type=BPRM_FCAPS msg=audit(1491468034.252:237): fver=2
fp=0000000000200000 fi=0000000000000000 fe=1 old_pp=0000000000000000
old_pi=0000000000000000 old_pe=0000000000000000 old_pa=0000000000000000
pp=0000000000200000 pi=0000000000000000 pe=0000000000200000
pa=0000000000000000

INTERPRET: type=BPRM_FCAPS msg=audit(04/06/2017 04:40:34.252:237):
fver=2 fp=sys_admin fi=none fe=chown old_pp=none old_pi=none
old_pe=none old_pa=none pp=sys_admin pi=none pe=sys_admin pa=none

A sample of the replaced CAPSET record:
RAW: type=CAPSET msg=audit(1491469502.371:242): pid=833
cap_pi=0000003fffffffff cap_pp=0000003fffffffff cap_pe=0000003fffffffff
cap_pa=0000000000000000

INTERPRET: type=CAPSET msg=audit(04/06/2017 05:05:02.371:242) : pid=833
cap_pi=chown,dac_override,dac_read_search,fowner,fsetid,kill,
setgid,setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,
net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,
sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,sys_time,
sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,
mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pp=chown,dac_override,dac_read_search,fowner,fsetid,kill,setgid,
setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,
net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,
sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,
sys_time,sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,
mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pe=chown,dac_override,dac_read_search,fowner,fsetid,kill,setgid,
setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,
net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,
sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,
sys_time,sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,
mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pa=none

See: https://github.com/linux-audit/audit-kernel/issues/40Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NPaul 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: NDeepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Currently we free fsnotify_mark_connector structure only when inode /
vfsmount is getting freed. This can however impose noticeable memory
overhead when marks get attached to inodes only temporarily. So free the
connector structure once the last mark is detached from the object.
Since notification infrastructure can be working with the connector
under the protection of fsnotify_mark_srcu, we have to be careful and
free the fsnotify_mark_connector only after SRCU period passes.
Reviewed-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently notification marks are attached to object (inode or vfsmnt) by
a hlist_head in the object. The list is also protected by a spinlock in
the object. So while there is any mark attached to the list of marks,
the object must be pinned in memory (and thus e.g. last iput() deleting
inode cannot happen). Also for list iteration in fsnotify() to work, we
must hold fsnotify_mark_srcu lock so that mark itself and
mark->obj_list.next cannot get freed. Thus we are required to wait for
response to fanotify events from userspace process with
fsnotify_mark_srcu lock held. That causes issues when userspace process
is buggy and does not reply to some event - basically the whole
notification subsystem gets eventually stuck.

So to be able to drop fsnotify_mark_srcu lock while waiting for
response, we have to pin the mark in memory and make sure it stays in
the object list (as removing the mark waiting for response could lead to
lost notification events for groups later in the list). However we don't
want inode reclaim to block on such mark as that would lead to system
just locking up elsewhere.

This commit is the first in the series that paves way towards solving
these conflicting lifetime needs. Instead of anchoring the list of marks
directly in the object, we anchor it in a dedicated structure
(fsnotify_mark_connector) and just point to that structure from the
object. The following commits will also add spinlock protecting the list
and object pointer to the structure.
Reviewed-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

Commit 5b52330b ("audit: fix auditd/kernel connection state
tracking") made inlining audit_signal_info() a bit pointless as
it was always calling into auditd_test_task() so let's remove the
inline function in kernel/audit.h and convert __audit_signal_info()
in kernel/auditsc.c into audit_signal_info().
Reviewed-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul 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: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Signed-off-by: NPaul Moore <paul@paul-moore.com>

This adds a new auxiliary record MODULE_INIT to the SYSCALL event.

We get finit_module for free since it made most sense to hook this in to
load_module().

https://github.com/linux-audit/audit-kernel/issues/7
https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-Load-Record-FormatSigned-off-by: NRichard Guy Briggs <rgb@redhat.com>
Acked-by: NJessica Yu <jeyu@redhat.com>
[PM: corrected links in the commit description]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

The audit event specification asks for certain fields to exist in
all events. Running 'ausearch -m anom_abend -sv yes' returns no
events. This patch adds the result field so that the
AUDIT_ANOM_ABEND event conforms to the rules.
Signed-off-by: NSteve Grubb <sgrubb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Define AUDIT_SESSIONID in the uapi and add support for specifying user
filters based on the session ID.  Also add the new session ID filter
to the feature bitmap so userspace knows it is available.

https://github.com/linux-audit/audit-kernel/issues/4
RFE: add a session ID filter to the kernel's user filter
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: combine multiple patches from Richard into this one]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

The value (unsigned int)-1 is used as a sentinel to indicate the
sessionID is unset.  Skip this value when the session_id value wraps.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Tame initialization warning of len_abuf in audit_log_execve_info even
though there isn't presently a bug introduced by commit 43761473
("audit: fix a double fetch in audit_log_single_execve_arg()").  Using
UNINITIALIZED_VAR instead may mask future bugs.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

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: NJeff Vander Stoep <jeffv@google.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

There is a double fetch problem in audit_log_single_execve_arg()
where we first check the execve(2) argumnets for any "bad" characters
which would require hex encoding and then re-fetch the arguments for
logging in the audit record[1].  Of course this leaves a window of
opportunity for an unsavory application to munge with the data.

This patch reworks things by only fetching the argument data once[2]
into a buffer where it is scanned and logged into the audit
records(s).  In addition to fixing the double fetch, this patch
improves on the original code in a few other ways: better handling
of large arguments which require encoding, stricter record length
checking, and some performance improvements (completely unverified,
but we got rid of some strlen() calls, that's got to be a good
thing).

As part of the development of this patch, I've also created a basic
regression test for the audit-testsuite, the test can be tracked on
GitHub at the following link:

 * https://github.com/linux-audit/audit-testsuite/issues/25

[1] If you pay careful attention, there is actually a triple fetch
problem due to a strnlen_user() call at the top of the function.

[2] This is a tiny white lie, we do make a call to strnlen_user()
prior to fetching the argument data.  I don't like it, but due to the
way the audit record is structured we really have no choice unless we
copy the entire argument at once (which would require a rather
wasteful allocation).  The good news is that with this patch the
kernel no longer relies on this strnlen_user() value for anything
beyond recording it in the log, we also update it with a trustworthy
value whenever possible.
Reported-by: NPengfei Wang <wpengfeinudt@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Fix the whitespace in the CWD record
Signed-off-by: NSteve Grubb <sgrubb@redhat.com>
[PM: fixed subject line]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

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: NPaul Moore <pmoore@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: line wrapped description]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Move the calculations of values after the allocation in case the
allocation fails.  This avoids wasting effort in the rare case that it
fails, but more importantly saves us extra logic to release the tty
ref.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Signed-off-by: NPaul Moore <paul@paul-moore.com>

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: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Except on SPARC, this is what the code always did.  SPARC compat seccomp
was buggy, although the impact of the bug was limited because SPARC
32-bit and 64-bit syscall numbers are the same.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make the inode argument of the inode_getsecid hook non-const so that we
can use it to revalidate invalid security labels.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

This adds the ability audit the actions of a not-yet-running process.

This patch implements the ability to filter on the executable path.  Instead of
just hard coding the ino and dev of the executable we care about at the moment
the rule is inserted into the kernel, use the new audit_fsnotify
infrastructure to manage this dynamically.  This means that if the filename
does not yet exist but the containing directory does, or if the inode in
question is unlinked and creat'd (aka updated) the rule will just continue to
work.  If the containing directory is moved or deleted or the filesystem is
unmounted, the rule is deleted automatically.  A future enhancement would be to
have the rule survive across directory disruptions.

This is a heavily modified version of a patch originally submitted by Eric
Paris with some ideas from Peter Moody.

Cc: Peter Moody <peter@hda3.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: minor whitespace clean to satisfy ./scripts/checkpatch]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Clean up a number of places were casted magic numbers are used to represent
unset inode and device numbers in preparation for the audit by executable path
patch set.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: enclosed the _UNSET macros in parentheses for ./scripts/checkpatch]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

The "fix" in commit 0b08c5e5 ("audit: Fix check of return value of
strnlen_user()") didn't fix anything, it broke things.  As reported by
Steven Rostedt:

 "Yes, strnlen_user() returns 0 on fault, but if you look at what len is
  set to, than you would notice that on fault len would be -1"

because we just subtracted one from the return value.  So testing
against 0 doesn't test for a fault condition, it tests against a
perfectly valid empty string.

Also fix up the usual braindamage wrt using WARN_ON() inside a
conditional - make it part of the conditional and remove the explicit
unlikely() (which is already part of the WARN_ON*() logic, exactly so
that you don't have to write unreadable code.
Reported-and-tested-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Paul Moore <pmoore@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

strnlen_user() returns 0 when it hits fault, not -1. Fix the test in
audit_log_single_execve_arg(). Luckily this shouldn't ever happen unless
there's a kernel bug so it's mostly a cosmetic fix.

CC: Paul Moore <pmoore@redhat.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Signed-off-by: NMikhail Klementyev <jollheef@riseup.net>
[PM: patch applied by hand due to HTML mangling, rewrote subject line]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch adds a audit_log_d_path_exe() helper function
to share how we handle auditing of the exe_file's path.
Used by both audit and auditsc. No functionality is changed.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
[PM: tweaked subject line]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In order to ensure that filenames are not released before the audit
subsystem is done with the strings there are a number of hacks built
into the fs and audit subsystems around getname() and putname().  To
say these hacks are "ugly" would be kind.

This patch removes the filename hackery in favor of a more
conventional reference count based approach.  The diffstat below tells
most of the story; lots of audit/fs specific code is replaced with a
traditional reference count based approach that is easily understood,
even by those not familiar with the audit and/or fs subsystems.

CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In all likelihood there were some subtle, and perhaps not so subtle,
bugs with filename matching in audit_inode() and audit_inode_child()
for some time, however, recent changes to the audit filename code have
definitely broken the filename matching code.  The breakage could
result in duplicate filenames in the audit log and other odd audit
record entries.  This patch fixes the filename matching code and
restores some sanity to the filename audit records.

CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Enable recording of filenames in getname_kernel() and remove the
kludgy workaround in __audit_inode() now that we have proper filename
logging for kernel users.

CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Reviewed-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Unfortunately, while commit 4a928436 ("audit: correctly record file
names with different path name types") fixed a problem where we were
not recording filenames, it created a new problem by attempting to use
these file names after they had been freed.  This patch resolves the
issue by creating a copy of the filename which the audit subsystem
frees after it is done with the string.

At some point it would be nice to resolve this issue with refcounts,
or something similar, instead of having to allocate/copy strings, but
that is almost surely beyond the scope of a -rcX patch so we'll defer
that for later.  On the plus side, only audit users should be impacted
by the string copying.
Reported-by: NToralf Foerster <toralf.foerster@gmx.de>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

There is a problem with the audit system when multiple audit records
are created for the same path, each with a different path name type.
The root cause of the problem is in __audit_inode() when an exact
match (both the path name and path name type) is not found for a
path name record; the existing code creates a new path name record,
but it never sets the path name in this record, leaving it NULL.
This patch corrects this problem by assigning the path name to these
newly created records.

There are many ways to reproduce this problem, but one of the
easiest is the following (assuming auditd is running):

  # mkdir /root/tmp/test
  # touch /root/tmp/test/567
  # auditctl -a always,exit -F dir=/root/tmp/test
  # touch /root/tmp/test/567

Afterwards, or while the commands above are running, check the audit
log and pay special attention to the PATH records.  A faulty kernel
will display something like the following for the file creation:

  type=SYSCALL msg=audit(1416957442.025:93): arch=c000003e syscall=2
    success=yes exit=3 ... comm="touch" exe="/usr/bin/touch"
  type=CWD msg=audit(1416957442.025:93):  cwd="/root/tmp"
  type=PATH msg=audit(1416957442.025:93): item=0 name="test/"
    inode=401409 ... nametype=PARENT
  type=PATH msg=audit(1416957442.025:93): item=1 name=(null)
    inode=393804 ... nametype=NORMAL
  type=PATH msg=audit(1416957442.025:93): item=2 name=(null)
    inode=393804 ... nametype=NORMAL

While a patched kernel will show the following:

  type=SYSCALL msg=audit(1416955786.566:89): arch=c000003e syscall=2
    success=yes exit=3 ... comm="touch" exe="/usr/bin/touch"
  type=CWD msg=audit(1416955786.566:89):  cwd="/root/tmp"
  type=PATH msg=audit(1416955786.566:89): item=0 name="test/"
    inode=401409 ... nametype=PARENT
  type=PATH msg=audit(1416955786.566:89): item=1 name="test/567"
    inode=393804 ... nametype=NORMAL

This issue was brought up by a number of people, but special credit
should go to hujianyang@huawei.com for reporting the problem along
with an explanation of the problem and a patch.  While the original
patch did have some problems (see the archive link below), it did
demonstrate the problem and helped kickstart the fix presented here.

  * https://lkml.org/lkml/2014/9/5/66Reported-by: Nhujianyang <hujianyang@huawei.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Acked-by: NRichard Guy Briggs <rgb@redhat.com>

... for situations when we don't have any candidate in pathnames - basically,
in descriptor-based syscalls.

[Folded the build fix for !CONFIG_AUDITSYSCALL configs from Chen Gang]
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>