There have been reports of auditd restarts resulting in kaudit not being able
to find a newly registered auditd.  It results in reports such as:
	kernel: [ 2077.233573] audit: *NO* daemon at audit_pid=1614
	kernel: [ 2077.234712] audit: audit_lost=97 audit_rate_limit=0 audit_backlog_limit=320
	kernel: [ 2077.234718] audit: auditd disappeared
		(previously mis-spelled "dissapeared")

One possible cause is a race between the shutdown of an older auditd and a
newer one.  If the newer one sets the daemon pid to itself in kauditd before
the older one has cleared the daemon pid, the newer daemon pid will be erased.
This could be caused by an automated system, or by manual intervention, but in
either case, there is no use in having the older daemon clear the daemon pid
reference since its old pid is no longer being referenced.  This patch will
prevent that specific case, returning an error of EACCES.

The case for preventing a newer auditd from registering itself if there is an
existing auditd is a more difficult case that is beyond the scope of this
patch.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

audit_receive_msg() needlessly contained a fallthrough case that called
audit_receive_filter(), containing no common code between the cases.  Separate
them to make the logic clearer.  Refactor AUDIT_LIST_RULES, AUDIT_ADD_RULE,
AUDIT_DEL_RULE cases to create audit_rule_change(), audit_list_rules_send()
functions.  This should not functionally change the logic.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Log transition of config changes when AUDIT_TTY_SET is called, including both
enabled and log_passwd values now in the struct.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

kauditd_send_skb is called after audit_pid was checked to be non-zero.

However, it can be set to 0 due to auditd exiting while kauditd_send_skb
is still executed and this can result in a spurious warning about missing
auditd.

Re-check audit_pid before printing the message.
Signed-off-by: NMateusz Guzik <mguzik@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Since audit can already be disabled by "audit=0" on the kernel boot line, or by
the command "auditctl -e 0", it would be more useful to have the
audit_backlog_limit set to zero mean effectively unlimited (limited only by
system RAM).
Acked-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

we already have old_lock, no need to calculate it again.
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

If audit is disabled,we shouldn't generate the audit log.
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

The order of new feature and old feature is incorrect,
this patch fix it.
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Since kernel parameter is operated before
initcall, so the audit_initialized must be
AUDIT_UNINITIALIZED or DISABLED in audit_enable.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

reaahead-collector abuses the audit logging facility to discover which files
are accessed at boot time to make a pre-load list

Add a tuning option to audit_backlog_wait_time so that if auditd can't keep up,
or gets blocked, the callers won't be blocked.

Bump audit_status API version to "2".
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Re-named confusing local variable names (status_set and status_get didn't agree
with their command type name) and reduced their scope.

Future-proof API changes by not depending on the exact size of the audit_status
struct and by adding an API version field.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

The default audit_backlog_limit is 64.  This was a reasonable limit at one time.

systemd causes so much audit queue activity on startup that auditd doesn't
start before the backlog queue has already overflowed by more than a factor of
2.  On a system with audit= not set on the kernel command line, this isn't an
issue since that history isn't kept for auditd when it is available.  On a
system with audit=1 set on the kernel command line, kaudit tries to keep that
history until auditd is able to drain the queue.

This default can be changed by the "-b" option in audit.rules once the system
has booted, but won't help with lost messages on boot.

One way to solve this would be to increase the default backlog queue size to
avoid losing any messages before auditd is able to consume them.  This would
be overkill to the embedded community and insufficient for some servers.

Another way to solve it might be to add a kconfig option to set the default
based on the system type.  An embedded system would get the current (or
smaller) default, while Workstations might get more than now and servers might
get more.

None of these solutions helps if a system's compiled default is too small to
see the lost messages without compiling a new kernel.

This patch adds a kernel set-up parameter (audit already has one to
enable/disable it) "audit_backlog_limit=<n>" that overrides the default to
allow the system administrator to set the backlog limit.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

These and similar errors were seen on a patched 3.8 kernel when the
audit subsystem was overrun during boot:

  udevd[876]: worker [887] unexpectedly returned with status 0x0100
  udevd[876]: worker [887] failed while handling
'/devices/pci0000:00/0000:00:03.0/0000:40:00.0'
  udevd[876]: worker [880] unexpectedly returned with status 0x0100
  udevd[876]: worker [880] failed while handling
'/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1'

  udevadm settle - timeout of 180 seconds reached, the event queue
contains:
    /sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995)
    /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034)

  audit: audit_backlog=258 > audit_backlog_limit=256
  audit: audit_lost=1 audit_rate_limit=0 audit_backlog_limit=256

The change below increases the efficiency of the audit code and prevents it
from being overrun:

Use add_wait_queue_exclusive() in wait_for_auditd() to put the
thread on the wait queue.  When kauditd dequeues an skb, all
of the waiting threads are waiting for the same resource, but
only one is going to get it, so there's no need to wake up
more than one waiter.

See: https://lkml.org/lkml/2013/9/2/479Signed-off-by: NDan Duval <dan.duval@oracle.com>
Signed-off-by: NChuck Anderson <chuck.anderson@oracle.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

These and similar errors were seen on a patched 3.8 kernel when the
audit subsystem was overrun during boot:

  udevd[876]: worker [887] unexpectedly returned with status 0x0100
  udevd[876]: worker [887] failed while handling
'/devices/pci0000:00/0000:00:03.0/0000:40:00.0'
  udevd[876]: worker [880] unexpectedly returned with status 0x0100
  udevd[876]: worker [880] failed while handling
'/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1'

  udevadm settle - timeout of 180 seconds reached, the event queue
contains:
    /sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995)
    /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034)

  audit: audit_backlog=258 > audit_backlog_limit=256
  audit: audit_lost=1 audit_rate_limit=0 audit_backlog_limit=256

The change below increases the efficiency of the audit code and prevents it
from being overrun:

Only issue a wake_up in kauditd if the length of the skb queue is less than the
backlog limit.  Otherwise, threads waiting in wait_for_auditd() will simply
wake up, discover that the queue is still too long for them to proceed, and go
back to sleep.  This results in wasted context switches and machine cycles.
kauditd_thread() is the only function that removes buffers from audit_skb_queue
so we can't race.  If we did, the timeout in wait_for_auditd() would expire and
the waiting thread would continue.

See: https://lkml.org/lkml/2013/9/2/479Signed-off-by: NDan Duval <dan.duval@oracle.com>
Signed-off-by: NChuck Anderson <chuck.anderson@oracle.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

If wait_for_auditd() times out, go immediately to the error function rather
than retesting the loop conditions.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

When the audit queue overflows and times out (audit_backlog_wait_time), the
audit queue overflow timeout is set to zero.  Once the audit queue overflow
timeout condition recovers, the timeout should be reset to the original value.

See also:
	https://lkml.org/lkml/2013/9/2/473

Cc: stable@vger.kernel.org # v3.8-rc4+
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NDan Duval <dan.duval@oracle.com>
Signed-off-by: NChuck Anderson <chuck.anderson@oracle.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Convert audit from only listening in init_net to use register_pernet_subsys()
to dynamically manage the netlink socket list.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

When being refactored from audit_log_start() to audit_log_task_info(), in
commit e23eb920 the tty and ses fields in the log output got transposed.
Restore to original order to avoid breaking search tools.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Normally, netlink ports use the PID of the userspace process as the port ID.
If the PID is already in use by a port, the kernel will allocate another port
ID to avoid conflict.  Re-name all references to netlink ports from pid to
portid to reflect this reality and avoid confusion with actual PIDs.  Ports
use the __u32 type, so re-type all portids accordingly.

(This patch is very similar to ebiederman's 5deadd69)
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

...to make it clear what the intent behind each record's operation was.

In many cases you can infer this, based on the context of the syscall
and the result. In other cases it's not so obvious. For instance, in
the case where you have a file being renamed over another, you'll have
two different records with the same filename but different inode info.
By logging this information we can clearly tell which one was created
and which was deleted.

This fixes what was broken in commit bfcec708.
Commit 79f6530c should also be backported to stable v3.7+.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

In send/GET, we don't want the kernel to lie about what value is set.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Using the nlmsg_len member of the netlink header to test if the message
is valid is wrong as it includes the size of the netlink header itself.
Thereby allowing to send short netlink messages that pass those checks.

Use nlmsg_len() instead to test for the right message length. The result
of nlmsg_len() is guaranteed to be non-negative as the netlink message
already passed the checks of nlmsg_ok().

Also switch to min_t() to please checkpatch.pl.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: stable@vger.kernel.org  # v2.6.6+ for the 1st hunk, v2.6.23+ for the 2nd
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

We currently are setting fields to 0 to initialize the structure
declared on the stack.  This is a bad idea as if the structure has holes
or unpacked space these will not be initialized.  Just use memset.  This
is not a performance critical section of code.
Signed-off-by: NEric Paris <eparis@redhat.com>

We leak 4 bytes of kernel stack in response to an AUDIT_GET request as
we miss to initialize the mask member of status_set. Fix that.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: stable@vger.kernel.org  # v2.6.6+
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

This adds a new 'audit_feature' bit which allows userspace to set it
such that the loginuid is absolutely immutable, even if you have
CAP_AUDIT_CONTROL.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

This is a new audit feature which only grants processes with
CAP_AUDIT_CONTROL the ability to unset their loginuid.  They cannot
directly set it from a valid uid to another valid uid.  The ability to
unset the loginuid is nice because a priviledged task, like that of
container creation, can unset the loginuid and then priv is not needed
inside the container when a login daemon needs to set the loginuid.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

The audit_status structure was not designed with extensibility in mind.
Define a new AUDIT_SET_FEATURE message type which takes a new structure
of bits where things can be enabled/disabled/locked one at a time.  This
structure should be able to grow in the future while maintaining forward
and backward compatibility (based loosly on the ideas from capabilities
and prctl)

This does not actually add any features, but is just infrastructure to
allow new on/off types of audit system features.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

When the audit=1 kernel parameter is absent and auditd is not running,
AUDIT_USER_AVC messages are being silently discarded.

AUDIT_USER_AVC messages should be sent to userspace using printk(), as
mentioned in the commit message of 4a4cd633 ("AUDIT: Optimise the
audit-disabled case for discarding user messages").

When audit_enabled is 0, audit_receive_msg() discards all user messages
except for AUDIT_USER_AVC messages. However, audit_log_common_recv_msg()
refuses to allocate an audit_buffer if audit_enabled is 0. The fix is to
special case AUDIT_USER_AVC messages in both functions.

It looks like commit 50397bd1 ("[AUDIT] clean up audit_receive_msg()")
introduced this bug.

Cc: <stable@kernel.org> # v2.6.25+
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Remove it.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

A newline was accidentally added during session ID helper refactorization in
commit 4d3fb709.  This needlessly uses up buffer space, messes up syslog
formatting and makes userspace processing less efficient.  Remove it.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Signed-off-by: NIlya V. Matveychikov <matvejchikov@gmail.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Messages of type AUDIT_USER_TTY were being formatted to 1024 octets,
truncating messages approaching MAX_AUDIT_MESSAGE_LENGTH (8970 octets).

Set the formatting to 8560 characters, given maximum estimates for prefix and
suffix budgets.

See the problem discussion:
https://www.redhat.com/archives/linux-audit/2009-January/msg00030.html

And the new size rationale:
https://www.redhat.com/archives/linux-audit/2013-September/msg00016.html

Test ~8k messages with:
auditctl -m "$(for i in $(seq -w 001 820);do echo -n "${i}0______";done)"
Reported-by: NLC Bruzenak <lenny@magitekltd.com>
Reported-by: NJustin Stephenson <jstephen@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

After commit 82919919 ("kernel/audit.c: avoid negative sleep
durations") audit emitters will block forever if userspace daemon cannot
handle backlog.

After the timeout the waiting loop turns into busy loop and runs until
daemon dies or returns back to work.  This is a minimal patch for that
bug.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Chuck Anderson <chuck.anderson@oracle.com>
Cc: Dan Duval <dan.duval@oracle.com>
Cc: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

audit_log_start() does wait_for_auditd() in a loop until
audit_backlog_wait_time passes or audit_skb_queue has a room.

If signal_pending() is true this becomes a busy-wait loop, schedule() in
TASK_INTERRUPTIBLE won't block.

Thanks to Guy for fully investigating and explaining the problem.

(akpm: that'll cause the system to lock up on a non-preemptible
uniprocessor kernel)

(Guy: "Our customer was in fact running a uniprocessor machine, and they
reported a system hang.")
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reported-by: NGuy Streeter <streeter@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The helper function didn't include a leading space, so it was jammed
against the previous text in the audit record.
Signed-off-by: NEric Paris <eparis@redhat.com>

This reverts commit 6ff5e459.

Conflicts:
	kernel/audit.c

This patch was starting a kthread for all the time.  Since the follow on
patches that required it didn't get finished in 3.10 time, we shouldn't
ship this change in 3.10.
Signed-off-by: NEric Paris <eparis@redhat.com>

The userspace audit tools didn't like the existing formatting of the
AUDIT_ANOM_LINK event. It needed to be expanded to emit an AUDIT_PATH
event as well, so this implements the change. The bulk of the patch is
moving code out of auditsc.c into audit.c and audit.h for general use.
It expands audit_log_name to include an optional "struct path" argument
for the simple case of just needing to report a pathname. This also
makes
audit_log_task_info available when syscall auditing is not enabled,
since
it is needed in either case for process details.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reported-by: NSteve Grubb <sgrubb@redhat.com>

This function is called when we receive a netlink message from
userspace.  We don't need to worry about it coming from irq context or
irqs making it re-entrant.
Signed-off-by: NEric Paris <eparis@redhat.com>

Most commands are entered one line at a time and processed as complete lines
in non-canonical mode.  Commands that interactively require a password, enter
canonical mode to do this while shutting off echo.  This pair of features
(icanon and !echo) can be used to avoid logging passwords by audit while still
logging the rest of the command.

Adding a member (log_passwd) to the struct audit_tty_status passed in by
pam_tty_audit allows control of canonical mode without echo per task.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Some of the callers of the audit tty function use spin_lock_irqsave/restore.
We were using the forced always enable version, which seems really bad.
Since I don't know every one of these code paths well enough, it makes
sense to just switch everything to the safe version.  Maybe it's a
little overzealous, but it's a lot better than an unlucky deadlock when
we return to a caller with irq enabled and they expect it to be
disabled.
Signed-off-by: NEric Paris <eparis@redhat.com>