04 Feb, 2019

1 commit

  • Remove audit_context from struct task_struct and struct audit_buffer
    when CONFIG_AUDIT is enabled but CONFIG_AUDITSYSCALL is not.

    Also, audit_log_name() (and supporting inode and fcaps functions) should
    have been put back in auditsc.c when soft and hard link logging was
    normalized since it is only used by syscall auditing.

    See github issue https://github.com/linux-audit/audit-kernel/issues/105

    Signed-off-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

31 Jan, 2019

1 commit

  • Don't fetch fcaps when umount2 is called to avoid a process hang while
    it waits for the missing resource to (possibly never) re-appear.

    Note the comment above user_path_mountpoint_at():
    * A umount is a special case for path walking. We're not actually interested
    * in the inode in this situation, and ESTALE errors can be a problem. We
    * simply want track down the dentry and vfsmount attached at the mountpoint
    * and avoid revalidating the last component.

    This can happen on ceph, cifs, 9p, lustre, fuse (gluster) or NFS.

    Please see the github issue tracker
    https://github.com/linux-audit/audit-kernel/issues/100

    Signed-off-by: Richard Guy Briggs
    [PM: merge fuzz in audit_log_fcaps()]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

26 Jan, 2019

2 commits

  • V3 namespaced file capabilities were introduced in
    commit 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")

    Add support for these by adding the "frootid" field to the existing
    fcaps fields in the NAME and BPRM_FCAPS records.

    Please see github issue
    https://github.com/linux-audit/audit-kernel/issues/103

    Signed-off-by: Richard Guy Briggs
    Acked-by: Serge Hallyn
    [PM: comment tweak to fit an 80 char line width]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     
  • loginuid and sessionid (and audit_log_session_info) should be part of
    CONFIG_AUDIT scope and not CONFIG_AUDITSYSCALL since it is used in
    CONFIG_CHANGE, ANOM_LINK, FEATURE_CHANGE (and INTEGRITY_RULE), none of
    which are otherwise dependent on AUDITSYSCALL.

    Please see github issue
    https://github.com/linux-audit/audit-kernel/issues/104

    Signed-off-by: Richard Guy Briggs
    [PM: tweaked subject line for better grep'ing]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

19 Jan, 2019

1 commit

  • Tie syscall information to all CONFIG_CHANGE calls since they are all a
    result of user actions.

    Exclude user records from syscall context:
    Since the function audit_log_common_recv_msg() is shared by a number of
    AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types,
    and since the AUDIT_CONFIG_CHANGE message type has been converted to a
    syscall accompanied record type, special-case the AUDIT_USER_* range of
    messages so they remain standalone records.

    See: https://github.com/linux-audit/audit-kernel/issues/59
    See: https://github.com/linux-audit/audit-kernel/issues/50

    Signed-off-by: Richard Guy Briggs
    [PM: fix line lengths in kernel/audit.c]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

15 Jan, 2019

1 commit

  • The failure to add an audit rule due to audit locked gives no clue
    what CONFIG_CHANGE operation failed.
    Similarly the set operation is the only other operation that doesn't
    give the "op=" field to indicate the action.
    All other CONFIG_CHANGE records include an op= field to give a clue as
    to what sort of configuration change is being executed.

    Since these are the only CONFIG_CHANGE records that that do not have an
    op= field, add them to bring them in line with the rest.

    Old records:
    type=CONFIG_CHANGE msg=audit(1519812997.781:374): pid=610 uid=0 auid=0 ses=1 subj=... audit_enabled=2 res=0
    type=CONFIG_CHANGE msg=audit(2018-06-14 14:55:04.507:47) : audit_enabled=1 old=1 auid=unset ses=unset subj=... res=yes

    New records:
    type=CONFIG_CHANGE msg=audit(1520958477.855:100): pid=610 uid=0 auid=0 ses=1 subj=... op=add_rule audit_enabled=2 res=0

    type=CONFIG_CHANGE msg=audit(2018-06-14 14:55:04.507:47) : op=set audit_enabled=1 old=1 auid=unset ses=unset subj=... res=yes

    See: https://github.com/linux-audit/audit-kernel/issues/59

    Signed-off-by: Richard Guy Briggs
    [PM: fixed checkpatch.pl line length problems]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

15 Dec, 2018

1 commit


04 Dec, 2018

1 commit

  • Since the vast majority of files (99.993% on a typical system) have no
    fcaps, display "0" instead of the full zero-padded 16 hex digits in the
    two PATH record cap_f* fields to save netlink bandwidth and disk space.

    Simply changing the format to %x won't work since the value is two (or
    possibly more in the future) 32-bit hexadecimal values concatenated and
    bits in higher order values will be misrepresented.

    Passes audit-testsuite and userspace tools already work fine.
    Please see the github issue tracker for more details
    https://github.com/linux-audit/audit-kernel/issues/101

    Signed-off-by: Richard Guy Briggs
    Acked-by: Steve Grubb
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

27 Nov, 2018

2 commits

  • There are many places, notably audit_log_task_info() and
    audit_log_exit(), that take task_struct pointers but in reality they
    are always working on the current task. This patch eliminates the
    task_struct arguments and uses current directly which allows a number
    of cleanups as well.

    Acked-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Paul Moore
     
  • There are some cases where we are making multiple audit_log_format()
    calls in a row, for no apparent reason. Squash these down to a
    single audit_log_format() call whenever possible.

    Acked-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Paul Moore
     

20 Nov, 2018

1 commit

  • There are still a couple of places (mark and watch config changes) that
    open code auid and ses fields in sequence in records instead of using
    the audit_log_session_info() helper. Use the helper. Adjust the helper
    to accommodate being the first fields. Passes audit-testsuite.

    Signed-off-by: Richard Guy Briggs
    [PM: fixed misspellings in the description]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

18 Jul, 2018

1 commit

  • Commit c72051d5778a ("audit: use ktime_get_coarse_ts64() for time
    access") converted audit's use of current_kernel_time64() to the
    new ktime_get_coarse_ts64() function. Unfortunately this resulted
    in incorrect timestamps, e.g. events stamped with the year 1969
    despite it being 2018. This patch corrects this by using
    ktime_get_coarse_real_ts64() just like the current_kernel_time64()
    wrapper.

    Fixes: c72051d5778a ("audit: use ktime_get_coarse_ts64() for time access")
    Reviewed-by: Arnd Bergmann
    Signed-off-by: Paul Moore

    Paul Moore
     

03 Jul, 2018

1 commit


19 Jun, 2018

2 commits

  • Remove comparison of audit_enabled to magic numbers outside of audit.

    Related: https://github.com/linux-audit/audit-kernel/issues/86

    Signed-off-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     
  • The AUDIT_FILTER_TYPE name is vague and misleading due to not describing
    where or when the filter is applied and obsolete due to its available
    filter fields having been expanded.

    Userspace has already renamed it from AUDIT_FILTER_TYPE to
    AUDIT_FILTER_EXCLUDE without checking if it already exists. The
    userspace maintainer assures that as long as it is set to the same value
    it will not be a problem since the userspace code does not treat
    compiler warnings as errors. If this policy changes then checks if it
    already exists can be added at the same time.

    See: https://github.com/linux-audit/audit-kernel/issues/89

    Signed-off-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

15 May, 2018

1 commit

  • 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
    [PM: merge fuzz in auditsc.c and selinuxfs.c, checkpatch.pl fixes]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

21 Apr, 2018

1 commit


07 Apr, 2018

1 commit

  • 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

    Linus Torvalds
     

26 Mar, 2018

1 commit

  • Some functions definitions have either the initial open brace and/or
    the closing brace outside of column 1.

    Move those braces to column 1.

    This allows various function analyzers like gnu complexity to work
    properly for these modified functions.

    Signed-off-by: Joe Perches
    Acked-by: Andy Shevchenko
    Acked-by: Paul Moore
    Acked-by: Alex Deucher
    Acked-by: Dave Chinner
    Reviewed-by: Darrick J. Wong
    Acked-by: Alexandre Belloni
    Acked-by: Martin K. Petersen
    Acked-by: Takashi Iwai
    Acked-by: Mauro Carvalho Chehab
    Acked-by: Rafael J. Wysocki
    Acked-by: Nicolin Chen
    Acked-by: Martin K. Petersen
    Acked-by: Steven Rostedt (VMware)
    Signed-off-by: Jiri Kosina

    Joe Perches
     

21 Mar, 2018

1 commit


09 Mar, 2018

2 commits


07 Mar, 2018

1 commit

  • 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
    Signed-off-by: Paul Moore

    Greg Edwards
     

24 Feb, 2018

1 commit

  • 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
    Reviewed-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Paul Moore
     

22 Feb, 2018

1 commit

  • 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
    [PM: not necessary (other funcs check for NULL), but a good practice]
    Signed-off-by: Paul Moore

    Richard Guy Briggs
     

15 Feb, 2018

1 commit


11 Nov, 2017

7 commits


05 Sep, 2017

2 commits

  • Update the function comments to match the code.

    Signed-off-by: Geliang Tang
    Signed-off-by: Paul Moore

    Geliang Tang
     
  • Commit 2115bb250f26 ("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
    Acked-by: Arnd Bergmann
    Acked-by: Deepa Dinamani
    Signed-off-by: Paul Moore

    Mel Gorman
     

21 Jul, 2017

1 commit


19 Jul, 2017

1 commit

  • Found this issue by kmemleak report, auditd_send_unicast_skb
    did not free skb if rcu_dereference(auditd_conn) returns null.

    unreferenced object 0xffff88082568ce00 (size 256):
    comm "auditd", pid 1119, jiffies 4294708499
    backtrace:
    [] kmemleak_alloc+0x4a/0xa0
    [] kmem_cache_alloc_node+0xcc/0x210
    [] __alloc_skb+0x5d/0x290
    [] audit_make_reply+0x54/0xd0
    [] audit_receive_msg+0x967/0xd70
    ----------------
    (gdb) list *audit_receive_msg+0x967
    0xffffffff8113dff7 is in audit_receive_msg (kernel/audit.c:1133).
    1132 skb = audit_make_reply(0, AUDIT_REPLACE, 0,
    0, &pvnr, sizeof(pvnr));
    ---------------
    [] audit_receive+0x52/0xa0
    [] netlink_unicast+0x181/0x240
    [] netlink_sendmsg+0x2c2/0x3b0
    [] sock_sendmsg+0x38/0x50
    [] SYSC_sendto+0x102/0x190
    [] SyS_sendto+0xe/0x10
    [] entry_SYSCALL_64_fastpath+0x1a/0xa5
    [] 0xffffffffffffffff

    Signed-off-by: Shu Wang
    Signed-off-by: Paul Moore

    Shu Wang
     

06 Jul, 2017

1 commit

  • 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

    Linus Torvalds
     

16 Jun, 2017

1 commit

  • 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
    Signed-off-by: Paul Moore

    Paul Moore
     

14 Jun, 2017

1 commit

  • 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
    Reported-by: Dusty Mabe
    Reviewed-by: Richard Guy Briggs
    Signed-off-by: Paul Moore

    Paul Moore