An io_uring openat operation can update an audit reference count
from multiple threads resulting in the call trace below.

A call to io_uring_submit() with a single openat op with a flag of
IOSQE_ASYNC results in the following reference count updates.

These first part of the system call performs two increments that do not race.

do_syscall_64()
  __do_sys_io_uring_enter()
    io_submit_sqes()
      io_openat_prep()
        __io_openat_prep()
          getname()
            getname_flags()       /* update 1 (increment) */
              __audit_getname()   /* update 2 (increment) */

The openat op is queued to an io_uring worker thread which starts the
opportunity for a race.  The system call exit performs one decrement.

do_syscall_64()
  syscall_exit_to_user_mode()
    syscall_exit_to_user_mode_prepare()
      __audit_syscall_exit()
        audit_reset_context()
           putname()              /* update 3 (decrement) */

The io_uring worker thread performs one increment and two decrements.
These updates can race with the system call decrement.

io_wqe_worker()
  io_worker_handle_work()
    io_wq_submit_work()
      io_issue_sqe()
        io_openat()
          io_openat2()
            do_filp_open()
              path_openat()
                __audit_inode()   /* update 4 (increment) */
            putname()             /* update 5 (decrement) */
        __audit_uring_exit()
          audit_reset_context()
            putname()             /* update 6 (decrement) */

The fix is to change the refcnt member of struct audit_names
from int to atomic_t.

kernel BUG at fs/namei.c:262!
Call Trace:
...
 ? putname+0x68/0x70
 audit_reset_context.part.0.constprop.0+0xe1/0x300
 __audit_uring_exit+0xda/0x1c0
 io_issue_sqe+0x1f3/0x450
 ? lock_timer_base+0x3b/0xd0
 io_wq_submit_work+0x8d/0x2b0
 ? __try_to_del_timer_sync+0x67/0xa0
 io_worker_handle_work+0x17c/0x2b0
 io_wqe_worker+0x10a/0x350

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/MW2PR2101MB1033FFF044A258F84AEAA584F1C9A@MW2PR2101MB1033.namprd21.prod.outlook.com/


Fixes: 5bd2182d ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Dan Clash <daclash@linux.microsoft.com>
Link: https://lore.kernel.org/r/20231012215518.GA4048@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net


Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Resetting rules' stateful data happens outside of the transaction logic,
so 'get' and 'dump' handlers have to emit audit log entries themselves.

Fixes: 8daa8fde ("netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Since set element reset is not integrated into nf_tables' transaction
logic, an explicit log call is needed, similar to NFT_MSG_GETOBJ_RESET
handling.

For the sake of simplicity, catchall element reset will always generate
a dedicated log entry. This relieves nf_tables_dump_set() from having to
adjust the logged element count depending on whether a catchall element
was found or not.

Fixes: 079cd633 ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

The patch fixes following checkpatch.pl issue:
ERROR: open brace '{' following function definitions go on the next line
ERROR: do not use assignment in if condition

Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Fixes following checkpatch.pl issue:
ERROR: space required before the open parenthesis '('
ERROR: spaces required around that '='
ERROR: spaces required around that '<'
ERROR: spaces required around that '=='

Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Tracefs or debugfs maybe cause hundreds to thousands of PATH records,
too many PATH records maybe cause soft lockup.

For example:
  1. CONFIG_KASAN=y && CONFIG_PREEMPTION=n
  2. auditctl -a exit,always -S open -k key
  3. sysctl -w kernel.watchdog_thresh=5
  4. mkdir /sys/kernel/debug/tracing/instances/test

There may be a soft lockup as follows:
  watchdog: BUG: soft lockup - CPU#45 stuck for 7s! [mkdir:15498]
  Kernel panic - not syncing: softlockup: hung tasks
  Call trace:
   dump_backtrace+0x0/0x30c
   show_stack+0x20/0x30
   dump_stack+0x11c/0x174
   panic+0x27c/0x494
   watchdog_timer_fn+0x2bc/0x390
   __run_hrtimer+0x148/0x4fc
   __hrtimer_run_queues+0x154/0x210
   hrtimer_interrupt+0x2c4/0x760
   arch_timer_handler_phys+0x48/0x60
   handle_percpu_devid_irq+0xe0/0x340
   __handle_domain_irq+0xbc/0x130
   gic_handle_irq+0x78/0x460
   el1_irq+0xb8/0x140
   __audit_inode_child+0x240/0x7bc
   tracefs_create_file+0x1b8/0x2a0
   trace_create_file+0x18/0x50
   event_create_dir+0x204/0x30c
   __trace_add_new_event+0xac/0x100
   event_trace_add_tracer+0xa0/0x130
   trace_array_create_dir+0x60/0x140
   trace_array_create+0x1e0/0x370
   instance_mkdir+0x90/0xd0
   tracefs_syscall_mkdir+0x68/0xa0
   vfs_mkdir+0x21c/0x34c
   do_mkdirat+0x1b4/0x1d4
   __arm64_sys_mkdirat+0x4c/0x60
   el0_svc_common.constprop.0+0xa8/0x240
   do_el0_svc+0x8c/0xc0
   el0_svc+0x20/0x30
   el0_sync_handler+0xb0/0xb4
   el0_sync+0x160/0x180

Therefore, we add cond_resched() to __audit_inode_child() to fix it.

Fixes: 5195d8e2 ("audit: dynamically allocate audit_names when not enough space is in the names array")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words.  It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.

That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more.  And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation.  It's a lose-lose
situation.

So just change the 'u32[2]' into a 'u64' and be done with it.

We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).

So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.

This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently.  By just using a saner data structure, it went from

	unsigned __capi;
	CAP_FOR_EACH_U32(__capi) {
		if (a.cap[__capi] != b.cap[__capi])
			return false;
	}
	return true;

to just being

	return a.val == b.val;

instead.  Which is rather more obvious both to humans and to compilers.

Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Richard Guy Briggs authored 2 years ago and Jan Kara committed 2 years ago

This patch passes the full response so that the audit function can use all
of it. The audit function was updated to log the additional information in
the AUDIT_FANOTIFY record.

Currently the only type of fanotify info that is defined is an audit
rule number, but convert it to hex encoding to future-proof the field.
Hex encoding suggested by Paul Moore <paul@paul-moore.com>.

The {subj,obj}_trust values are {0,1,2}, corresponding to no, yes, unknown.

Sample records:
  type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3137 subj_trust=3 obj_trust=5
  type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=0 subj_trust=2 obj_trust=2

Suggested-by: Steve Grubb <sgrubb@redhat.com>
Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2


Tested-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <bcb6d552e517b8751ece153e516d8b073459069c.1675373475.git.rgb@redhat.com>

Richard Guy Briggs authored 2 years ago and Jan Kara committed 2 years ago

The user space API for the response variable is __u32. This patch makes
sure that the whole path through the kernel uses u32 so that there is
no sign extension or truncation of the user space response.

Suggested-by: Steve Grubb <sgrubb@redhat.com>
Link: https://lore.kernel.org/r/12617626.uLZWGnKmhe@x2


Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Tested-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <3778cb0b3501bc4e686ba7770b20eb9ab0506cf4.1675373475.git.rgb@redhat.com>

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

audit_filter_uring(), audit_filter_inode_name() are substantially
similar to audit_filter_syscall(). Move the core logic to
__audit_filter_op() which can be parametrized for all three.

On a Skylakex system, getpid() latency (all results aggregated
across 12 boot cycles):

         Min     Mean    Median   Max      pstdev
         (ns)    (ns)    (ns)     (ns)

 -    196.63   207.86  206.60  230.98      (+- 3.92%)
 +    183.73   196.95  192.31  232.49	   (+- 6.04%)

Performance counter stats for 'bin/getpid' (3 runs) go from:
    cycles               805.58  (  +-  4.11% )
    instructions        1654.11  (  +-   .05% )
    IPC                    2.06  (  +-  3.39% )
    branches             430.02  (  +-   .05% )
    branch-misses          1.55  (  +-  7.09% )
    L1-dcache-loads      440.01  (  +-   .09% )
    L1-dcache-load-misses  9.05  (  +- 74.03% )
to:
    cycles		 765.37  (  +-  6.66% )
    instructions        1677.07  (  +-  0.04% )
    IPC		           2.20  (  +-  5.90% )
    branches	         431.10  (  +-  0.04% )
    branch-misses	   1.60  (  +- 11.25% )
    L1-dcache-loads	 521.04  (  +-  0.05% )
    L1-dcache-load-misses  6.92  (  +- 77.60% )

(Both aggregated over 12 boot cycles.)

The increased L1-dcache-loads are due to some intermediate values now
coming from the stack.

The improvement in cycles is due to a slightly denser loop (the list
parameter in the list_for_each_entry_rcu() exit check now comes from
a register rather than a constant as before.)

Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

ctx->major contains the current syscall number. This is, of course, a
constant for the duration of the syscall. Unfortunately, GCC's alias
analysis cannot prove that it is not modified via a pointer in the
audit_filter_syscall() loop, and so always loads it from memory.

In and of itself the load isn't very expensive (ops dependent on the
ctx->major load are only used to determine the direction of control flow
and have short dependence chains and, in any case the related branches
get predicted perfectly in the fastpath) but still cache ctx->major
in a local for two reasons:

* ctx->major is in the first cacheline of struct audit_context and has
  similar alignment as audit_entry::list audit_entry. For cases
  with a lot of audit rules, doing this reduces one source of contention
  from a potentially busy cache-set.

* audit_in_mask() (called in the hot loop in audit_filter_syscall())
  does cast manipulation and error checking on ctx->major:

     audit_in_mask(const struct audit_krule *rule, unsigned long val):
             if (val > 0xffffffff)
                     return false;

             word = AUDIT_WORD(val);
             if (word >= AUDIT_BITMASK_SIZE)
                     return false;

             bit = AUDIT_BIT(val);

             return rule->mask[word] & bit;

  The clauses related to the rule need to be evaluated in the loop, but
  the rest is unnecessarily re-evaluated for every loop iteration.
  (Note, however, that most of these are cheap ALU ops and the branches
   are perfectly predicted. However, see discussion on cycles
   improvement below for more on why it is still worth hoisting.)

On a Skylakex system change in getpid() latency (aggregated over
12 boot cycles):

             Min     Mean  Median     Max       pstdev
            (ns)     (ns)    (ns)    (ns)

 -        201.30   216.14  216.22  228.46      (+- 1.45%)
 +        196.63   207.86  206.60  230.98      (+- 3.92%)

Performance counter stats for 'bin/getpid' (3 runs) go from:
    cycles               836.89  (  +-   .80% )
    instructions        2000.19  (  +-   .03% )
    IPC                    2.39  (  +-   .83% )
    branches             430.14  (  +-   .03% )
    branch-misses          1.48  (  +-  3.37% )
    L1-dcache-loads      471.11  (  +-   .05% )
    L1-dcache-load-misses  7.62  (  +- 46.98% )

 to:
    cycles               805.58  (  +-  4.11% )
    instructions        1654.11  (  +-   .05% )
    IPC                    2.06  (  +-  3.39% )
    branches             430.02  (  +-   .05% )
    branch-misses          1.55  (  +-  7.09% )
    L1-dcache-loads      440.01  (  +-   .09% )
    L1-dcache-load-misses  9.05  (  +- 74.03% )

(Both aggregated over 12 boot cycles.)

instructions: we reduce around 8 instructions/iteration because some of
the computation is now hoisted out of the loop (branch count does not
change because GCC, for reasons unclear, only hoists the computations
while keeping the basic-blocks.)

cycles: improve by about 5% (in aggregate and looking at individual run
numbers.) This is likely because we now waste fewer pipeline resources
on unnecessary instructions which allows the control flow to
speculatively execute further ahead shortening the execution of the loop
a little. The final gating factor on the performance of this loop
remains the long dependence chain due to the linked-list load.

Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Since audit_proctitle is generated at syscall exit time, its value is
used immediately and cached for the next syscall.  Since this is the
case, then only clear it at task exit time.  Otherwise, there is no
point in caching the value OR bearing the overhead of regenerating it.

Fixes: 12c5e81d ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Be explicit in checking the struct audit_context "context" member enum
value rather than assuming the order of context enum values.

Fixes: 12c5e81d ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

The pid member of struct audit_context is never used.  Remove it.

The audit_reset_context() comment about unconditionally resetting
"ctx->state" should read "ctx->context".

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

The success and return_code are needed by the filters.  Move
audit_return_fixup() before the filters.  This was causing syscall
auditing events to be missed.

Link: https://github.com/linux-audit/audit-kernel/issues/138


Cc: stable@vger.kernel.org
Fixes: 12c5e81d ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: manual merge required]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Delete the redundant word 'doesn't'.

Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Currently @audit_context is allocated twice for io_uring workers:

  1. copy_process() calls audit_alloc();
  2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which
     is effectively audit_alloc()) and overwrites @audit_context,
     causing:

  BUG: memory leak
  unreferenced object 0xffff888144547400 (size 1024):
<...>
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<ffffffff8135cfc3>] audit_alloc+0x133/0x210
      [<ffffffff81239e63>] copy_process+0xcd3/0x2340
      [<ffffffff8123b5f3>] create_io_thread+0x63/0x90
      [<ffffffff81686604>] create_io_worker+0xb4/0x230
      [<ffffffff81686f68>] io_wqe_enqueue+0x248/0x3b0
      [<ffffffff8167663a>] io_queue_iowq+0xba/0x200
      [<ffffffff816768b3>] io_queue_async+0x113/0x180
      [<ffffffff816840df>] io_req_task_submit+0x18f/0x1a0
      [<ffffffff816841cd>] io_apoll_task_func+0xdd/0x120
      [<ffffffff8167d49f>] tctx_task_work+0x11f/0x570
      [<ffffffff81272c4e>] task_work_run+0x7e/0xc0
      [<ffffffff8125a688>] get_signal+0xc18/0xf10
      [<ffffffff8111645b>] arch_do_signal_or_restart+0x2b/0x730
      [<ffffffff812ea44e>] exit_to_user_mode_prepare+0x5e/0x180
      [<ffffffff844ae1b2>] syscall_exit_to_user_mode+0x12/0x20
      [<ffffffff844a7e80>] do_syscall_64+0x40/0x80

Then,

  3. io_sq_thread() or io_wqe_worker() frees @audit_context using
     audit_free();
  4. do_exit() eventually calls audit_free() again, which is okay
     because audit_free() does a NULL check.

As suggested by Paul Moore, fix it by deleting audit_alloc_kernel() and
redundant audit_free() calls.

Fixes: 5bd2182d ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Suggested-by: Paul Moore <paul@paul-moore.com>
Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220803222343.31673-1-yepeilin.cs@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Reset the type of the record last as the helper `audit_free_module()`
depends on it.

    unreferenced object 0xffff888153b707f0 (size 16):
      comm "modprobe", pid 1319, jiffies 4295110033 (age 1083.016s)
      hex dump (first 16 bytes):
        62 69 6e 66 6d 74 5f 6d 69 73 63 00 6b 6b 6b a5  binfmt_misc.kkk.
      backtrace:
        [<ffffffffa07dbf9b>] kstrdup+0x2b/0x50
        [<ffffffffa04b0a9d>] __audit_log_kern_module+0x4d/0xf0
        [<ffffffffa03b6664>] load_module+0x9d4/0x2e10
        [<ffffffffa03b8f44>] __do_sys_finit_module+0x114/0x1b0
        [<ffffffffa1f47124>] do_syscall_64+0x34/0x80
        [<ffffffffa200007e>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Cc: stable@vger.kernel.org
Fixes: 12c5e81d ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Not calling the function for dummy contexts will cause the context to
not be reset. During the next syscall, this will cause an error in
__audit_syscall_entry:

	WARN_ON(context->context != AUDIT_CTX_UNUSED);
	WARN_ON(context->name_count);
	if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
		audit_panic("unrecoverable error in audit_syscall_entry()");
		return;
	}

These problematic dummy contexts are created via the following call
chain:

       exit_to_user_mode_prepare
    -> arch_do_signal_or_restart
    -> get_signal
    -> task_work_run
    -> tctx_task_work
    -> io_req_task_submit
    -> io_issue_sqe
    -> audit_uring_entry

Cc: stable@vger.kernel.org
Fixes: 5bd2182d ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Julian Orth <ju.orth@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>

AUDIT_TIME_* events are generated when there are syscall rules present
that are not related to time keeping.  This will produce noisy log
entries that could flood the logs and hide events we really care about.

Rather than immediately produce the AUDIT_TIME_* records, store the data
in the context and log it at syscall exit time respecting the filter
rules.

Note: This eats the audit_buffer, unlike any others in show_special().

Please see https://bugzilla.redhat.com/show_bug.cgi?id=1991919



Fixes: 7e8eda73 ("ntp: Audit NTP parameters adjustment")
Fixes: 2d87a067 ("timekeeping: Audit clock adjustments")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fixed style/whitespace issues]
Signed-off-by: Paul Moore <paul@paul-moore.com>

As reported by Jeff, dereferencing the openat2 syscall argument in
audit_match_perm() to obtain the open_how::flags can result in an
oops/page-fault.  This patch fixes this by using the open_how struct
that we store in the audit_context with audit_openat2_how().

Independent of this patch, Richard Guy Briggs posted a similar patch
to the audit mailing list roughly 40 minutes after this patch was
posted.

Cc: stable@vger.kernel.org
Fixes: 1c30e3af ("audit: add support for the openat2 syscall")
Reported-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

The security_task_getsecid_subj() LSM hook invites misuse by allowing
callers to specify a task even though the hook is only safe when the
current task is referenced.  Fix this by removing the task_struct
argument to the hook, requiring LSM implementations to use the
current task.  While we are changing the hook declaration we also
rename the function to security_current_getsecid_subj() in an effort
to reinforce that the hook captures the subjective credentials of the
current task and not an arbitrary task on the system.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

It is not necessary for audit_filter_rules() functions to check
audit fileds of the rule with a lower priority, and if we did,
there might be some unintended effects, such as the ctx->ppid
may be changed unexpectedly, so return early if the rule has
a lower priority.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
[PM: slight tweak to the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Fix  possible null-pointer dereference in audit_filter_rules.

audit_filter_rules() error: we previously assumed 'ctx' could be null

Cc: stable@vger.kernel.org
Fixes: bf361231 ("audit: add saddr_fam filter field")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Since the openat2(2) syscall uses a struct open_how pointer to communicate
its parameters they are not usefully recorded by the audit SYSCALL record's
four existing arguments.

Add a new audit record type OPENAT2 that reports the parameters in its
third argument, struct open_how with fields oflag, mode and resolve.

The new record in the context of an event would look like:
time->Wed Mar 17 16:28:53 2021
type=PROCTITLE msg=audit(1616012933.531:184): proctitle=
  73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D
  7465737473756974652D737641440066696C652D6F70656E617432
type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2"
  inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00
  obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE
  cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=PATH msg=audit(1616012933.531:184):
  item=0 name="/root/rgb/git/audit-testsuite/tests"
  inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00
  obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT
  cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=CWD msg=audit(1616012933.531:184):
  cwd="/root/rgb/git/audit-testsuite/tests"
type=OPENAT2 msg=audit(1616012933.531:184):
  oflag=0100302 mode=0600 resolve=0xa
type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437
  success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18
  items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0
  fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2"
  exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2"
  subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
  key="testsuite-1616012933-bjAUcEPO"

Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com


Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: tweak subject, wrap example, move AUDIT_OPENAT2 to 1337]
Signed-off-by: Paul Moore <paul@paul-moore.com>

The openat2(2) syscall was added in kernel v5.6 with commit
fddb5d43 ("open: introduce openat2(2) syscall").

Add the openat2(2) syscall to the audit syscall classifier.

Link: https://github.com/linux-audit/audit-kernel/issues/67
Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com


Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: merge fuzz due to previous header rename, commit line wraps]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Replace audit syscall class magic numbers with macros.

This required putting the macros into new header file
include/linux/audit_arch.h since the syscall macros were
included for both 64 bit and 32 bit in any compat code, causing
redefinition warnings.

Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com


Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: renamed header to audit_arch.h after consulting with Richard]
Signed-off-by: Paul Moore <paul@paul-moore.com>

This patch adds basic audit io_uring filtering, using as much of the
existing audit filtering infrastructure as possible.  In order to do
this we reuse the audit filter rule's syscall mask for the io_uring
operation and we create a new filter for io_uring operations as
AUDIT_FILTER_URING_EXIT/audit_filter_list[7].

Thanks to Richard Guy Briggs for his review, feedback, and work on
the corresponding audit userspace changes.

Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

This patch adds basic auditing to io_uring operations, regardless of
their context.  This is accomplished by allocating audit_context
structures for the io-wq worker and io_uring SQPOLL kernel threads
as well as explicitly auditing the io_uring operations in
io_issue_sqe().  Individual io_uring operations can bypass auditing
through the "audit_skip" field in the struct io_op_def definition for
the operation; although great care must be taken so that security
relevant io_uring operations do not bypass auditing; please contact
the audit mailing list (see the MAINTAINERS file) with any questions.

The io_uring operations are audited using a new AUDIT_URINGOP record,
an example is shown below:

  type=UNKNOWN[1336] msg=audit(1631800225.981:37289):
    uring_op=19 success=yes exit=0 items=0 ppid=15454 pid=15681
    uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
    subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
    key=(null)

Thanks to Richard Guy Briggs for review and feedback.

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

This patch cleans up some of our audit_context handling by
abstracting out the reset and return code fixup handling to dedicated
functions.  Not only does this help make things easier to read and
inspect, it allows for easier reuse by future patches.  We also
convert the simple audit_context->in_syscall flag into an enum which
can be used to by future patches to indicate a calling context other
than the syscall context.

Thanks to Richard Guy Briggs for review and feedback.

Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Use SPDX-License-Identifier instead of a verbose license text.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Run the following command to find and remove the trailing spaces and tabs:

sed -r -i 's/[ \t]+$//' <audit_files>

The files to be checked are as follows:
kernel/audit*
include/linux/audit.h
include/uapi/linux/audit.h

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

AUDIT_DISABLED defined in kernel/audit.h as element of enum audit_state
and redefined in kernel/audit.c. This produces a warning when kernel builds
with syscalls audit disabled and brokes kernel build if -Werror used.
enum audit_state used in syscall audit code only. This patch changes
enum audit_state constants prefix AUDIT to AUDIT_STATE to avoid
AUDIT_DISABLED redefinition.

Signed-off-by: Sergey Nazarov <s-nazarov@yandex.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Fix the following checkpatch warning in auditsc.c:

WARNING: Missing a blank line after declarations

Signed-off-by: Roni Nevalainen <kitten@kittenz.dev>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials.  This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.

This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.

  void security_task_getsecid_subj(struct task_struct *p,
				   u32 *secid);
  void security_task_getsecid_obj(struct task_struct *p,
				  u32 *secid);

While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks.  The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.

Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

Remove the list parameter from the function call since the exit filter
list is the only remaining list used by this function.

This cleans up commit 5260ecc2
("audit: deprecate the AUDIT_FILTER_ENTRY filter")

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

No invoker uses the return value of audit_filter_syscall().
So make it return void, and amend the comment of
audit_filter_syscall().

Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
[PM: removed the changelog from the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>

When interacting with user namespace and non-user namespace aware
filesystem capabilities the vfs will perform various security checks to
determine whether or not the filesystem capabilities can be used by the
caller, whether they need to be removed and so on. The main
infrastructure for this resides in the capability codepaths but they are
called through the LSM security infrastructure even though they are not
technically an LSM or optional. This extends the existing security hooks
security_inode_removexattr(), security_inode_killpriv(),
security_inode_getsecurity() to pass down the mount's user namespace and
makes them aware of idmapped mounts.

In order to actually get filesystem capabilities from disk the
capability infrastructure exposes the get_vfs_caps_from_disk() helper.
For user namespace aware filesystem capabilities a root uid is stored
alongside the capabilities.

In order to determine whether the caller can make use of the filesystem
capability or whether it needs to be ignored it is translated according
to the superblock's user namespace. If it can be translated to uid 0
according to that id mapping the caller can use the filesystem
capabilities stored on disk. If we are accessing the inode that holds
the filesystem capabilities through an idmapped mount we map the root
uid according to the mount's user namespace. Afterwards the checks are
identical to non-idmapped mounts: reading filesystem caps from disk
enforces that the root uid associated with the filesystem capability
must have a mapping in the superblock's user namespace and that the
caller is either in the same user namespace or is a descendant of the
superblock's user namespace. For filesystems that are mountable inside
user namespace the caller can just mount the filesystem and won't
usually need to idmap it. If they do want to idmap it they can create an
idmapped mount and mark it with a user namespace they created and which
is thus a descendant of s_user_ns. For filesystems that are not
mountable inside user namespaces the descendant rule is trivially true
because the s_user_ns will be the initial user namespace.

If the initial user namespace is passed nothing changes so non-idmapped
mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com


Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Some unused macros could cause gcc warning:
kernel/audit.c:68:0: warning: macro "AUDIT_UNINITIALIZED" is not used
[-Wunused-macros]
kernel/auditsc.c:104:0: warning: macro "AUDIT_AUX_IPCPERM" is not used
[-Wunused-macros]
kernel/auditsc.c:82:0: warning: macro "AUDITSC_INVALID" is not used
[-Wunused-macros]

AUDIT_UNINITIALIZED and AUDITSC_INVALID are still meaningful and should
be in incorporated.

Just remove AUDIT_AUX_IPCPERM.

Thanks comments from Richard Guy Briggs and Paul Moore.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Moore <paul@paul-moore.com>