commit 86c8db86af43f52f682e53a0f2f0828683be1e52 upstream.

We should count the terminating NUL byte as part of the ctx_len.
Otherwise, UBSAN logs a warning:
  UBSAN: array-index-out-of-bounds in security/selinux/xfrm.c:99:14
  index 60 is out of range for type 'char [*]'

The allocation itself is correct so there is no actual out of bounds
indexing, just a warning.

Cc: stable@vger.kernel.org
Suggested-by: Christian Göttsche <cgzones@googlemail.com>
Link: https://lore.kernel.org/selinux/CAEjxPJ6tA5+LxsGfOJokzdPeRomBHjKLBVR6zbrg+_w3ZZbM3A@mail.gmail.com/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the BIT() and BIT_ULL() macros in the new audit code instead of
explicit shifts to improve readability.  Use bitmask instead of modulo
operation to simplify code.

Add test_range1_rand15() and test_range2_rand15() KUnit tests to improve
get_id_range() coverage.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20250512093732.1408485-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

A KUnit test checking boundaries triggers a canary warning, which may be
disturbing.  Let's remove this test for now.  Hopefully, KUnit will soon
get support for suppressing warning backtraces [1].

Cc: Alessandro Carminati <acarmina@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Günther Noack <gnoack@google.com>
Reported-by: Tingmao Wang <m@maowtm.org>
Closes: https://lore.kernel.org/r/20250327213807.12964-1-m@maowtm.org
Link: https://lore.kernel.org/r/20250425193249.78b45d2589575c15f483c3d8@linux-foundation.org [1]
Link: https://lore.kernel.org/r/20250503065359.3625407-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

Pull landlock fixes from Mickaël Salaün:
 "Fix some Landlock audit issues, add related tests, and updates
  documentation"

* tag 'landlock-6.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
  landlock: Update log documentation
  landlock: Fix documentation for landlock_restrict_self(2)
  landlock: Fix documentation for landlock_create_ruleset(2)
  selftests/landlock: Add PID tests for audit records
  selftests/landlock: Factor out audit fixture in audit_test
  landlock: Log the TGID of the domain creator
  landlock: Remove incorrect warning

On IMA policy update, if a measure rule exists in the policy,
IMA_MEASURE is set for ima_policy_flags which makes the violation_check
variable always true. Coupled with a no-action on MAY_READ for a
FILE_CHECK call, we're always taking the inode_lock().

This becomes a performance problem for extremely heavy read-only workloads.
Therefore, prevent this only in the case there's no action to be taken.

Signed-off-by: Frederick Lawler <fred@cloudflare.com>
Acked-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Fix, deduplicate, and improve rendering of landlock_restrict_self(2)'s
flags documentation.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250416154716.1799902-2-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

Move and fix the flags documentation, and improve formatting.

It makes more sense and it eases maintenance to document syscall flags
in landlock.h, where they are defined.  This is already the case for
landlock_restrict_self(2)'s flags.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250416154716.1799902-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

There is a GCC crash bug in the randstruct for latest GCC versions that
is being tickled by landlock[1]. Temporarily disable GCC randstruct for
COMPILE_TEST builds to unbreak CI systems for the coming -rc2. This can
be restored once the bug is fixed.

Suggested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/all/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/ [1]
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250409151154.work.872-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

As for other Audit's "pid" fields, Landlock should use the task's TGID
instead of its TID.  Fix this issue by keeping a reference to the TGID
of the domain creator.

Existing tests already check for the PID but only with the thread group
leader, so always the TGID.  A following patch adds dedicated tests for
non-leader thread.

Remove the current_real_cred() check which does not make sense because
we only reference a struct pid, whereas a previous version did reference
a struct cred instead.

Cc: Christian Brauner <brauner@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20250410171725.1265860-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

landlock_put_hierarchy() can be called when an error occurs in
landlock_merge_ruleset() due to insufficient memory.  In this case, the
domain's audit details might not have been allocated yet, which would
cause landlock_free_hierarchy_details() to print a warning (but still
safely handle this case).

We could keep the WARN_ON_ONCE(!hierarchy) but it's not worth it for
this kind of function, so let's remove it entirely.

Cc: Paul Moore <paul@paul-moore.com>
Reported-by: syzbot+8bca99e91de7e060e4ea@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20250331104709.897062-1-mic@digikod.net
Reviewed-by: Günther Noack <gnoack@google.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>