[SRU] [Jammy] [PATCH 0/1] UBUNTU: audit: fix memory leak of audit_log_lsm()

[Jianlin Lv]

BugLink: https://bugs.launchpad.net/bugs/1987430

[Impact]

Under upgrading server to Ubuntu 22.04 with kernel 5.15.0-XX, memory
started to ramp up slowly that growth ~1 GB a day.

[Fix]

The memory leak is an allocated struct audit_buffer object in
audit_log_lsm() that to record LSM attributes.
Free audit buffer before audit_log_lsm() return.

[Test Plan]

1.Disable apparmor module by append apparmor=0 to grub

2.Start auditd service with following audit rule:
-a exit,always -F arch=b64 -S execve
-a exit,always -F arch=b32 -S execve

3.Using Kmemleak to check if memory leak has occurred
    $ cat /sys/kernel/debug/kmemleak
  or Keep watching for changes in slabinfo
    $ watch "sudo cat /proc/slabinfo | grep kmalloc-2k"

Jianlin Lv (1):
  UBUNTU: audit: fix memory leak of audit_log_lsm()

 kernel/auditsc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

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2.25.1