[SRU][J/F][PATCH 0/2] CVE-2024-38570

[Bethany Jamison]

[Impact]

gfs2: Fix potential glock use-after-free on unmount

When a DLM lockspace is released and there are still locks in that
lockspace, DLM will unlock those locks automatically.  Commit
fb6791d started exploiting this behavior to speed up filesystem
unmount: gfs2 would simply free glocks it didn't want to unlock and then
release the lockspace.  This didn't take the bast callbacks for
asynchronous lock contention notifications into account, which remain
active until until a lock is unlocked or its lockspace is released.

To prevent those callbacks from accessing deallocated objects, put the
glocks that should not be unlocked on the sd_dead_glocks list, release
the lockspace, and only then free those glocks.

As an additional measure, ignore unexpected ast and bast callbacks if
the receiving glock is dead.

[Fix]

Noble:	released
Jammy:	Cleanly cherry-picked prereq commit, backported fix commit: 
	context conflicts from neighboring lines, shouldn't affect the
	fix changes
Focal:	same as Jammy put with slightly different neighboring context
	conflicts so the Jammy patch unfortunatly couldn't be applied
Bionic:	fix sent to esm ML
Xenial:	fix sent to esm ML
Trusty:	won't fix

[Test Case]

Compiled

[Where problems could occur]

This fix affects those who use GFS2 (Global File System 2), an issue
with this fix would be visible to the user via unexpected system 
behavior or a system crash.

Andreas Gruenbacher (2):
  gfs2: Rename sd_{ glock => kill }_wait
  gfs2: Fix potential glock use-after-free on unmount

 fs/gfs2/glock.c      | 41 +++++++++++++++++++++++++++++++++++------
 fs/gfs2/glock.h      |  1 +
 fs/gfs2/incore.h     |  3 ++-
 fs/gfs2/lock_dlm.c   | 12 +++++++++++-
 fs/gfs2/ops_fstype.c |  3 ++-
 fs/gfs2/super.c      |  3 ---
 6 files changed, 51 insertions(+), 12 deletions(-)

-- 
2.34.1