[SRU][N][PATCH 0/1] CVE-2024-56672

[Massimiliano Pellizzer]

[Impact]

blk-cgroup: Fix UAF in blkcg_unpin_online()

blkcg_unpin_online() walks up the blkcg hierarchy putting the online pin. To
walk up, it uses blkcg_parent(blkcg) but it was calling that after
blkcg_destroy_blkgs(blkcg) which could free the blkcg, leading to a UAF.

Fix it by reading the parent pointer before destroying the blkcg's blkg's.

[Fix]

Oracular: Fixed via upstream stable updates (LP: #2097332)
Noble: Cherry picked from mainline
Jammy: Fixed via upstream stable updates (LP: #2097298)
Focal: Not affected

[Test case]

Compile tested only.

[Where problems could occur]

A regression here is unlikely due to the very limited scope of the
patch.

Tejun Heo (1):
  blk-cgroup: Fix UAF in blkcg_unpin_online()

 block/blk-cgroup.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

-- 
2.43.0