This is a note to let you know that I've just added the patch titled ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() to the 5.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ceph-fix-possible-null-pointer-dereference-in-ceph_m.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 77837783fc16dbeccf04dca9c7ba2d6c40def849 Author: Tuo Li <islituo@xxxxxxxxx> Date: Thu Aug 5 08:14:34 2021 -0700 ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() [ Upstream commit a9e6ffbc5b7324b6639ee89028908b1e91ceed51 ] kcalloc() is called to allocate memory for m->m_info, and if it fails, ceph_mdsmap_destroy() behind the label out_err will be called: ceph_mdsmap_destroy(m); In ceph_mdsmap_destroy(), m->m_info is dereferenced through: kfree(m->m_info[i].export_targets); To fix this possible null-pointer dereference, check m->m_info before the for loop to free m->m_info[i].export_targets. [ jlayton: fix up whitespace damage only kfree(m->m_info) if it's non-NULL ] Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx> Signed-off-by: Tuo Li <islituo@xxxxxxxxx> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index abd9af7727ad..3c444b9cb17b 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -394,9 +394,11 @@ void ceph_mdsmap_destroy(struct ceph_mdsmap *m) { int i; - for (i = 0; i < m->possible_max_rank; i++) - kfree(m->m_info[i].export_targets); - kfree(m->m_info); + if (m->m_info) { + for (i = 0; i < m->possible_max_rank; i++) + kfree(m->m_info[i].export_targets); + kfree(m->m_info); + } kfree(m->m_data_pg_pools); kfree(m); }