This is a note to let you know that I've just added the patch titled
ceph: avoid putting the realm twice when decoding snaps fails
to the 4.19-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-avoid-putting-the-realm-twice-when-decoding-sna.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 900cbf938ced6cb58fe20abf535c5c7a07e2fca4
Author: Xiubo Li <xiubli@xxxxxxxxxx>
Date: Wed Nov 9 11:00:39 2022 +0800
ceph: avoid putting the realm twice when decoding snaps fails
[ Upstream commit 51884d153f7ec85e18d607b2467820a90e0f4359 ]
When decoding the snaps fails it maybe leaving the 'first_realm'
and 'realm' pointing to the same snaprealm memory. And then it'll
put it twice and could cause random use-after-free, BUG_ON, etc
issues.
Cc: stable@xxxxxxxxxxxxxxx
Link: https://tracker.ceph.com/issues/57686
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 642040beef91..a5ef8275440d 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -671,7 +671,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
struct ceph_mds_snap_realm *ri; /* encoded */
__le64 *snaps; /* encoded */
__le64 *prior_parent_snaps; /* encoded */
- struct ceph_snap_realm *realm = NULL;
+ struct ceph_snap_realm *realm;
struct ceph_snap_realm *first_realm = NULL;
struct ceph_snap_realm *realm_to_rebuild = NULL;
int rebuild_snapcs;
@@ -680,6 +680,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
dout("update_snap_trace deletion=%d\n", deletion);
more:
+ realm = NULL;
rebuild_snapcs = 0;
ceph_decode_need(&p, e, sizeof(*ri), bad);
ri = p;
