From: Xiubo Li <xiubli@redhat.com>
Date: Wed, 9 Nov 2022 11:00:39 +0800
Subject: ceph: avoid putting the realm twice when decoding snaps fails
Git-commit: 51884d153f7ec85e18d607b2467820a90e0f4359
Patch-mainline: v6.1-rc6
References: bsc#1206051
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@vger.kernel.org
Link: https://tracker.ceph.com/issues/57686
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/snap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -705,7 +705,7 @@ int ceph_update_snap_trace(struct ceph_m
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;
@@ -716,6 +716,7 @@ int ceph_update_snap_trace(struct ceph_m
dout("update_snap_trace deletion=%d\n", deletion);
more:
+ realm = NULL;
rebuild_snapcs = 0;
ceph_decode_need(&p, e, sizeof(*ri), bad);
ri = p;