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Commit cb7495fe authored by Xiubo Li's avatar Xiubo Li Committed by Greg Kroah-Hartman
Browse files

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@vger.kernel.org
Link: https://tracker.ceph.com/issues/57686


Signed-off-by: default avatarXiubo Li <xiubli@redhat.com>
Reviewed-by: default avatarIlya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 12a93545

fs/ceph/snap.c

+2 −1
Original line number Diff line number Diff line
@@ -694,7 +694,7 @@ 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;
@@ -705,6 +705,7 @@ 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;