From: Xiubo Li Date: Wed, 9 Nov 2022 03:00:39 +0000 (+0800) Subject: ceph: avoid putting the realm twice when decoding snaps fails X-Git-Tag: v6.1-rc6~28^2~1 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=51884d153f7ec85e18d607b2467820a90e0f4359;p=users%2Fdwmw2%2Flinux.git ceph: avoid putting the realm twice when decoding snaps fails 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 Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov --- diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 864cdaa0d2bd6..e4151852184e0 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -763,7 +763,7 @@ 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; @@ -774,6 +774,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, dout("%s deletion=%d\n", __func__, deletion); more: + realm = NULL; rebuild_snapcs = 0; ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p;