On Wed, Nov 9, 2022 at 4:00 AM <xiubli@xxxxxxxxxx> wrote: > > From: Xiubo Li <xiubli@xxxxxxxxxx> > > 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 > URL: https://tracker.ceph.com/issues/57686 > Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> > --- > > Changed in V4: > - remove initilizing of 'realm'. > > fs/ceph/snap.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c > index 9bceed2ebda3..c1c452afa84d 100644 > --- a/fs/ceph/snap.c > +++ b/fs/ceph/snap.c > @@ -764,7 +764,7 @@ 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; > @@ -775,6 +775,7 @@ 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; > -- > 2.31.1 > Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx> Thanks, Ilya
