From c338c07c51e3106711fad5eb599e375eadb6855d Mon Sep 17 00:00:00 2001 From: Nathaniel Yazdani Date: Sun, 4 Aug 2013 21:04:30 -0700 Subject: [PATCH] ceph: fix null pointer dereference When register_session() is given an out-of-range argument for mds, ceph_mdsmap_get_addr() will return a null pointer, which would be given to ceph_con_open() & be dereferenced, causing a kernel oops. This fixes bug #4685 in the Ceph bug tracker . Signed-off-by: Nathaniel Yazdani Reviewed-by: Sage Weil --- fs/ceph/mds_client.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 3eb1b4470c85..6b40d8112c64 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -414,6 +414,9 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc, { struct ceph_mds_session *s; + if (mds >= mdsc->mdsmap->m_max_mds) + return ERR_PTR(-EINVAL); + s = kzalloc(sizeof(*s), GFP_NOFS); if (!s) return ERR_PTR(-ENOMEM); -- 2.20.1