From: Nathaniel Yazdani Subject: [PATCH] ceph: fix null pointer dereference Date: Sun, 04 Aug 2013 21:04:30 -0700 Message-ID: <1375675470.19205.2.camel@lizardlounge> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: sage@inktank.com Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: ceph-devel.vger.kernel.org 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 --- diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 187bf21..ddff072 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);