From patchwork Mon Nov 26 16:56:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [093/270] libceph: fix overflow in osdmap_decode() From: Herton Ronaldo Krzesinski X-Patchwork-Id: 201826 Message-Id: <1353949160-26803-94-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Xi Wang Date: Mon, 26 Nov 2012 14:56:23 -0200 3.5.7u1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Xi Wang commit e91a9b639a691e0982088b5954eaafb5a25c8f1c upstream. On 32-bit systems, a large `n' would overflow `n * sizeof(u32)' and bypass the check ceph_decode_need(p, end, n * sizeof(u32), bad). It would also overflow the subsequent kmalloc() size, leading to out-of-bounds write. Signed-off-by: Xi Wang Reviewed-by: Alex Elder Signed-off-by: Herton Ronaldo Krzesinski --- net/ceph/osdmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c index 95b2762..bc73341 100644 --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -667,6 +667,9 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end) ceph_decode_need(p, end, sizeof(u32) + sizeof(u64), bad); ceph_decode_copy(p, &pgid, sizeof(pgid)); n = ceph_decode_32(p); + err = -EINVAL; + if (n > (UINT_MAX - sizeof(*pg)) / sizeof(u32)) + goto bad; ceph_decode_need(p, end, n * sizeof(u32), bad); err = -ENOMEM; pg = kmalloc(sizeof(*pg) + n*sizeof(u32), GFP_NOFS);