Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Xi Wang , Alex Elder Subject: [ 112/171] libceph: fix overflow in osdmap_decode() Date: Wed, 21 Nov 2012 16:40:58 -0800 Message-Id: <20121122004044.590722021@linuxfoundation.org> In-Reply-To: <20121122004033.298367941@linuxfoundation.org> References: <20121122004033.298367941@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xi Wang (cherry picked from commit e91a9b639a691e0982088b5954eaafb5a25c8f1c) 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: Greg Kroah-Hartman --- net/ceph/osdmap.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -674,6 +674,9 @@ struct ceph_osdmap *osdmap_decode(void * 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);