From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933076Ab2HGXLr (ORCPT ); Tue, 7 Aug 2012 19:11:47 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:56801 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030475Ab2HGWi3 (ORCPT ); Tue, 7 Aug 2012 18:38:29 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ben Hutchings , Jan Kara Subject: [ 044/109] udf: Improve table length check to avoid possible overflow Date: Tue, 7 Aug 2012 15:35:03 -0700 Message-Id: <20120807222046.970058242@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120807222043.089735600@linuxfoundation.org> References: <20120807222043.089735600@linuxfoundation.org> User-Agent: quilt/0.60-20.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 57b9655d01ef057a523e810d29c37ac09b80eead upstream. When a partition table length is corrupted to be close to 1 << 32, the check for its length may overflow on 32-bit systems and we will think the length is valid. Later on the kernel can crash trying to read beyond end of buffer. Fix the check to avoid possible overflow. Reported-by: Ben Hutchings Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/udf/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -1283,7 +1283,7 @@ static int udf_load_logicalvol(struct su BUG_ON(ident != TAG_IDENT_LVD); lvd = (struct logicalVolDesc *)bh->b_data; table_len = le32_to_cpu(lvd->mapTableLength); - if (sizeof(*lvd) + table_len > sb->s_blocksize) { + if (table_len > sb->s_blocksize - sizeof(*lvd)) { udf_err(sb, "error loading logical volume descriptor: " "Partition table too long (%u > %lu)\n", table_len, sb->s_blocksize - sizeof(*lvd));