From patchwork Fri Nov 20 01:18:54 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 7663461 X-Patchwork-Delegate: axboe@kernel.dk Return-Path: X-Original-To: patchwork-linux-block@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 24D009F7CA for ; Fri, 20 Nov 2015 01:27:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 61779204A0 for ; Fri, 20 Nov 2015 01:27:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7314B204D1 for ; Fri, 20 Nov 2015 01:27:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934765AbbKTB1V (ORCPT ); Thu, 19 Nov 2015 20:27:21 -0500 Received: from smtp.outflux.net ([198.145.64.163]:53508 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934750AbbKTB1K (ORCPT ); Thu, 19 Nov 2015 20:27:10 -0500 X-Greylist: delayed 491 seconds by postgrey-1.27 at vger.kernel.org; Thu, 19 Nov 2015 20:27:10 EST Received: from www.outflux.net (serenity.outflux.net [10.2.0.2]) by vinyl.outflux.net (8.14.4/8.14.4/Debian-4.1ubuntu1) with ESMTP id tAK1Is3H030295; Thu, 19 Nov 2015 17:18:55 -0800 Date: Thu, 19 Nov 2015 17:18:54 -0800 From: Kees Cook To: Andrew Morton Cc: Jens Axboe , Dan Carpenter , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][RESEND] mac: validate mac_partition is within sector Message-ID: <20151120011854.GA12836@www.outflux.net> MIME-Version: 1.0 Content-Disposition: inline X-MIMEDefang-Filter: outflux$Revision: 1.316 $ X-HELO: www.outflux.net X-Scanned-By: MIMEDefang 2.73 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single 512 byte sector would be read (secsize / 512). However the partition structure would be located past the end of the buffer (secsize % 512). Signed-off-by: Kees Cook Cc: stable@vger.kernel.org --- There doesn't seem to be a mac partition maintainer... --- block/partitions/mac.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/block/partitions/mac.c b/block/partitions/mac.c index c2c48ec64b27..621317ac4d59 100644 --- a/block/partitions/mac.c +++ b/block/partitions/mac.c @@ -32,7 +32,7 @@ int mac_partition(struct parsed_partitions *state) Sector sect; unsigned char *data; int slot, blocks_in_map; - unsigned secsize; + unsigned secsize, datasize, partoffset; #ifdef CONFIG_PPC_PMAC int found_root = 0; int found_root_goodness = 0; @@ -50,10 +50,14 @@ int mac_partition(struct parsed_partitions *state) } secsize = be16_to_cpu(md->block_size); put_dev_sector(sect); - data = read_part_sector(state, secsize/512, §); + datasize = round_down(secsize, 512); + data = read_part_sector(state, datasize / 512, §); if (!data) return -1; - part = (struct mac_partition *) (data + secsize%512); + partoffset = secsize % 512; + if (partoffset + sizeof(*part) > datasize) + return -1; + part = (struct mac_partition *) (data + partoffset); if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) { put_dev_sector(sect); return 0; /* not a MacOS disk */