From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753232AbbALSFs (ORCPT ); Mon, 12 Jan 2015 13:05:48 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:57441 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752947AbbALSFq (ORCPT ); Mon, 12 Jan 2015 13:05:46 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jens Axboe , Luis Henriques Subject: [PATCH 3.16.y-ckt 035/216] genhd: check for int overflow in disk_expand_part_tbl() Date: Mon, 12 Jan 2015 18:02:32 +0000 Message-Id: <1421085933-32536-36-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1421085933-32536-1-git-send-email-luis.henriques@canonical.com> References: <1421085933-32536-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe commit 5fabcb4c33fe11c7e3afdf805fde26c1a54d0953 upstream. We can get here from blkdev_ioctl() -> blkpg_ioctl() -> add_partition() with a user passed in partno value. If we pass in 0x7fffffff, the new target in disk_expand_part_tbl() overflows the 'int' and we access beyond the end of ptbl->part[] and even write to it when we do the rcu_assign_pointer() to assign the new partition. Reported-by: David Ramos Signed-off-by: Jens Axboe Signed-off-by: Luis Henriques --- block/genhd.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index e6723bd4d7a1..a8d586a729bb 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1070,9 +1070,16 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno) struct disk_part_tbl *old_ptbl = disk->part_tbl; struct disk_part_tbl *new_ptbl; int len = old_ptbl ? old_ptbl->len : 0; - int target = partno + 1; + int i, target; size_t size; - int i; + + /* + * check for int overflow, since we can get here from blkpg_ioctl() + * with a user passed 'partno'. + */ + target = partno + 1; + if (target < 0) + return -EINVAL; /* disk_max_parts() is zero during initialization, ignore if so */ if (disk_max_parts(disk) && target > disk_max_parts(disk)) -- 2.1.4