Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935135AbbDIKCF (ORCPT ); Thu, 9 Apr 2015 06:02:05 -0400 Received: from mail.kernel.org ([198.145.29.136]:41186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932952AbbDIIvp (ORCPT ); Thu, 9 Apr 2015 04:51:45 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jens Axboe , Zefan Li Subject: [PATCH 3.4 039/176] genhd: check for int overflow in disk_expand_part_tbl() Date: Thu, 9 Apr 2015 16:44:47 +0800 Message-Id: <1428569224-23820-39-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1428569028-23762-1-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1693 Lines: 53 From: Jens Axboe 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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: Zefan Li --- block/genhd.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 60f7e6c..7a2a8dc 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1069,9 +1069,16 @@ 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)) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/