Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754747AbaKKLQs (ORCPT ); Tue, 11 Nov 2014 06:16:48 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:57904 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754502AbaKKLLc (ORCPT ); Tue, 11 Nov 2014 06:11:32 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jan Kara , "Theodore Ts'o" , Luis Henriques Subject: [PATCH 3.16.y-ckt 157/170] ext4: fix overflow when updating superblock backups after resize Date: Tue, 11 Nov 2014 11:08:36 +0000 Message-Id: <1415704129-12709-158-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1415704129-12709-1-git-send-email-luis.henriques@canonical.com> References: <1415704129-12709-1-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-ckt1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 9378c6768e4fca48971e7b6a9075bc006eda981d upstream. When there are no meta block groups update_backups() will compute the backup block in 32-bit arithmetics thus possibly overflowing the block number and corrupting the filesystem. OTOH filesystems without meta block groups larger than 16 TB should be rare. Fix the problem by doing the counting in 64-bit arithmetics. Coverity-id: 741252 Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Reviewed-by: Lukas Czerner Signed-off-by: Luis Henriques --- fs/ext4/resize.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index f298c60f907d..ca4588388fc3 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1081,7 +1081,7 @@ static void update_backups(struct super_block *sb, int blk_off, char *data, break; if (meta_bg == 0) - backup_block = group * bpg + blk_off; + backup_block = ((ext4_fsblk_t)group) * bpg + blk_off; else backup_block = (ext4_group_first_block_no(sb, group) + ext4_bg_has_super(sb, group)); -- 2.1.0 -- 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/