From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932943AbdA0K6I (ORCPT ); Fri, 27 Jan 2017 05:58:08 -0500 Received: from mx2.suse.de ([195.135.220.15]:60263 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932550AbdA0K6E (ORCPT ); Fri, 27 Jan 2017 05:58:04 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Chandan Rajendra , "Theodore Ts'o" , Jiri Slaby Subject: [PATCH 3.12 027/235] ext4: fix stack memory corruption with 64k block size Date: Fri, 27 Jan 2017 11:52:40 +0100 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> References: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chandan Rajendra 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 30a9d7afe70ed6bd9191d3000e2ef1a34fb58493 upstream. The number of 'counters' elements needed in 'struct sg' is super_block->s_blocksize_bits + 2. Presently we have 16 'counters' elements in the array. This is insufficient for block sizes >= 32k. In such cases the memcpy operation performed in ext4_mb_seq_groups_show() would cause stack memory corruption. Fixes: c9de560ded61f Signed-off-by: Chandan Rajendra Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara Signed-off-by: Jiri Slaby --- fs/ext4/mballoc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index d775b7b02dd0..2b4ed2bf9569 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2243,7 +2243,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) struct ext4_group_info *grinfo; struct sg { struct ext4_group_info info; - ext4_grpblk_t counters[16]; + ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2]; } sg; group--; -- 2.11.0