From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752296AbcHLKM4 (ORCPT ); Fri, 12 Aug 2016 06:12:56 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:33867 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751254AbcHLKMm (ORCPT ); Fri, 12 Aug 2016 06:12:42 -0400 From: Salah Triki To: akpm@linux-foundation.org, viro@zeniv.linux.org.uk, luisbg@osg.samsung.com Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, salah.triki@gmail.com Subject: [PATCH] befs: return BEFS_ERR if validation of ag_shift fails Date: Fri, 12 Aug 2016 11:12:31 +0100 Message-Id: <1470996751-18466-1-git-send-email-salah.triki@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ag_shift is used by blockno2iaddr() to get allocation group number from block. If ag_shift is inconsistent with block_per_ag, an out of bounds allocation group may occur [1]. So add return BEFS_ERR and update comment and error message to reflect this change. [1] https://lkml.org/lkml/2016/8/12/42 Signed-off-by: Salah Triki --- fs/befs/super.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/befs/super.c b/fs/befs/super.c index 7c50025..2e3a3fd 100644 --- a/fs/befs/super.c +++ b/fs/befs/super.c @@ -101,10 +101,13 @@ befs_check_sb(struct super_block *sb) /* ag_shift also encodes the same information as blocks_per_ag in a - * different way, non-fatal consistency check + * different way as a consistency check. */ - if ((1 << befs_sb->ag_shift) != befs_sb->blocks_per_ag) - befs_error(sb, "ag_shift disagrees with blocks_per_ag."); + if ((1 << befs_sb->ag_shift) != befs_sb->blocks_per_ag) { + befs_error(sb, "ag_shift disagrees with blocks_per_ag. " + "Corruption likely."); + return BEFS_ERR; + } if (befs_sb->log_start != befs_sb->log_end || befs_sb->flags == BEFS_DIRTY) { -- 1.9.1