From: Lukas Czerner Subject: [PATCH v2] ext4: Avoid underflow of in ext4_trim_fs() Date: Thu, 11 Oct 2012 10:34:45 +0200 Message-ID: <1349944485-13868-1-git-send-email-lczerner@redhat.com> References: <1349784762-28069-1-git-send-email-lczerner@redhat.com> Cc: tytso@mit.edu, Lukas Czerner To: linux-ext4@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:20633 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751656Ab2JKIfB (ORCPT ); Thu, 11 Oct 2012 04:35:01 -0400 In-Reply-To: <1349784762-28069-1-git-send-email-lczerner@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Currently if len argument in ext4_trim_fs() is smaller than one block, the 'end' variable underflow. Avoid that by returning EINVAL if len is smaller than file system block. Also remove useless unlikely(). Signed-off-by: Lukas Czerner --- v2: reworked, return EINVAL if len < FSB fs/ext4/mballoc.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index f8b27bf..e02ae6c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4993,8 +4993,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) minlen = EXT4_NUM_B2C(EXT4_SB(sb), range->minlen >> sb->s_blocksize_bits); - if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) || - unlikely(start >= max_blks)) + if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || + start >= max_blks || + range->len < sb->s_blocksize) return -EINVAL; if (end >= max_blks) end = max_blks - 1; -- 1.7.7.6