From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Lukas Czerner , "Theodore Tso" Subject: [ 03/85] ext4: Avoid underflow in ext4_trim_fs() Date: Thu, 25 Oct 2012 17:05:21 -0700 Message-Id: <20121026000031.475967873@linuxfoundation.org> In-Reply-To: <20121026000031.107227138@linuxfoundation.org> References: <20121026000031.107227138@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Czerner commit 5de35e8d5c02d271c20e18337e01bc20e6ef472e upstream. 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 Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/mballoc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4987,8 +4987,9 @@ int ext4_trim_fs(struct super_block *sb, end = start + (range->len >> sb->s_blocksize_bits) - 1; minlen = 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;