From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukas Czerner Subject: [PATCH] ext4: fix possible overflow in ext4_trim_fs() Date: Thu, 25 Nov 2010 16:53:45 +0100 Message-ID: <1290700425-4094-1-git-send-email-lczerner@redhat.com> Cc: Lukas Czerner To: linux-ext4@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:28769 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753289Ab0KYPxw (ORCPT ); Thu, 25 Nov 2010 10:53:52 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id oAPFrqtB003821 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 25 Nov 2010 10:53:52 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: When determining last group through ext4_get_group_no_and_offset() the result may be wrong in cases when range->start and range-len are too big, because it may overflow when summing up those two numbers. Fix that by checking range->len and limit its value to ext4_blocks_count(). This commit was tested by myself with expected result. Signed-off-by: Lukas Czerner --- fs/ext4/mballoc.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5b4d4e3..7b05d92 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4819,6 +4819,7 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) ext4_group_t group, ngroups = ext4_get_groups_count(sb); ext4_grpblk_t cnt = 0, first_block, last_block; uint64_t start, len, minlen, trimmed; + ext4_fsblk_t blocks_count = ext4_blocks_count(EXT4_SB(sb)->s_es); int ret = 0; start = range->start >> sb->s_blocksize_bits; @@ -4826,6 +4827,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) minlen = range->minlen >> sb->s_blocksize_bits; trimmed = 0; + if (len > blocks_count) + len = blocks_count - start; + if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb))) return -EINVAL; -- 1.7.2.3