From: Akira Fujita Subject: Re: [PATCH 1/4]ext4: Fix wrong comparisons in mext_check_arguments() Date: Wed, 16 Sep 2009 13:56:04 +0900 Message-ID: <4AB06FE4.2010405@rs.jp.nec.com> References: <4A9DE3DE.2010509@rs.jp.nec.com> <20090906021032.GA3055@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Theodore Tso Return-path: Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:39844 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751402AbZIPE4V (ORCPT ); Wed, 16 Sep 2009 00:56:21 -0400 In-Reply-To: <20090906021032.GA3055@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi Ted, We found that "fix-wrong-comparisons-in-mext_check_arguments" in the ext4 patch queue does not fix the objective issue completely. (The last partial block is not checked in mext_check_arguments().) Could you replace "fix-wrong-comparisons-in-mext_check_arguments" in the ext4 patch queue with this patch ? Regards, Akira Fujita Theodore Tso wrote: > On Wed, Sep 02, 2009 at 12:17:50PM +0900, Akira Fujita wrote: >> ext4: Fix wrong comparisons in mext_check_arguments() >> >> From: Akira Fujita >> >> mext_check_arguments() in move_extents.c has wrong comparisons. >> orig_start which is passed from user-space is block unit, >> but i_size of inode is byte unit, therefore the checks do not work fine. >> This mis-check leads to the overflow of 'len' and then hits BUG_ON() >> in ext4_move_extens(). The patch fixes this issue. > > Thanks, I've added this to the ext4 patch queue to be pushed when the > 2.6.32 merge window opens. > > - Ted Signed-off-by: Akira Fujita Reviewed-by: Greg Freemyer --- move_extent.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 429fb6f..0670464 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -898,6 +898,10 @@ mext_check_arguments(struct inode *orig_inode, struct inode *donor_inode, __u64 orig_start, __u64 donor_start, __u64 *len, __u64 moved_len) { + ext4_lblk_t orig_blocks, donor_blocks; + unsigned int blkbits = orig_inode->i_blkbits; + unsigned int blocksize = 1 << blkbits; + /* Regular file check */ if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { ext4_debug("ext4 move extent: The argument files should be " @@ -972,43 +976,47 @@ mext_check_arguments(struct inode *orig_inode, } if (orig_inode->i_size > donor_inode->i_size) { - if (orig_start >= donor_inode->i_size) { + donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits; + /* TODO: eliminate this artificial restriction */ + if (orig_start >= donor_blocks) { ext4_debug("ext4 move extent: orig start offset " - "[%llu] should be less than donor file size " - "[%lld] [ino:orig %lu, donor_inode %lu]\n", - orig_start, donor_inode->i_size, + "[%llu] should be less than donor file blocks " + "[%u] [ino:orig %lu, donor %lu]\n", + orig_start, donor_blocks, orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } - if (orig_start + *len > donor_inode->i_size) { + /* TODO: eliminate this artificial restriction */ + if (orig_start + *len > donor_blocks) { ext4_debug("ext4 move extent: End offset [%llu] should " - "be less than donor file size [%lld]." - "So adjust length from %llu to %lld " + "be less than donor file blocks [%u]." + "So adjust length from %llu to %llu " "[ino:orig %lu, donor %lu]\n", - orig_start + *len, donor_inode->i_size, - *len, donor_inode->i_size - orig_start, + orig_start + *len, donor_blocks, + *len, donor_blocks - orig_start, orig_inode->i_ino, donor_inode->i_ino); - *len = donor_inode->i_size - orig_start; + *len = donor_blocks - orig_start; } } else { - if (orig_start >= orig_inode->i_size) { + orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits; + if (orig_start >= orig_blocks) { ext4_debug("ext4 move extent: start offset [%llu] " - "should be less than original file size " - "[%lld] [inode:orig %lu, donor %lu]\n", - orig_start, orig_inode->i_size, + "should be less than original file blocks " + "[%u] [ino:orig %lu, donor %lu]\n", + orig_start, orig_blocks, orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } - if (orig_start + *len > orig_inode->i_size) { + if (orig_start + *len > orig_blocks) { ext4_debug("ext4 move extent: Adjust length " - "from %llu to %lld. Because it should be " - "less than original file size " + "from %llu to %llu. Because it should be " + "less than original file blocks " "[ino:orig %lu, donor %lu]\n", - *len, orig_inode->i_size - orig_start, + *len, orig_blocks - orig_start, orig_inode->i_ino, donor_inode->i_ino); - *len = orig_inode->i_size - orig_start; + *len = orig_blocks - orig_start; } }