From: Theodore Ts'o Subject: [PATCH 2/4] ext4: fix overflows in SEEK_HOLE, SEEK_DATA implementations Date: Tue, 9 Jul 2013 10:39:30 -0400 Message-ID: <1373380772-16803-2-git-send-email-tytso@mit.edu> References: <20130709143855.GF6000@thunk.org> <1373380772-16803-1-git-send-email-tytso@mit.edu> Cc: Ext4 Developers List , Jan Kara , Theodore Ts'o To: stable@vger.kernel.org Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:36214 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753869Ab3GIOjf (ORCPT ); Tue, 9 Jul 2013 10:39:35 -0400 In-Reply-To: <1373380772-16803-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Jan Kara ext4_lblk_t is just u32 so multiplying it by blocksize can easily overflow for files larger than 4 GB. Fix that by properly typing the block offsets before shifting. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Reviewed-by: Zheng Liu --- fs/ext4/file.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index b1b4d51..b19f0a4 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -312,7 +312,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode, blkbits = inode->i_sb->s_blocksize_bits; startoff = *offset; lastoff = startoff; - endoff = (map->m_lblk + map->m_len) << blkbits; + endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits; index = startoff >> PAGE_CACHE_SHIFT; end = endoff >> PAGE_CACHE_SHIFT; @@ -457,7 +457,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize) ret = ext4_map_blocks(NULL, inode, &map, 0); if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) { if (last != start) - dataoff = last << blkbits; + dataoff = (loff_t)last << blkbits; break; } @@ -468,7 +468,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize) ext4_es_find_delayed_extent_range(inode, last, last, &es); if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) { if (last != start) - dataoff = last << blkbits; + dataoff = (loff_t)last << blkbits; break; } @@ -486,7 +486,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize) } last++; - dataoff = last << blkbits; + dataoff = (loff_t)last << blkbits; } while (last <= end); mutex_unlock(&inode->i_mutex); @@ -540,7 +540,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize) ret = ext4_map_blocks(NULL, inode, &map, 0); if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) { last += ret; - holeoff = last << blkbits; + holeoff = (loff_t)last << blkbits; continue; } @@ -551,7 +551,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize) ext4_es_find_delayed_extent_range(inode, last, last, &es); if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) { last = es.es_lblk + es.es_len; - holeoff = last << blkbits; + holeoff = (loff_t)last << blkbits; continue; } @@ -566,7 +566,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize) &map, &holeoff); if (!unwritten) { last += ret; - holeoff = last << blkbits; + holeoff = (loff_t)last << blkbits; continue; } } -- 1.7.12.rc0.22.gcdd159b