linux-kernel - [83/85] ext4: fix data offset overflow in ext4_xattr

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Date:	Wed, 24 Jul 2013 15:02:45 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Jan Kara" <jack@...e.cz>,
	"Theodore Ts'o" <tytso@....edu>
Subject: [83/85] ext4: fix data offset overflow in ext4_xattr_fiemap() on
 32-bit archs

3.2.49-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@...e.cz>

commit a60697f411eb365fb09e639e6f183fe33d1eb796 upstream.

On 32-bit architectures with 32-bit sector_t computation of data offset
in ext4_xattr_fiemap() can overflow resulting in reporting bogus data
location. Fix the problem by typing block number to proper type before
shifting.

Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Theodore Ts'o <tytso@....edu>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/ext4/extents.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4801,7 +4801,7 @@ static int ext4_xattr_fiemap(struct inod
 		error = ext4_get_inode_loc(inode, &iloc);
 		if (error)
 			return error;
-		physical = iloc.bh->b_blocknr << blockbits;
+		physical = (__u64)iloc.bh->b_blocknr << blockbits;
 		offset = EXT4_GOOD_OLD_INODE_SIZE +
 				EXT4_I(inode)->i_extra_isize;
 		physical += offset;
@@ -4809,7 +4809,7 @@ static int ext4_xattr_fiemap(struct inod
 		flags |= FIEMAP_EXTENT_DATA_INLINE;
 		brelse(iloc.bh);
 	} else { /* external block */
-		physical = EXT4_I(inode)->i_file_acl << blockbits;
+		physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
 		length = inode->i_sb->s_blocksize;
 	}
 

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