Patch "ext4: fix xattr shifting when expanding inodes part 2" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

ext4: fix xattr shifting when expanding inodes part 2

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ext4-fix-xattr-shifting-when-expanding-inodes-part-2.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jan Kara <[email protected]>
Date: Thu, 11 Aug 2016 11:58:32 -0400
Subject: ext4: fix xattr shifting when expanding inodes part 2

From: Jan Kara <[email protected]>

commit 418c12d08dc64a45107c467ec1ba29b5e69b0715 upstream.

When multiple xattrs need to be moved out of inode, we did not properly recompute total size of xattr headers in the inode and the new header position. Thus when moving the second and further xattr we asked ext4_xattr_shift_entries() to move too much and from the wrong place, resulting in possible xattr value corruption or general memory corruption.

---
 fs/ext4/xattr.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -1423,6 +1423,7 @@ retry:
 		error = ext4_xattr_ibody_set(handle, inode, &i, is);
 		if (error)
 			goto cleanup;
+		total_ino -= entry_size;
 
 		entry = IFIRST(header);
 		if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff)

@@ -1433,11 +1434,11 @@ retry:
 		ext4_xattr_shift_entries(entry, -shift_bytes,
 			(void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
 			EXT4_I(inode)->i_extra_isize + shift_bytes,
-			(void *)header, total_ino - entry_size,
-			inode->i_sb->s_blocksize);
+			(void *)header, total_ino, inode->i_sb->s_blocksize);
 
 		isize_diff -= shift_bytes;
 		EXT4_I(inode)->i_extra_isize += shift_bytes;
+		header = IHDR(inode, raw_inode);
 
 		i.name = b_entry_name;
 		i.value = buffer;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/ext4-fix-xattr-shifting-when-expanding-inodes-part-2.patch queue-4.4/ext4-fix-xattr-shifting-when-expanding-inodes.patch queue-4.4/ext4-avoid-deadlock-when-expanding-inode-size.patch queue-4.4/ext4-properly-align-shifted-xattrs-when-expanding-inodes.patch