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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 418c12d08dc64a45107c467ec1ba29b5e69b0715 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Thu, 11 Aug 2016 11:58:32 -0400
Subject: ext4: fix xattr shifting when expanding inodes part 2

From: Jan Kara <jack@suse.cz>

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.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -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 jack@suse.cz 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