eCryptfs: Copy up lower inode attrs after setting lower xattr

commit 545d6809 upstream.

After passing through a ->setxattr() call, eCryptfs needs to copy the
inode attributes from the lower inode to the eCryptfs inode, as they
may have changed in the lower filesystem's ->setxattr() path.

One example is if an extended attribute containing a POSIX Access
Control List is being set. The new ACL may cause the lower filesystem to
modify the mode of the lower inode and the eCryptfs inode would need to
be updated to reflect the new mode.

https://launchpad.net/bugs/926292Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Sebastien Bacher <seb128@ubuntu.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: <stable@vger.kernel.org>
Acked-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

fs/ecryptfs/inode.c

@@ -1035,6 +1035,8 @@ ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 	rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 						   size, flags);
 	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+	if (!rc)
+		fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode, NULL);
 out:
 	return rc;
 }