[CVE-2011-1833] race condition when checking source during mount

[Andy Whitcroft]

On Thu, Aug 11, 2011 at 12:39:42AM -0700, John Johansen wrote:
> Fix userspace race in checking source of mount by having the kernel do
> the check at mount time when a flag is specified.
> 
> The second patch fixes the parameter type in the already upstream patch.


I see that the 1/2 has hit mainline already so we can clean up the
attribution as we go.

  commit 764355487ea220fdc2faf128d577d7f679b91f97
  Author: John Johansen <john.johansen at canonical.com>
  Date:   Fri Jul 22 08:14:15 2011 -0700

    Ecryptfs: Add mount option to check uid of device being mounted = expect uid 

    Close a TOCTOU race for mounts done via ecryptfs-mount-private.  The mount
    source (device) can be raced when the ownership test is done in userspace.
    Provide Ecryptfs a means to force the uid check at mount time.
    
    Signed-off-by: John Johansen <john.johansen at canonical.com>
    Cc: <stable at kernel.org>
    Signed-off-by: Tyler Hicks <tyhicks at linux.vnet.ibm.com>

I have some issues with the Maverick backport here.  Comments against
that backport.  I am also wondering if you are doing a Lucid and Hardy
one or if there is some reason we do not need it; currently the tracker
says they are required.

-apw