Open Stack

Hi, I'd like you to take a look at this patch for potential
SecurityImpact.
https://review.openstack.org/80398

Log:
commit a3db0516c136767e493e1125e3980f057165a585
Author: Brant Knudson <bknudson at us.ibm.com>
Date:   Thu Mar 13 15:38:34 2014 -0500

    Allow hash tokens with sha256
    
    PKI Tokens were always hashed with MD5. This change allows
    tokens to be hashed with SHA256 or any other algorithm
    supported by hashlib. This is for security hardening.
    
    If the new 'hash_algorithm' configuration option is set to
    'sha256' then the auth_token middleware will hash tokens using
    SHA256 when tokens are stored in the cache. The
    'hash_algorithm' option defaults to 'md5' for backwards
    compatiblity.
    
    The auth_token middleware will also accept a new format for
    the revocation list. If the revocation list has the
    'hash_algorithm' field set then that algorithm will be used to
    hash the PKI token to compare against the IDs in the
    revocation list. If the revocation list doesn't have the
    'hash_algorithm' field set then MD5 will be used for backwards
    compatibility.
    
    SecurityImpact
    DocImpact
    Closes-Bug: #1174499
    
    Change-Id: Ie524125dc5f6f1076bfd47db3a414b178e4dac80