[security-dev] Undertow / IdentityManager and Digest Authentication

Darran Lofthouse darran.lofthouse at jboss.com
Tue Apr 30 09:47:53 EDT 2013

Sent my last message using the wrong account so it may arrive but 
writing again just in case.

The Digest Credential is what we need stored but we would potentially 
need more than one to be stored to cope with different hash algorithms 
being used.

The issue regarding what is currently in PicketLink is that it is 
causing HTTP specific aspects of Digest authentication to leak into the 
IDM and at the same time is only implementing a small subset of the 
RFC2617 specification.  We need access to the same pre-prepared digests 
for SASL authentication but this is using a slightly different format 
for the digests that are compared.

In addition to this we need the entire messages being exchanged both 
inbound and outbound to be digested along with these pre-prepared hashes 
for the purpose of adding integrity protection for the messages 
exchanged.  There is also a middle ground of providing an appropriate 
header so that the server can also prove it knows the clients password.

This is why we need access to the pre-prepared digest for the chosen 
algorithm or at the very least an option to request PLIDM pushed it into 
a MessageDigest instance (Maybe PLIDM provides the MessageDigest and 
wraps it).

Otherwise there is going to be a lot of HTTP specific and SASL specific 
code to potentially push into an IDM and the IDM is going to have to be 
much more involved in the actual message exchanges.

Darran Lofthouse.

On 30/04/13 13:58, Shane Bryzak wrote:
> What PicketLink stores for digests is the latter [1] (in no situation do
> we ever store plain text passwords).  There are essentially two methods
> for validating and managing credentials in the IdentityManager [2]
> (three if you count one extra overloaded method):
> void validateCredentials(Credentials credentials);
> void updateCredential(Agent agent, Object credential);
> There is no API method for retrieving an actual credential value so by
> design credential storage is quite secure.
> To briefly summarise how things work for a digest authentication in
> PicketLink; we would pass in an instance of DigestCredentials [3] to the
> IdentityManager.validateCredentials() method, which is essentially a
> wrapper around a Digest [4] (which should look quite familiar).  The
> actual implementation of the validation logic can be found in
> DigestCredentialHandler [5].
> [1]
> https://github.com/picketlink/picketlink/blob/master/idm/impl/src/main/java/org/picketlink/idm/credential/internal/DigestCredentialStorage.java
> [2]
> https://github.com/picketlink/picketlink/blob/master/idm/api/src/main/java/org/picketlink/idm/IdentityManager.java
> [3]
> https://github.com/picketlink/picketlink/blob/master/idm/api/src/main/java/org/picketlink/idm/credential/DigestCredentials.java
> [4]
> https://github.com/picketlink/picketlink/blob/master/idm/api/src/main/java/org/picketlink/idm/credential/Digest.java
> [5]
> https://github.com/picketlink/picketlink/blob/master/idm/impl/src/main/java/org/picketlink/idm/credential/internal/DigestCredentialHandler.java
> Shane
> On 30/04/13 22:26, Darran Lofthouse wrote:
>> As there is going to be an integration layer between Undertow and
>> PicketLink IDM I think the main requirement for PicketLink IDM is going
>> to be: -
>>    - Where PLIDM has access to plain text passwords for a specified
>> account and using the specified digest algorithm generate the digest for
>> the username, realm and password separated by colons.
>>    - Where PLIDM is storing pre-prepared digests for a specified account
>> look up the pre-prepared username, realm, password digest for the
>> algorithm specified.
>> This latter option relates to something I brought up a while ago where a
>> single credential could be associated with an account in a number of
>> different formats - what this means is that the Digest algorithms can
>> potentially go beyond MD5 to use stronger digest algorithms.
>> The pre-prepared digests do offer some protection but PLIDM would still
>> be responsible for storing them securely to provide protection against
>> accidental disclosure.  The most important thing however is that we do
>> not need the plain text passwords to be passed onto the Undertow or SASL
>> classes handling the actual authentication.
>> Regards,
>> Darran Lofthouse.
>> On 30/04/13 12:56, Shane Bryzak wrote:
>>> Looks pretty straight forward - what do you need from the PicketLink
>>> side for this?  The PLIDM implementation should be quite simple, I can
>>> help out with it if required.
>>> Shane
>>> On 30/04/13 19:24, Darran Lofthouse wrote:
>>>> I have been saying for a while that I need to raise a discussion
>>>> regarding the verification of Digest based requests against an
>>>> IdentityManager.
>>>> At the moment this is predominantly needed for Undertow although there
>>>> is also a need for same with SASL.
>>>> The following document describes the proposed use of the Undertow
>>>> IdentityManager API and the requirement for the implementation i.e. what
>>>> we would need from PicketLink IDM once wrapped in the WildFly integration: -
>>>> https://community.jboss.org/wiki/Undertow-IdentityManager-DigestAuthentication
>>>> The three methods on the IdentityManager interface previously used for
>>>> Digest based authentication will all be removed.
>>>> An identity manager that can provide this capability will also be
>>>> compatible with SASL based authentication without needing to be aware of
>>>> the actual verification requirements within SASL.
>>>> Regards,
>>>> Darran Lofthouse.
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