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Posted to dev@tomcat.apache.org by bu...@apache.org on 2013/02/04 11:54:16 UTC

[Bug 54521] New: DigestAuthenticator: nonceCountValid() fails in case of simultaneous asynchronous requests of the same client

https://issues.apache.org/bugzilla/show_bug.cgi?id=54521

            Bug ID: 54521
           Summary: DigestAuthenticator: nonceCountValid() fails in case
                    of simultaneous asynchronous requests of the same
                    client
           Product: Tomcat 7
           Version: 7.0.35
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Catalina
          Assignee: dev@tomcat.apache.org
          Reporter: sven.stieber@traveltainment.de
    Classification: Unclassified

Concerned components:
org.apache.catalina.authenticator.DigestAuthenticator
org.apache.catalina.authenticator.DigestAuthenticator.NonceInfo

Scenario:
A multithreaded client sends two requests within one millisecond. The
DigestAuthenticator creates for each request a nonce as well as a NonceInfo
instance. The two nonces are equal, as they were created within the same
millisecond. When writing data into the cache (method generateNonce()), the
second NonceInfo instance overwrites the first one (same key!).

Problem:
The two client threads then send a second request with a digest authentication
header. In both requests, “nc” (nonce count) is equal “1”, as the nonce has
been newly created. In the NonceInfo of the first request, array “seen” is set
to “true” for index ((nonceCount + offset) % seen.length). In the second
request the same NonceInfo instance is used, as the instance is retrieved from
map “nonces” using “nonce” as a key, that is, in both requests the same key is
used. Consequently, method “nonceCountValid()“ returns „false“, as 
seen[(nonceCount + offset) % seen.length)] has already been set to „true“. 
Therefore the authentication fails, although the client has sent a valid digest
authentication header.

Conclusion:
Working with multi-threaded clients with many requests, digest authentication
does not function reliably.

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[Bug 54521] DigestAuthenticator: nonceCountValid() fails in case of simultaneous asynchronous requests of the same client

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=54521

Mark Thomas <ma...@apache.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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[Bug 54521] DigestAuthenticator: nonceCountValid() fails in case of simultaneous asynchronous requests of the same client

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=54521

--- Comment #1 from Mark Thomas <ma...@apache.org> ---
Thanks for the report.

This has been fixed in trunk and 7.0.x and will be included in 7.0.37 onwards.

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[Bug 54521] DigestAuthenticator: nonceCountValid() fails in case of simultaneous asynchronous requests of the same client

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=54521

--- Comment #2 from Sven Stieber <sv...@traveltainment.de> ---
Thank you for fixing this that quick. One additional question: Will this fix be
included into the next Tomcat 6 Release, too?

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