[cifs-protocol] [REG:111101553031054] RE: SystemLibraryDTC

Hongwei Sun hongweis at microsoft.com
Tue Oct 18 13:57:21 MDT 2011


  I confirmed that the fixed session key "SystemLibraryDTC" is only used by NTLM when the client and server are both on the same machine.  This type of loopback behavior doesn't affect  interoperability and thus is not covered by the protocol documentation.   Please let me know if you have more questions.



-----Original Message-----
From: cifs-protocol-bounces at cifs.org [mailto:cifs-protocol-bounces at cifs.org] On Behalf Of Andrew Bartlett
Sent: Saturday, October 15, 2011 12:51 AM
To: Interoperability Documentation Help
Cc: cifs-protocol at cifs.org
Subject: [cifs-protocol] SystemLibraryDTC

Tridge and I out of curiosity looked up SystemLibraryDTC in the documentation, and couldn't find it.  For those unaware of the history here, this is the fixed-value key used for encryption of passwords and other sensitive data over RPC pipes, when RPC-level authentication is used (ie, not inherited named pipe authentication).  

(The exception is DRSUAPI, which uses the real session key from the authentication context).

Did our grep simply miss it, or did this never get documented?

Recent work we did with calls needing this key (CreateTrustedDomainEx2) returning NT_STATUS_NO_SESSION_KEY, which suggests a possible windows behaviour change. 

I hope what I've written above gives enough detail to start looking into the problem.  


Andrew Bartlett
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org

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