Metze,

   Thanks for your question.  I will be working on this request.  I will let 
you know as soon as I complete the investigation.

Thanks!

--------------------------------------------------------------------
Hongwei  Sun - Sr. Support Escalation Engineer
DSC Protocol  Team, Microsoft
hongw...@microsoft.com
Tel:  469-7757027 x 57027
---------------------------------------------------------------------



-----Original Message-----
From: Stefan (metze) Metzmacher [mailto:me...@samba.org]
Sent: Tuesday, August 25, 2009 11:13 AM
To: Interoperability Documentation Help
Cc: p...@tridgell.net; cifs-proto...@samba.org
Subject: MS-NRPC: AES Schannel problems

Hi,

I'm currently trying to implement the AES based Netlogon Secure Channel in 
Samba.

But the documentation is not really clear about the used algorithms.

I have started with the implementation here:
http://gitweb.samba.org/?p=metze/samba/wip.git;a=shortlog;h=refs/heads/master4-schannel

And here's the actual commit that tries to add aes support:
http://gitweb.samba.org/?p=metze/samba/wip.git;a=commitdiff;h=50dca9ce0f051c863f00cc949db2c19bf247887b

In Section "3.1.4.3 Session-Key Computation" the hmac-sha256 base computation 
of the session-key seems to use the plain SharedSecret and not the NT-HASH of 
it (MD4(UNICODE(ShareSecret))), is that correct?
I thought the plain text is never stored in AD by default...
Where should the netlogon server get the plain text from?
I just tried the NT-HASH see my netlogon_creds_init_hmac_sha256() function.

In Section "3.1.4.4 Netlogon Credential Computation" there's a AesEncrypt 
function used. Can you please document the exact algorithm that's used there. 
You say AES128 is used in CFB mode without initialization vector.

http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
says that all modes except ECB require an IV.

It would also be nice if you could add some more example values in secion 4.2 
Cryptographic Values for Session Key Validation.

metze




_______________________________________________
cifs-protocol mailing list
cifs-protocol@cifs.org
https://lists.samba.org/mailman/listinfo/cifs-protocol

Reply via email to