Metze,

   Yes,  your initial observation is right.   Checksum is only 8 bytes and the 
cofounder follows with 8 bytes of checksum.  I filed a request to update the 
document.  

   I will look at the code and compare it with the documentation and Windows 
implementation.  I will let you know.

Thanks!

Hongwei 

-----Original Message-----
From: Stefan (metze) Metzmacher [mailto:[email protected]] 
Sent: Thursday, September 17, 2009 11:17 AM
To: Hongwei Sun; [email protected]; [email protected]; Nick Meier; 
Guenther Deschner
Subject: Re: [Pfif] MS-NRPC: AES Schannel problems

Hi Hongwei,

Nick just told me that Windows seems to have a bug there and I tried to 
"reproduce" this bug in our code, but I still can't get windows to accept 
signed or sealed traffic from us.

See the attached capture:

Frames 178 and 179 are with signing
Frames 330 and 331 are with sealing

You can take a look at my code here (see the top 5 commits) 
http://gitweb.samba.org/?p=metze/samba/wip.git;a=shortlog;h=refs/heads/master4-schannel

metze
> -----Original Message-----
> From: Stefan (metze) Metzmacher [mailto:[email protected]]
> Sent: Wednesday, September 16, 2009 1:46 PM
> To: Hongwei Sun
> Cc: [email protected]; [email protected]; Nick Meier; Guenther 
> Deschner
> Subject: Re: [Pfif] MS-NRPC: AES Schannel problems
> 
> Hi Hongwei,
> 
>>    I think that Nick already informed you that AES 128 with 8 bit CFB mode 
>> has to be used.  I filed a request to add the information into 3.1.4.4 of 
>> MS-NRPC.  I also noticed that in  mxnrpc.c you attached , you used 
>> AES_cfb128_encrypt() (128 bit CFB mode) for computing server credential.  
>> Please let us know if you have resolved the issue and if we can provide 
>> further help.
> 
> Yes, he does and we got that part working. Thanks!
> using AES_cfb8_encrypt() instead of AES_cfb128_encrypt().
> 
> However we have the next challenge, the Netlogon SSPI provider.
> 
> I used tried both AES_cfb8_encrypt() and AES_cfb128_encrypt() but both don't 
> work.
> 
> Looking at the frame 308 and the following in 
> w2k8r2rc-l4-w2k8r2-trust-aes-schannel-01.pcap.
> 
> I think there's a bug in w2k8r2 in the docs.
> 
> The NL_AUTH_SHA2_SIGNATURE is filled in with very strange values.
> 
> It seem that the checksum is still 8 byte and the confounder directly 
> follows. The last 24 bytes are just uninitalized memory.
> 
> They are:
> Frame 308:
> 
> 32 00 2e 00 33 00 31 00
> 2e 00 39 00 2e 00 32 00
> 31 00 34 00 00 00 00 00
> 
> Frame 310:
> 
> 35 00 00 00 00 00 00 00
> 00 00 00 00 00 00 00 00
> 00 00 02 00 00 00 00 00
> 
> Frame 311: (I think it's random because the pdu is so long and point 
> memory in other aeas)
> 
> 51 03 21 9b 41 84 cc 90
> e7 e8 70 1c 52 60 55 5a
> 64 0c 6a 17 be 07 de 80
> 
> Looks like a unicode string instead of parts of a checksum and a confounder.
> 
> metze
> 
>> Meanwhile, I provide some sample values that I captured from debugger
> for you to verify your logic.
>>      OWF Password :
>>
>>          13 c0 b0 4b 66 25 0d 08-b8 a3 90 4d cc 8b 34 e3
>>
>>      Client Challenge:
>>
>>         25 63 e3 5f 69 e1 5a 24
>>
>>      Server Challenge:
>>
>>         9C 66 5F 90 D9 83 DF 43
>>
>>      Session Key calculated: 
>>   
>>          c9 c7 f7 2f c6 b9 13 e3-67 ae a9 1d 0a e3 a7 70
>>
>>      Client Credential:
>>
>>         58 6a df 53 ef 72 78 d9
>>
>>      Server Credential
>>
>>         E1 41 62 09 B2 3E 57 51
>>
> 
> It would be great if you could add this values to the docs.
> 
> metze
> 

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