SMB3.0 alternate channel

Arnab Bakshi arnab.bakshi at gmail.com
Tue Feb 26 00:15:01 MST 2013


Hi,

    Does the crypto (mainly the signing) code work for 64 bit machine. Does
it require any changes in byteorder.h?..

Regards
Arnab


On Thu, Feb 14, 2013 at 7:48 PM, Arnab Bakshi <arnab.bakshi at gmail.com>wrote:

> Thanks Stefan..got it..sorry for bothering I figured it out after sending
> out my question..my bad :(
>
> Much thanks for the answer...
>
>
> On Thu, Feb 14, 2013 at 7:22 PM, Stefan (metze) Metzmacher <
> metze at samba.org> wrote:
>
>> Hi Arnab,
>>
>> >   Was going through the smb2_key_derivation() function which generates
>> the
>> > session->signingKey from the session->sessionKey. As per the MS_SMB2
>> spec
>> > section-3.1.4.2 page 130 the algorithm should be as specified
>> > in [SP800-108] section 5.1 i.e KDF in counter mode with PRF as HMAC-256.
>> > Also the [MS-SMB2] spec specifies a *'r'* value of 32 and 'L' value of
>> 128.
>> >
>> > In the Samba-4.0.3  implementation that I downloaded I could see the
>> > *'L'*value being defined but did not find the
>> > *'r*' value anywhere which is supposed to be the size of binary string
>> > representing the counter *'i'*.
>>
>>         uint8_t buf[4];
>> ...
>>
>>         RSIVAL(buf, 0, i);
>>         hmac_sha256_update(buf, sizeof(buf), &ctx);
>> ...
>>
>> =>
>> sizeof(buf)*8 = 32
>>
>> RSIVAL() fills buf with the 32-bit big endian representation of 'i'.
>>
>> >     Can anybody please throw some light on this?..Also do you have any
>> > example values of session->sessionKey and session->signingKey using
>> which
>> > this function was validated..
>>
>> Ping me if you still need them.
>>
>> metze
>>
>>
>


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