[PATCH] NTLMSSP client updates (RPC pipes)

Tim Potter tpot at samba.org
Mon Jul 14 02:21:29 GMT 2003

On Sun, Jul 13, 2003 at 05:50:01AM +0000, Andrew Bartlett wrote:

> This patch revives the client-side NTLMSSP support for RPC named pipes
> in Samba.  Currently enabled by the 'sign' and 'seal' commands in 
> rpcclient, this code is the result of a research effort on my part.
> The hope is that knowing this will assist us in correctly implementing 
> NTLMSSP signing for SMB packets.
> This patch replaces the NTLMSSP implementation in rpc_client/cli_pipe.c with
> calls to libsmb/ntlmssp.c.  In the process, we have gained the ability to
> use the more secure NT password, and the ability to sign, but not seal, 
> the pipe connection.  (Previously we were limited to sealing with the 
> LM-password derived key).

Very nice!  As you may have discovered the various cryptographic bits
and pieces are a collection of if statements.  Have you seen the way
TNG has cleaned this up using the table of function pointers pattern?

Ethereal is supposed to decode ntlmssp sign and seal over RPC.  The
signing seemed to work OK (not sure whether the signature was checked
against the data) but I couldn't get sealing working, even after hacking
the client code to negotiate LM keys.  I doubt that NTLM keys are 

It would be nice to be able to specify client side LM or NT here to
facilitate testing the different signing methods.

> This code is also much more secure than the previous code, as changes to our
> cli_pipe routines ensure that the authentication footer cannot be removed
> by an attacker, and more error states are correctly handled.


> (The same needs to be done to our server)


> +/* Generic flags to indicate signing or sealing of an RPC pipe */

These are actually the values used in the DCERPC header for the
auth level field - packet integrity and packet privacy, respectively.
They're not flags.

> -void string_replace(char *s,char oldc,char newc)
> +void string_replace(pstring s,char oldc,char newc)
>  {
>  	push_ucs2(NULL, tmpbuf,s, sizeof(tmpbuf), STR_TERMINATE);
>  	string_replace_w(tmpbuf, UCS2_CHAR(oldc), UCS2_CHAR(newc));

Er, should this be a separate fix applied to 3.0?


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