[pptp-server] Forcing encryption (was: Optimizing pppd for PPTP)

[Patrick J. LoPresti]

Martin Mueller <mm at lunetix.de> writes:

> I think my patch is doing 2) at the moment, at least I´m hopeing to
> achieve it with the following snippet:
> 
> +++ ppp-2.3.11.mppe/pppd/ccp.c
> @ -450,6 +455,8 @@
>  {
>      ccp_flags_set(unit, 0, 0);
>      fsm_lowerdown(&ccp_fsm[unit]);
> +    if ( ccp_wantoptions[unit].require_mppe || ccp_wantoptions[unit].require_mppe_stateless )
> +       lcp_close(unit,"Encryption negotiation rejected");
>  }
> 
> Which should close the connection on the closing of the CCP.
> 
> Correct me if I´m wrong.

I believe you are wrong, although I am not enough of a pppd expert to
be sure.  My reasoning follows.

Open up ppp-2.3.11/pppd/ccp.c and follow along...

Find the call to ccp_fatal_error().  This returns true when a fatal
error has occurred.  If so, we log a message and call ccp_close().

Now look at ccp_close().  It does something very similar to
ccp_protrej(), which is the function you have changed to terminate the
connection when CCP negotiation fails.  I believe you need to make a
similar change to ccp_close(), and possibly to ccp_down() as well (to
be completely safe).

Now you can correct me if *I* am wrong :-).

 - Pat