[lwip-devel] [patch #6969] PPP: missing PAP authentication UNTIMEOUT

[Iordan Neshev]

URL:
  <http://savannah.nongnu.org/patch/?6969>

                 Summary: PPP: missing PAP authentication UNTIMEOUT
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: iordan_neshev
            Submitted on: Fri 06 Nov 2009 10:17:40 AM GMT
                Category: None
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

    _______________________________________________________

Details:

static void
upap_rauthack(upap_state *u, u_char *inp, int id, int len)
{
  u_char msglen;
  char *msg;

  LWIP_UNUSED_ARG(id);

  UPAPDEBUG((LOG_INFO, "pap_rauthack: Rcvd id %d s=%d\n", id,
u->us_clientstate));

  if (u->us_clientstate != UPAPCS_AUTHREQ) { /* XXX */
    UPAPDEBUG((LOG_INFO, "pap_rauthack: us_clientstate != UPAPCS_AUTHREQ;
returning\n"));
    return;
  }

  /*
   * Parse message.
   */
  if (len < (int)sizeof (u_char)) {
    UPAPDEBUG((LOG_INFO, "pap_rauthack: rcvd short packet.\n"));
    return;
  }
  GETCHAR(msglen, inp);
  len -= sizeof (u_char);
  if (len < msglen) {
    UPAPDEBUG((LOG_INFO, "pap_rauthack: rcvd short packet.\n"));
    return;
  }
// THIS IS MISSING --->
#if 1
  UNTIMEOUT(upap_timeout, u);    /* Cancel timeout */
#endif
// <----

  msg = (char *) inp;
  PRINTMSG(msg, msglen);

  u->us_clientstate = UPAPCS_OPEN;

  auth_withpeer_success(u->us_unit, PPP_PAP); // follows NETWORK phase
}

When the LCP layer is up, lwip sends PAP authenticate request using
upap_sauthreq(). It sends the packet and sets a TIMEOUT(upap_timeout) which is
supposed to resend the request if we do not receive ACK in a reasonable time.


upap_rauthack() is called when the peer acknowledges our PAP authenticate
request. It starts the network phase of the PPP phase diagram. Before that the
PAP timeout should be canceled (but it's not). As a result I see it a little
bit after the PPP session is completely ready. 

It's harmless, because this if() prevents sending 
another auth request.

if (u->us_clientstate != UPAPCS_AUTHREQ) {
  return;
}

Anyway, I think it should be avoided. This bug is missing in
ChapReceiveSuccess() (this does the same as upap_rauthack when tha auth
protocol is CHAP).
 






    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/patch/?6969>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.nongnu.org/