Re: [nmap-svn] r14148 - in nmap-exp/daniel: ncat-sctp nmap-sctp

[David Fifield <david () bamsoftware com>]

On Fri, Jul 10, 2009 at 01:17:47PM +0200, Daniel Roethlisberger wrote:
> David Fifield <david () bamsoftware com> 2009-07-09:
> > On Thu, Jul 09, 2009 at 02:30:05PM -0700, commit-mailer () insecure org wrote:
> > > Author: daniel
> > > Date: Thu Jul  9 14:30:05 2009
> > > New Revision: 14148
> > >
> > > Modified:
> > >    nmap-exp/daniel/ncat-sctp/ncat_broker.c
> > >    nmap-exp/daniel/ncat-sctp/ncat_listen.c
> > >    nmap-exp/daniel/ncat-sctp/ncat_main.c
> > >    nmap-exp/daniel/ncat-sctp/ncat_proxy.c
> > >    nmap-exp/daniel/ncat-sctp/util.c
> > >    nmap-exp/daniel/ncat-sctp/util.h
> > >    nmap-exp/daniel/nmap-sctp/CHANGELOG
> > >
> > > Log:
> > > o [Ncat] Implemented support for SCTP listening sockets, including SSL
> > >   support.  Since there is no SSL support for SCTP client sockets yet,
> > >   SSL support is not terribly useful yet. [Daniel Roethlisberger]
> >
> > Is this code ready to merge? I'd like to have at least the listen mode
> > changes as soon as they are ready. If you're happy with the Nsock
> > changes for connect mode then I want those to be merged too.
>
> The listen and connect mode SCTP changes are ready.  I'll merge
> them probably tonight after some more pre-merge testing.  If you
> had a chance to test the code currently in the nmap-sctp branch
> please let me know about any issues or success.

Yeah, I don't have libsctp installed but I have SCTP in the Linux
kernel. Because of a lack of <netinet/sctp.h>, the configure script in
nsock and ncat doesn't build in SCTP support. But if I edit the config.h
files to define HAVE_SCTP, Ncat works with SCTP anyway (after the fix
described in the next paragraph). So a different test would be nice.

I was getting this error:

$ ./ncat --sctp scanme.csnc.ch 7 -vvv
Ncat version 4.85BETA10 ( http://nmap.org/ncat )
NSOCK (0.0030s) SCTP association requested to 213.144.141.30:7 (IOD #1) EID 8
NSOCK (0.3870s) Callback: CONNECT ERROR [Connection refused (111)] for EID 8 [213.144.141.30:7]
DEBUG: Received callback of type CONNECT with status ERROR
Invalid argument.

I tracked the "Invalid argument" to the send call in this code:

    /* First we want to determine whether the socket really is connected */
    if (getsockopt(iod->sd, SOL_SOCKET, SO_ERROR, (char *) &optval, &optlen) != 0)
      optval = socket_errno(); /* Stupid Solaris */
    switch(optval) {
    case 0:
#ifdef LINUX
      if (!FD_ISSET(iod->sd, &ms->mioi.fds_results_r)) {
        /* Linux goofiness -- We need to actually test that it is writeable */
        rc = send(iod->sd, "", 0, 0);

If I comment out the send and assign 0 to rc, Ncat works as expected.
Maybe SCTP doesn't support zero-length messages or something? I don't
know what the "Linux goofiness" is for, but maybe that test only applies
to TCP.

Also, it looks like the <netinet/sctp.h> test is present in
ncat/configure.ac but not ncat/configure. I think it was there before,
so it might have gotten lost during a merge.

David Fifield

_______________________________________________
Sent through the nmap-dev mailing list
http://cgi.insecure.org/mailman/listinfo/nmap-dev
Archived at http://SecLists.Org