[dev] [sic] support for PLAIN SASL authentication on freenode

[Marcin Cieslak]

Some servers, like freenode when used with Tor[1] require user authentication
on connect via SASL against the NickServ database. This done using CAP[2]
command and simple SASL exchange[3].  

Here's the patch to sic trunk to support this, it adds a new 
argument (-a) that needs to be an base64 encoded SASL PLAIN response.
This can be generated with python like this:

python -c 'import base64; print base64.encodestring("nick\x00nick\x00password")'

diff -r 904b7747c223 sic.1
--- a/sic.1     Fri Aug 06 09:52:12 2010 +0100
+++ b/sic.1     Fri Jan 28 14:23:44 2011 +0000
@@ -7,6 +7,7 @@
 .RB [ \-p " <port>"]
 .RB [ \-n " <nick>"]
 .RB [ \-k " <keyword>"]
+.RB [ \-a " <token>"]
 .RB [ \-v ]
 .SH DESCRIPTION
 .B sic
@@ -28,6 +29,12 @@
 .B \-k <keyword>
 Specifies the keyword to authenticate your nick on the host
 .TP
+.B \-a <token>
+Requests use of SASL authentication to the server. The token
+is a Base64-encoded message as required by SASL PLAIN mechanism:
+.IP ""
+username\\0username\\0password
+.TP
 .BI \-v
 Prints version information to standard output, then exits.
 .SH COMMANDS
diff -r 904b7747c223 sic.c
--- a/sic.c     Fri Aug 06 09:52:12 2010 +0100
+++ b/sic.c     Fri Jan 28 14:23:44 2011 +0000
@@ -12,6 +12,7 @@
 static char *port = "ircd";
 static char *password;
 static char nick[32];
+static char *auth;
 static char bufin[4096];
 static char bufout[4096];
 static char channel[256];
@@ -124,7 +125,16 @@
                pout(par, "<%s> %s", usr, txt);
        else if(!strcmp("PING", cmd))
                sout("PONG %s", txt);
+       else if (!strcmp("CAP", cmd) && auth != NULL) {
+               sout("AUTHENTICATE PLAIN");
+       }
+       else if (!strcmp("AUTHENTICATE", cmd) && auth != NULL) {
+               sout("AUTHENTICATE %s", auth);
+               pout(usr, "AUTHENTICATE KioqKioAKioqKioAKioqKio=");
+       }
        else {
+               if (!strncmp("90", cmd, 2))
+                       sout("CAP END");
                pout(usr, ">< %s (%s): %s", cmd, par, txt);
                if(!strcmp("NICK", cmd) && !strcmp(usr, nick))
                        strlcpy(nick, txt, sizeof nick);
@@ -138,6 +148,7 @@
        const char *user = getenv("USER");
        fd_set rd;
 
+       auth = NULL;
        strlcpy(nick, user ? user : "unknown", sizeof nick);
        for(i = 1; i < argc; i++) {
                c = argv[i][1];
@@ -153,19 +164,24 @@
                case 'n':
                        if(++i < argc) strlcpy(nick, argv[i], sizeof nick);
                        break;
+               case 'a':
+                       if(++i < argc) auth = argv[i];
+                       break;
                case 'k':
                        if(++i < argc) password = argv[i];
                        break;
                case 'v':
                        eprint("sic-"VERSION", © 2005-2009 Kris Maglione, 
Anselm R. Garbe, Nico Golde\n");
                default:
-                       eprint("usage: sic [-h host] [-p port] [-n nick] [-k 
keyword] [-v]\n");
+                       eprint("usage: sic [-h host] [-p port] [-n nick] [-a 
auth] [-k keyword] [-v]\n");
                }
        }
        /* init */
        i = dial(host, port);
        srv = fdopen(i, "r+");
        /* login */
+       if(auth)
+               sout("CAP REQ :sasl");
        if(password)
                sout("PASS %s", password);
        sout("NICK %s", nick);

//Marcin

[1] http://freenode.net/irc_servers.shtml#tor 
[2] http://www.leeh.co.uk/draft-mitchell-irc-capabilities-02.html
[3] http://www.beuc.net/tor/