Add support for linking using SSL certificate fingerprints as the link credential rather than the traditional server-password pair.

doc/example.conf

@@ -347,6 +347,8 @@ connect "irc.uplink.com" {
 	class = "server";
 	flags = compressed, topicburst;
 
+	#fingerprint = "c77106576abf7f9f90cca0f63874a60f2e40a64b";
+
 	/* If the connection is IPv6, uncomment below.
 	 * Use 0::1, not ::1, for IPv6 localhost. */
 	#aftype = ipv6;

doc/reference.conf

@@ -584,6 +584,12 @@ connect "irc.uplink.com" {
 	send_password = "password";
 	accept_password = "anotherpassword";
 
+	/* fingerprint: if specified, the server's client certificate
+	 * fingerprint will be checked against the specified fingerprint
+	 * below.
+	 */
+	#fingerprint = "c77106576abf7f9f90cca0f63874a60f2e40a64b";
+
 	/* port: the port to connect to this server on */
 	port = 6666;
 

include/s_newconf.h

@@ -187,6 +187,7 @@ struct server_conf
 	char *host;
 	char *passwd;
 	char *spasswd;
+	char *certfp;
 	int port;
 	int flags;
 	int servers;

modules/core/m_server.c

@@ -150,14 +150,14 @@ mr_server(struct Client *client_p, struct Client *source_p, int parc, const char
 	case -2:
 		sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) ? L_NETWIDE : L_ALL,
 				     "Unauthorised server connection attempt from %s: "
-				     "Bad password for server %s",
+				     "Bad credentials for server %s",
 				     "[@255.255.255.255]", name);
 
-		ilog(L_SERVER, "Access denied, invalid password for server %s%s",
+		ilog(L_SERVER, "Access denied, invalid credentials for server %s%s",
 		     EmptyString(client_p->name) ? name : "",
 		     log_client_name(client_p, SHOW_IP));
 
-		exit_client(client_p, client_p, client_p, "Invalid password.");
+		exit_client(client_p, client_p, client_p, "Invalid credentials.");
 		return 0;
 		/* NOT REACHED */
 		break;

src/newconf.c

@@ -1309,9 +1309,9 @@ conf_end_connect(struct TopConf *tc)
 		return 0;
 	}
 
-	if(EmptyString(yy_server->passwd) || EmptyString(yy_server->spasswd))
+	if((EmptyString(yy_server->passwd) || EmptyString(yy_server->spasswd)) && EmptyString(yy_server->certfp))
 	{
-		conf_report_error("Ignoring connect block for %s -- missing password.",
+		conf_report_error("Ignoring connect block for %s -- no certfp or password credentials provided.",
 					yy_server->name);
 		return 0;
 	}
@@ -1383,6 +1383,15 @@ conf_set_connect_accept_password(void *data)
 	yy_server->passwd = rb_strdup(data);
 }
 
+static void
+conf_set_connect_fingerprint(void *data)
+{
+	yy_server->certfp = rb_strdup((char *) data);
+
+	/* force SSL to be enabled if fingerprint is enabled. */
+	yy_server->flags |= SERVER_SSL;
+}
+
 static void
 conf_set_connect_port(void *data)
 {
@@ -2164,6 +2173,7 @@ static struct ConfEntry conf_connect_table[] =
 {
 	{ "send_password",	CF_QSTRING,   conf_set_connect_send_password,	0, NULL },
 	{ "accept_password",	CF_QSTRING,   conf_set_connect_accept_password,	0, NULL },
+	{ "fingerprint",	CF_QSTRING,   conf_set_connect_fingerprint,	0, NULL },
 	{ "flags",	CF_STRING | CF_FLIST, conf_set_connect_flags,	0, NULL },
 	{ "host",	CF_QSTRING, conf_set_connect_host,	0, NULL },
 	{ "vhost",	CF_QSTRING, conf_set_connect_vhost,	0, NULL },

src/s_serv.c

@@ -320,6 +320,8 @@ check_server(const char *name, struct Client *client_p)
 		{
 			error = -2;
 
+			if(tmp_p->passwd)
+			{
 				if(ServerConfEncrypted(tmp_p))
 				{
 					if(!strcmp(tmp_p->passwd, rb_crypt(client_p->localClient->passwd,
@@ -328,14 +330,23 @@ check_server(const char *name, struct Client *client_p)
 						server_p = tmp_p;
 						break;
 					}
+					else
+						continue;
 				}
-			else if(!strcmp(tmp_p->passwd, client_p->localClient->passwd))
+				else if(strcmp(tmp_p->passwd, client_p->localClient->passwd))
+					continue;
+			}
+
+			if(tmp_p->certfp)
 			{
+				if(!client_p->certfp || strcasecmp(tmp_p->certfp, client_p->certfp) != 0)
+					continue;
+			}
+
 			server_p = tmp_p;
 			break;
 		}
 	}
-	}
 
 	if(server_p == NULL)
 		return error;
@@ -781,15 +792,9 @@ server_estab(struct Client *client_p)
 
 	if(IsUnknown(client_p))
 	{
-		/*
-		 * jdc -- 1.  Use EmptyString(), not [0] index reference.
-		 *        2.  Check ->spasswd, not ->passwd.
-		 */
-		if(!EmptyString(server_p->spasswd))
-		{
+		/* the server may be linking based on certificate fingerprint now. --nenolod */
 		sendto_one(client_p, "PASS %s TS %d :%s", 
-				   server_p->spasswd, TS_CURRENT, me.id);
-		}
+			   EmptyString(server_p->spasswd) ? "*" : server_p->spasswd, TS_CURRENT, me.id);
 
 		/* pass info to new server */
 		send_capabilities(client_p, default_server_capabs
@@ -1350,11 +1355,9 @@ serv_connect_callback(rb_fde_t *F, int status, void *data)
 	/* Next, send the initial handshake */
 	SetHandshake(client_p);
 
-	if(!EmptyString(server_p->spasswd))
-	{
+	/* the server may be linking based on certificate fingerprint now. --nenolod */
 	sendto_one(client_p, "PASS %s TS %d :%s", 
-			   server_p->spasswd, TS_CURRENT, me.id);
-	}
+		   EmptyString(server_p->spasswd) ? "*" : server_p->spasswd, TS_CURRENT, me.id);
 
 	/* pass my info to the new server */
 	send_capabilities(client_p, default_server_capabs