m_sasl: add configuration option for the nick of the SASL agent

This allows multiple improvements to m_sasl. With this change, the SASL
authentication gets aborted immediately when services are offline.
Additionally, we send the SASL ENCAP messages directly to the specified
SASL agent.

doc/ircd.conf.example

@@ -461,6 +461,14 @@ general {
 	default_operstring = "is an IRC Operator";
 	default_adminstring = "is a Server Administrator";
 	servicestring = "is a Network Service";
+
+	/*
+	 * Nick of the network's SASL agent. Used to check whether services are here,
+	 * SASL credentials are only sent to its server. Needs to be a service.
+	 *
+	 * Defaults to SaslServ if unspecified.
+	 */
+	sasl_service = "SaslServ";
 	disable_fake_channels = no;
 	tkline_expire_notices = no;
 	default_floodcount = 10;

doc/reference.conf

@@ -955,6 +955,14 @@ general {
 	 */
 	servicestring = "is a Network Service";
 
+	/*
+	 * Nick of the network's SASL agent. Used to check whether services are here,
+	 * SASL credentials are only sent to its server. Needs to be a service.
+	 *
+	 * Defaults to SaslServ if unspecified.
+	 */
+	sasl_service = "SaslServ";
+
 	/* disable fake channels: disable local users joining fake versions
 	 * of channels, eg #foo^B^B.  Disables bold, mirc colour, reverse,
 	 * underline and hard space.  (ASCII 2, 3, 22, 31, 160 respectively).

include/s_conf.h

@@ -151,6 +151,8 @@ struct config_file_entry
 	char *identifyservice;
 	char *identifycommand;
 
+	char *sasl_service;
+
 	char *fname_userlog;
 	char *fname_fuserlog;
 	char *fname_operlog;

modules/m_sasl.c

@@ -40,6 +40,8 @@
 #include "s_serv.h"
 #include "s_stats.h"
 #include "string.h"
+#include "s_newconf.h"
+#include "s_conf.h"
 
 static int mr_authenticate(struct Client *, struct Client *, int, const char **);
 static int me_sasl(struct Client *, struct Client *, int, const char **);
@@ -72,6 +74,7 @@ mr_authenticate(struct Client *client_p, struct Client *source_p,
 	int parc, const char *parv[])
 {
 	struct Client *agent_p = NULL;
+	struct Client *saslserv_p = NULL;
 
 	/* They really should use CAP for their own sake. */
 	if(!IsCapable(source_p, CLICAP_SASL))
@@ -83,6 +86,13 @@ mr_authenticate(struct Client *client_p, struct Client *source_p,
 		return 0;
 	}
 
+	saslserv_p = find_named_client(ConfigFileEntry.sasl_service);
+	if (saslserv_p == NULL || !IsService(saslserv_p))
+	{
+		sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
+		return 0;
+	}
+
 	if(source_p->preClient->sasl_complete)
 	{
 		sendto_one(source_p, form_str(ERR_SASLALREADY), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
@@ -108,16 +118,20 @@ mr_authenticate(struct Client *client_p, struct Client *source_p,
 	if(agent_p == NULL)
 	{
 		if (!strcmp(parv[1], "EXTERNAL") && source_p->certfp != NULL)
-			sendto_server(NULL, NULL, CAP_TS6|CAP_ENCAP, NOCAPS, ":%s ENCAP * SASL %s * S %s %s", me.id,
+			sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s %s", me.id, saslserv_p->servptr->name,
-					source_p->id, parv[1],
+					source_p->id, saslserv_p->id,
-					source_p->certfp);
+					parv[1], source_p->certfp);
 		else
-			sendto_server(NULL, NULL, CAP_TS6|CAP_ENCAP, NOCAPS, ":%s ENCAP * SASL %s * S %s", me.id,
+			sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s", me.id, saslserv_p->servptr->name,
-					source_p->id, parv[1]);
+					source_p->id, saslserv_p->id,
+					parv[1]);
+
+		rb_strlcpy(source_p->preClient->sasl_agent, saslserv_p->id, IDLEN);
 	}
 	else
 		sendto_one(agent_p, ":%s ENCAP %s SASL %s %s C %s", me.id, agent_p->servptr->name,
-				source_p->id, agent_p->id, parv[1]);
+				source_p->id, agent_p->id,
+				parv[1]);
 	source_p->preClient->sasl_out++;
 
 	return 0;

src/newconf.c

@@ -2315,6 +2315,7 @@ static struct ConfEntry conf_general_table[] =
 	{ "kline_reason",	CF_QSTRING, NULL, REALLEN, &ConfigFileEntry.kline_reason },
 	{ "identify_service",	CF_QSTRING, NULL, REALLEN, &ConfigFileEntry.identifyservice },
 	{ "identify_command",	CF_QSTRING, NULL, REALLEN, &ConfigFileEntry.identifycommand },
+	{ "sasl_service",	CF_QSTRING, NULL, REALLEN, &ConfigFileEntry.sasl_service },
 
 	{ "anti_spam_exit_message_time", CF_TIME,  NULL, 0, &ConfigFileEntry.anti_spam_exit_message_time },
 	{ "disable_fake_channels",	 CF_YESNO, NULL, 0, &ConfigFileEntry.disable_fake_channels },

src/s_conf.c

@@ -692,6 +692,7 @@ set_default_conf(void)
 	ConfigFileEntry.default_operstring = NULL;
 	ConfigFileEntry.default_adminstring = NULL;
 	ConfigFileEntry.servicestring = NULL;
+	ConfigFileEntry.sasl_service = NULL;
 
 	ConfigFileEntry.default_umodes = UMODE_INVISIBLE;
 	ConfigFileEntry.failed_oper_notice = YES;
@@ -886,6 +887,9 @@ validate_conf(void)
 	if (ConfigFileEntry.servicestring == NULL)
 		ConfigFileEntry.servicestring = rb_strdup("is a Network Service");
 
+	if (ConfigFileEntry.sasl_service == NULL)
+		ConfigFileEntry.sasl_service = rb_strdup("SaslServ");
+
 	/* RFC 1459 says 1 message per 2 seconds on average and bursts of
 	 * 5 messages are acceptable, so allow at least that.
 	 */
@@ -1489,6 +1493,8 @@ clear_out_old_conf(void)
 	ConfigFileEntry.servicestring = NULL;
 	rb_free(ConfigFileEntry.kline_reason);
 	ConfigFileEntry.kline_reason = NULL;
+	rb_free(ConfigFileEntry.sasl_service);
+	ConfigFileEntry.sasl_service = NULL;
 
 	/* clean out log */
 	rb_free(ConfigFileEntry.fname_userlog);