authd: fix crash/restart breaking DNSBL lookups (#394)

authd child processes are only told about configured DNSBLs when the
configuration is being parsed.

This is bad, because when authd crashes or is killed, IRCd will restart
it, but will not tell it about any configured DNSBLs until IRCd is next
rehashed.

We already have a dictionary that stores configured DNSBLs (for hit
statistics for `STATS n'), so store the additional needed fields in
that structure, and loop over that dictionary's entries when authd is
restarted, sending the fields just as if the configuration were being
reloaded.

Reported-By: @Unit193

include/authproc.h

@@ -30,9 +30,11 @@
 #include "rb_dictionary.h"
 #include "client.h"
 
-struct DNSBLEntryStats
+struct DNSBLEntry
 {
 	char *host;
+	char *reason;
+	char *filters;
 	uint8_t iptype;
 	unsigned int hits;
 };

ircd/authproc.c

@@ -348,6 +348,15 @@ configure_authd(void)
 	}
 	else
 		opm_check_enable(false);
+
+	/* Configure DNSBLs */
+	rb_dictionary_iter iter;
+	struct DNSBLEntry *entry;
+	RB_DICTIONARY_FOREACH(entry, &iter, dnsbl_stats)
+	{
+		rb_helper_write(authd_helper, "O rbl %s %hhu %s :%s", entry->host,
+		                entry->iptype, entry->filters, entry->reason);
+	}
 }
 
 static void
@@ -584,7 +593,7 @@ void
 add_dnsbl_entry(const char *host, const char *reason, uint8_t iptype, rb_dlink_list *filters)
 {
 	rb_dlink_node *ptr;
-	struct DNSBLEntryStats *stats = rb_malloc(sizeof(*stats));
+	struct DNSBLEntry *entry = rb_malloc(sizeof(*entry));
 	char filterbuf[BUFSIZE] = "*";
 	size_t s = 0;
 
@@ -610,11 +619,13 @@ add_dnsbl_entry(const char *host, const char *reason, uint8_t iptype, rb_dlink_l
 	if(s)
 		filterbuf[s - 1] = '\0';
 
-	stats->host = rb_strdup(host);
-	stats->iptype = iptype;
-	stats->hits = 0;
-	rb_dictionary_add(dnsbl_stats, stats->host, stats);
+	entry->host = rb_strdup(host);
+	entry->reason = rb_strdup(reason);
+	entry->filters = rb_strdup(filterbuf);
+	entry->iptype = iptype;
+	entry->hits = 0;
 
+	rb_dictionary_add(dnsbl_stats, entry->host, entry);
 	rb_helper_write(authd_helper, "O rbl %s %hhu %s :%s", host, iptype, filterbuf, reason);
 }
 
@@ -622,12 +633,15 @@ add_dnsbl_entry(const char *host, const char *reason, uint8_t iptype, rb_dlink_l
 void
 del_dnsbl_entry(const char *host)
 {
-	struct DNSBLEntryStats *stats = rb_dictionary_retrieve(dnsbl_stats, host);
-	if(stats != NULL)
+	struct DNSBLEntry *entry = rb_dictionary_retrieve(dnsbl_stats, host);
+
+	if(entry != NULL)
 	{
-		rb_dictionary_delete(dnsbl_stats, host);
-		rb_free(stats->host);
-		rb_free(stats);
+		rb_dictionary_delete(dnsbl_stats, entry->host);
+		rb_free(entry->host);
+		rb_free(entry->reason);
+		rb_free(entry->filters);
+		rb_free(entry);
 	}
 
 	rb_helper_write(authd_helper, "O rbl_del %s", host);
@@ -636,10 +650,12 @@ del_dnsbl_entry(const char *host)
 static void
 dnsbl_delete_elem(rb_dictionary_element *delem, void *unused)
 {
-	struct DNSBLEntryStats *stats = delem->data;
+	struct DNSBLEntry *entry = delem->data;
 
-	rb_free(stats->host);
-	rb_free(stats);
+	rb_free(entry->host);
+	rb_free(entry->reason);
+	rb_free(entry->filters);
+	rb_free(entry);
 }
 
 /* Delete all the DNSBL entries. */

ircd/s_user.c

@@ -215,12 +215,12 @@ authd_check(struct Client *client_p, struct Client *source_p)
 	{
 	case 'B':	/* DNSBL */
 		{
-			struct DNSBLEntryStats *stats;
+			struct DNSBLEntry *entry;
 			char *dnsbl_name = source_p->preClient->auth.data;
 
 			if(dnsbl_stats != NULL)
-				if((stats = rb_dictionary_retrieve(dnsbl_stats, dnsbl_name)) != NULL)
-					stats->hits++;
+				if((entry = rb_dictionary_retrieve(dnsbl_stats, dnsbl_name)) != NULL)
+					entry->hits++;
 
 			if(IsExemptKline(source_p) || IsConfExemptDNSBL(aconf))
 			{

modules/m_stats.c

@@ -727,16 +727,16 @@ static void
 stats_dnsbl(struct Client *source_p)
 {
 	rb_dictionary_iter iter;
-	struct DNSBLEntryStats *stats;
+	struct DNSBLEntry *entry;
 
 	if(dnsbl_stats == NULL)
 		return;
 
-	RB_DICTIONARY_FOREACH(stats, &iter, dnsbl_stats)
+	RB_DICTIONARY_FOREACH(entry, &iter, dnsbl_stats)
 	{
 		/* use RPL_STATSDEBUG for now -- jilles */
 		sendto_one_numeric(source_p, RPL_STATSDEBUG, "n :%d %s",
-				stats->hits, (const char *)iter.cur->key);
+				entry->hits, entry->host);
 	}
 }