Fix a possible crash when sending the HUP signal.

When the HUP signal is sent while some outgoing connections have not been made
yet, or are being retried, a NULL pointer could be dereferenced resulting in
tinc crashing. We fix this by more careful handling of outgoing_ts, and by
deleting all connections that have not been fully activated yet at the HUP
signal is received.

src/event.h

@@ -27,7 +27,7 @@ extern avl_tree_t *event_tree;
 
 typedef void (*event_handler_t)(void *);
 
-typedef struct {
+typedef struct event {
 	time_t time;
 	int id;
 	event_handler_t handler;

src/net.c

@@ -431,7 +431,7 @@ int main_loop(void) {
 
 		if(sighup) {
 			connection_t *c;
-			avl_node_t *node;
+			avl_node_t *node, *next;
 			char *fname;
 			struct stat s;
 			
@@ -447,6 +447,31 @@ int main_loop(void) {
 				return 1;
 			}
 
+			/* Cancel non-active outgoing connections */
+
+			for(node = connection_tree->head; node; node = next) {
+				next = node->next;
+				c = node->data;
+
+				c->outgoing = NULL;
+
+				if(c->status.connecting) {
+					terminate_connection(c, false);
+					connection_del(c);
+				}
+			}
+
+			/* Wipe list of outgoing connections */
+
+			for(list_node_t *node = outgoing_list->head; node; node = node->next) {
+				outgoing_t *outgoing = node->data;
+
+				if(outgoing->event)
+					event_del(outgoing->event);
+			}
+
+			list_delete_list(outgoing_list);
+
 			/* Close connections to hosts that have a changed or deleted host config file */
 			
 			for(node = connection_tree->head; node; node = node->next) {

src/net.h

@@ -98,6 +98,7 @@ typedef struct outgoing_t {
 	struct config_t *cfg;
 	struct addrinfo *ai;
 	struct addrinfo *aip;
+	struct event *event;
 } outgoing_t;
 
 extern list_t *outgoing_list;

src/net_setup.c

@@ -541,10 +541,17 @@ void close_network_connections(void) {
 	for(node = connection_tree->head; node; node = next) {
 		next = node->next;
 		c = node->data;
-		c->outgoing = false;
+		c->outgoing = NULL;
 		terminate_connection(c, false);
 	}
 
+	for(list_node_t *node = outgoing_list->head; node; node = node->next) {
+		outgoing_t *outgoing = node->data;
+
+		if(outgoing->event)
+			event_del(outgoing->event);
+	}
+
 	list_delete_list(outgoing_list);
 
 	if(myself && myself->connection) {

src/net_socket.c

@@ -306,18 +306,18 @@ int setup_vpn_in_socket(const sockaddr_t *sa) {
 } /* int setup_vpn_in_socket */
 
 void retry_outgoing(outgoing_t *outgoing) {
-	event_t *event;
-
 	outgoing->timeout += 5;
 
 	if(outgoing->timeout > maxtimeout)
 		outgoing->timeout = maxtimeout;
 
-	event = new_event();
+	if(outgoing->event)
-	event->handler = (event_handler_t) setup_outgoing_connection;
+		event_del(outgoing->event);
-	event->time = now + outgoing->timeout;
+	outgoing->event = new_event();
-	event->data = outgoing;
+	outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
-	event_add(event);
+	outgoing->event->time = now + outgoing->timeout;
+	outgoing->event->data = outgoing;
+	event_add(outgoing->event);
 
 	ifdebug(CONNECTIONS) logger(LOG_NOTICE,
 			   "Trying to re-establish outgoing connection in %d seconds",
@@ -338,6 +338,11 @@ void do_outgoing_connection(connection_t *c) {
 	char *address, *port;
 	int result;
 
+	if(!c->outgoing) {
+		logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
+		abort();
+	}
+
 begin:
 	if(!c->outgoing->ai) {
 		if(!c->outgoing->cfg) {
@@ -345,6 +350,7 @@ begin:
 					   c->name);
 			c->status.remove = true;
 			retry_outgoing(c->outgoing);
+			c->outgoing = NULL;
 			return;
 		}
 
@@ -431,6 +437,8 @@ void setup_outgoing_connection(outgoing_t *outgoing) {
 	connection_t *c;
 	node_t *n;
 
+	outgoing->event = NULL;
+
 	n = lookup_node(outgoing->name);
 
 	if(n)
@@ -525,17 +533,6 @@ void try_outgoing_connections(void) {
 	static config_t *cfg = NULL;
 	char *name;
 	outgoing_t *outgoing;
-	connection_t *c;
-	avl_node_t *node;
-	
-	if(outgoing_list) {
-		for(node = connection_tree->head; node; node = node->next) {
-			c = node->data;
-			c->outgoing = NULL;
-		}
-
-		list_delete_list(outgoing_list);
-	}
 	
 	outgoing_list = list_alloc((list_action_t)free_outgoing);