Don't allow masquerading into oneself (bug #3040)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4726 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channel.c

@@ -2208,6 +2208,10 @@ int ast_channel_masquerade(struct ast_channel *original, struct ast_channel *clo
 {
 	struct ast_frame null = { AST_FRAME_NULL, };
 	int res = -1;
+	if (original == clone) {
+		ast_log(LOG_WARNING, "Can't masquerade channel '%s' into itself!\n", original->name);
+		return -1;
+	}
 	ast_mutex_lock(&original->lock);
 	while(ast_mutex_trylock(&clone->lock)) {
 		ast_mutex_unlock(&original->lock);

channels/chan_sip.c

@@ -5335,9 +5335,13 @@ static int get_refer_info(struct sip_pvt *p, struct sip_request *oreq)
 			p2 = p2->next;
 		}
 		ast_mutex_unlock(&iflock);
-		if (p->refer_call)
-			return 0;
-		else
+		if (p->refer_call) {
+			if (p->refer_call == p) {
+				ast_log(LOG_NOTICE, "Supervised transfer attempted to transfer into same call id (%s == %s)!\n", tmp5, p->callid);
+				p->refer_call = NULL;
+			} else
+				return 0;
+		} else
 			ast_log(LOG_NOTICE, "Supervised transfer requested, but unable to find callid '%s'\n", tmp5);
 	} else if (ast_exists_extension(NULL, p->context, c, 1, NULL) || !strcmp(c, ast_parking_ext())) {
 		/* This is an unsupervised transfer */