Fix potential memory leaks.

Closes #1773. Closes #1774. Thanks to Yingpei Zeng.

ChangeLog.txt

@@ -19,6 +19,7 @@ Broker:
   than the generic "socket error".
 - Don't try to start DLT logging if DLT unavailable, to avoid a long delay
   when shutting down the broker. Closes #1735.
+- Fix potential memory leaks. Closes #1773. Closes #1774.
 
 Client library:
 - Improved documentation around connect callback return codes. Close #1730.

src/handle_publish.c

@@ -109,7 +109,10 @@ int handle__publish(struct mosquitto_db *db, struct mosquitto *context)
 	/* Handle properties */
 	if(context->protocol == mosq_p_mqtt5){
 		rc = property__read_all(CMD_PUBLISH, &context->in_packet, &properties);
-		if(rc) return rc;
+		if(rc){
+			mosquitto__free(topic);
+			return rc;
+		}
 
 		p = properties;
 		p_prev = NULL;

src/handle_subscribe.c

@@ -119,6 +119,8 @@ int handle__subscribe(struct mosquitto_db *db, struct mosquitto *context)
 
 				retain_handling = (subscription_options & 0x30);
 				if(retain_handling == 0x30 || (subscription_options & 0xC0) != 0){
+					mosquitto__free(sub);
+					mosquitto__free(payload);
 					return MOSQ_ERR_PROTOCOL;
 				}
 			}