Agent: Fix min_range in get_free_tcp_port()

get_free_tcp_port() effectively ignored the min_range parameter by using
min(1, min_range). This meant that min_range was always 1 (unless a
negative value was passed). As ports lower than 1024 are privileged on
Linux, this lead to the agent trying to bind to ports that it did not
have permission to. By using max(1, min_range), We insure that min_range
is always at least 1, but will still use the provided parameter (1024 by
default).

monkey/infection_monkey/network/info.py

@@ -108,14 +108,14 @@ else:
         return routes
 
 
-def get_free_tcp_port(min_range=1000, max_range=65535):
-    start_range = min(1, min_range)
+def get_free_tcp_port(min_range=1024, max_range=65535):
+    min_range = max(1, min_range)
     max_range = min(65535, max_range)
 
     in_use = [conn.laddr[1] for conn in psutil.net_connections()]
 
     for i in range(min_range, max_range):
-        port = randint(start_range, max_range)
+        port = randint(min_range, max_range)
 
         if port not in in_use:
             return port