Merge pull request #6180 from egbertbouman/dns_leak_fix

Fix DNS leak in TorrentChecker

src/tribler-core/run_tunnel_helper.py

@@ -178,7 +178,7 @@ def main(argv):
     parser.add_argument('--ipv8_address', '-i', default='0.0.0.0', type=str, help='IPv8 listening address', action=IPAction)
     parser.add_argument('--ipv8_bootstrap_override', '-b', default=None, type=str,
                         help='Force the usage of specific IPv8 bootstrap server (ip:port)', action=IPPortAction)
-    parser.add_argument('--restapi', '-p', default=52194, type=str,
+    parser.add_argument('--restapi', '-p', default=52194, type=int,
                         help='Use an alternate port for the REST API', action=PortAction, metavar='{0..65535}')
     parser.add_argument('--cert-file', '-e', help='Path to combined certificate/key file. If not given HTTP is used.')
     parser.add_argument('--api-key', '-k', help='API key to use. If not given API key protection is disabled.')

src/tribler-core/tribler_core/modules/torrent_checker/torrent_checker.py

@@ -322,13 +322,9 @@ async def check_torrent_health(self, infohash, timeout=20, scrape_now=False):
                 # get torrent's tracker list from DB
                 tracker_set = self.get_valid_trackers_of_torrent(torrent_id)
 
-        hops = self.tribler_session.config.get_default_number_hops()
-        socks_listen_ports = self.tribler_session.config.get_tunnel_community_socks5_listen_ports()
-        proxy = ('127.0.0.1', socks_listen_ports[hops - 1]) if hops > 0 else None
-
         tasks = []
         for tracker_url in tracker_set:
-            session = self._create_session_for_request(tracker_url, timeout=timeout, proxy=proxy)
+            session = self._create_session_for_request(tracker_url, timeout=timeout)
             session.add_infohash(infohash)
             tasks.append(self.connect_to_tracker(session))
 
@@ -346,7 +342,10 @@ async def check_torrent_health(self, infohash, timeout=20, scrape_now=False):
         res = await gather(*tasks, return_exceptions=True)
         return self.on_torrent_health_check_completed(infohash, res)
 
-    def _create_session_for_request(self, tracker_url, timeout=20, proxy=None):
+    def _create_session_for_request(self, tracker_url, timeout=20):
+        hops = self.tribler_session.config.get_default_number_hops()
+        socks_listen_ports = self.tribler_session.config.get_tunnel_community_socks5_listen_ports()
+        proxy = ('127.0.0.1', socks_listen_ports[hops - 1]) if hops > 0 else None
         session = create_tracker_session(tracker_url, timeout, proxy, self.socket_mgr)
 
         if tracker_url not in self._session_list:

src/tribler-core/tribler_core/modules/torrent_checker/torrentchecker_session.py

@@ -228,8 +228,9 @@ async def send_request(self, data, tracker_session):
             if proxy not in self.proxy_transports:
                 self.proxy_transports[proxy] = transport
 
+        host = tracker_session.ip_address or tracker_session.tracker_address[0]
         try:
-            transport.sendto(data, (tracker_session.ip_address, tracker_session.port))
+            transport.sendto(data, (host, tracker_session.port))
             f = self.tracker_sessions[tracker_session.transaction_id] = Future()
             return await f
         except OSError as e:
@@ -321,13 +322,16 @@ async def connect_to_tracker(self):
 
         try:
             async with async_timeout.timeout(self.timeout):
-                # Resolve the hostname to an IP address if not done already
-                coro = get_event_loop().getaddrinfo(self.tracker_address[0], 0, family=socket.AF_INET)
-                if isinstance(coro, Future):
-                    infos = await coro  # In Python <=3.6 getaddrinfo returns a Future
-                else:
-                    infos = await self.register_anonymous_task("resolve", ensure_future(coro))
-                self.ip_address = infos[0][-1][0]
+                # We only resolve the hostname if we're not using a proxy.
+                # If a proxy is used, the TunnelCommunity will resolve the hostname at the exit nodes.
+                if not self.proxy:
+                    # Resolve the hostname to an IP address if not done already
+                    coro = get_event_loop().getaddrinfo(self.tracker_address[0], 0, family=socket.AF_INET)
+                    if isinstance(coro, Future):
+                        infos = await coro  # In Python <=3.6 getaddrinfo returns a Future
+                    else:
+                        infos = await self.register_anonymous_task("resolve", ensure_future(coro))
+                    self.ip_address = infos[0][-1][0]
                 await self.connect()
                 return await self.scrape()
         except TimeoutError:

src/tribler-core/tribler_core/modules/tunnel/socks5/client.py

@@ -1,3 +1,4 @@
+import ipaddress
 import logging
 import socket
 from asyncio import DatagramProtocol, Protocol, Queue, get_event_loop
@@ -43,6 +44,10 @@ def datagram_received(self, data, _):
             self.callback(request.data, request.destination)
 
     def sendto(self, data, target_addr):
+        try:
+            ipaddress.IPv4Address(target_addr[0])
+        except ipaddress.AddressValueError:
+            target_addr = DomainAddress(*target_addr)
         packet = socks5_serializer.pack_serializable(UdpPacket(0, 0, target_addr, data))
         self.transport.sendto(packet, self.proxy_udp_addr)
 

src/tribler-core/tribler_core/modules/tunnel/socks5/tests/test_server.py

@@ -29,7 +29,7 @@ async def test_start_server(socks5_server):
 @pytest.mark.asyncio
 async def test_socks5_udp_associate(socks5_server):
     """
-    Test is sending a UDP associate request to the server succeeds.
+    Test if sending a UDP associate request to the server succeeds.
     """
     await socks5_server.start()
     client = Socks5Client(('127.0.0.1', socks5_server.port), Mock())
@@ -79,7 +79,7 @@ async def test_socks5_sendto_success(socks5_server):
 @pytest.mark.asyncio
 async def test_socks5_tcp_connect(socks5_server):
     """
-    Test is sending a TCP connect request to the server succeeds.
+    Test if sending a TCP connect request to the server succeeds.
     """
     await socks5_server.start()
     client = Socks5Client(('127.0.0.1', socks5_server.port), Mock())
@@ -91,7 +91,7 @@ async def test_socks5_tcp_connect(socks5_server):
 @pytest.mark.asyncio
 async def test_socks5_write(socks5_server):
     """
-    Test is sending a TCP data to the server succeeds.
+    Test if sending a TCP data to the server succeeds.
     """
     await socks5_server.start()
     client = Socks5Client(('127.0.0.1', socks5_server.port), Mock())