torcontrol: Use the default/standard network port for Tor hidden services, even if the internal port is set differently

luke-jr · luke-jr · commit 8a2656702b4b · 2019-03-23T06:13:37.000Z
Currently, the hidden service is published on the same port as the public listening port.
But if a non-standard port is configured, this can be used to guess (pretty reliably) that the public IP and the hidden service are the same node.
diff --git a/src/torcontrol.cpp b/src/torcontrol.cpp
@@ -3,6 +3,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <chainparams.h>
 #include <torcontrol.h>
 #include <util/strencodings.h>
 #include <netbase.h>
@@ -500,7 +501,7 @@ void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlRe
             }
             return;
         }
-        service = LookupNumeric(std::string(service_id+".onion").c_str(), GetListenPort());
+        service = LookupNumeric(std::string(service_id+".onion").c_str(), Params().GetDefaultPort());
         LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString());
         if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
             LogPrint(BCLog::TOR, "tor: Cached service private key to %s\n", GetPrivateKeyFile().string());
@@ -534,9 +535,8 @@ void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply&
         if (private_key.empty()) // No private key, generate one
             private_key = "NEW:RSA1024"; // Explicitly request RSA1024 - see issue #9214
         // Request hidden service, redirect port.
-        // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient
-        // choice.  TODO; refactor the shutdown sequence some day.
-        _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()),
+        // Note that the 'virtual' port is always the default port to avoid decloaking nodes using other ports.
+        _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, Params().GetDefaultPort(), GetListenPort()),
             std::bind(&TorController::add_onion_cb, this, std::placeholders::_1, std::placeholders::_2));
     } else {
         LogPrintf("tor: Authentication failed\n");
