rpcbind: Warn about exposing RPC to untrusted networks

luke-jr · furszy · commit 5d7f86441935 · 2021-08-10T09:43:22.000-03:00
diff --git a/src/httpserver.cpp b/src/httpserver.cpp
@@ -327,6 +327,10 @@ static bool HTTPBindAddresses(struct evhttp* http)
         LogPrint(BCLog::HTTP, "Binding RPC on address %s port %i\n", i->first, i->second);
         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? NULL : i->first.c_str(), i->second);
         if (bind_handle) {
+            CNetAddr addr;
+            if (i->first.empty() || (LookupHost(i->first, addr, false) && addr.IsBindAny())) {
+                LogPrintf("WARNING: the RPC server is not safe to expose to untrusted networks such as the public internet\n");
+            }
             boundSockets.push_back(bind_handle);
         } else {
             LogPrintf("Binding RPC on address %s port %i failed.\n", i->first, i->second);
diff --git a/src/init.cpp b/src/init.cpp
@@ -600,7 +600,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageGroup(_("RPC server options:"));
     strUsage += HelpMessageOpt("-server", _("Accept command line and JSON-RPC commands"));
     strUsage += HelpMessageOpt("-rest", strprintf(_("Accept public REST requests (default: %u)"), DEFAULT_REST_ENABLE));
-    strUsage += HelpMessageOpt("-rpcbind=<addr>", _("Bind to given address to listen for JSON-RPC connections. This option is ignored unless -rpcallowip is also passed. Port is optional and overrides -rpcport. Use [host]:port notation for IPv6. This option can be specified multiple times (default: 127.0.0.1 and ::1 i.e., localhost)"));
+    strUsage += HelpMessageOpt("-rpcbind=<addr>", _("Bind to given address to listen for JSON-RPC connections. Do not expose the RPC server to untrusted networks such as the public internet! This option is ignored unless -rpcallowip is also passed. Port is optional and overrides -rpcport. Use [host]:port notation for IPv6. This option can be specified multiple times (default: 127.0.0.1 and ::1 i.e., localhost)"));
     strUsage += HelpMessageOpt("-rpccookiefile=<loc>", _("Location of the auth cookie (default: data dir)"));
     strUsage += HelpMessageOpt("-rpcuser=<user>", _("Username for JSON-RPC connections"));
     strUsage += HelpMessageOpt("-rpcpassword=<pw>", _("Password for JSON-RPC connections"));
