Merge pull request #10548 from SomberNight/202603_lockdown_rpcserver

in GUI mode, only start a limited minimal RPC server

electrum/daemon.py

@@ -287,25 +287,31 @@ class AuthenticatedServer(Logger):
 
 class CommandsServer(AuthenticatedServer):
 
-    def __init__(self, daemon: 'Daemon', fd):
+    def __init__(self, daemon: 'Daemon', fd, *, only_minimal_jsonrpc: bool):
         rpc_user, rpc_password = get_rpc_credentials(daemon.config)
         AuthenticatedServer.__init__(self, rpc_user, rpc_password)
         self.daemon = daemon
         self.fd = fd
+        self._only_minimal_jsonrpc = only_minimal_jsonrpc
         self.config = daemon.config
         sockettype = self.config.RPC_SOCKET_TYPE
         self.socktype = sockettype if sockettype != 'auto' else get_rpcsock_default_type(self.config)
         self.sockpath = self.config.RPC_SOCKET_FILEPATH or get_rpcsock_defaultpath(self.config)
         self.host = self.config.RPC_HOST
         self.port = self.config.RPC_PORT
+        self.cmd_runner = Commands(config=self.config, network=self.daemon.network, daemon=self.daemon)
         self.app = web.Application()
         self.app.router.add_post("/", self.handle)
+        # First add always-enabled commands that are also available for "minimal" rpc server.
+        # - "ping" RPC is needed for the lockfile fd to work.
         self.register_method('ping', self.ping)
+        # - "gui" RPC is needed for URI handling. (TODO restrict further: disallow opening arbitrary file paths)
         self.register_method('gui', self.gui)
-        self.cmd_runner = Commands(config=self.config, network=self.daemon.network, daemon=self.daemon)
+        # Add other commands:
-        for cmdname in known_commands:
+        if not only_minimal_jsonrpc:
-            self.register_method(cmdname, getattr(self.cmd_runner, cmdname))
+            for cmdname in known_commands:
-        self.register_method('run_cmdline', self.run_cmdline)
+                self.register_method(cmdname, getattr(self.cmd_runner, cmdname))
+            self.register_method('run_cmdline', self.run_cmdline)
 
     def _socket_config_str(self) -> str:
         if self.socktype == 'unix':
@@ -343,7 +349,9 @@ class CommandsServer(AuthenticatedServer):
             raise Exception(f"impossible socktype ({self.socktype!r})")
         os.write(self.fd, bytes(repr((self.socktype, addr, time.time())), 'utf8'))
         os.close(self.fd)
-        self.logger.info(f"now running and listening. socktype={self.socktype}, addr={addr}")
+        self.logger.info(
+            f"now running and listening. socktype={self.socktype}, addr={addr}. "
+            f"only_minimal_jsonrpc={self._only_minimal_jsonrpc}")
 
     async def ping(self):
         return True
@@ -401,6 +409,7 @@ class Daemon(Logger):
         fd=None,
         *,
         listen_jsonrpc: bool = True,
+        only_minimal_jsonrpc: bool = True,
         start_network: bool = True,  # setting to False allows customising network settings before starting it
     ):
         Logger.__init__(self)
@@ -430,7 +439,7 @@ class Daemon(Logger):
         # Setup commands server
         self.commands_server = None
         if listen_jsonrpc:
-            self.commands_server = CommandsServer(self, fd)
+            self.commands_server = CommandsServer(self, fd, only_minimal_jsonrpc=only_minimal_jsonrpc)
             asyncio.run_coroutine_threadsafe(self.taskgroup.spawn(self.commands_server.run()), self.asyncio_loop)
 
     @log_exceptions

electrum/gui/qt/__init__.py

@@ -439,6 +439,14 @@ class ElectrumGui(BaseElectrumGui, Logger):
         window.activateWindow()
         if uri:
             window.show_send_tab()
+            # Handle URI defensively - local attacker with access to RPC server and config file could get here:
+            #   - tell user something happened
+            window.notify(_("Updated 'Pay To' field to handle external URI"))
+            #   - clear all fields in Send tab:
+            #     - perhaps user was just filling out the fields, trying to make another payment.
+            #       e.g. if the given URI does not have an amount, we should clear the amount field
+            window.send_tab.do_clear()
+            #   - update "Pay To" field (and maybe others)
             window.send_tab.set_payment_identifier(uri)
         return window
 

run_electrum

@@ -132,6 +132,7 @@ from electrum.commands import get_parser, get_simple_parser, known_commands, Com
 from electrum import daemon
 from electrum.util import create_and_start_event_loop, UserFacingException, JsonRPCError
 from electrum.i18n import set_language
+from electrum import constants
 
 if TYPE_CHECKING:
     import threading
@@ -518,7 +519,9 @@ def handle_cmd(*, cmdname: str, config: 'SimpleConfig', config_options: dict):
         configure_logging(config)
         fd = daemon.get_file_descriptor(config)
         if fd is not None:
-            d = daemon.Daemon(config, fd, start_network=False)
+            # When running in GUI mode, only start a limited minimal RPC server, to limit attack surface.
+            only_minimal_jsonrpc = not constants.net.TESTNET
+            d = daemon.Daemon(config, fd, start_network=False, only_minimal_jsonrpc=only_minimal_jsonrpc)
             try:
                 d.run_gui()
             except BaseException as e:
@@ -544,7 +547,7 @@ def handle_cmd(*, cmdname: str, config: 'SimpleConfig', config_options: dict):
         fd = daemon.get_file_descriptor(config)
         if fd is not None:
             # run daemon
-            d = daemon.Daemon(config, fd)
+            d = daemon.Daemon(config, fd, only_minimal_jsonrpc=False)
             d.run_daemon()
             sys_exit(0)
         else:
@@ -586,7 +589,7 @@ def handle_cmd(*, cmdname: str, config: 'SimpleConfig', config_options: dict):
             except Exception as e:
                 _logger.exception("error running command (with daemon)")
                 sys_exit(1)
-        else:
+        else:  # --offline
             if cmd.requires_network:
                 print_msg("This command cannot be run offline")
                 sys_exit(1)