Handle SMP_Security_Request

Pandora server has it's own config that we load from the 'server'
property of the current bumble config file

apps/pandora_server.py

@@ -3,7 +3,7 @@ import click
 import logging
 import json
 
-from bumble.pandora import PandoraDevice, serve
+from bumble.pandora import PandoraDevice, Config, serve
 from typing import Dict, Any
 
 BUMBLE_SERVER_GRPC_PORT = 7999
@@ -29,12 +29,14 @@ def main(grpc_port: int, rootcanal_port: int, transport: str, config: str) -> No
         transport = transport.replace('<rootcanal-port>', str(rootcanal_port))
 
     bumble_config = retrieve_config(config)
-    if 'transport' not in bumble_config.keys():
-        bumble_config.update({'transport': transport})
+    bumble_config.setdefault('transport', transport)
     device = PandoraDevice(bumble_config)
 
+    server_config = Config()
+    server_config.load_from_dict(bumble_config.get('server', {}))
+
     logging.basicConfig(level=logging.DEBUG)
-    asyncio.run(serve(device, port=grpc_port))
+    asyncio.run(serve(device, config=server_config, port=grpc_port))
 
 
 def retrieve_config(config: str) -> Dict[str, Any]:

bumble/pandora/security.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import asyncio
+import contextlib
 import grpc
 import logging
 
@@ -27,8 +28,8 @@ from bumble.core import (
 )
 from bumble.device import Connection as BumbleConnection, Device
 from bumble.hci import HCI_Error
+from bumble.utils import EventWatcher
 from bumble.pairing import PairingConfig, PairingDelegate as BasePairingDelegate
-from contextlib import suppress
 from google.protobuf import any_pb2  # pytype: disable=pyi-error
 from google.protobuf import empty_pb2  # pytype: disable=pyi-error
 from google.protobuf import wrappers_pb2  # pytype: disable=pyi-error
@@ -294,23 +295,35 @@ class SecurityService(SecurityServicer):
             try:
                 self.log.debug('Pair...')
 
-                if (
-                    connection.transport == BT_LE_TRANSPORT
-                    and connection.role == BT_PERIPHERAL_ROLE
-                ):
-                    wait_for_security: asyncio.Future[
-                        bool
-                    ] = asyncio.get_running_loop().create_future()
-                    connection.on("pairing", lambda *_: wait_for_security.set_result(True))  # type: ignore
-                    connection.on("pairing_failure", wait_for_security.set_exception)
+                security_result = asyncio.get_running_loop().create_future()
 
-                    connection.request_pairing()
+                with contextlib.closing(EventWatcher()) as watcher:
 
-                    await wait_for_security
-                else:
-                    await connection.pair()
+                    @watcher.on(connection, 'pairing')
+                    def on_pairing(*_: Any) -> None:
+                        security_result.set_result('success')
 
-                self.log.debug('Paired')
+                    @watcher.on(connection, 'pairing_failure')
+                    def on_pairing_failure(*_: Any) -> None:
+                        security_result.set_result('pairing_failure')
+
+                    @watcher.on(connection, 'disconnection')
+                    def on_disconnection(*_: Any) -> None:
+                        security_result.set_result('connection_died')
+
+                    if (
+                        connection.transport == BT_LE_TRANSPORT
+                        and connection.role == BT_PERIPHERAL_ROLE
+                    ):
+                        connection.request_pairing()
+                    else:
+                        await connection.pair()
+
+                    result = await security_result
+
+                self.log.debug(f'Pairing session complete, status={result}')
+                if result != 'success':
+                    return SecureResponse(**{result: empty_pb2.Empty()})
             except asyncio.CancelledError:
                 self.log.warning("Connection died during encryption")
                 return SecureResponse(connection_died=empty_pb2.Empty())
@@ -369,6 +382,7 @@ class SecurityService(SecurityServicer):
             str
         ] = asyncio.get_running_loop().create_future()
         authenticate_task: Optional[asyncio.Future[None]] = None
+        pair_task: Optional[asyncio.Future[None]] = None
 
         async def authenticate() -> None:
             assert connection
@@ -415,6 +429,10 @@ class SecurityService(SecurityServicer):
                 if authenticate_task is None:
                     authenticate_task = asyncio.create_task(authenticate())
 
+        def pair(*_: Any) -> None:
+            if self.need_pairing(connection, level):
+                pair_task = asyncio.create_task(connection.pair())
+
         listeners: Dict[str, Callable[..., None]] = {
             'disconnection': set_failure('connection_died'),
             'pairing_failure': set_failure('pairing_failure'),
@@ -425,6 +443,7 @@ class SecurityService(SecurityServicer):
             'connection_encryption_change': on_encryption_change,
             'classic_pairing': try_set_success,
             'classic_pairing_failure': set_failure('pairing_failure'),
+            'security_request': pair,
         }
 
         # register event handlers
@@ -452,6 +471,15 @@ class SecurityService(SecurityServicer):
                 pass
             self.log.debug('Authenticated')
 
+        # wait for `pair` to finish if any
+        if pair_task is not None:
+            self.log.debug('Wait for authentication...')
+            try:
+                await pair_task  # type: ignore
+            except:
+                pass
+            self.log.debug('paired')
+
         return WaitSecurityResponse(**kwargs)
 
     def reached_security_level(
@@ -523,7 +551,7 @@ class SecurityStorageService(SecurityStorageServicer):
         self.log.debug(f"DeleteBond: {address}")
 
         if self.device.keystore is not None:
-            with suppress(KeyError):
+            with contextlib.suppress(KeyError):
                 await self.device.keystore.delete(str(address))
 
         return empty_pb2.Empty()

bumble/smp.py

@@ -37,6 +37,7 @@ from typing import (
     Optional,
     Tuple,
     Type,
+    cast,
 )
 
 from pyee import EventEmitter
@@ -1771,7 +1772,26 @@ class Manager(EventEmitter):
         cid = SMP_BR_CID if connection.transport == BT_BR_EDR_TRANSPORT else SMP_CID
         connection.send_l2cap_pdu(cid, command.to_bytes())
 
+    def on_smp_security_request_command(
+        self, connection: Connection, request: SMP_Security_Request_Command
+    ) -> None:
+        connection.emit('security_request', request.auth_req)
+
     def on_smp_pdu(self, connection: Connection, pdu: bytes) -> None:
+        # Parse the L2CAP payload into an SMP Command object
+        command = SMP_Command.from_bytes(pdu)
+        logger.debug(
+            f'<<< Received SMP Command on connection [0x{connection.handle:04X}] '
+            f'{connection.peer_address}: {command}'
+        )
+
+        # Security request is more than just pairing, so let applications handle them
+        if command.code == SMP_SECURITY_REQUEST_COMMAND:
+            self.on_smp_security_request_command(
+                connection, cast(SMP_Security_Request_Command, command)
+            )
+            return
+
         # Look for a session with this connection, and create one if none exists
         if not (session := self.sessions.get(connection.handle)):
             if connection.role == BT_CENTRAL_ROLE:
@@ -1782,13 +1802,6 @@ class Manager(EventEmitter):
             )
             self.sessions[connection.handle] = session
 
-        # Parse the L2CAP payload into an SMP Command object
-        command = SMP_Command.from_bytes(pdu)
-        logger.debug(
-            f'<<< Received SMP Command on connection [0x{connection.handle:04X}] '
-            f'{connection.peer_address}: {command}'
-        )
-
         # Delegate the handling of the command to the session
         session.on_smp_command(command)
 

bumble/utils.py

@@ -15,12 +15,24 @@
 # -----------------------------------------------------------------------------
 # Imports
 # -----------------------------------------------------------------------------
+from __future__ import annotations
 import asyncio
 import logging
 import traceback
 import collections
 import sys
-from typing import Awaitable, Set, TypeVar
+from typing import (
+    Awaitable,
+    Set,
+    TypeVar,
+    List,
+    Tuple,
+    Callable,
+    Any,
+    Optional,
+    Union,
+    overload,
+)
 from functools import wraps
 from pyee import EventEmitter
 
@@ -64,6 +76,102 @@ def composite_listener(cls):
     return cls
 
 
+# -----------------------------------------------------------------------------
+_Handler = TypeVar('_Handler', bound=Callable)
+
+
+class EventWatcher:
+    '''A wrapper class to control the lifecycle of event handlers better.
+
+    Usage:
+    ```
+    watcher = EventWatcher()
+
+    def on_foo():
+        ...
+    watcher.on(emitter, 'foo', on_foo)
+
+    @watcher.on(emitter, 'bar')
+    def on_bar():
+        ...
+
+    # Close all event handlers watching through this watcher
+    watcher.close()
+    ```
+
+    As context:
+    ```
+    with contextlib.closing(EventWatcher()) as context:
+        @context.on(emitter, 'foo')
+        def on_foo():
+            ...
+    # on_foo() has been removed here!
+    ```
+    '''
+
+    handlers: List[Tuple[EventEmitter, str, Callable[..., Any]]]
+
+    def __init__(self) -> None:
+        self.handlers = []
+
+    @overload
+    def on(self, emitter: EventEmitter, event: str) -> Callable[[_Handler], _Handler]:
+        ...
+
+    @overload
+    def on(self, emitter: EventEmitter, event: str, handler: _Handler) -> _Handler:
+        ...
+
+    def on(
+        self, emitter: EventEmitter, event: str, handler: Optional[_Handler] = None
+    ) -> Union[_Handler, Callable[[_Handler], _Handler]]:
+        '''Watch an event until the context is closed.
+
+        Args:
+            emitter: EventEmitter to watch
+            event: Event name
+            handler: (Optional) Event handler. When nothing is passed, this method works as a decorator.
+        '''
+
+        def wrapper(f: _Handler) -> _Handler:
+            self.handlers.append((emitter, event, f))
+            emitter.on(event, f)
+            return f
+
+        return wrapper if handler is None else wrapper(handler)
+
+    @overload
+    def once(self, emitter: EventEmitter, event: str) -> Callable[[_Handler], _Handler]:
+        ...
+
+    @overload
+    def once(self, emitter: EventEmitter, event: str, handler: _Handler) -> _Handler:
+        ...
+
+    def once(
+        self, emitter: EventEmitter, event: str, handler: Optional[_Handler] = None
+    ) -> Union[_Handler, Callable[[_Handler], _Handler]]:
+        '''Watch an event for once.
+
+        Args:
+            emitter: EventEmitter to watch
+            event: Event name
+            handler: (Optional) Event handler. When nothing passed, this method works as a decorator.
+        '''
+
+        def wrapper(f: _Handler) -> _Handler:
+            self.handlers.append((emitter, event, f))
+            emitter.once(event, f)
+            return f
+
+        return wrapper if handler is None else wrapper(handler)
+
+    def close(self) -> None:
+        for emitter, event, handler in self.handlers:
+            if handler in emitter.listeners(event):
+                emitter.remove_listener(event, handler)
+
+
 # -----------------------------------------------------------------------------
 _T = TypeVar('_T')
 

tests/utils_test.py

@@ -0,0 +1,77 @@
+# Copyright 2021-2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import contextlib
+import logging
+import os
+
+from bumble import utils
+from pyee import EventEmitter
+from unittest.mock import MagicMock
+
+
+def test_on() -> None:
+    emitter = EventEmitter()
+    with contextlib.closing(utils.EventWatcher()) as context:
+        mock = MagicMock()
+        context.on(emitter, 'event', mock)
+
+        emitter.emit('event')
+
+    assert not emitter.listeners('event')
+    assert mock.call_count == 1
+
+
+def test_on_decorator() -> None:
+    emitter = EventEmitter()
+    with contextlib.closing(utils.EventWatcher()) as context:
+        mock = MagicMock()
+
+        @context.on(emitter, 'event')
+        def on_event(*_) -> None:
+            mock()
+
+        emitter.emit('event')
+
+    assert not emitter.listeners('event')
+    assert mock.call_count == 1
+
+
+def test_multiple_handlers() -> None:
+    emitter = EventEmitter()
+    with contextlib.closing(utils.EventWatcher()) as context:
+        mock = MagicMock()
+
+        context.once(emitter, 'a', mock)
+        context.once(emitter, 'b', mock)
+
+        emitter.emit('b', 'b')
+
+    assert not emitter.listeners('a')
+    assert not emitter.listeners('b')
+
+    mock.assert_called_once_with('b')
+
+
+# -----------------------------------------------------------------------------
+def run_tests():
+    test_on()
+    test_on_decorator()
+    test_multiple_handlers()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+    run_tests()