Merge pull request #129 from google/gbg/smp-improvements

improve smp compatibility with other OS flows

.vscode/settings.json

@@ -71,5 +71,10 @@
         "editor.rulers": [88]
     },
     "python.formatting.provider": "black",
-    "pylint.importStrategy": "useBundled"
+    "pylint.importStrategy": "useBundled",
+    "python.testing.pytestArgs": [
+        "."
+    ],
+    "python.testing.unittestEnabled": false,
+    "python.testing.pytestEnabled": true
 }

apps/pair.py

@@ -19,8 +19,8 @@
 import os
 import logging
 import click
-import aioconsole
 from colors import color
+from prompt_toolkit.shortcuts import PromptSession
 
 from bumble.device import Device, Peer
 from bumble.transport import open_transport_or_link
@@ -42,9 +42,23 @@
 )
 
 
+# -----------------------------------------------------------------------------
+class Waiter:
+    instance = None
+
+    def __init__(self):
+        self.done = asyncio.get_running_loop().create_future()
+
+    def terminate(self):
+        self.done.set_result(None)
+
+    async def wait_until_terminated(self):
+        return await self.done
+
+
 # -----------------------------------------------------------------------------
 class Delegate(PairingDelegate):
-    def __init__(self, mode, connection, capability_string, prompt):
+    def __init__(self, mode, connection, capability_string, do_prompt):
         super().__init__(
             {
                 'keyboard': PairingDelegate.KEYBOARD_INPUT_ONLY,
@@ -58,7 +72,18 @@ def __init__(self, mode, connection, capability_string, prompt):
         self.mode = mode
         self.peer = Peer(connection)
         self.peer_name = None
-        self.prompt = prompt
+        self.do_prompt = do_prompt
+
+    def print(self, message):
+        print(color(message, 'yellow'))
+
+    async def prompt(self, message):
+        # Wait a bit to allow some of the log lines to print before we prompt
+        await asyncio.sleep(1)
+
+        session = PromptSession(message)
+        response = await session.prompt_async()
+        return response.lower().strip()
 
     async def update_peer_name(self):
         if self.peer_name is not None:
@@ -73,19 +98,15 @@ async def update_peer_name(self):
             self.peer_name = '[?]'
 
     async def accept(self):
-        if self.prompt:
+        if self.do_prompt:
             await self.update_peer_name()
 
-            # Wait a bit to allow some of the log lines to print before we prompt
-            await asyncio.sleep(1)
-
             # Prompt for acceptance
-            print(color('###-----------------------------------', 'yellow'))
-            print(color(f'### Pairing request from {self.peer_name}', 'yellow'))
-            print(color('###-----------------------------------', 'yellow'))
+            self.print('###-----------------------------------')
+            self.print(f'### Pairing request from {self.peer_name}')
+            self.print('###-----------------------------------')
             while True:
-                response = await aioconsole.ainput(color('>>> Accept? ', 'yellow'))
-                response = response.lower().strip()
+                response = await self.prompt('>>> Accept? ')
 
                 if response == 'yes':
                     return True
@@ -96,23 +117,17 @@ async def accept(self):
         # Accept silently
         return True
 
-    async def compare_numbers(self, number, digits=6):
+    async def compare_numbers(self, number, digits):
         await self.update_peer_name()
 
-        # Wait a bit to allow some of the log lines to print before we prompt
-        await asyncio.sleep(1)
-
         # Prompt for a numeric comparison
-        print(color('###-----------------------------------', 'yellow'))
-        print(color(f'### Pairing with {self.peer_name}', 'yellow'))
-        print(color('###-----------------------------------', 'yellow'))
+        self.print('###-----------------------------------')
+        self.print(f'### Pairing with {self.peer_name}')
+        self.print('###-----------------------------------')
         while True:
-            response = await aioconsole.ainput(
-                color(
-                    f'>>> Does the other device display {number:0{digits}}? ', 'yellow'
-                )
+            response = await self.prompt(
+                f'>>> Does the other device display {number:0{digits}}? '
             )
-            response = response.lower().strip()
 
             if response == 'yes':
                 return True
@@ -123,30 +138,24 @@ async def compare_numbers(self, number, digits=6):
     async def get_number(self):
         await self.update_peer_name()
 
-        # Wait a bit to allow some of the log lines to print before we prompt
-        await asyncio.sleep(1)
-
         # Prompt for a PIN
         while True:
             try:
-                print(color('###-----------------------------------', 'yellow'))
-                print(color(f'### Pairing with {self.peer_name}', 'yellow'))
-                print(color('###-----------------------------------', 'yellow'))
-                return int(await aioconsole.ainput(color('>>> Enter PIN: ', 'yellow')))
+                self.print('###-----------------------------------')
+                self.print(f'### Pairing with {self.peer_name}')
+                self.print('###-----------------------------------')
+                return int(await self.prompt('>>> Enter PIN: '))
             except ValueError:
                 pass
 
-    async def display_number(self, number, digits=6):
+    async def display_number(self, number, digits):
         await self.update_peer_name()
 
-        # Wait a bit to allow some of the log lines to print before we prompt
-        await asyncio.sleep(1)
-
         # Display a PIN code
-        print(color('###-----------------------------------', 'yellow'))
-        print(color(f'### Pairing with {self.peer_name}', 'yellow'))
-        print(color(f'### PIN: {number:0{digits}}', 'yellow'))
-        print(color('###-----------------------------------', 'yellow'))
+        self.print('###-----------------------------------')
+        self.print(f'### Pairing with {self.peer_name}')
+        self.print(f'### PIN: {number:0{digits}}')
+        self.print('###-----------------------------------')
 
 
 # -----------------------------------------------------------------------------
@@ -238,13 +247,15 @@ def on_pairing(keys):
     print(color('*** Paired!', 'cyan'))
     keys.print(prefix=color('*** ', 'cyan'))
     print(color('***-----------------------------------', 'cyan'))
+    Waiter.instance.terminate()
 
 
 # -----------------------------------------------------------------------------
 def on_pairing_failure(reason):
     print(color('***-----------------------------------', 'red'))
     print(color(f'*** Pairing failed: {smp_error_name(reason)}', 'red'))
     print(color('***-----------------------------------', 'red'))
+    Waiter.instance.terminate()
 
 
 # -----------------------------------------------------------------------------
@@ -262,6 +273,8 @@ async def pair(
     hci_transport,
     address_or_name,
 ):
+    Waiter.instance = Waiter()
+
     print('<<< connecting to HCI...')
     async with await open_transport_or_link(hci_transport) as (hci_source, hci_sink):
         print('<<< connected')
@@ -332,7 +345,19 @@ async def pair(
             # Advertise so that peers can find us and connect
             await device.start_advertising(auto_restart=True)
 
-        await hci_source.wait_for_termination()
+        # Run until the user asks to exit
+        await Waiter.instance.wait_until_terminated()
+
+
+# -----------------------------------------------------------------------------
+class LogHandler(logging.Handler):
+    def __init__(self):
+        super().__init__()
+        self.setFormatter(logging.Formatter('%(levelname)s:%(name)s:%(message)s'))
+
+    def emit(self, record):
+        message = self.format(record)
+        print(message)
 
 
 # -----------------------------------------------------------------------------
@@ -388,7 +413,13 @@ def main(
     hci_transport,
     address_or_name,
 ):
-    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+    # Setup logging
+    log_handler = LogHandler()
+    root_logger = logging.getLogger()
+    root_logger.addHandler(log_handler)
+    root_logger.setLevel(os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+
+    # Pair
     asyncio.run(
         pair(
             mode,

bumble/smp.py

@@ -518,13 +518,15 @@ async def accept(self) -> bool:
     async def confirm(self) -> bool:
         return True
 
-    async def compare_numbers(self, _number: int, _digits: int = 6) -> bool:
+    # pylint: disable-next=unused-argument
+    async def compare_numbers(self, number: int, digits: int) -> bool:
         return True
 
     async def get_number(self) -> int:
         return 0
 
-    async def display_number(self, _number: int, _digits: int = 6) -> None:
+    # pylint: disable-next=unused-argument
+    async def display_number(self, number: int, digits: int) -> None:
         pass
 
     async def key_distribution_response(
@@ -661,7 +663,8 @@ def __init__(self, manager, connection, pairing_config):
         self.peer_expected_distributions = []
         self.dh_key = None
         self.confirm_value = None
-        self.passkey = 0
+        self.passkey = None
+        self.passkey_ready = asyncio.Event()
         self.passkey_step = 0
         self.passkey_display = False
         self.pairing_method = 0
@@ -839,6 +842,7 @@ def display_passkey(self):
         # Generate random Passkey/PIN code
         self.passkey = secrets.randbelow(1000000)
         logger.debug(f'Pairing PIN CODE: {self.passkey:06}')
+        self.passkey_ready.set()
 
         # The value of TK is computed from the PIN code
         if not self.sc:
@@ -859,6 +863,8 @@ def after_input(passkey):
                 self.tk = passkey.to_bytes(16, byteorder='little')
                 logger.debug(f'TK from passkey = {self.tk.hex()}')
 
+            self.passkey_ready.set()
+
             if next_steps is not None:
                 next_steps()
 
@@ -910,17 +916,29 @@ def send_pairing_confirm_command(self):
         logger.debug(f'generated random: {self.r.hex()}')
 
         if self.sc:
-            if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
-                z = 0
-            elif self.pairing_method == self.PASSKEY:
-                z = 0x80 + ((self.passkey >> self.passkey_step) & 1)
-            else:
-                return
 
-            if self.is_initiator:
-                confirm_value = crypto.f4(self.pka, self.pkb, self.r, bytes([z]))
-            else:
-                confirm_value = crypto.f4(self.pkb, self.pka, self.r, bytes([z]))
+            async def next_steps():
+                if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
+                    z = 0
+                elif self.pairing_method == self.PASSKEY:
+                    # We need a passkey
+                    await self.passkey_ready.wait()
+
+                    z = 0x80 + ((self.passkey >> self.passkey_step) & 1)
+                else:
+                    return
+
+                if self.is_initiator:
+                    confirm_value = crypto.f4(self.pka, self.pkb, self.r, bytes([z]))
+                else:
+                    confirm_value = crypto.f4(self.pkb, self.pka, self.r, bytes([z]))
+
+                self.send_command(
+                    SMP_Pairing_Confirm_Command(confirm_value=confirm_value)
+                )
+
+            # Perform the next steps asynchronously in case we need to wait for input
+            self.connection.abort_on('disconnection', next_steps())
         else:
             confirm_value = crypto.c1(
                 self.tk,
@@ -933,7 +951,7 @@ def send_pairing_confirm_command(self):
                 self.ra,
             )
 
-        self.send_command(SMP_Pairing_Confirm_Command(confirm_value=confirm_value))
+            self.send_command(SMP_Pairing_Confirm_Command(confirm_value=confirm_value))
 
     def send_pairing_random_command(self):
         self.send_command(SMP_Pairing_Random_Command(random_value=self.r))
@@ -1364,8 +1382,8 @@ def on_smp_pairing_response_command(self, command):
 
         # Start phase 2
         if self.sc:
-            if self.pairing_method == self.PASSKEY and self.passkey_display:
-                self.display_passkey()
+            if self.pairing_method == self.PASSKEY:
+                self.display_or_input_passkey()
 
             self.send_public_key_command()
         else:
@@ -1426,18 +1444,22 @@ def on_smp_pairing_random_command_legacy(self, command):
         else:
             srand = self.r
             mrand = command.random_value
-        stk = crypto.s1(self.tk, srand, mrand)
-        logger.debug(f'STK = {stk.hex()}')
+        self.stk = crypto.s1(self.tk, srand, mrand)
+        logger.debug(f'STK = {self.stk.hex()}')
 
         # Generate LTK
         self.ltk = crypto.r()
 
         if self.is_initiator:
-            self.start_encryption(stk)
+            self.start_encryption(self.stk)
         else:
             self.send_pairing_random_command()
 
     def on_smp_pairing_random_command_secure_connections(self, command):
+        if self.pairing_method == self.PASSKEY and self.passkey is None:
+            logger.warning('no passkey entered, ignoring command')
+            return
+
         # pylint: disable=too-many-return-statements
         if self.is_initiator:
             if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
@@ -1565,17 +1587,13 @@ def on_smp_pairing_public_key_command(self, command):
         logger.debug(f'DH key: {self.dh_key.hex()}')
 
         if self.is_initiator:
-            if self.pairing_method == self.PASSKEY:
-                if self.passkey_display:
-                    self.send_pairing_confirm_command()
-                else:
-                    self.input_passkey(self.send_pairing_confirm_command)
+            self.send_pairing_confirm_command()
         else:
-            # Send our public key back to the initiator
             if self.pairing_method == self.PASSKEY:
-                self.display_or_input_passkey(self.send_public_key_command)
-            else:
-                self.send_public_key_command()
+                self.display_or_input_passkey()
+
+            # Send our public key back to the initiator
+            self.send_public_key_command()
 
             if self.pairing_method in (self.JUST_WORKS, self.NUMERIC_COMPARISON):
                 # We can now send the confirmation value

setup.cfg

@@ -30,7 +30,6 @@ package_dir =
     bumble.apps = apps
 include-package-data = True
 install_requires =
-    aioconsole >= 0.4.1
     ansicolors >= 1.1
     appdirs >= 1.4
     click >= 7.1.2; platform_system!='Emscripten'