vendor: update to the latest version of ferny

This has some breaking API changes, so make adjustments as necessary.

One slightly non-obvious change comes from the removal of
InteractionAgent.add_handlers(), which had the potential to be racy in
case a message arrived before its handler was registered.  We now have
to specify all handlers up-front, which means that the block for doing
that needs to move up to before the transport is connected.  Of course,
we can only write the stage1 bootloader after the transport is online,
so we need to keep that in its current location.

src/cockpit/beiboot.py

@@ -126,7 +126,7 @@ def shutdown(self) -> None:
         self.peer.close()
 
 
-class AuthorizeResponder(ferny.InteractionResponder):
+class AuthorizeResponder(ferny.AskpassHandler):
     commands = ('ferny.askpass', 'cockpit.report-exists')
     router: Router
 
@@ -184,8 +184,7 @@ def __init__(self, router: Router, destination: str, args: argparse.Namespace):
     async def do_connect_transport(self) -> None:
         beiboot_helper = BridgeBeibootHelper(self)
 
-        agent = ferny.InteractionAgent(AuthorizeResponder(self.router))
-        agent.add_handler(beiboot_helper)
+        agent = ferny.InteractionAgent([AuthorizeResponder(self.router), beiboot_helper])
 
         # We want to run a python interpreter somewhere...
         cmd: Sequence[str] = ('python3', '-ic', '# cockpit-bridge')

src/cockpit/polkit.py

@@ -22,7 +22,7 @@
 import pwd
 from typing import Dict, List, Sequence, Tuple
 
-from cockpit._vendor.ferny import InteractionResponder
+from cockpit._vendor.ferny import AskpassHandler
 from cockpit._vendor.systemd_ctypes import Variant, bus
 
 # that path is valid on at least Debian, Fedora/RHEL, and Arch
@@ -43,7 +43,7 @@
 # mapping, but that method is not available for Python 3.6 yet.
 
 class org_freedesktop_PolicyKit1_AuthenticationAgent(bus.Object):
-    def __init__(self, responder: InteractionResponder):
+    def __init__(self, responder: AskpassHandler):
         super().__init__()
         self.responder = responder
 
@@ -125,7 +125,7 @@ class PolkitAgent:
 
     Use this as a context manager to ensure that the agent gets unregistered again.
     """
-    def __init__(self, responder: InteractionResponder):
+    def __init__(self, responder: AskpassHandler):
         self.responder = responder
         self.agent_slot = None
 

src/cockpit/remote.py

@@ -30,7 +30,7 @@
 logger = logging.getLogger(__name__)
 
 
-class PasswordResponder(ferny.InteractionResponder):
+class PasswordResponder(ferny.AskpassHandler):
     PASSPHRASE_RE = re.compile(r"Enter passphrase for key '(.*)': ")
 
     password: Optional[str]
@@ -104,7 +104,7 @@ async def do_connect_transport(self) -> None:
             logger.debug('connecting to host %s failed: %s', host, exc)
             raise PeerError('no-host', error='no-host', message=str(exc)) from exc
 
-        except ferny.HostKeyError as exc:
+        except ferny.SshHostKeyError as exc:
             if responder.hostkeys_seen:
                 # If we saw a hostkey then we can issue a detailed error message
                 # containing the key that would need to be accepted.  That will
@@ -114,7 +114,7 @@ async def do_connect_transport(self) -> None:
             else:
                 error_args = {}
 
-            if isinstance(exc, ferny.ChangedHostKeyError):
+            if isinstance(exc, ferny.SshChangedHostKeyError):
                 error = 'invalid-hostkey'
             elif self.private:
                 error = 'unknown-hostkey'
@@ -126,7 +126,7 @@ async def do_connect_transport(self) -> None:
                          type(exc), exc, self.private, responder.hostkeys_seen, error, error_args)
             raise PeerError(error, error=error, auth_method_results={}, **error_args) from exc
 
-        except ferny.AuthenticationError as exc:
+        except ferny.SshAuthenticationError as exc:
             logger.debug('authentication to host %s failed: %s', host, exc)
 
             results = {method: 'not-provided' for method in exc.methods}

src/cockpit/superuser.py

@@ -40,9 +40,9 @@
 
 
 class SuperuserPeer(ConfiguredPeer):
-    responder: ferny.InteractionResponder
+    responder: ferny.AskpassHandler
 
-    def __init__(self, router: Router, config: BridgeConfig, responder: ferny.InteractionResponder):
+    def __init__(self, router: Router, config: BridgeConfig, responder: ferny.AskpassHandler):
         super().__init__(router, config)
         self.responder = responder
 
@@ -54,7 +54,17 @@ async def do_connect_transport(self) -> None:
             else:
                 logger.debug('connecting non-polkit superuser peer transport %r', self.args)
 
-            agent = ferny.InteractionAgent(self.responder)
+            responders: 'list[ferny.InteractionHandler]' = [self.responder]
+
+            if '# cockpit-bridge' in self.args:
+                logger.debug('going to beiboot superuser bridge %r', self.args)
+                helper = BridgeBeibootHelper(self, ['--privileged'])
+                responders.append(helper)
+                stage1 = make_bootloader(helper.steps, gadgets=ferny.BEIBOOT_GADGETS).encode()
+            else:
+                stage1 = None
+
+            agent = ferny.InteractionAgent(responders)
 
             if 'SUDO_ASKPASS=ferny-askpass' in self.env:
                 tmpdir = context.enter_context(TemporaryDirectory())
@@ -65,19 +75,16 @@ async def do_connect_transport(self) -> None:
 
             transport = await self.spawn(self.args, env, stderr=agent, start_new_session=True)
 
-            if '# cockpit-bridge' in self.args:
-                logger.debug('going to beiboot superuser bridge %r', self.args)
-                helper = BridgeBeibootHelper(self, ['--privileged'])
-                agent.add_handler(helper)
-                transport.write(make_bootloader(helper.steps, gadgets=ferny.BEIBOOT_GADGETS).encode())
+            if stage1 is not None:
+                transport.write(stage1)
 
             try:
                 await agent.communicate()
             except ferny.InteractionError as exc:
                 raise PeerError('authentication-failed', message=str(exc)) from exc
 
 
-class CockpitResponder(ferny.InteractionResponder):
+class CockpitResponder(ferny.AskpassHandler):
     commands = ('ferny.askpass', 'cockpit.send-stderr')
 
     async def do_custom_command(self, command: str, args: Tuple, fds: List[int], stderr: str) -> None:
@@ -125,7 +132,7 @@ def apply_rule(self, options: JsonObject) -> Optional[Peer]:
             # superuser requested, but not active?  That's an error.
             raise RoutingError('access-denied')
 
-    # ferny.InteractionResponder
+    # ferny.AskpassHandler
     async def do_askpass(self, messages: str, prompt: str, hint: str) -> Optional[str]:
         assert self.pending_prompt is None
         echo = hint == "confirm"
@@ -153,7 +160,7 @@ def peer_done(self):
         self.current = 'none'
         self.peer = None
 
-    async def go(self, name: str, responder: ferny.InteractionResponder) -> None:
+    async def go(self, name: str, responder: ferny.AskpassHandler) -> None:
         if self.current != 'none':
             raise bus.BusError('cockpit.Superuser.Error', 'Superuser bridge already running')
 

test/pytest/test_beiboot.py

@@ -12,7 +12,7 @@
 class BeibootPeer(Peer):
     async def do_connect_transport(self) -> None:
         helper = BridgeBeibootHelper(self)
-        agent = ferny.InteractionAgent(helper)
+        agent = ferny.InteractionAgent([helper])
         transport = await self.spawn([sys.executable, '-iq'], env=[], stderr=agent)
         transport.write(bootloader.make_bootloader(helper.steps, gadgets=ferny.BEIBOOT_GADGETS).encode())
         await agent.communicate()