You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
460 lines
16 KiB
460 lines
16 KiB
"""
|
|
# Wire
|
|
|
|
Handles on-the-wire communication with a host computer. The communication is:
|
|
|
|
- Request / response.
|
|
- Protobuf-encoded, see `protobuf.py`.
|
|
- Wrapped in a simple envelope format, see `trezor/wire/codec_v1.py`.
|
|
- Transferred over USB interface, or UDP in case of Unix emulation.
|
|
|
|
This module:
|
|
|
|
1. Provides API for registering messages. In other words binds what functions are invoked
|
|
when some particular message is received. See the `add` function.
|
|
2. Runs workflows, also called `handlers`, to process the message.
|
|
3. Creates and passes the `Context` object to the handlers. This provides an interface to
|
|
wait, read, write etc. on the wire.
|
|
|
|
## `add` function
|
|
|
|
The `add` function registers what function is invoked when some particular `message_type`
|
|
is received. The following example binds the `apps.wallet.get_address` function with
|
|
the `GetAddress` message:
|
|
|
|
```python
|
|
wire.add(MessageType.GetAddress, "apps.wallet", "get_address")
|
|
```
|
|
|
|
## Session handler
|
|
|
|
When the `wire.setup` is called the `handle_session` coroutine is scheduled. The
|
|
`handle_session` waits for some messages to be received on some particular interface and
|
|
reads the message's header. When the message type is known the first handler is called. This way the
|
|
`handle_session` goes through all the workflows.
|
|
|
|
"""
|
|
|
|
import protobuf
|
|
from storage.cache import InvalidSessionError
|
|
from trezor import log, loop, messages, ui, utils, workflow
|
|
from trezor.messages import FailureType
|
|
from trezor.messages.Failure import Failure
|
|
from trezor.wire import codec_v1
|
|
from trezor.wire.errors import ActionCancelled, DataError, Error
|
|
|
|
# Import all errors into namespace, so that `wire.Error` is available from
|
|
# other packages.
|
|
from trezor.wire.errors import * # isort:skip # noqa: F401,F403
|
|
|
|
if False:
|
|
from typing import (
|
|
Any,
|
|
Awaitable,
|
|
Callable,
|
|
Coroutine,
|
|
Iterable,
|
|
TypeVar,
|
|
)
|
|
from trezorio import WireInterface
|
|
|
|
Msg = TypeVar("Msg", bound=protobuf.MessageType)
|
|
HandlerTask = Coroutine[Any, Any, protobuf.MessageType]
|
|
Handler = Callable[["Context", Msg], HandlerTask]
|
|
|
|
|
|
# If set to False protobuf messages marked with "unstable" option are rejected.
|
|
experimental_enabled: bool = False
|
|
|
|
|
|
def setup(iface: WireInterface, is_debug_session: bool = False) -> None:
|
|
"""Initialize the wire stack on passed USB interface."""
|
|
loop.schedule(handle_session(iface, codec_v1.SESSION_ID, is_debug_session))
|
|
|
|
|
|
if False:
|
|
from typing import Protocol
|
|
|
|
class GenericContext(Protocol):
|
|
async def call(
|
|
self,
|
|
msg: protobuf.MessageType,
|
|
expected_type: type[protobuf.LoadedMessageType],
|
|
) -> Any:
|
|
...
|
|
|
|
async def read(self, expected_type: type[protobuf.LoadedMessageType]) -> Any:
|
|
...
|
|
|
|
async def write(self, msg: protobuf.MessageType) -> None:
|
|
...
|
|
|
|
# XXX modify type signature so that the return value must be of the same type?
|
|
async def wait(self, *tasks: Awaitable) -> Any:
|
|
...
|
|
|
|
|
|
def _wrap_protobuf_load(
|
|
reader: protobuf.Reader,
|
|
expected_type: type[protobuf.LoadedMessageType],
|
|
field_cache: protobuf.FieldCache | None = None,
|
|
) -> protobuf.LoadedMessageType:
|
|
try:
|
|
return protobuf.load_message(
|
|
reader, expected_type, field_cache, experimental_enabled
|
|
)
|
|
except Exception as e:
|
|
if e.args:
|
|
raise DataError("Failed to decode message: {}".format(e.args[0]))
|
|
else:
|
|
raise DataError("Failed to decode message")
|
|
|
|
|
|
class DummyContext:
|
|
async def call(self, *argv: Any) -> None:
|
|
pass
|
|
|
|
async def read(self, *argv: Any) -> None:
|
|
pass
|
|
|
|
async def write(self, *argv: Any) -> None:
|
|
pass
|
|
|
|
async def wait(self, *tasks: Awaitable) -> Any:
|
|
return await loop.race(*tasks)
|
|
|
|
|
|
DUMMY_CONTEXT = DummyContext()
|
|
|
|
PROTOBUF_BUFFER_SIZE = 8192
|
|
|
|
WIRE_BUFFER = bytearray(PROTOBUF_BUFFER_SIZE)
|
|
if __debug__:
|
|
WIRE_BUFFER_DEBUG = bytearray(PROTOBUF_BUFFER_SIZE)
|
|
|
|
|
|
class Context:
|
|
def __init__(self, iface: WireInterface, sid: int, buffer: bytearray) -> None:
|
|
self.iface = iface
|
|
self.sid = sid
|
|
self.buffer = buffer
|
|
self.buffer_reader = utils.BufferReader(self.buffer)
|
|
self.buffer_writer = utils.BufferWriter(self.buffer)
|
|
|
|
self._field_cache: protobuf.FieldCache = {}
|
|
|
|
async def call(
|
|
self,
|
|
msg: protobuf.MessageType,
|
|
expected_type: type[protobuf.LoadedMessageType],
|
|
field_cache: protobuf.FieldCache | None = None,
|
|
) -> protobuf.LoadedMessageType:
|
|
await self.write(msg, field_cache)
|
|
del msg
|
|
return await self.read(expected_type, field_cache)
|
|
|
|
async def call_any(
|
|
self, msg: protobuf.MessageType, *expected_wire_types: int
|
|
) -> protobuf.MessageType:
|
|
await self.write(msg)
|
|
del msg
|
|
return await self.read_any(expected_wire_types)
|
|
|
|
async def read_from_wire(self) -> codec_v1.Message:
|
|
self.buffer_writer.seek(0)
|
|
return await codec_v1.read_message(self.iface, self.buffer_writer.buffer)
|
|
|
|
async def read(
|
|
self,
|
|
expected_type: type[protobuf.LoadedMessageType],
|
|
field_cache: protobuf.FieldCache | None = None,
|
|
) -> protobuf.LoadedMessageType:
|
|
if __debug__:
|
|
log.debug(
|
|
__name__,
|
|
"%s:%x expect: %s",
|
|
self.iface.iface_num(),
|
|
self.sid,
|
|
expected_type,
|
|
)
|
|
|
|
# Load the full message into a buffer, parse out type and data payload
|
|
msg = await self.read_from_wire()
|
|
|
|
# If we got a message with unexpected type, raise the message via
|
|
# `UnexpectedMessageError` and let the session handler deal with it.
|
|
if msg.type != expected_type.MESSAGE_WIRE_TYPE:
|
|
raise UnexpectedMessageError(msg)
|
|
|
|
if __debug__:
|
|
log.debug(
|
|
__name__,
|
|
"%s:%x read: %s",
|
|
self.iface.iface_num(),
|
|
self.sid,
|
|
expected_type,
|
|
)
|
|
|
|
workflow.idle_timer.touch()
|
|
|
|
# look up the protobuf class and parse the message
|
|
return _wrap_protobuf_load(msg.data, expected_type, field_cache)
|
|
|
|
async def read_any(
|
|
self, expected_wire_types: Iterable[int]
|
|
) -> protobuf.MessageType:
|
|
if __debug__:
|
|
log.debug(
|
|
__name__,
|
|
"%s:%x expect: %s",
|
|
self.iface.iface_num(),
|
|
self.sid,
|
|
expected_wire_types,
|
|
)
|
|
|
|
# Load the full message into a buffer, parse out type and data payload
|
|
msg = await self.read_from_wire()
|
|
|
|
# If we got a message with unexpected type, raise the message via
|
|
# `UnexpectedMessageError` and let the session handler deal with it.
|
|
if msg.type not in expected_wire_types:
|
|
raise UnexpectedMessageError(msg)
|
|
|
|
# find the protobuf type
|
|
exptype = messages.get_type(msg.type)
|
|
|
|
if __debug__:
|
|
log.debug(
|
|
__name__, "%s:%x read: %s", self.iface.iface_num(), self.sid, exptype
|
|
)
|
|
|
|
workflow.idle_timer.touch()
|
|
|
|
# parse the message and return it
|
|
return _wrap_protobuf_load(msg.data, exptype)
|
|
|
|
async def write(
|
|
self,
|
|
msg: protobuf.MessageType,
|
|
field_cache: protobuf.FieldCache | None = None,
|
|
) -> None:
|
|
if __debug__:
|
|
log.debug(
|
|
__name__, "%s:%x write: %s", self.iface.iface_num(), self.sid, msg
|
|
)
|
|
|
|
if field_cache is None:
|
|
field_cache = self._field_cache
|
|
|
|
# write the message
|
|
msg_size = protobuf.count_message(msg, field_cache)
|
|
|
|
# prepare buffer
|
|
if msg_size <= len(self.buffer_writer.buffer):
|
|
# reuse preallocated
|
|
buffer_writer = self.buffer_writer
|
|
else:
|
|
# message is too big, we need to allocate a new buffer
|
|
buffer_writer = utils.BufferWriter(bytearray(msg_size))
|
|
|
|
buffer_writer.seek(0)
|
|
protobuf.dump_message(buffer_writer, msg, field_cache)
|
|
await codec_v1.write_message(
|
|
self.iface,
|
|
msg.MESSAGE_WIRE_TYPE,
|
|
memoryview(buffer_writer.buffer)[:msg_size],
|
|
)
|
|
|
|
# make sure we don't keep around fields of all protobuf types ever
|
|
self._field_cache.clear()
|
|
|
|
def wait(self, *tasks: Awaitable) -> Any:
|
|
"""
|
|
Wait until one of the passed tasks finishes, and return the result,
|
|
while servicing the wire context. If a message comes until one of the
|
|
tasks ends, `UnexpectedMessageError` is raised.
|
|
"""
|
|
return loop.race(self.read_any(()), *tasks)
|
|
|
|
|
|
class UnexpectedMessageError(Exception):
|
|
def __init__(self, msg: codec_v1.Message) -> None:
|
|
super().__init__()
|
|
self.msg = msg
|
|
|
|
|
|
async def handle_session(
|
|
iface: WireInterface, session_id: int, is_debug_session: bool = True
|
|
) -> None:
|
|
if __debug__ and is_debug_session:
|
|
ctx_buffer = WIRE_BUFFER_DEBUG
|
|
else:
|
|
ctx_buffer = WIRE_BUFFER
|
|
ctx = Context(iface, session_id, ctx_buffer)
|
|
next_msg: codec_v1.Message | None = None
|
|
res_msg: protobuf.MessageType | None = None
|
|
req_type = None
|
|
req_msg = None
|
|
while True:
|
|
try:
|
|
if next_msg is None:
|
|
# We are not currently reading a message, so let's wait for one.
|
|
# If the decoding fails, exception is raised and we try again
|
|
# (with the same `Reader` instance, it's OK). Even in case of
|
|
# de-synchronized wire communication, report with a message
|
|
# header is eventually received, after a couple of tries.
|
|
msg = await ctx.read_from_wire()
|
|
|
|
if __debug__:
|
|
try:
|
|
msg_type = messages.get_type(msg.type).__name__
|
|
except KeyError:
|
|
msg_type = "%d - unknown message type" % msg.type
|
|
log.debug(
|
|
__name__,
|
|
"%s:%x receive: <%s>",
|
|
iface.iface_num(),
|
|
session_id,
|
|
msg_type,
|
|
)
|
|
else:
|
|
# We have a reader left over from earlier. We should process
|
|
# this message instead of waiting for new one.
|
|
msg = next_msg
|
|
next_msg = None
|
|
|
|
# Now we are in a middle of reading a message and we need to decide
|
|
# what to do with it, based on its type from the message header.
|
|
# From this point on, we should take care to read it in full and
|
|
# send a response.
|
|
|
|
# Take a mark of modules that are imported at this point, so we can
|
|
# roll back and un-import any others. Should not raise.
|
|
modules = utils.unimport_begin()
|
|
|
|
# We need to find a handler for this message type. Should not
|
|
# raise.
|
|
handler = find_handler(iface, msg.type)
|
|
|
|
if handler is None:
|
|
# If no handler is found, we can skip decoding and directly
|
|
# respond with failure. Should not raise.
|
|
res_msg = unexpected_message()
|
|
|
|
else:
|
|
# We found a valid handler for this message type.
|
|
|
|
# Workflow task, declared for the finally block
|
|
wf_task: HandlerTask | None = None
|
|
|
|
# Here we make sure we always respond with a Failure response
|
|
# in case of any errors.
|
|
try:
|
|
# Find a protobuf.MessageType subclass that describes this
|
|
# message. Raises if the type is not found.
|
|
req_type = messages.get_type(msg.type)
|
|
|
|
# Try to decode the message according to schema from
|
|
# `req_type`. Raises if the message is malformed.
|
|
req_msg = _wrap_protobuf_load(msg.data, req_type)
|
|
|
|
# At this point, message reports are all processed and
|
|
# correctly parsed into `req_msg`.
|
|
|
|
# Create the workflow task.
|
|
wf_task = handler(ctx, req_msg)
|
|
|
|
# Run the workflow task. Workflow can do more on-the-wire
|
|
# communication inside, but it should eventually return a
|
|
# response message, or raise an exception (a rather common
|
|
# thing to do). Exceptions are handled in the code below.
|
|
if not is_debug_session:
|
|
res_msg = await workflow.spawn(wf_task)
|
|
else:
|
|
res_msg = await wf_task
|
|
|
|
except UnexpectedMessageError as exc:
|
|
# Workflow was trying to read a message from the wire, and
|
|
# something unexpected came in. See Context.read() for
|
|
# example, which expects some particular message and raises
|
|
# UnexpectedMessageError if another one comes in.
|
|
# In order not to lose the message, we pass on the reader
|
|
# to get picked up by the workflow logic in the beginning of
|
|
# the cycle, which processes it in the usual manner.
|
|
# TODO:
|
|
# We might handle only the few common cases here, like
|
|
# Initialize and Cancel.
|
|
next_msg = exc.msg
|
|
res_msg = None
|
|
|
|
except Exception as exc:
|
|
# Either:
|
|
# - the first workflow message had a type that has a
|
|
# registered handler, but does not have a protobuf class
|
|
# - the first workflow message was not a valid protobuf
|
|
# - workflow raised some kind of an exception while running
|
|
# - something canceled the workflow from the outside
|
|
if __debug__:
|
|
if isinstance(exc, ActionCancelled):
|
|
log.debug(__name__, "cancelled: {}".format(exc.message))
|
|
elif isinstance(exc, loop.TaskClosed):
|
|
log.debug(__name__, "cancelled: loop task was closed")
|
|
else:
|
|
log.exception(__name__, exc)
|
|
res_msg = failure(exc)
|
|
|
|
finally:
|
|
# If we ran a workflow task, and a default workflow is on, make sure
|
|
# we do not race against the layout that is inside.
|
|
# TODO: this is very hacky and complects wire with the ui
|
|
if wf_task is not None and workflow.default_task is not None:
|
|
await ui.wait_until_layout_is_running()
|
|
|
|
if res_msg is not None:
|
|
# Either the workflow returned a response, or we created one.
|
|
# Write it on the wire. Possibly, the incoming message haven't
|
|
# been read in full. We ignore this case here and let the rest
|
|
# of the reports get processed while waiting for the message
|
|
# header.
|
|
# TODO: if the write fails, we do not unimport the loaded modules
|
|
await ctx.write(res_msg)
|
|
|
|
# Cleanup, so garbage collection triggered after un-importing can
|
|
# pick up the trash.
|
|
req_type = None
|
|
req_msg = None
|
|
res_msg = None
|
|
handler = None
|
|
wf_task = None
|
|
|
|
# Unload modules imported by the workflow. Should not raise.
|
|
utils.unimport_end(modules)
|
|
|
|
except Exception as exc:
|
|
# The session handling should never exit, just log and continue.
|
|
if __debug__:
|
|
log.exception(__name__, exc)
|
|
|
|
|
|
def _find_handler_placeholder(iface: WireInterface, msg_type: int) -> Handler | None:
|
|
"""Placeholder handler lookup before a proper one is registered."""
|
|
return None
|
|
|
|
|
|
find_handler = _find_handler_placeholder
|
|
|
|
|
|
def failure(exc: BaseException) -> Failure:
|
|
if isinstance(exc, Error):
|
|
return Failure(code=exc.code, message=exc.message)
|
|
elif isinstance(exc, loop.TaskClosed):
|
|
return Failure(code=FailureType.ActionCancelled, message="Cancelled")
|
|
elif isinstance(exc, InvalidSessionError):
|
|
return Failure(code=FailureType.InvalidSession, message="Invalid session")
|
|
else:
|
|
return Failure(code=FailureType.FirmwareError, message="Firmware error")
|
|
|
|
|
|
def unexpected_message() -> Failure:
|
|
return Failure(code=FailureType.UnexpectedMessage, message="Unexpected message")
|