This commit breaks session handling (which matters with Bridge) and regresses Bridge to an older code state. Both of these issues will be rectified in subsequent commits. Explanation of this big API reshuffle follows: * protocols are moved to trezorlib.transport, and to a single common file. * there is a cleaner definition of Transport and Protocol API (see below) * fully valid mypy type hinting * session handle counters and open handle counters mostly went away. Transports and Protocols are meant to be "raw" APIs; TrezorClient will implement context-handler-based sessions, session tracking, etc. I'm calling this a "reshuffle" because it involved very small number of code changes. Most of it is moving things around where they sit better. The API changes are as follows. Transport is now a thing that can: * open and close sessions * read and write protobuf messages * enumerate and find devices Some transports (all except bridge) are technically bytes-based and need a separate protocol implementation (because we have two existing protocols, although only the first one is actually used). Hence a protocol superclass. Protocol is a thing that *also* can: * open and close sessions * read and write protobuf messages For that, it requires a `handle`. Handle is a physical layer for a protocol. It can: * open and close some sort of device connection (this is distinct from session! Connection is a channel over which you can send data. Session is a logical arrangement on top of that; you can have multiple sessions on a single connection.) * read and write 64-byte chunks of data With that, we introduce ProtocolBasedTransport, which simply delegates the appropriate Transport functionality to respective Protocol methods. hid and webusb transports are ProtocolBasedTransport-s that provide separate device handles. HidHandle and WebUsbHandle existed before, but the distinction of functionality between a Transport and its Handle was unclear. Some methods were moved and now the handles implement the Handle API, while the transports provide the enumeration parts of the Transport API, as well as glue between the respective Protocols and Handles. udp transport is also a ProtocolBasedTransport, but it acts as its own handle. (That might be changed. For now, I went with the pre-existing structure.) In addition, session_begin/end is renamed to begin/end_session to keep consistent verb_noun naming.pull/25/head
matejcik
6 years ago
parent
560a5215c5
commit
aac7726824
@ -1,91 +0,0 @@
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# This file is part of the Trezor project.
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#
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# Copyright (C) 2012-2018 SatoshiLabs and contributors
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#
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# This library is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License version 3
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# as published by the Free Software Foundation.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the License along with this library.
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# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
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import logging
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import struct
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from io import BytesIO
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from typing import Tuple
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from . import mapping, protobuf
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from .transport import Transport
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REPLEN = 64
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LOG = logging.getLogger(__name__)
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class ProtocolV1:
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def session_begin(self, transport: Transport) -> None:
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pass
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def session_end(self, transport: Transport) -> None:
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pass
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def write(self, transport: Transport, msg: protobuf.MessageType) -> None:
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LOG.debug(
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"sending message: {}".format(msg.__class__.__name__),
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extra={"protobuf": msg},
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)
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data = BytesIO()
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protobuf.dump_message(data, msg)
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ser = data.getvalue()
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header = struct.pack(">HL", mapping.get_type(msg), len(ser))
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data = bytearray(b"##" + header + ser)
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while data:
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# Report ID, data padded to 63 bytes
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chunk = b"?" + data[: REPLEN - 1]
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chunk = chunk.ljust(REPLEN, b"\x00")
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transport.write_chunk(chunk)
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data = data[63:]
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def read(self, transport: Transport) -> protobuf.MessageType:
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# Read header with first part of message data
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chunk = transport.read_chunk()
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msg_type, datalen, data = self.parse_first(chunk)
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# Read the rest of the message
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while len(data) < datalen:
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chunk = transport.read_chunk()
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data.extend(self.parse_next(chunk))
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# Strip padding
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data = BytesIO(data[:datalen])
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# Parse to protobuf
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msg = protobuf.load_message(data, mapping.get_class(msg_type))
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LOG.debug(
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"received message: {}".format(msg.__class__.__name__),
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extra={"protobuf": msg},
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)
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return msg
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def parse_first(self, chunk: bytes) -> Tuple[int, int, bytes]:
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if chunk[:3] != b"?##":
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raise RuntimeError("Unexpected magic characters")
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try:
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headerlen = struct.calcsize(">HL")
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msg_type, datalen = struct.unpack(">HL", chunk[3 : 3 + headerlen])
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except Exception:
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raise RuntimeError("Cannot parse header")
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data = chunk[3 + headerlen :]
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return msg_type, datalen, data
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def parse_next(self, chunk: bytes) -> bytes:
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if chunk[:1] != b"?":
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raise RuntimeError("Unexpected magic characters")
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return chunk[1:]
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@ -1,147 +0,0 @@
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# This file is part of the Trezor project.
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#
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# Copyright (C) 2012-2018 SatoshiLabs and contributors
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#
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# This library is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License version 3
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# as published by the Free Software Foundation.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the License along with this library.
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# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
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import logging
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import struct
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from io import BytesIO
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from typing import Tuple
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from . import mapping, protobuf
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from .transport import Transport
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REPLEN = 64
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LOG = logging.getLogger(__name__)
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class ProtocolV2:
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def __init__(self) -> None:
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self.session = None
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def session_begin(self, transport: Transport) -> None:
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chunk = struct.pack(">B", 0x03)
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chunk = chunk.ljust(REPLEN, b"\x00")
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transport.write_chunk(chunk)
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resp = transport.read_chunk()
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self.session = self.parse_session_open(resp)
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LOG.debug("[session {}] session started".format(self.session))
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def session_end(self, transport: Transport) -> None:
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if not self.session:
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return
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chunk = struct.pack(">BL", 0x04, self.session)
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chunk = chunk.ljust(REPLEN, b"\x00")
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transport.write_chunk(chunk)
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resp = transport.read_chunk()
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(magic,) = struct.unpack(">B", resp[:1])
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if magic != 0x04:
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raise RuntimeError("Expected session close")
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LOG.debug("[session {}] session ended".format(self.session))
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self.session = None
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def write(self, transport: Transport, msg: protobuf.MessageType) -> None:
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if not self.session:
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raise RuntimeError("Missing session for v2 protocol")
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LOG.debug(
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"[session {}] sending message: {}".format(
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self.session, msg.__class__.__name__
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),
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extra={"protobuf": msg},
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)
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# Serialize whole message
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data = BytesIO()
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protobuf.dump_message(data, msg)
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data = data.getvalue()
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dataheader = struct.pack(">LL", mapping.get_type(msg), len(data))
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data = dataheader + data
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seq = -1
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# Write it out
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while data:
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if seq < 0:
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repheader = struct.pack(">BL", 0x01, self.session)
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else:
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repheader = struct.pack(">BLL", 0x02, self.session, seq)
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datalen = REPLEN - len(repheader)
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chunk = repheader + data[:datalen]
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chunk = chunk.ljust(REPLEN, b"\x00")
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transport.write_chunk(chunk)
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data = data[datalen:]
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seq += 1
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def read(self, transport: Transport) -> protobuf.MessageType:
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if not self.session:
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raise RuntimeError("Missing session for v2 protocol")
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# Read header with first part of message data
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chunk = transport.read_chunk()
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msg_type, datalen, data = self.parse_first(chunk)
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# Read the rest of the message
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while len(data) < datalen:
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chunk = transport.read_chunk()
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next_data = self.parse_next(chunk)
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data.extend(next_data)
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# Strip padding
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data = BytesIO(data[:datalen])
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# Parse to protobuf
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msg = protobuf.load_message(data, mapping.get_class(msg_type))
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LOG.debug(
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"[session {}] received message: {}".format(
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self.session, msg.__class__.__name__
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),
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extra={"protobuf": msg},
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)
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return msg
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def parse_first(self, chunk: bytes) -> Tuple[int, int, bytes]:
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try:
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headerlen = struct.calcsize(">BLLL")
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magic, session, msg_type, datalen = struct.unpack(
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">BLLL", chunk[:headerlen]
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)
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except Exception:
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raise RuntimeError("Cannot parse header")
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if magic != 0x01:
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raise RuntimeError("Unexpected magic character")
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if session != self.session:
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raise RuntimeError("Session id mismatch")
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return msg_type, datalen, chunk[headerlen:]
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def parse_next(self, chunk: bytes) -> bytes:
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try:
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headerlen = struct.calcsize(">BLL")
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magic, session, sequence = struct.unpack(">BLL", chunk[:headerlen])
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except Exception:
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raise RuntimeError("Cannot parse header")
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if magic != 0x02:
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raise RuntimeError("Unexpected magic characters")
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if session != self.session:
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raise RuntimeError("Session id mismatch")
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return chunk[headerlen:]
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def parse_session_open(self, chunk: bytes) -> int:
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try:
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headerlen = struct.calcsize(">BL")
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magic, session = struct.unpack(">BL", chunk[:headerlen])
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except Exception:
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raise RuntimeError("Cannot parse header")
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if magic != 0x03:
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raise RuntimeError("Unexpected magic character")
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return session
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@ -0,0 +1,348 @@
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# This file is part of the Trezor project.
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#
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# Copyright (C) 2012-2018 SatoshiLabs and contributors
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#
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# This library is free software: you can redistribute it and/or modify
|
||||
# it under the terms of the GNU Lesser General Public License version 3
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# as published by the Free Software Foundation.
|
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#
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# This library is distributed in the hope that it will be useful,
|
||||
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
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# GNU Lesser General Public License for more details.
|
||||
#
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# You should have received a copy of the License along with this library.
|
||||
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
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import logging
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import os
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import struct
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from io import BytesIO
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from typing import Tuple
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from typing_extensions import Protocol as StructuralType
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from . import Transport
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from .. import mapping, protobuf
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REPLEN = 64
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V2_FIRST_CHUNK = 0x01
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V2_NEXT_CHUNK = 0x02
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V2_BEGIN_SESSION = 0x03
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V2_END_SESSION = 0x04
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LOG = logging.getLogger(__name__)
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class Handle(StructuralType):
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"""PEP 544 structural type for Handle functionality.
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(called a "Protocol" in the proposed PEP, name which is impractical here)
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Handle is a "physical" layer for a protocol.
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It can open/close a connection and read/write bare data in 64-byte chunks.
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Functionally we gain nothing from making this an (abstract) base class for handle
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implementations, so this definition is for type hinting purposes only. You can,
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but don't have to, inherit from it.
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"""
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def open(self) -> None:
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...
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def close(self) -> None:
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...
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def read_chunk(self) -> bytes:
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...
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def write_chunk(self, chunk: bytes) -> None:
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...
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class Protocol:
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"""Wire protocol that can communicate with a Trezor device, given a Handle.
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A Protocol implements the part of the Transport API that relates to communicating
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logical messages over a physical layer. It is a thing that can:
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- open and close sessions,
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- send and receive protobuf messages,
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given the ability to:
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- open and close physical connections,
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- and send and receive binary chunks.
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We declare a protocol version (we have implementations of v1 and v2).
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For now, the class also handles session counting and opening the underlying Handle.
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This will probably be removed in the future.
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We will need a new Protocol class if we change the way a Trezor device encapsulates
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its messages.
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"""
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||||
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VERSION = None # type: int
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||||
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def __init__(self, handle: Handle) -> None:
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self.handle = handle
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self.session_counter = 0
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|
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def begin_session(self) -> None:
|
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if self.session_counter == 0:
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self.handle.open()
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self.session_counter += 1
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||||
|
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def end_session(self) -> None:
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self.session_counter = max(self.session_counter - 1, 0)
|
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if self.session_counter == 0:
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self.handle.close()
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|
||||
def read(self) -> protobuf.MessageType:
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raise NotImplementedError
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|
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def write(self, message: protobuf.MessageType) -> None:
|
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raise NotImplementedError
|
||||
|
||||
|
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class ProtocolBasedTransport(Transport):
|
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"""Transport that implements its communications through a Protocol.
|
||||
|
||||
Intended as a base class for implementations that proxy their communication
|
||||
operations to a Protocol.
|
||||
"""
|
||||
|
||||
def __init__(self, protocol: Protocol) -> None:
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self.protocol = protocol
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||||
|
||||
def write(self, message: protobuf.MessageType) -> None:
|
||||
self.protocol.write(message)
|
||||
|
||||
def read(self) -> protobuf.MessageType:
|
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return self.protocol.read()
|
||||
|
||||
def begin_session(self) -> None:
|
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self.protocol.begin_session()
|
||||
|
||||
def end_session(self) -> None:
|
||||
self.protocol.end_session()
|
||||
|
||||
|
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class ProtocolV1(Protocol):
|
||||
"""Protocol version 1. Currently (11/2018) in use on all Trezors.
|
||||
Does not understand sessions.
|
||||
"""
|
||||
|
||||
VERSION = 1
|
||||
|
||||
def write(self, msg: protobuf.MessageType) -> None:
|
||||
LOG.debug(
|
||||
"sending message: {}".format(msg.__class__.__name__),
|
||||
extra={"protobuf": msg},
|
||||
)
|
||||
data = BytesIO()
|
||||
protobuf.dump_message(data, msg)
|
||||
ser = data.getvalue()
|
||||
header = struct.pack(">HL", mapping.get_type(msg), len(ser))
|
||||
buffer = bytearray(b"##" + header + ser)
|
||||
|
||||
while buffer:
|
||||
# Report ID, data padded to 63 bytes
|
||||
chunk = b"?" + buffer[: REPLEN - 1]
|
||||
chunk = chunk.ljust(REPLEN, b"\x00")
|
||||
self.handle.write_chunk(chunk)
|
||||
buffer = buffer[63:]
|
||||
|
||||
def read(self) -> protobuf.MessageType:
|
||||
buffer = bytearray()
|
||||
# Read header with first part of message data
|
||||
msg_type, datalen, first_chunk = self.read_first()
|
||||
buffer.extend(first_chunk)
|
||||
|
||||
# Read the rest of the message
|
||||
while len(buffer) < datalen:
|
||||
buffer.extend(self.read_next())
|
||||
|
||||
# Strip padding
|
||||
data = BytesIO(buffer[:datalen])
|
||||
|
||||
# Parse to protobuf
|
||||
msg = protobuf.load_message(data, mapping.get_class(msg_type))
|
||||
LOG.debug(
|
||||
"received message: {}".format(msg.__class__.__name__),
|
||||
extra={"protobuf": msg},
|
||||
)
|
||||
return msg
|
||||
|
||||
def read_first(self) -> Tuple[int, int, bytes]:
|
||||
chunk = self.handle.read_chunk()
|
||||
if chunk[:3] != b"?##":
|
||||
raise RuntimeError("Unexpected magic characters")
|
||||
try:
|
||||
headerlen = struct.calcsize(">HL")
|
||||
msg_type, datalen = struct.unpack(">HL", chunk[3 : 3 + headerlen])
|
||||
except Exception:
|
||||
raise RuntimeError("Cannot parse header")
|
||||
|
||||
data = chunk[3 + headerlen :]
|
||||
return msg_type, datalen, data
|
||||
|
||||
def read_next(self) -> bytes:
|
||||
chunk = self.handle.read_chunk()
|
||||
if chunk[:1] != b"?":
|
||||
raise RuntimeError("Unexpected magic characters")
|
||||
return chunk[1:]
|
||||
|
||||
|
||||
class ProtocolV2(Protocol):
|
||||
"""Protocol version 2. Currently (11/2018) not used.
|
||||
Intended to mimic U2F/WebAuthN session handling.
|
||||
"""
|
||||
|
||||
VERSION = 2
|
||||
|
||||
def __init__(self, handle: Handle) -> None:
|
||||
self.session = None
|
||||
super().__init__(handle)
|
||||
|
||||
def begin_session(self) -> None:
|
||||
# ensure open connection
|
||||
super().begin_session()
|
||||
|
||||
# initiate session
|
||||
chunk = struct.pack(">B", V2_BEGIN_SESSION)
|
||||
chunk = chunk.ljust(REPLEN, b"\x00")
|
||||
self.handle.write_chunk(chunk)
|
||||
|
||||
# get session identifier
|
||||
resp = self.handle.read_chunk()
|
||||
try:
|
||||
headerlen = struct.calcsize(">BL")
|
||||
magic, session = struct.unpack(">BL", resp[:headerlen])
|
||||
except Exception:
|
||||
raise RuntimeError("Cannot parse header")
|
||||
if magic != V2_BEGIN_SESSION:
|
||||
raise RuntimeError("Unexpected magic character")
|
||||
self.session = session
|
||||
|
||||
LOG.debug("[session {}] session started".format(self.session))
|
||||
|
||||
def end_session(self) -> None:
|
||||
if not self.session:
|
||||
return
|
||||
|
||||
try:
|
||||
chunk = struct.pack(">BL", V2_END_SESSION, self.session)
|
||||
chunk = chunk.ljust(REPLEN, b"\x00")
|
||||
self.handle.write_chunk(chunk)
|
||||
resp = self.handle.read_chunk()
|
||||
(magic,) = struct.unpack(">B", resp[:1])
|
||||
if magic != V2_END_SESSION:
|
||||
raise RuntimeError("Expected session close")
|
||||
LOG.debug("[session {}] session ended".format(self.session))
|
||||
finally:
|
||||
self.session = None
|
||||
# close connection if appropriate
|
||||
super().end_session()
|
||||
|
||||
def write(self, msg: protobuf.MessageType) -> None:
|
||||
if not self.session:
|
||||
raise RuntimeError("Missing session for v2 protocol")
|
||||
|
||||
LOG.debug(
|
||||
"[session {}] sending message: {}".format(
|
||||
self.session, msg.__class__.__name__
|
||||
),
|
||||
extra={"protobuf": msg},
|
||||
)
|
||||
# Serialize whole message
|
||||
data = BytesIO()
|
||||
protobuf.dump_message(data, msg)
|
||||
data = data.getvalue()
|
||||
dataheader = struct.pack(">LL", mapping.get_type(msg), len(data))
|
||||
data = dataheader + data
|
||||
seq = -1
|
||||
|
||||
# Write it out
|
||||
while data:
|
||||
if seq < 0:
|
||||
repheader = struct.pack(">BL", V2_FIRST_CHUNK, self.session)
|
||||
else:
|
||||
repheader = struct.pack(">BLL", V2_NEXT_CHUNK, self.session, seq)
|
||||
datalen = REPLEN - len(repheader)
|
||||
chunk = repheader + data[:datalen]
|
||||
chunk = chunk.ljust(REPLEN, b"\x00")
|
||||
self.handle.write_chunk(chunk)
|
||||
data = data[datalen:]
|
||||
seq += 1
|
||||
|
||||
def read(self) -> protobuf.MessageType:
|
||||
if not self.session:
|
||||
raise RuntimeError("Missing session for v2 protocol")
|
||||
|
||||
buffer = bytearray()
|
||||
|
||||
# Read header with first part of message data
|
||||
msg_type, datalen, chunk = self.read_first()
|
||||
buffer.extend(chunk)
|
||||
|
||||
# Read the rest of the message
|
||||
while len(buffer) < datalen:
|
||||
next_chunk = self.read_next()
|
||||
buffer.extend(next_chunk)
|
||||
|
||||
# Strip padding
|
||||
buffer = BytesIO(buffer[:datalen])
|
||||
|
||||
# Parse to protobuf
|
||||
msg = protobuf.load_message(buffer, mapping.get_class(msg_type))
|
||||
LOG.debug(
|
||||
"[session {}] received message: {}".format(
|
||||
self.session, msg.__class__.__name__
|
||||
),
|
||||
extra={"protobuf": msg},
|
||||
)
|
||||
return msg
|
||||
|
||||
def read_first(self) -> Tuple[int, int, bytes]:
|
||||
chunk = self.handle.read_chunk()
|
||||
try:
|
||||
headerlen = struct.calcsize(">BLLL")
|
||||
magic, session, msg_type, datalen = struct.unpack(
|
||||
">BLLL", chunk[:headerlen]
|
||||
)
|
||||
except Exception:
|
||||
raise RuntimeError("Cannot parse header")
|
||||
if magic != V2_FIRST_CHUNK:
|
||||
raise RuntimeError("Unexpected magic character")
|
||||
if session != self.session:
|
||||
raise RuntimeError("Session id mismatch")
|
||||
return msg_type, datalen, chunk[headerlen:]
|
||||
|
||||
def read_next(self) -> bytes:
|
||||
chunk = self.handle.read_chunk()
|
||||
try:
|
||||
headerlen = struct.calcsize(">BLL")
|
||||
magic, session, sequence = struct.unpack(">BLL", chunk[:headerlen])
|
||||
except Exception:
|
||||
raise RuntimeError("Cannot parse header")
|
||||
if magic != V2_NEXT_CHUNK:
|
||||
raise RuntimeError("Unexpected magic characters")
|
||||
if session != self.session:
|
||||
raise RuntimeError("Session id mismatch")
|
||||
return chunk[headerlen:]
|
||||
|
||||
|
||||
def get_protocol(handle: Handle, want_v2: bool) -> Protocol:
|
||||
"""Make a Protocol instance for the given handle.
|
||||
|
||||
Each transport can have a preference for using a particular protocol version.
|
||||
This preference is overridable through `TREZOR_PROTOCOL_V1` environment variable,
|
||||
which forces the library to use V1 anyways.
|
||||
|
||||
As of 11/2018, no devices support V2, so we enforce V1 here. It is still possible
|
||||
to set `TREZOR_PROTOCOL_V1=0` and thus enable V2 protocol for transports that ask
|
||||
for it (i.e., USB transports for Trezor T).
|
||||
"""
|
||||
force_v1 = int(os.environ.get("TREZOR_PROTOCOL_V1", 1))
|
||||
if want_v2 and not force_v1:
|
||||
return ProtocolV2(handle)
|
||||
else:
|
||||
return ProtocolV1(handle)
|
||||
Loading…
Reference in new issue