mirror of
https://github.com/trezor/trezor-firmware.git
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54f1599a5a
This clarifies the intent: the project is licenced under terms of LGPL version 3 only, but the standard headers cover only "3 or later", so we had to rewrite them. In the same step, we removed author information from individual files in favor of "SatoshiLabs and contributors", and include an AUTHORS file that lists the contributors. Apologies to those whose names are missing; please contact us if you wish to add your info to the AUTHORS file.
142 lines
5.0 KiB
Python
142 lines
5.0 KiB
Python
# 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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from __future__ import absolute_import
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from io import BytesIO
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import logging
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import struct
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from typing import Tuple
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from . import mapping
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from . import 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("[session {}] sending message: {}".format(self.session, msg.__class__.__name__),
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extra={'protobuf': msg})
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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("[session {}] received message: {}".format(self.session, msg.__class__.__name__),
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extra={'protobuf': msg})
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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('>BLLL', chunk[:headerlen])
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except:
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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:
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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:
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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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