mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-18 05:28:40 +00:00
92 lines
2.9 KiB
Python
92 lines
2.9 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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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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