From 80ffa27052712e6c4ee24632a12b55cf1c4dc234 Mon Sep 17 00:00:00 2001 From: Jan Pochyla Date: Wed, 21 Sep 2016 16:51:17 +0200 Subject: [PATCH] enable crc32, update protocol, add session closing --- trezorlib/transport.py | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) diff --git a/trezorlib/transport.py b/trezorlib/transport.py index 619049f47..4e08b42a6 100644 --- a/trezorlib/transport.py +++ b/trezorlib/transport.py @@ -1,5 +1,6 @@ import struct import mapping +import binascii class NotImplementedException(Exception): pass @@ -156,7 +157,7 @@ class TransportV2(Transport): data = bytearray(msg.SerializeToString()) # Convert to unsigned in python2 - checksum = 0 # binascii.crc32(data) & 0xffffffff + checksum = binascii.crc32(data) & 0xffffffff header1 = struct.pack(">L", self.session_id) header2 = struct.pack(">LL", mapping.get_type(msg), len(data)) @@ -169,12 +170,12 @@ class TransportV2(Transport): if first: # Magic character, header1, header2, data padded to 64 bytes datalen = 63 - len(header1) - chunk = b'!' + header1 + \ + chunk = b'H' + header1 + \ data[:datalen] + b'\0' * (datalen - len(data[:datalen])) else: # Magic character, header1, data padded to 64 bytes datalen = 63 - len(header1) - chunk = b'#' + header1 + \ + chunk = b'D' + header1 + \ data[:datalen] + b'\0' * (datalen - len(data[:datalen])) self._write_chunk(chunk) @@ -199,13 +200,16 @@ class TransportV2(Transport): footer = data[-4:] data = data[:-4] - # csum = struct.unpack('>L', footer) - # assert csum == binascii.crc32(data), "Checksum mismatch" + csum, = struct.unpack('>L', footer) + csum_comp = binascii.crc32(data) & 0xffffffff + if csum != csum_comp: + raise Exception("Message checksum mismatch. Expected %d, got %d" % + (csum_comp, csum)) return (session_id, msg_type, data) def parse_first(self, chunk): - if chunk[0:1] != b"!": + if chunk[0:1] != b"H": raise Exception("Unexpected magic character") try: @@ -218,7 +222,7 @@ class TransportV2(Transport): return (session_id, msg_type, datalen, data) def parse_next(self, chunk): - if chunk[0:1] != b"#": + if chunk[0:1] != b"D": raise Exception("Unexpected magic characters") try: @@ -230,27 +234,28 @@ class TransportV2(Transport): data = chunk[1 + headerlen:] return (session_id, data) - def parse_session(self, chunk): - if chunk[0:1] != b"!": + def parse_session_open(self, chunk): + if chunk[0:1] != b"O": raise Exception("Unexpected magic character") try: - headerlen = struct.calcsize(">LL") - (null_session_id, new_session_id) = struct.unpack( - ">LL", bytes(chunk[1:1 + headerlen])) + headerlen = struct.calcsize(">L") + (session_id,) = struct.unpack(">L", bytes(chunk[1:1 + headerlen])) except: raise Exception("Cannot parse header") - if null_session_id != 0: - raise Exception("Session response needs to use session ID 0") - return new_session_id + return session_id def _session_begin(self): - self._write_chunk(b'!' + b'\0' * 63) - self.session_id = self.parse_session(self._read_chunk()) + self._write_chunk(b'O' + b'\0' * 63) + self.session_id = self.parse_session_open(self._read_chunk()) def _session_end(self): - pass + header = struct.pack(">L", self.session_id) + self._write_chunk(b'C' + header + b'\0' * (63 - len(header))) + if self._read_chunk()[0] != ord('C'): + raise Exception("Expected session close") + self.session_id = None ''' def read_headers(self, read_f):