commit 2e51a01c1fa96f24f44b744d37915ef2ffd7762d Author: Damian Johnson <atagar@torproject.org> Date: Sat Aug 25 12:39:44 2018 -0700 Resume size check for circuit responses Maybe this check is redundant with the cell module additions? Not sure. Regardless, unlike the hamhanded 'relay_cell_size' calculation I did prior to Dave's branch our LinkProtocol's 'fixed_cell_length' now makes this check trivial to do upfront. --- stem/client/__init__.py | 10 +++++++--- stem/client/datatype.py | 5 ++++- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/stem/client/__init__.py b/stem/client/__init__.py index 46a82428..a216696a 100644 --- a/stem/client/__init__.py +++ b/stem/client/__init__.py @@ -243,16 +243,20 @@ class Circuit(object): self.forward_digest = forward_digest self.forward_key = forward_key + # Decrypt relay cells received in response. Again, our digest/key only + # updates when handled successfully. + reply = self.relay._orport.recv() reply_cells = [] - relay_cell_cmd = stem.client.cell.RelayCell.VALUE + if len(reply) % self.relay.link_protocol.fixed_cell_length != 0: + raise stem.ProtocolError('Circuit response should be a series of RELAY cells, but received an unexpected size for a response: %i' % len(reply)) while reply: raw_cell, reply = stem.client.cell.Cell.pop(reply, self.relay.link_protocol) - if raw_cell.VALUE != relay_cell_cmd: - raise stem.ProtocolError('RELAY cell responses should be %i but was %i' % (relay_cell_cmd, raw_cell.VALUE)) + if raw_cell.VALUE != stem.client.cell.RelayCell.VALUE: + raise stem.ProtocolError('RELAY cell responses should be %i but was %i' % (stem.client.cell.RelayCell.VALUE, raw_cell.VALUE)) elif raw_cell.circ_id != self.id: raise stem.ProtocolError('Response should be for circuit id %i, not %i' % (self.id, raw_cell.circ_id)) diff --git a/stem/client/datatype.py b/stem/client/datatype.py index 43bdfe9d..644d4993 100644 --- a/stem/client/datatype.py +++ b/stem/client/datatype.py @@ -116,6 +116,7 @@ import collections import hashlib import struct +import stem.client.cell import stem.prereq import stem.util import stem.util.connection @@ -246,9 +247,11 @@ class LinkProtocol(int): protocol = int.__new__(cls, version) protocol.version = version protocol.circ_id_size = Size.LONG if version > 3 else Size.SHORT - protocol.fixed_cell_length = 514 if version > 3 else 512 protocol.first_circ_id = 0x80000000 if version > 3 else 0x01 + cell_header_size = protocol.circ_id_size.size + 1 # circuit id (2 or 4 bytes) + command (1 byte) + protocol.fixed_cell_length = cell_header_size + stem.client.cell.FIXED_PAYLOAD_LEN + return protocol def __hash__(self):