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[tor-commits] [stem/master] Rearrange the digest/key copies to be a bit more spec-compliant
commit 13cc211070c2cf1d0d571461eed688ac1e69a735
Author: Dave Rolek <dmr-x@xxxxxxxxxx>
Date: Sat Aug 18 04:26:42 2018 +0000
Rearrange the digest/key copies to be a bit more spec-compliant
This arrangement is better, as it better keeps track of the digest/key
on a cell-by-cell basis, but it's still not spec-compliant in a number
of ways, such as its potential to drop cells or get corrupted backward
digest/key state in the case of an exception.
That's ok - this is just an interim implementation, and this change is
just to make things a bit better for illustrative purposes.
---
stem/client/__init__.py | 33 +++++++++++++++++++--------------
1 file changed, 19 insertions(+), 14 deletions(-)
diff --git a/stem/client/__init__.py b/stem/client/__init__.py
index 91e8c4ca..8c96b8c2 100644
--- a/stem/client/__init__.py
+++ b/stem/client/__init__.py
@@ -236,20 +236,27 @@ class Circuit(object):
with self.relay._orport_lock:
orig_forward_digest = self.forward_digest.copy()
orig_forward_key = copy.copy(self.forward_key)
- orig_backward_digest = self.backward_digest.copy()
- orig_backward_key = copy.copy(self.backward_key)
try:
cell = stem.client.cell.RelayCell(self.id, command, data, stream_id = stream_id)
encrypted_cell, self.forward_digest, self.forward_key = cell.encrypt(self.forward_digest, self.forward_key)
- reply_cells = []
self.relay._orport.send(encrypted_cell.pack(self.relay.link_protocol))
- reply = self.relay._orport.recv()
+ except:
+ self.forward_digest = orig_forward_digest
+ self.forward_key = orig_forward_key
+ raise
+
+ reply = self.relay._orport.recv()
+ reply_cells = []
- relay_cell_cmd = stem.client.cell.RelayCell.VALUE
+ relay_cell_cmd = stem.client.cell.RelayCell.VALUE
- while reply:
+ while reply:
+ orig_backward_digest = self.backward_digest.copy()
+ orig_backward_key = copy.copy(self.backward_key)
+
+ try:
raw_cell, reply = stem.client.cell.Cell.pop(reply, self.relay.link_protocol)
if raw_cell.VALUE != relay_cell_cmd:
@@ -260,16 +267,14 @@ class Circuit(object):
decrypted_cell, fully_decrypted, self.backward_digest, self.backward_key = raw_cell.decrypt(self.backward_digest, self.backward_key, interpret = True)
if not fully_decrypted:
raise stem.ProtocolError('Response for circuit id %i was not fully decrypted, when expected to be' % self.id)
+ except:
+ self.backward_digest = orig_backward_digest
+ self.backward_key = orig_backward_key
+ raise
- reply_cells.append(decrypted_cell)
+ reply_cells.append(decrypted_cell)
- return reply_cells
- except:
- self.forward_digest = orig_forward_digest
- self.forward_key = orig_forward_key
- self.backward_digest = orig_backward_digest
- self.backward_key = orig_backward_key
- raise
+ return reply_cells
def close(self):
with self.relay._orport_lock:
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