TROVE-2017-005: Fix assertion failure in connection_edge_process_relay_cell

On an hidden service rendezvous circuit, a BEGIN_DIR could be sent
(maliciously) which would trigger a tor_assert() because
connection_edge_process_relay_cell() thought that the circuit is an
or_circuit_t but is an origin circuit in reality.

Fixes #22494

Reported-by: Roger Dingledine <arma@torproject.org>
Signed-off-by: David Goulet <dgoulet@torproject.org>
This commit is contained in:
David Goulet 2017-06-05 11:11:42 -04:00 committed by Nick Mathewson
parent 4ee48cb434
commit 56a7c5bc15
2 changed files with 9 additions and 1 deletions

7
changes/trove-2017-005 Normal file
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@ -0,0 +1,7 @@
o Major bugfixes (hidden service, relay, security):
- Fix an assertion failure caused by receiving a BEGIN_DIR cell on
a hidden service rendezvous circuit. Fixes bug 22494, tracked as
TROVE-2017-005 and CVE-2017-0376; bugfix on 0.2.2.1-alpha. Found
by armadev.

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@ -1297,7 +1297,8 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
"Begin cell for known stream. Dropping.");
return 0;
}
if (rh.command == RELAY_COMMAND_BEGIN_DIR) {
if (rh.command == RELAY_COMMAND_BEGIN_DIR &&
circ->purpose != CIRCUIT_PURPOSE_S_REND_JOINED) {
/* Assign this circuit and its app-ward OR connection a unique ID,
* so that we can measure download times. The local edge and dir
* connection will be assigned the same ID when they are created