commit 56a7c5bc15e0447203a491c1ee37de9939ad1dcd Author: David Goulet dgoulet@torproject.org Date: Mon Jun 5 11:11:42 2017 -0400

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 --- changes/trove-2017-005 | 7 +++++++ src/or/relay.c | 3 ++- 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/changes/trove-2017-005 b/changes/trove-2017-005 new file mode 100644 index 0000000..cebb013 --- /dev/null +++ b/changes/trove-2017-005 @@ -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. + + diff --git a/src/or/relay.c b/src/or/relay.c index 7f06c6e..59b79f9 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -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