From c1bd10411116c549326f74b09658a50bbae812b4 Mon Sep 17 00:00:00 2001 From: Roger Dingledine Date: Thu, 28 Jun 2012 14:00:01 -0400 Subject: Detect bug 6252 (unexpected sendme cell) I only check on circuits, not streams, since bloating your stream window past the initial circuit window can't help you much. Also, I compare to CIRCWINDOW_START_MAX so we don't have surprising races if we lower CIRCWINDOW_START for an experiment. --- src/or/relay.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'src') diff --git a/src/or/relay.c b/src/or/relay.c index 3e418ea13..3d261c265 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -1265,11 +1265,25 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, case RELAY_COMMAND_SENDME: if (!rh.stream_id) { if (layer_hint) { + if (layer_hint->package_window + CIRCWINDOW_INCREMENT > + CIRCWINDOW_START_MAX) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Bug/attack: unexpected sendme cell from exit relay. " + "Closing circ."); + return -END_CIRC_REASON_TORPROTOCOL; + } layer_hint->package_window += CIRCWINDOW_INCREMENT; log_debug(LD_APP,"circ-level sendme at origin, packagewindow %d.", layer_hint->package_window); circuit_resume_edge_reading(circ, layer_hint); } else { + if (circ->package_window + CIRCWINDOW_INCREMENT > + CIRCWINDOW_START_MAX) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Bug/attack: unexpected sendme cell from client. " + "Closing circ."); + return -END_CIRC_REASON_TORPROTOCOL; + } circ->package_window += CIRCWINDOW_INCREMENT; log_debug(LD_APP, "circ-level sendme at non-origin, packagewindow %d.", -- cgit v1.2.3