Implement the last of proposal 110

Reject all EXTEND requests not received in a relay_early cell

1 files changed, 19 insertions, 0 deletions

diff --git a/src/or/relay.c b/src/or/relay.c
index 6cf4b73a5..60d439aca 100644
--- a/src/or/relay.c
+++ b/src/or/relay.c
@@ -1194,6 +1194,25 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
                "'extend' cell received for non-zero stream. Dropping.");
         return 0;
       }
+      if (cell->command != CELL_RELAY_EARLY) {
+#define EARLY_WARNING_INTERVAL 900
+        static ratelim_t early_warning_limit =
+          RATELIM_INIT(EARLY_WARNING_INTERVAL);
+        char *m;
+        if (cell->command == CELL_RELAY) {
+          if ((m = rate_limit_log(&early_warning_limit, approx_time()))) {
+            /* XXXX make this a protocol_warn once we're happier with it*/
+            log_fn(LOG_WARN, domain, "EXTEND cell received, "
+                   "but not via RELAY_EARLY. Dropping.%s", m);
+            tor_free(m);
+          }
+        } else {
+          log_fn(LOG_WARN, domain,
+                 "EXTEND cell received, in a cell with type %d! Dropping.",
+                 cell->command);
+        }
+        return 0;
+      }
       return circuit_extend(cell, circ);
     case RELAY_COMMAND_EXTENDED:
       if (!layer_hint) {