Fix a bug handling SENDME cells on nonexistent streams.

This could result in bizarre window values. Report and patch
contributed pseudymously.  Fixes part of bug 6271. This bug was
introduced before the first Tor release, in svn commit r152.

(bug 6271, part a.)

1 files changed, 6 insertions, 1 deletions

diff --git a/src/or/relay.c b/src/or/relay.c
index b637fadf59..50c14556ff 100644
--- a/src/or/relay.c
+++ b/src/or/relay.c
@@ -1220,7 +1220,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
                "'connected' received, no conn attached anymore. Ignoring.");
       return 0;
     case RELAY_COMMAND_SENDME:
-      if (!conn) {
+      if (!rh.stream_id) {
         if (layer_hint) {
           layer_hint->package_window += CIRCWINDOW_INCREMENT;
           log_debug(LD_APP,"circ-level sendme at origin, packagewindow %d.",
@@ -1235,6 +1235,11 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
         }
         return 0;
       }
+      if (!conn) {
+        log_info(domain,"sendme cell dropped, unknown stream (streamid %d).",
+                 rh.stream_id);
+        return 0;
+      }
       conn->package_window += STREAMWINDOW_INCREMENT;
       log_debug(domain,"stream-level sendme, packagewindow now %d.",
                 conn->package_window);