Merge branch 'bug9072-023' into bug9072-024

changes/bug9072

@@ -0,0 +1,3 @@
+  o Critical bugfixes:
+    - Disable middle relay queue overfill detection code due to possible
+      guard discovery attack, pending further analysis.  Fixes bug #9072.

src/or/relay.c

@@ -2482,6 +2482,10 @@ append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan,
     streams_blocked = circ->streams_blocked_on_p_chan;
   }
 
+  /*
+   * Disabling this for now because of a possible guard discovery attack
+   */
+#if 0
   /* Are we a middle circuit about to exceed ORCIRC_MAX_MIDDLE_CELLS? */
   if ((circ->n_chan != NULL) && CIRCUIT_IS_ORCIRC(circ)) {
     orcirc = TO_OR_CIRCUIT(circ);
@@ -2505,6 +2509,7 @@ append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan,
       }
     }
   }
+#endif
 
   cell_queue_append_packed_copy(queue, cell, chan->wide_circ_ids);