r13738@catbus: nickm | 2007-07-12 13:00:35 -0400

 Backport r10730: Do not choose guard nodes that appear after any never-before-connected-to guard.


svn:r10817

3 files changed, 15 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 5a012ebee3..ed6cea4200 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,12 +9,17 @@ Changes in version 0.1.2.15 - 2007-0?-??
       routerlist while inserting a new router.
     - Fix eventdns.c behavior on Solaris: It is critical to include
       orconfig.h _before_ sys/types.h, so that we can get the expected
-      definition of _FILE_OFFSET_BITS.  [Bugfix on 0.1.2.x]
+      definition of _FILE_OFFSET_BITS.
 
   o Major bugfixes (security):
     - Fix a possible buffer overrun when using BSD natd support.  Bug found
       by "Mr. Croup."
 
+  o Minor bugfixes (guard nodes):
+    - If there's a never-before-connected-to guard node in our list,
+      never choose any guards past it. This way we don't expand our
+      guard list unless we need to.
+
   o Minor bugfixes (security):
     - When sending destroy cells from a circuit's origin, don't include
       the reason for tearing down the circuit. The spec says we didn't,
diff --git a/doc/TODO.012 b/doc/TODO.012
index e84b47d5fa..5d70450e8c 100644
--- a/doc/TODO.012
+++ b/doc/TODO.012
@@ -13,7 +13,7 @@ Backport items for 0.1.2:
   o r10563: use correct types with desc_digest_map.
   o r10566: build correctly on systems where size_t is bigger than ulong. 
   o r10643: eventdns.c behavior fix for solaris.
-  - r10730: Don't choose guards after any never-connected-to guard. (??)
+  o r10730: Don't choose guards after any never-connected-to guard.
   o r10760: fix possible buffer overrun in old BSD natd code
   o r10790: Don't include reasons in destroy cells from the origin.
   - Some fix for bug 455.
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 7ae2abbc8b..ac0db6e5d8 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -2354,6 +2354,13 @@ choose_random_entry(cpath_build_state_t *state)
       r = entry_is_live(entry, need_uptime, need_capacity, 0);
       if (r && !smartlist_isin(exit_family, r)) {
         smartlist_add(live_entry_guards, r);
+        if (!entry->made_contact) {
+          /* Always start with the first not-yet-contacted entry
+           * guard. Otherwise we might add several new ones, pick
+           * the second new one, and now we've expanded our entry
+           * guard list without needing to. */
+          goto choose_and_finish;
+        }
         if (smartlist_len(live_entry_guards) >= options->NumEntryGuards)
           break; /* we have enough */
       }
@@ -2387,6 +2394,7 @@ choose_random_entry(cpath_build_state_t *state)
     /* live_entry_guards will be empty below. Oh well, we tried. */
   }
 
+ choose_and_finish:
   r = smartlist_choose(live_entry_guards);
   smartlist_free(live_entry_guards);
   smartlist_free(exit_family);