[or-cvs] [tor/master 3/4] Proper NULL checking in circuit_list_path_impl()

[nickm at torproject.org]

Author: Sebastian Hahn <sebastian at torproject.org>
Date: Wed, 24 Feb 2010 09:36:15 +0100
Subject: Proper NULL checking in circuit_list_path_impl()
Commit: 86828e2004058d01fba09215a44d51d53f82e5c3

Another dereference-then-NULL-check sequence. No reports of this bug
triggered in the wild. Fixes bugreport 1256.

Thanks to ekir for discovering and reporting this bug.
---
 ChangeLog             |    2 ++
 src/or/circuitbuild.c |    2 +-
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 525a00b..8ec64c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,8 @@ Changes in version 0.2.1.25 - 2010-??-??
     - Fix a dereference-then-NULL-check sequence when publishing
       descriptors. Bugfix on tor-0.2.1.5-alpha. Discovered by ekir,
       fixes bug 1255.
+    - Fix another dereference-then-NULL-check sequence. Bugfix on
+      0.2.1.14-rc. Discovered by ekir, fixes bug 1256.
 
 Changes in version 0.2.1.24 - 2010-02-21
   Tor 0.2.1.24 makes Tor work again on the latest OS X -- this time
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 3441c30..0926dfb 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -137,11 +137,11 @@ circuit_list_path_impl(origin_circuit_t *circ, int verbose, int verbose_names)
     const char *id;
     if (!hop)
       break;
-    id = hop->extend_info->identity_digest;
     if (!verbose && hop->state != CPATH_STATE_OPEN)
       break;
     if (!hop->extend_info)
       break;
+    id = hop->extend_info->identity_digest;
     if (verbose_names) {
       elt = tor_malloc(MAX_VERBOSE_NICKNAME_LEN+1);
       if ((ri = router_get_by_digest(id))) {
-- 
1.6.5