commit 8b5787ec0d99a130ead302f7c6b4a256325ac08f Author: Nick Mathewson nickm@torproject.org Date: Tue Dec 18 21:32:53 2012 -0500

When there are no dir_server_ts to choose, don't crash

It's important not to call choose_array_element_by_weight and then pass its return value unchecked to smartlist_get : it is allowed to return -1.

Fixes bug 7756; bugfix on 4e3d07a6 (not in any released Tor) --- src/or/routerlist.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/or/routerlist.c b/src/or/routerlist.c index 972d451..898b9b5 100644 --- a/src/or/routerlist.c +++ b/src/or/routerlist.c @@ -1270,7 +1270,7 @@ dirserver_choose_by_weight(const smartlist_t *servers, double authority_weight) scale_array_elements_to_u64(weights, n, NULL); i = choose_array_element_by_weight(weights, n); tor_free(weights); - return smartlist_get(servers, i); + return (i < 0) ? NULL : smartlist_get(servers, i); }

/** Choose randomly from among the dir_server_ts in sourcelist that