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)
This commit is contained in:
Nick Mathewson 2012-12-18 21:32:53 -05:00
parent 7a99d26c79
commit 8b5787ec0d

View File

@ -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