diff --git a/changes/bug2366 b/changes/bug2366
new file mode 100644
index 0000000000..d171be453f
--- /dev/null
+++ b/changes/bug2366
@@ -0,0 +1,8 @@
+ o Minor bugfixes
+ - When a relay decides that its DNS is too broken for it to serve
+ as an exit server, it advertised itself as a non-exit, but
+ continued to act as an exit. This could create accidental
+ partitioning opportunities for users. Instead, if a relay is
+ going to advertise reject *:* as its exit policy, it should
+ really act with exit policy "reject *:*". Fixes bug 2366.
+ Bugfix on Tor 0.1.2.5-alpha. Bugfix by user "postman" on trac.
diff --git a/src/or/policies.c b/src/or/policies.c
index 62e048cfc2..38c2f7c0fd 100644
--- a/src/or/policies.c
+++ b/src/or/policies.c
@@ -858,6 +858,14 @@ policies_parse_exit_policy(config_line_t *cfg, smartlist_t **dest,
return 0;
}
+/** Add "reject *:*" to the end of the policy in *dest, allocating
+ * *dest as needed. */
+void
+policies_exit_policy_append_reject_star(smartlist_t **dest)
+{
+ append_exit_policy_string(dest, "reject *:*");
+}
+
/** Replace the exit policy of r with reject *:*. */
void
policies_set_router_exitpolicy_to_reject_all(routerinfo_t *r)
diff --git a/src/or/policies.h b/src/or/policies.h
index a954ac4f5f..b2947c67e7 100644
--- a/src/or/policies.h
+++ b/src/or/policies.h
@@ -41,6 +41,7 @@ addr_policy_result_t compare_addr_to_addr_policy(uint32_t addr,
int policies_parse_exit_policy(config_line_t *cfg, smartlist_t **dest,
int rejectprivate, const char *local_address,
int add_default_policy);
+void policies_exit_policy_append_reject_star(smartlist_t **dest);
void policies_set_router_exitpolicy_to_reject_all(routerinfo_t *exitrouter);
int exit_policy_is_general_exit(smartlist_t *policy);
int policy_is_reject_star(const smartlist_t *policy);
diff --git a/src/or/router.c b/src/or/router.c
index 59276bac3a..4c5eb7a392 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -1410,9 +1410,14 @@ router_rebuild_descriptor(int force)
ri->bandwidthcapacity = hibernating ? 0 : rep_hist_bandwidth_assess();
- policies_parse_exit_policy(options->ExitPolicy, &ri->exit_policy,
- options->ExitPolicyRejectPrivate,
- ri->address, !options->BridgeRelay);
+ if (dns_seems_to_be_broken() || has_dns_init_failed()) {
+ /* DNS is screwed up; don't claim to be an exit. */
+ policies_exit_policy_append_reject_star(&ri->exit_policy);
+ } else {
+ policies_parse_exit_policy(options->ExitPolicy, &ri->exit_policy,
+ options->ExitPolicyRejectPrivate,
+ ri->address, !options->BridgeRelay);
+ }
ri->policy_is_reject_star =
policy_is_reject_star(ri->exit_policy);
@@ -1866,9 +1871,7 @@ router_dump_router_to_string(char *s, size_t maxlen, routerinfo_t *router,
}
/* Write the exit policy to the end of 's'. */
- if (dns_seems_to_be_broken() || has_dns_init_failed() ||
- !router->exit_policy || !smartlist_len(router->exit_policy)) {
- /* DNS is screwed up; don't claim to be an exit. */
+ if (!router->exit_policy || !smartlist_len(router->exit_policy)) {
strlcat(s+written, "reject *:*\n", maxlen-written);
written += strlen("reject *:*\n");
tmpe = NULL;