Backport r17138: Fix the rest of bug 619: reject *:* servers should not do DNS lookups, even if broken clients send them RELAY_BEGIN cells. Patch from rovv.

svn:r17870

ChangeLog

@@ -56,6 +56,10 @@ Changes in version 0.2.0.33 - 2009-??-??
       prevent possible guess-the-streamid injection attacks from
       intermediate hops.  Fixes another case of bug 446. Based on patch
       from rovv.
+    - If a broken client asks a non-exit router to connect somewhere,
+      do not even do the DNS lookup before rejecting the connection.
+      Fixes another case of bug 619.  Patch from rovv.
+
 
   o Minor features:
     - Report the case where all signatures in a detached set are rejected

doc/TODO.020

@@ -17,7 +17,7 @@ Backport for 0.2.0 once better tested:
     o See also r17181...
     o ... and r17184.
   o r17137: send END cell in response to connect to nonexistent hidserv port.
-  - r17138: reject *:* servers should never do DNS lookups.
+  o r17138: reject *:* servers should never do DNS lookups.
   o r17139: Fix another case of overriding .exit choices.
   o r17162 and r17164: fix another case of not checking cpath_layer.
   - r17208,r17209,r7211,r17212,r17214: Avoid gotterdammerung when an

src/or/dns.c

@@ -563,14 +563,10 @@ dns_resolve(edge_connection_t *exitconn)
   or_circuit_t *oncirc = TO_OR_CIRCUIT(exitconn->on_circuit);
   int is_resolve, r;
   char *hostname = NULL;
-  routerinfo_t *me = router_get_my_routerinfo();
   is_resolve = exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE;
 
-  if (is_resolve && me &&
-      policy_is_reject_star(me->exit_policy)) /* non-exit */
-    r = -1;
-  else
-    r = dns_resolve_impl(exitconn, is_resolve, oncirc, &hostname);
+  r = dns_resolve_impl(exitconn, is_resolve, oncirc, &hostname);
+
   switch (r) {
     case 1:
       /* We got an answer without a lookup -- either the answer was
@@ -645,6 +641,7 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
   cached_resolve_t *resolve;
   cached_resolve_t search;
   pending_connection_t *pending_connection;
+  routerinfo_t *me;
   struct in_addr in;
   time_t now = time(NULL);
   uint8_t is_reverse = 0;
@@ -661,6 +658,11 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
     exitconn->address_ttl = DEFAULT_DNS_TTL;
     return 1;
   }
+  /* If we're a non-exit, don't even do DNS lookups. */
+  if (!(me = router_get_my_routerinfo()) ||
+      policy_is_reject_star(me->exit_policy)) {
+    return -1;
+  }
   if (address_is_invalid_destination(exitconn->_base.address, 0)) {
     log(LOG_PROTOCOL_WARN, LD_EXIT,
         "Rejecting invalid destination address %s",