[tor-bugs] #619 [Tor]: exit-policy-reject-star relays should refuse dns?

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#619: exit-policy-reject-star relays should refuse dns?
------------------------+---------------------------
     Reporter:  arma    |      Owner:
         Type:  defect  |     Status:  reopened
     Priority:  minor   |  Milestone:  0.2.0.x-final
    Component:  Tor     |    Version:  0.2.0.21-rc
   Resolution:          |   Keywords:
Actual Points:          |  Parent ID:
       Points:          |
------------------------+---------------------------
Changes (by mttp):

 * status:  closed => reopened
 * resolution:  Fixed =>


Old description:

> lodger points out that non-exit relays could reject dns and reverse dns
> attempts. (Currently clients try not to ask them any questions, but the
> relays don't enforce it. Non-exit relays might be surprised at the dns
> requests they are forced to do. "also permit reverse resolve for private
> addresses, which could lead to leaks of names, in normal circumstances,
> only available locally."
>
> Here's his patch:
>
> --- dns.c       Tue Feb 26 19:56:28 2008
> +++ dns.c       Sat Mar  8 12:11:34 2008
> @@ -550,7 +550,12 @@
>    char *hostname = NULL;
>    is_resolve = exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE;
>
> -  r = dns_resolve_impl(exitconn, is_resolve, oncirc, &hostname);
> +  routerinfo_t *me = router_get_my_routerinfo();
> +  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);
>    switch (r) {
>      case 1:
>        /* We got an answer without a lookup -- either the answer was
> @@ -659,9 +664,12 @@
>     * .in-addr.arpa address but this isn't a resolve request, kill the
>     * connection.
>     */
> -  if ((r = parse_inaddr_arpa_address(exitconn->_base.address, NULL)) !=
> 0) {
> -    if (r == 1)
> +  if ((r = parse_inaddr_arpa_address(exitconn->_base.address, &in)) !=
> 0) {
> +    if (r == 1) {
>        is_reverse = 1;
> +         if (is_internal_IP(ntohl(in.s_addr), 0)) /* internal address */
> +           return -1;
> +    }
>
>      if (!is_reverse || !is_resolve) {
>        if (!is_reverse)
>

> [Automatically added by flyspray2trac: Operating System: All]

New description:

 lodger points out that non-exit relays could reject dns and reverse dns
 attempts. (Currently clients try not to ask them any questions, but the
 relays don't enforce it. Non-exit relays might be surprised at the dns
 requests they are forced to do. "also permit reverse resolve for private
 addresses, which could lead to leaks of names, in normal circumstances,
 only available locally."

 Here's his patch:

 --- dns.c       Tue Feb 26 19:56:28 2008
 +++ dns.c       Sat Mar  8 12:11:34 2008
 @@ -550,7 +550,12 @@
    char *hostname = NULL;
    is_resolve = exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE;

 -  r = dns_resolve_impl(exitconn, is_resolve, oncirc, &hostname);
 +  routerinfo_t *me = router_get_my_routerinfo();
 +  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);
    switch (r) {
      case 1:
        /* We got an answer without a lookup -- either the answer was
 @@ -659,9 +664,12 @@
     * .in-addr.arpa address but this isn't a resolve request, kill the
     * connection.
     */
 -  if ((r = parse_inaddr_arpa_address(exitconn->_base.address, NULL)) !=
 0) {
 -    if (r == 1)
 +  if ((r = parse_inaddr_arpa_address(exitconn->_base.address, &in)) != 0)
 {
 +    if (r == 1) {
        is_reverse = 1;
 +         if (is_internal_IP(ntohl(in.s_addr), 0)) /* internal address */
 +           return -1;
 +    }

      if (!is_reverse || !is_resolve) {
        if (!is_reverse)


 [Automatically added by flyspray2trac: Operating System: All]

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/619#comment:11>
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