[tor-commits] [tor/master] relay: Don't publish IPv6 if found ORPort is 0

[nickm at torproject.org]

commit fbee4d25cc5672cd9b4fb79a8cb17c7464053ef8
Author: David Goulet <dgoulet at torproject.org>
Date:   Tue Jul 21 08:12:47 2020 -0400

    relay: Don't publish IPv6 if found ORPort is 0
    
    The ORPort can be IPv4Only which means that even if we can auto discover an
    IPv6 address, we should not publish it because it would have an ORPort of 0.
    
    Fixes #40054
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 src/feature/relay/router.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/feature/relay/router.c b/src/feature/relay/router.c
index b75241160f..c2b01a641d 100644
--- a/src/feature/relay/router.c
+++ b/src/feature/relay/router.c
@@ -2032,6 +2032,7 @@ router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
   int hibernating = we_are_hibernating();
   const or_options_t *options = get_options();
   int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+  uint16_t ipv6_orport = 0;
 
   if (BUG(!ri_out)) {
     result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
@@ -2067,10 +2068,13 @@ router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
   ri->ipv4_orport = router_get_advertised_or_port_by_af(options, AF_INET);
   ri->ipv4_dirport = router_get_advertised_dir_port(options, 0);
 
-  /* IPv6. */
-  if (have_v6) {
+  /* IPv6. Do not publish an IPv6 if we don't have an ORPort that can be used
+   * with the address. This is possible for instance if the ORPort is
+   * IPv4Only. */
+  ipv6_orport = router_get_advertised_or_port_by_af(options, AF_INET6);
+  if (have_v6 && ipv6_orport != 0) {
     tor_addr_copy(&ri->ipv6_addr, &ipv6_addr);
-    ri->ipv6_orport = router_get_advertised_or_port_by_af(options, AF_INET6);
+    ri->ipv6_orport = ipv6_orport;
   }
 
   ri->supports_tunnelled_dir_requests =