c-ares.patch

# Workaround c-ares trusting /etc/hosts entries for localhost
diff --git a/src/lib/ares_getaddrinfo.c b/src/lib/ares_getaddrinfo.c
index eabd17fc..83bcf06f 100644
--- a/src/lib/ares_getaddrinfo.c
+++ b/src/lib/ares_getaddrinfo.c
@@ -449,6 +449,26 @@ static void next_lookup(struct host_query *hquery, ares_status_t status)
       break;
 
     case 'f':
+      /* FIXME: This works around wonky /etc/hosts files having localhost
+       * entries with IPs that are *not* valid loop-back IPs. Imagine a
+       * scenario where resolving localhost returns a non-loopback IP but
+       * the server we're trying to connect to is only listening on a
+       * loopback IP. Then resolution succeeds but we still cannot connect.
+       * RFC 6751 Section 6.3 #3 seems to support that localhost should
+       * only resolve to loopback IPs:
+       * "Name resolution APIs ... SHOULD always return the IP loopback
+       * address" */
+      if (ares_is_localhost(hquery->name)) {
+          if (ares_addrinfo_localhost(hquery->name, hquery->port, &hquery->hints,
+                                      hquery->ai) == ARES_SUCCESS) {
+            end_hquery(hquery, ARES_SUCCESS);
+            break;
+          }
+          hquery->remaining_lookups++;
+          next_lookup(hquery, status);
+          break;
+      }
+
       /* Host file lookup */
       if (file_lookup(hquery) == ARES_SUCCESS) {
         end_hquery(hquery, ARES_SUCCESS);