Changeset 6000

Timestamp:

May 23, 2019 1:42:27 PM (5 years ago)

Author:

riza

Message:

Close #2200: Ignore/discard DNS SRV response with truncated flag set.

Location:

pjproject/trunk/pjlib-util/src/pjlib-util

Files:

• resolver.c (modified) (1 diff)
• srv_resolver.c (modified) (1 diff)

pjproject/trunk/pjlib-util/src/pjlib-util/resolver.c

@@ -1777 +1777 @@
     pj_grp_lock_acquire(resolver->grp_lock);
 
-    /* Save/update response cache. */
-    update_res_cache(resolver, &q->key, status, PJ_TRUE, dns_pkt);
-    
+    /* Truncated responses MUST NOT be saved (cached). */
+    if (PJ_DNS_GET_TC(dns_pkt->hdr.flags) == 0) {
+        /* Save/update response cache. */
+        update_res_cache(resolver, &q->key, status, PJ_TRUE, dns_pkt);
+    }
+
     /* Recycle query objects, starting with the child queries */
     if (!pj_list_empty(&q->child_head)) {

pjproject/trunk/pjlib-util/src/pjlib-util/srv_resolver.c

@@ -586 +586 @@
         query_job->q_srv = NULL;
 
-        if (status == PJ_SUCCESS && pkt->hdr.anscount != 0) {
-            /* Got SRV response, build server entry. If A records are available
-             * in additional records section of the DNS response, save them too.
-             */
-            build_server_entries(query_job, pkt);
-
-        } else if (status != PJ_SUCCESS) {
+        if (status == PJ_SUCCESS) {
+            if (PJ_DNS_GET_TC(pkt->hdr.flags)) {
+                /* Got truncated answer, the standard recommends to follow up
+                 * the query using TCP. Since we currently don't support it,
+                 * just return error.
+                 */
+                PJ_LOG(4,(query_job->objname,
+                          "Discard truncated DNS SRV response for %.*s",
+                          (int)query_job->full_name.slen,
+                          query_job->full_name.ptr));
+
+                status = PJ_EIGNORED;
+                query_job->last_error = status;
+                goto on_error;
+            } else if (pkt->hdr.anscount != 0) {
+                /* Got SRV response, build server entry. If A records are
+                 * available in additional records section of the DNS response,
+                 * save them too.
+                 */
+                build_server_entries(query_job, pkt);
+            }
+
+        } else {
             char errmsg[PJ_ERR_MSG_SIZE];