Disable qname minimization if we encounter a bad server

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index f8b8e3950541e2ff7fb12a92b646333224a6af53..d311ff33e19bce916f8c37c61063ffc6879c8548 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -65,7 +65,7 @@
 #include <dns/stats.h>
 #include <dns/tsig.h>
 #include <dns/validator.h>
-
+#define WANT_QUERYTRACE
 #ifdef WANT_QUERYTRACE
 #define RTRACE(m)       isc_log_write(dns_lctx, \
                                      DNS_LOGCATEGORY_RESOLVER, \
@@ -8507,10 +8507,6 @@ rctx_answer_none(respctx_t *rctx) {
                 * If we're minimizing in relaxed mode, retry with full name,
                 * just to be safe. The error will be logged.
                 */
-               isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
-                             DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
-                             "XXX %d %d", fctx->minimized,
-                             fctx->options & DNS_FETCHOPT_QMIN_STRICT);
                if (fctx->minimized &&
                    (fctx->options & DNS_FETCHOPT_QMIN_STRICT) == 0) {
                        isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
@@ -8553,7 +8549,7 @@ rctx_answer_none(respctx_t *rctx) {
         * NXDOMAIN we go straight to the full query.
         */
        if (fctx->minimized && !(fctx->options & DNS_FETCHOPT_QMIN_STRICT)) {
-               fctx->qmin_labels = DNS_MAX_LABELS+1;
+               fctx->qmin_labels = DNS_MAX_LABELS + 1;
                return rctx_answer_minimized(rctx);
        }
        /*
@@ -9398,15 +9394,27 @@ rctx_badserver(respctx_t *rctx, isc_result_t result) {
        }
 
        /*
-        * Some servers do not ignore unknown EDNS options.
+        * If we're minimizing in relaxed mode try to disable minimization.
         */
-       if (!NOCOOKIE(query->addrinfo) &&
+       if (fctx->minimized &&
+           (fctx->options & DNS_FETCHOPT_QMIN_STRICT) == 0)
+       {
+               isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
+                             DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
+                             "disabling qname minimization for '%s'"
+                             " due to bad server", fctx->info);
+               fctx->qmin_labels = DNS_MAX_LABELS + 1;
+               result = rctx_answer_minimized(rctx);
+       } else if (!NOCOOKIE(query->addrinfo) &&
            (fctx->rmessage->rcode == dns_rcode_formerr ||
             fctx->rmessage->rcode == dns_rcode_notimp ||
             fctx->rmessage->rcode == dns_rcode_refused) &&
             dns_adb_getcookie(fctx->adb, query->addrinfo,
                               cookie, sizeof(cookie)) == 0U)
        {
+               /*
+                * Some servers do not ignore unknown EDNS options.
+                */
                dns_adb_changeflags(fctx->adb, query->addrinfo,
                                    FCTX_ADDRINFO_NOCOOKIE,
                                    FCTX_ADDRINFO_NOCOOKIE);