layer/validate: fix duplicate records in AUTHORITY section in case of WC expansion proof

lib/layer/validate.c

@@ -710,7 +710,7 @@ static int validate(kr_layer_t *ctx, knot_pkt_t *pkt)
 	/* Check if wildcard expansion detected for final query.
 	 * If yes, copy authority. */
 	if ((qry->parent == NULL) && (qry->flags & QUERY_DNSSEC_WEXPAND)) {
-		kr_ranked_rrarray_set_wire(&req->auth_selected, true, qry->uid);
+		kr_ranked_rrarray_set_wire(&req->auth_selected, true, qry->uid, true);
 	}
 
 	/* Check and update current delegation point security status. */

lib/utils.c

@@ -493,12 +493,33 @@ int kr_ranked_rrarray_add(ranked_rr_array_t *array, const knot_rrset_t *rr,
 	return kr_ok();
 }
 
-int kr_ranked_rrarray_set_wire(ranked_rr_array_t *array, bool to_wire, uint32_t qry_uid)
+int kr_ranked_rrarray_set_wire(ranked_rr_array_t *array, bool to_wire,
+			       uint32_t qry_uid, bool check_dups)
 {
 	for (size_t i = 0; i < array->len; ++i) {
 		ranked_rr_array_entry_t *entry = array->at[i];
-		if (entry->qry_uid == qry_uid) {
-			entry->to_wire = to_wire;
+		if (entry->qry_uid != qry_uid) {
+			continue;
+		}
+		entry->to_wire = to_wire;
+		if (!check_dups) {
+			continue;
+		}
+		knot_rrset_t *rr = entry->rr;
+		for (size_t j = 0; j < array->len; ++j) {
+			ranked_rr_array_entry_t *stashed = array->at[j];
+			if (stashed->qry_uid == qry_uid) {
+				continue;
+			}
+			if (stashed->rr->rclass != rr->rclass ||
+			    stashed->rr->type != rr->type) {
+				continue;
+			}
+			bool is_equal = knot_rrset_equal(rr, stashed->rr,
+							 KNOT_RRSET_COMPARE_WHOLE);
+			if (is_equal && to_wire) {
+				stashed->to_wire = false;
+			}
 		}
 	}
 	return kr_ok();

lib/utils.h

@@ -193,7 +193,8 @@ int kr_rrarray_add(rr_array_t *array, const knot_rrset_t *rr, knot_mm_t *pool);
 int kr_ranked_rrarray_add(ranked_rr_array_t *array, const knot_rrset_t *rr,
 			  uint8_t rank, bool to_wire, uint32_t qry_uid, knot_mm_t *pool);
 
-int kr_ranked_rrarray_set_wire(ranked_rr_array_t *array, bool to_wire, uint32_t qry_uid);
+int kr_ranked_rrarray_set_wire(ranked_rr_array_t *array, bool to_wire,
+			       uint32_t qry_uid, bool check_dups);
 
 void kr_rrset_print(const knot_rrset_t *rr, const char *prefix);
 void kr_pkt_print(knot_pkt_t *pkt);

[Petr Špaček]

Could you please add comment explaining what the parameter is supposed to do? The name check_dups seems confusing because it seems that the parameter actually skips dups when constructing the answer.