1 files changed, 37 insertions, 0 deletions
diff --git a/debian/patches/0005-validator-refuse-to-validate-answers-with-more-than-.patch b/debian/patches/0005-validator-refuse-to-validate-answers-with-more-than-.patch
new file mode 100644
index 0000000..dd547a1
--- /dev/null
+++ b/debian/patches/0005-validator-refuse-to-validate-answers-with-more-than-.patch
@@ -0,0 +1,37 @@
+From: =?utf-8?b?VmxhZGltw61yIMSMdW7DoXQ=?= <vladimir.cunat@nic.cz>
+Date: Mon, 12 Feb 2024 11:16:47 +0100
+Subject: validator: refuse to validate answers with more than 8 NSEC3 records
+
+---
+ lib/layer/validate.c | 18 ++++++++++++++++++
+ 1 file changed, 18 insertions(+)
+
+diff --git a/lib/layer/validate.c b/lib/layer/validate.c
+index 5fea99d..95a7624 100644
+--- a/lib/layer/validate.c
++++ b/lib/layer/validate.c
+@@ -1120,6 +1120,24 @@ static int validate(kr_layer_t *ctx, knot_pkt_t *pkt)
+ 		}
+ 	}
+ 
++	/* Check for too many NSEC3 records.  That's an issue, as some parts of validation
++	 * are quadratic in their count, doing nontrivial computations inside.
++	 * Also there seems to be no use in sending many NSEC3 records. */
++	if (!qry->flags.CACHED) {
++		const knot_pktsection_t *sec = knot_pkt_section(pkt, KNOT_AUTHORITY);
++		int count = 0;
++		for (int i = 0; i < sec->count; ++i)
++			count += (knot_pkt_rr(sec, i)->type == KNOT_RRTYPE_NSEC3);
++		if (count > 8) {
++			VERBOSE_MSG(qry, "<= too many NSEC3 records in AUTHORITY (%d)\n", count);
++			kr_request_set_extended_error(req, KNOT_EDNS_EDE_NSEC3_ITERS,
++				/* It's not about iteration values per se, but close enough. */
++				"DYRH: too many NSEC3 records");
++			qry->flags.DNSSEC_BOGUS = true;
++			return KR_STATE_FAIL;
++		}
++	}
++
+ 	if (knot_wire_get_aa(pkt->wire) && qtype == KNOT_RRTYPE_DNSKEY) {
+ 		const knot_rrset_t *ds = qry->zone_cut.trust_anchor;
+ 		if (ds && !kr_ds_algo_support(ds)) {