From 882903f2fa800c4cb6f5e225b728e2887bb7b9ae Mon Sep 17 00:00:00 2001
From: "W.C.A. Wijngaards" <wouter@nlnetlabs.nl>
Date: Tue, 13 Feb 2024 13:02:08 +0100
Subject: [PATCH] - Fix CVE-2023-50387, CVE-2023-50868

CVE-2023-50387:
DNSSEC verification complexity can be exploited to exhaust CPU resources and stall DNS resolvers.
CVE-2023-50868:
NSEC3 closest encloser proof can exhaust CPU.

---
 services/authzone.c                 |   3 +-
 services/cache/dns.c                |  18 +
 services/cache/dns.h                |   9 +
 testcode/unitverify.c               |   7 +-
 testdata/val_any.rpl                |   3 +
 testdata/val_any_dname.rpl          |   3 +
 testdata/val_nx_nsec3_collision.rpl |   3 +
 util/fptr_wlist.c                   |   1 +
 validator/val_nsec.c                |   3 +-
 validator/val_nsec3.c               | 316 ++++++++++++++----
 validator/val_nsec3.h               |  60 +++-
 validator/val_sigcrypt.c            |  37 +-
 validator/val_sigcrypt.h            |   3 +-
 validator/val_utils.c               |  22 +-
 validator/val_utils.h               |   4 +-
 validator/validator.c               | 500 ++++++++++++++++++++++++----
 validator/validator.h               |  18 +
 17 files changed, 839 insertions(+), 171 deletions(-)

diff --git a/services/authzone.c b/services/authzone.c
index 3898767c..4c63b2e0 100644
--- a/services/authzone.c
+++ b/services/authzone.c
@@ -7767,6 +7767,7 @@ static int zonemd_dnssec_verify_rrset(struct auth_zone* z,
 	enum sec_status sec;
 	struct val_env* ve;
 	int m;
+	int verified = 0;
 	m = modstack_find(mods, "validator");
 	if(m == -1) {
 		auth_zone_log(z->name, VERB_ALGO, "zonemd dnssec verify: have "
@@ -7790,7 +7791,7 @@ static int zonemd_dnssec_verify_rrset(struct auth_zone* z,
 			"zonemd: verify %s RRset with DNSKEY", typestr);
 	}
 	sec = dnskeyset_verify_rrset(env, ve, &pk, dnskey, sigalg, why_bogus, NULL,
-		LDNS_SECTION_ANSWER, NULL);
+		LDNS_SECTION_ANSWER, NULL, &verified);
 	if(sec == sec_status_secure) {
 		return 1;
 	}
diff --git a/services/cache/dns.c b/services/cache/dns.c
index 6fc9919e..1ced1143 100644
--- a/services/cache/dns.c
+++ b/services/cache/dns.c
@@ -703,6 +703,24 @@ tomsg(struct module_env* env, struct query_info* q, struct reply_info* r,
 	return msg;
 }
 
+struct dns_msg*
+dns_msg_deepcopy_region(struct dns_msg* origin, struct regional* region)
+{
+	size_t i;
+	struct dns_msg* res = NULL;
+	res = gen_dns_msg(region, &origin->qinfo, origin->rep->rrset_count);
+	if(!res) return NULL;
+	*res->rep = *origin->rep;
+	for(i=0; i<res->rep->rrset_count; i++) {
+		res->rep->rrsets[i] = packed_rrset_copy_region(
+			origin->rep->rrsets[i], region, 0);
+		if(!res->rep->rrsets[i]) {
+			return NULL;
+		}
+	}
+	return res;
+}
+
 /** synthesize RRset-only response from cached RRset item */
 static struct dns_msg*
 rrset_msg(struct ub_packed_rrset_key* rrset, struct regional* region, 
diff --git a/services/cache/dns.h b/services/cache/dns.h
index 147f992c..c2bf23c6 100644
--- a/services/cache/dns.h
+++ b/services/cache/dns.h
@@ -164,6 +164,15 @@ struct dns_msg* tomsg(struct module_env* env, struct query_info* q,
 	struct reply_info* r, struct regional* region, time_t now,
 	int allow_expired, struct regional* scratch);
 
+/**
+ * Deep copy a dns_msg to a region.
+ * @param origin: the dns_msg to copy.
+ * @param region: the region to copy all the data to.
+ * @return the new dns_msg or NULL on malloc error.
+ */
+struct dns_msg* dns_msg_deepcopy_region(struct dns_msg* origin,
+	struct regional* region);
+
 /** 
  * Find cached message 
  * @param env: module environment with the DNS cache.
diff --git a/testcode/unitverify.c b/testcode/unitverify.c
index ff069a1b..395b4c25 100644
--- a/testcode/unitverify.c
+++ b/testcode/unitverify.c
@@ -180,6 +180,7 @@ verifytest_rrset(struct module_env* env, struct val_env* ve,
 	enum sec_status sec;
 	char* reason = NULL;
 	uint8_t sigalg[ALGO_NEEDS_MAX+1];
+	int verified = 0;
 	if(vsig) {
 		log_nametypeclass(VERB_QUERY, "verify of rrset",
 			rrset->rk.dname, ntohs(rrset->rk.type),
@@ -188,7 +189,7 @@ verifytest_rrset(struct module_env* env, struct val_env* ve,
 	setup_sigalg(dnskey, sigalg); /* check all algorithms in the dnskey */
 	/* ok to give null as qstate here, won't be used for answer section. */
 	sec = dnskeyset_verify_rrset(env, ve, rrset, dnskey, sigalg, &reason, NULL,
-		LDNS_SECTION_ANSWER, NULL);
+		LDNS_SECTION_ANSWER, NULL, &verified);
 	if(vsig) {
 		printf("verify outcome is: %s %s\n", sec_status_to_string(sec),
 			reason?reason:"");
@@ -442,9 +443,9 @@ nsec3_hash_test_entry(struct entry* e, rbtree_type* ct,
 
 	ret = nsec3_hash_name(ct, region, buf, nsec3, 0, qname,
 		qinfo.qname_len, &hash);
-	if(ret != 1) {
+	if(ret < 1) {
 		printf("Bad nsec3_hash_name retcode %d\n", ret);
-		unit_assert(ret == 1);
+		unit_assert(ret == 1 || ret == 2);
 	}
 	unit_assert(hash->dname && hash->hash && hash->hash_len &&
 		hash->b32 && hash->b32_len);
diff --git a/testdata/val_any.rpl b/testdata/val_any.rpl
index 4ce19513..90263af8 100644
--- a/testdata/val_any.rpl
+++ b/testdata/val_any.rpl
@@ -161,6 +161,9 @@ SECTION QUESTION
 example.com. IN ANY
 ENTRY_END
 
+; Allow validation resuming for the RRSIGs
+STEP 2 TIME_PASSES ELAPSE 0.05
+
 ; recursion happens here.
 STEP 10 CHECK_ANSWER
 ENTRY_BEGIN
diff --git a/testdata/val_any_dname.rpl b/testdata/val_any_dname.rpl
index 6ab3cded..dd65e97b 100644
--- a/testdata/val_any_dname.rpl
+++ b/testdata/val_any_dname.rpl
@@ -163,6 +163,9 @@ SECTION QUESTION
 example.com. IN ANY
 ENTRY_END
 
+; Allow validation resuming for the RRSIGs
+STEP 2 TIME_PASSES ELAPSE 0.05
+
 ; recursion happens here.
 STEP 10 CHECK_ANSWER
 ENTRY_BEGIN
diff --git a/testdata/val_nx_nsec3_collision.rpl b/testdata/val_nx_nsec3_collision.rpl
index 8ff7e4b0..87a55f56 100644
--- a/testdata/val_nx_nsec3_collision.rpl
+++ b/testdata/val_nx_nsec3_collision.rpl
@@ -156,6 +156,9 @@ SECTION QUESTION
 www.example.com. IN A
 ENTRY_END
 
+; Allow validation resuming for NSEC3 hash calculations
+STEP 2 TIME_PASSES ELAPSE 0.05
+
 ; recursion happens here.
 STEP 10 CHECK_ANSWER
 ENTRY_BEGIN
diff --git a/util/fptr_wlist.c b/util/fptr_wlist.c
index dc8ab669..00b73253 100644
--- a/util/fptr_wlist.c
+++ b/util/fptr_wlist.c
@@ -131,6 +131,7 @@ fptr_whitelist_comm_timer(void (*fptr)(void*))
 	else if(fptr == &pending_udp_timer_delay_cb) return 1;
 	else if(fptr == &worker_stat_timer_cb) return 1;
 	else if(fptr == &worker_probe_timer_cb) return 1;
+	else if(fptr == &validate_suspend_timer_cb) return 1;
 #ifdef UB_ON_WINDOWS
 	else if(fptr == &wsvc_cron_cb) return 1;
 #endif
diff --git a/validator/val_nsec.c b/validator/val_nsec.c
index 876bfab6..5871db90 100644
--- a/validator/val_nsec.c
+++ b/validator/val_nsec.c
@@ -180,6 +180,7 @@ nsec_verify_rrset(struct module_env* env, struct val_env* ve,
 {
 	struct packed_rrset_data* d = (struct packed_rrset_data*)
 		nsec->entry.data;
+	int verified = 0;
 	if(!d) return 0;
 	if(d->security == sec_status_secure)
 		return 1;
@@ -187,7 +188,7 @@ nsec_verify_rrset(struct module_env* env, struct val_env* ve,
 	if(d->security == sec_status_secure)
 		return 1;
 	d->security = val_verify_rrset_entry(env, ve, nsec, kkey, reason,
-		NULL, LDNS_SECTION_AUTHORITY, qstate);
+		NULL, LDNS_SECTION_AUTHORITY, qstate, &verified);
 	if(d->security == sec_status_secure) {
 		rrset_update_sec_status(env->rrset_cache, nsec, *env->now);
 		return 1;
diff --git a/validator/val_nsec3.c b/validator/val_nsec3.c
index a2b3794f..95d1e4d7 100644
--- a/validator/val_nsec3.c
+++ b/validator/val_nsec3.c
@@ -57,6 +57,19 @@
 /* we include nsec.h for the bitmap_has_type function */
 #include "validator/val_nsec.h"
 #include "sldns/sbuffer.h"
+#include "util/config_file.h"
+
+/**
+ * Max number of NSEC3 calculations at once, suspend query for later.
+ * 8 is low enough and allows for cases where multiple proofs are needed.
+ */
+#define MAX_NSEC3_CALCULATIONS 8
+/**
+ * When all allowed NSEC3 calculations at once resulted in error treat as
+ * bogus. NSEC3 hash errors are not cached and this helps breaks loops with
+ * erroneous data.
+ */
+#define MAX_NSEC3_ERRORS -1
 
 /** 
  * This function we get from ldns-compat or from base system 
@@ -532,6 +545,17 @@ nsec3_hash_cmp(const void* c1, const void* c2)
 	return memcmp(s1, s2, s1len);
 }
 
+int
+nsec3_cache_table_init(struct nsec3_cache_table* ct, struct regional* region)
+{
+	if(ct->ct) return 1;
+	ct->ct = (rbtree_type*)regional_alloc(region, sizeof(*ct->ct));
+	if(!ct->ct) return 0;
+	ct->region = region;
+	rbtree_init(ct->ct, &nsec3_hash_cmp);
+	return 1;
+}
+
 size_t
 nsec3_get_hashed(sldns_buffer* buf, uint8_t* nm, size_t nmlen, int algo, 
 	size_t iter, uint8_t* salt, size_t saltlen, uint8_t* res, size_t max)
@@ -646,7 +670,7 @@ nsec3_hash_name(rbtree_type* table, struct regional* region, sldns_buffer* buf,
 	c = (struct nsec3_cached_hash*)rbtree_search(table, &looki);
 	if(c) {
 		*hash = c;
-		return 1;
+		return 2;
 	}
 	/* create a new entry */
 	c = (struct nsec3_cached_hash*)regional_alloc(region, sizeof(*c));
@@ -658,10 +682,10 @@ nsec3_hash_name(rbtree_type* table, struct regional* region, sldns_buffer* buf,
 	c->dname_len = dname_len;
 	r = nsec3_calc_hash(region, buf, c);
 	if(r != 1)
-		return r;
+		return r;  /* returns -1 or 0 */
 	r = nsec3_calc_b32(region, buf, c);
 	if(r != 1)
-		return r;
+		return r;  /* returns 0 */
 #ifdef UNBOUND_DEBUG
 	n =
 #else
@@ -704,6 +728,7 @@ nsec3_hash_matches_owner(struct nsec3_filter* flt,
 	struct nsec3_cached_hash* hash, struct ub_packed_rrset_key* s)
 {
 	uint8_t* nm = s->rk.dname;
+	if(!hash) return 0; /* please clang */
 	/* compare, does hash of name based on params in this NSEC3
 	 * match the owner name of this NSEC3? 
 	 * name must be: <hashlength>base32 . zone name 
@@ -730,34 +755,50 @@ nsec3_hash_matches_owner(struct nsec3_filter* flt,
  * @param nmlen: length of name.
  * @param rrset: nsec3 that matches is returned here.
  * @param rr: rr number in nsec3 rrset that matches.
+ * @param calculations: current hash calculations.
  * @return true if a matching NSEC3 is found, false if not.
  */
 static int
 find_matching_nsec3(struct module_env* env, struct nsec3_filter* flt,
-	rbtree_type* ct, uint8_t* nm, size_t nmlen, 
-	struct ub_packed_rrset_key** rrset, int* rr)
+	struct nsec3_cache_table* ct, uint8_t* nm, size_t nmlen,
+	struct ub_packed_rrset_key** rrset, int* rr,
+	int* calculations)
 {
 	size_t i_rs;
 	int i_rr;
 	struct ub_packed_rrset_key* s;
 	struct nsec3_cached_hash* hash = NULL;
 	int r;
+	int calc_errors = 0;
 
 	/* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
 	for(s=filter_first(flt, &i_rs, &i_rr); s; 
 		s=filter_next(flt, &i_rs, &i_rr)) {
+		/* check if we are allowed more calculations */
+		if(*calculations >= MAX_NSEC3_CALCULATIONS) {
+			if(calc_errors == *calculations) {
+				*calculations = MAX_NSEC3_ERRORS;
+			}
+			break;
+		}
 		/* get name hashed for this NSEC3 RR */
-		r = nsec3_hash_name(ct, env->scratch, env->scratch_buffer,
+		r = nsec3_hash_name(ct->ct, ct->region, env->scratch_buffer,
 			s, i_rr, nm, nmlen, &hash);
 		if(r == 0) {
 			log_err("nsec3: malloc failure");
 			break; /* alloc failure */
-		} else if(r != 1)
-			continue; /* malformed NSEC3 */
-		else if(nsec3_hash_matches_owner(flt, hash, s)) {
-			*rrset = s; /* rrset with this name */
-			*rr = i_rr; /* matches hash with these parameters */
-			return 1;
+		} else if(r < 0) {
+			/* malformed NSEC3 */
+			calc_errors++;
+			(*calculations)++;
+			continue;
+		} else {
+			if(r == 1) (*calculations)++;
+			if(nsec3_hash_matches_owner(flt, hash, s)) {
+				*rrset = s; /* rrset with this name */
+				*rr = i_rr; /* matches hash with these parameters */
+				return 1;
+			}
 		}
 	}
 	*rrset = NULL;
@@ -775,6 +816,7 @@ nsec3_covers(uint8_t* zone, struct nsec3_cached_hash* hash,
 	if(!nsec3_get_nextowner(rrset, rr, &next, &nextlen))
 		return 0; /* malformed RR proves nothing */
 
+	if(!hash) return 0; /* please clang */
 	/* check the owner name is a hashed value . apex
 	 * base32 encoded values must have equal length. 
 	 * hash_value and next hash value must have equal length. */
@@ -823,35 +865,51 @@ nsec3_covers(uint8_t* zone, struct nsec3_cached_hash* hash,
  * @param nmlen: length of name.
  * @param rrset: covering NSEC3 rrset is returned here.
  * @param rr: rr of cover is returned here.
+ * @param calculations: current hash calculations.
  * @return true if a covering NSEC3 is found, false if not.
  */
 static int
 find_covering_nsec3(struct module_env* env, struct nsec3_filter* flt,
-        rbtree_type* ct, uint8_t* nm, size_t nmlen, 
-	struct ub_packed_rrset_key** rrset, int* rr)
+	struct nsec3_cache_table* ct, uint8_t* nm, size_t nmlen,
+	struct ub_packed_rrset_key** rrset, int* rr,
+	int* calculations)
 {
 	size_t i_rs;
 	int i_rr;
 	struct ub_packed_rrset_key* s;
 	struct nsec3_cached_hash* hash = NULL;
 	int r;
+	int calc_errors = 0;
 
 	/* this loop skips other-zone and unknown NSEC3s, also non-NSEC3 RRs */
 	for(s=filter_first(flt, &i_rs, &i_rr); s; 
 		s=filter_next(flt, &i_rs, &i_rr)) {
+		/* check if we are allowed more calculations */
+		if(*calculations >= MAX_NSEC3_CALCULATIONS) {
+			if(calc_errors == *calculations) {
+				*calculations = MAX_NSEC3_ERRORS;
+			}
+			break;
+		}
 		/* get name hashed for this NSEC3 RR */
-		r = nsec3_hash_name(ct, env->scratch, env->scratch_buffer,
+		r = nsec3_hash_name(ct->ct, ct->region, env->scratch_buffer,
 			s, i_rr, nm, nmlen, &hash);
 		if(r == 0) {
 			log_err("nsec3: malloc failure");
 			break; /* alloc failure */
-		} else if(r != 1)
-			continue; /* malformed NSEC3 */
-		else if(nsec3_covers(flt->zone, hash, s, i_rr, 
-			env->scratch_buffer)) {
-			*rrset = s; /* rrset with this name */
-			*rr = i_rr; /* covers hash with these parameters */
-			return 1;
+		} else if(r < 0) {
+			/* malformed NSEC3 */
+			calc_errors++;
+			(*calculations)++;
+			continue;
+		} else {
+			if(r == 1) (*calculations)++;
+			if(nsec3_covers(flt->zone, hash, s, i_rr,
+				env->scratch_buffer)) {
+				*rrset = s; /* rrset with this name */
+				*rr = i_rr; /* covers hash with these parameters */
+				return 1;
+			}
 		}
 	}
 	*rrset = NULL;
@@ -869,11 +927,13 @@ find_covering_nsec3(struct module_env* env, struct nsec3_filter* flt,
  * @param ct: cached hashes table.
  * @param qinfo: query that is verified for.
  * @param ce: closest encloser information is returned in here.
+ * @param calculations: current hash calculations.
  * @return true if a closest encloser candidate is found, false if not.
  */
 static int
-nsec3_find_closest_encloser(struct module_env* env, struct nsec3_filter* flt, 
-	rbtree_type* ct, struct query_info* qinfo, struct ce_response* ce)
+nsec3_find_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
+	struct nsec3_cache_table* ct, struct query_info* qinfo,
+	struct ce_response* ce, int* calculations)
 {
 	uint8_t* nm = qinfo->qname;
 	size_t nmlen = qinfo->qname_len;
@@ -888,8 +948,12 @@ nsec3_find_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
 	 * may be the case. */
 
 	while(dname_subdomain_c(nm, flt->zone)) {
+		if(*calculations >= MAX_NSEC3_CALCULATIONS ||
+			*calculations == MAX_NSEC3_ERRORS) {
+			return 0;
+		}
 		if(find_matching_nsec3(env, flt, ct, nm, nmlen, 
-			&ce->ce_rrset, &ce->ce_rr)) {
+			&ce->ce_rrset, &ce->ce_rr, calculations)) {
 			ce->ce = nm;
 			ce->ce_len = nmlen;
 			return 1;
@@ -933,22 +997,38 @@ next_closer(uint8_t* qname, size_t qnamelen, uint8_t* ce,
  * 	If set true, and the return value is true, then you can be 
  * 	certain that the ce.nc_rrset and ce.nc_rr are set properly.
  * @param ce: closest encloser information is returned in here.
+ * @param calculations: pointer to the current NSEC3 hash calculations.
  * @return bogus if no closest encloser could be proven.
  * 	secure if a closest encloser could be proven, ce is set.
  * 	insecure if the closest-encloser candidate turns out to prove
  * 		that an insecure delegation exists above the qname.
+ *	unchecked if no more hash calculations are allowed at this point.
  */
 static enum sec_status
-nsec3_prove_closest_encloser(struct module_env* env, struct nsec3_filter* flt, 
-	rbtree_type* ct, struct query_info* qinfo, int prove_does_not_exist,
-	struct ce_response* ce)
+nsec3_prove_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
+	struct nsec3_cache_table* ct, struct query_info* qinfo,
+	int prove_does_not_exist, struct ce_response* ce, int* calculations)
 {
 	uint8_t* nc;
 	size_t nc_len;
 	/* robust: clean out ce, in case it gets abused later */
 	memset(ce, 0, sizeof(*ce));
 
-	if(!nsec3_find_closest_encloser(env, flt, ct, qinfo, ce)) {
+	if(!nsec3_find_closest_encloser(env, flt, ct, qinfo, ce, calculations)) {
+		if(*calculations == MAX_NSEC3_ERRORS) {
+			verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
+				"not find a candidate for the closest "
+				"encloser; all attempted hash calculations "
+				"were erroneous; bogus");
+			return sec_status_bogus;
+		} else if(*calculations >= MAX_NSEC3_CALCULATIONS) {
+			verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
+				"not find a candidate for the closest "
+				"encloser; reached MAX_NSEC3_CALCULATIONS "
+				"(%d); unchecked still",
+				MAX_NSEC3_CALCULATIONS);
+			return sec_status_unchecked;
+		}
 		verbose(VERB_ALGO, "nsec3 proveClosestEncloser: could "
 			"not find a candidate for the closest encloser.");
 		return sec_status_bogus;
@@ -989,9 +1069,23 @@ nsec3_prove_closest_encloser(struct module_env* env, struct nsec3_filter* flt,
 	/* Otherwise, we need to show that the next closer name is covered. */
 	next_closer(qinfo->qname, qinfo->qname_len, ce->ce, &nc, &nc_len);
 	if(!find_covering_nsec3(env, flt, ct, nc, nc_len, 
-		&ce->nc_rrset, &ce->nc_rr)) {
+		&ce->nc_rrset, &ce->nc_rr, calculations)) {
+		if(*calculations == MAX_NSEC3_ERRORS) {
+			verbose(VERB_ALGO, "nsec3: Could not find proof that the "
+				"candidate encloser was the closest encloser; "
+				"all attempted hash calculations were "
+				"erroneous; bogus");
+			return sec_status_bogus;
+		} else if(*calculations >= MAX_NSEC3_CALCULATIONS) {
+			verbose(VERB_ALGO, "nsec3: Could not find proof that the "
+				"candidate encloser was the closest encloser; "
+				"reached MAX_NSEC3_CALCULATIONS (%d); "
+				"unchecked still",
+				MAX_NSEC3_CALCULATIONS);
+			return sec_status_unchecked;
+		}
 		verbose(VERB_ALGO, "nsec3: Could not find proof that the "
-		          "candidate encloser was the closest encloser");
+			"candidate encloser was the closest encloser");
 		return sec_status_bogus;
 	}
 	return sec_status_secure;
@@ -1019,8 +1113,8 @@ nsec3_ce_wildcard(struct regional* region, uint8_t* ce, size_t celen,
 
 /** Do the name error proof */
 static enum sec_status
-nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt, 
-	rbtree_type* ct, struct query_info* qinfo)
+nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
+	struct nsec3_cache_table* ct, struct query_info* qinfo, int* calc)
 {
 	struct ce_response ce;
 	uint8_t* wc;
@@ -1032,11 +1126,15 @@ nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
 	/* First locate and prove the closest encloser to qname. We will 
 	 * use the variant that fails if the closest encloser turns out 
 	 * to be qname. */
-	sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce);
+	sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce, calc);
 	if(sec != sec_status_secure) {
 		if(sec == sec_status_bogus)
 			verbose(VERB_ALGO, "nsec3 nameerror proof: failed "
 				"to prove a closest encloser");
+		else if(sec == sec_status_unchecked)
+			verbose(VERB_ALGO, "nsec3 nameerror proof: will "
+				"continue proving closest encloser after "
+				"suspend");
 		else 	verbose(VERB_ALGO, "nsec3 nameerror proof: closest "
 				"nsec3 is an insecure delegation");
 		return sec;
@@ -1046,9 +1144,27 @@ nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
 	/* At this point, we know that qname does not exist. Now we need 
 	 * to prove that the wildcard does not exist. */
 	log_assert(ce.ce);
-	wc = nsec3_ce_wildcard(env->scratch, ce.ce, ce.ce_len, &wclen);
-	if(!wc || !find_covering_nsec3(env, flt, ct, wc, wclen, 
-		&wc_rrset, &wc_rr)) {
+	wc = nsec3_ce_wildcard(ct->region, ce.ce, ce.ce_len, &wclen);
+	if(!wc) {
+		verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
+			"that the applicable wildcard did not exist.");
+		return sec_status_bogus;
+	}
+	if(!find_covering_nsec3(env, flt, ct, wc, wclen, &wc_rrset, &wc_rr, calc)) {
+		if(*calc == MAX_NSEC3_ERRORS) {
+			verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
+				"that the applicable wildcard did not exist; "
+				"all attempted hash calculations were "
+				"erroneous; bogus");
+			return sec_status_bogus;
+		} else if(*calc >= MAX_NSEC3_CALCULATIONS) {
+			verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
+				"that the applicable wildcard did not exist; "
+				"reached MAX_NSEC3_CALCULATIONS (%d); "
+				"unchecked still",
+				MAX_NSEC3_CALCULATIONS);
+			return sec_status_unchecked;
+		}
 		verbose(VERB_ALGO, "nsec3 nameerror proof: could not prove "
 			"that the applicable wildcard did not exist.");
 		return sec_status_bogus;
@@ -1064,14 +1180,13 @@ nsec3_do_prove_nameerror(struct module_env* env, struct nsec3_filter* flt,
 enum sec_status
 nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num,
-	struct query_info* qinfo, struct key_entry_key* kkey)
+	struct query_info* qinfo, struct key_entry_key* kkey,
+	struct nsec3_cache_table* ct, int* calc)
 {
-	rbtree_type ct;
 	struct nsec3_filter flt;
 
 	if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
 		return sec_status_bogus; /* no valid NSEC3s, bogus */
-	rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
 	filter_init(&flt, list, num, qinfo); /* init RR iterator */
 	if(!flt.zone)
 		return sec_status_bogus; /* no RRs */
@@ -1079,7 +1194,7 @@ nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
 		return sec_status_insecure; /* iteration count too high */
 	log_nametypeclass(VERB_ALGO, "start nsec3 nameerror proof, zone", 
 		flt.zone, 0, 0);
-	return nsec3_do_prove_nameerror(env, &flt, &ct, qinfo);
+	return nsec3_do_prove_nameerror(env, &flt, ct, qinfo, calc);
 }
 
 /* 
@@ -1089,8 +1204,9 @@ nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
 
 /** Do the nodata proof */
 static enum sec_status
-nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt, 
-	rbtree_type* ct, struct query_info* qinfo)
+nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
+	struct nsec3_cache_table* ct, struct query_info* qinfo,
+	int* calc)
 {
 	struct ce_response ce;
 	uint8_t* wc;
@@ -1100,7 +1216,7 @@ nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
 	enum sec_status sec;
 
 	if(find_matching_nsec3(env, flt, ct, qinfo->qname, qinfo->qname_len, 
-		&rrset, &rr)) {
+		&rrset, &rr, calc)) {
 		/* cases 1 and 2 */
 		if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
 			verbose(VERB_ALGO, "proveNodata: Matching NSEC3 "
@@ -1144,11 +1260,23 @@ nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
 		}
 		return sec_status_secure;
 	}
+	if(*calc == MAX_NSEC3_ERRORS) {
+		verbose(VERB_ALGO, "proveNodata: all attempted hash "
+			"calculations were erroneous while finding a matching "
+			"NSEC3, bogus");
+		return sec_status_bogus;
+	} else if(*calc >= MAX_NSEC3_CALCULATIONS) {
+		verbose(VERB_ALGO, "proveNodata: reached "
+			"MAX_NSEC3_CALCULATIONS (%d) while finding a "
+			"matching NSEC3; unchecked still",
+			MAX_NSEC3_CALCULATIONS);
+		return sec_status_unchecked;
+	}
 
 	/* For cases 3 - 5, we need the proven closest encloser, and it 
 	 * can't match qname. Although, at this point, we know that it 
 	 * won't since we just checked that. */
-	sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce);
+	sec = nsec3_prove_closest_encloser(env, flt, ct, qinfo, 1, &ce, calc);
 	if(sec == sec_status_bogus) {
 		verbose(VERB_ALGO, "proveNodata: did not match qname, "
 		          "nor found a proven closest encloser.");
@@ -1157,14 +1285,17 @@ nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
 		verbose(VERB_ALGO, "proveNodata: closest nsec3 is insecure "
 		          "delegation.");
 		return sec_status_insecure;
+	} else if(sec==sec_status_unchecked) {
+		return sec_status_unchecked;
 	}
 
 	/* Case 3: removed */
 
 	/* Case 4: */
 	log_assert(ce.ce);
-	wc = nsec3_ce_wildcard(env->scratch, ce.ce, ce.ce_len, &wclen);
-	if(wc && find_matching_nsec3(env, flt, ct, wc, wclen, &rrset, &rr)) {
+	wc = nsec3_ce_wildcard(ct->region, ce.ce, ce.ce_len, &wclen);
+	if(wc && find_matching_nsec3(env, flt, ct, wc, wclen, &rrset, &rr,
+		calc)) {
 		/* found wildcard */
 		if(nsec3_has_type(rrset, rr, qinfo->qtype)) {
 			verbose(VERB_ALGO, "nsec3 nodata proof: matching "
@@ -1195,6 +1326,18 @@ nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
 		}
 		return sec_status_secure;
 	}
+	if(*calc == MAX_NSEC3_ERRORS) {
+		verbose(VERB_ALGO, "nsec3 nodata proof: all attempted hash "
+			"calculations were erroneous while matching "
+			"wildcard, bogus");
+		return sec_status_bogus;
+	} else if(*calc >= MAX_NSEC3_CALCULATIONS) {
+		verbose(VERB_ALGO, "nsec3 nodata proof: reached "
+			"MAX_NSEC3_CALCULATIONS (%d) while matching "
+			"wildcard, unchecked still",
+			MAX_NSEC3_CALCULATIONS);
+		return sec_status_unchecked;
+	}
 
 	/* Case 5: */
 	/* Due to forwarders, cnames, and other collating effects, we
@@ -1223,28 +1366,27 @@ nsec3_do_prove_nodata(struct module_env* env, struct nsec3_filter* flt,
 enum sec_status
 nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num,
-	struct query_info* qinfo, struct key_entry_key* kkey)
+	struct query_info* qinfo, struct key_entry_key* kkey,
+	struct nsec3_cache_table* ct, int* calc)
 {
-	rbtree_type ct;
 	struct nsec3_filter flt;
 
 	if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
 		return sec_status_bogus; /* no valid NSEC3s, bogus */
-	rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
 	filter_init(&flt, list, num, qinfo); /* init RR iterator */
 	if(!flt.zone)
 		return sec_status_bogus; /* no RRs */
 	if(nsec3_iteration_count_high(ve, &flt, kkey))
 		return sec_status_insecure; /* iteration count too high */
-	return nsec3_do_prove_nodata(env, &flt, &ct, qinfo);
+	return nsec3_do_prove_nodata(env, &flt, ct, qinfo, calc);
 }
 
 enum sec_status
 nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
         struct ub_packed_rrset_key** list, size_t num,
-	struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc)
+	struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc,
+	struct nsec3_cache_table* ct, int* calc)
 {
-	rbtree_type ct;
 	struct nsec3_filter flt;
 	struct ce_response ce;
 	uint8_t* nc;
@@ -1254,7 +1396,6 @@ nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
 
 	if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
 		return sec_status_bogus; /* no valid NSEC3s, bogus */
-	rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
 	filter_init(&flt, list, num, qinfo); /* init RR iterator */
 	if(!flt.zone)
 		return sec_status_bogus; /* no RRs */
@@ -1272,8 +1413,22 @@ nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
 	/* Now we still need to prove that the original data did not exist.
 	 * Otherwise, we need to show that the next closer name is covered. */
 	next_closer(qinfo->qname, qinfo->qname_len, ce.ce, &nc, &nc_len);
-	if(!find_covering_nsec3(env, &flt, &ct, nc, nc_len, 
-		&ce.nc_rrset, &ce.nc_rr)) {
+	if(!find_covering_nsec3(env, &flt, ct, nc, nc_len,
+		&ce.nc_rrset, &ce.nc_rr, calc)) {
+		if(*calc == MAX_NSEC3_ERRORS) {
+			verbose(VERB_ALGO, "proveWildcard: did not find a "
+				"covering NSEC3 that covered the next closer "
+				"name; all attempted hash calculations were "
+				"erroneous; bogus");
+			return sec_status_bogus;
+		} else if(*calc >= MAX_NSEC3_CALCULATIONS) {
+			verbose(VERB_ALGO, "proveWildcard: did not find a "
+				"covering NSEC3 that covered the next closer "
+				"name; reached MAX_NSEC3_CALCULATIONS "
+				"(%d); unchecked still",
+				MAX_NSEC3_CALCULATIONS);
+			return sec_status_unchecked;
+		}
 		verbose(VERB_ALGO, "proveWildcard: did not find a covering "
 			"NSEC3 that covered the next closer name.");
 		return sec_status_bogus;
@@ -1294,6 +1449,7 @@ list_is_secure(struct module_env* env, struct val_env* ve,
 {
 	struct packed_rrset_data* d;
 	size_t i;
+	int verified = 0;
 	for(i=0; i<num; i++) {
 		d = (struct packed_rrset_data*)list[i]->entry.data;
 		if(list[i]->rk.type != htons(LDNS_RR_TYPE_NSEC3))
@@ -1304,7 +1460,8 @@ list_is_secure(struct module_env* env, struct val_env* ve,
 		if(d->security == sec_status_secure)
 			continue;
 		d->security = val_verify_rrset_entry(env, ve, list[i], kkey,
-			reason, reason_bogus, LDNS_SECTION_AUTHORITY, qstate);
+			reason, reason_bogus, LDNS_SECTION_AUTHORITY, qstate,
+			&verified);
 		if(d->security != sec_status_secure) {
 			verbose(VERB_ALGO, "NSEC3 did not verify");
 			return 0;
@@ -1318,13 +1475,16 @@ enum sec_status
 nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num,
 	struct query_info* qinfo, struct key_entry_key* kkey, char** reason,
-	sldns_ede_code* reason_bogus, struct module_qstate* qstate)
+	sldns_ede_code* reason_bogus, struct module_qstate* qstate,
+	struct nsec3_cache_table* ct)
 {
-	rbtree_type ct;
 	struct nsec3_filter flt;
 	struct ce_response ce;
 	struct ub_packed_rrset_key* rrset;
 	int rr;
+	int calc = 0;
+	enum sec_status sec;
+
 	log_assert(qinfo->qtype == LDNS_RR_TYPE_DS);
 
 	if(!list || num == 0 || !kkey || !key_entry_isgood(kkey)) {
@@ -1335,7 +1495,6 @@ nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 		*reason = "not all NSEC3 records secure";
 		return sec_status_bogus; /* not all NSEC3 records secure */
 	}
-	rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
 	filter_init(&flt, list, num, qinfo); /* init RR iterator */
 	if(!flt.zone) {
 		*reason = "no NSEC3 records";
@@ -1346,8 +1505,8 @@ nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 
 	/* Look for a matching NSEC3 to qname -- this is the normal 
 	 * NODATA case. */
-	if(find_matching_nsec3(env, &flt, &ct, qinfo->qname, qinfo->qname_len, 
-		&rrset, &rr)) {
+	if(find_matching_nsec3(env, &flt, ct, qinfo->qname, qinfo->qname_len,
+		&rrset, &rr, &calc)) {
 		/* If the matching NSEC3 has the SOA bit set, it is from 
 		 * the wrong zone (the child instead of the parent). If 
 		 * it has the DS bit set, then we were lied to. */
@@ -1370,10 +1529,24 @@ nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 		/* Otherwise, this proves no DS. */
 		return sec_status_secure;
 	}
+	if(calc == MAX_NSEC3_ERRORS) {
+		verbose(VERB_ALGO, "nsec3 provenods: all attempted hash "
+			"calculations were erroneous while finding a matching "
+			"NSEC3, bogus");
+		return sec_status_bogus;
+	} else if(calc >= MAX_NSEC3_CALCULATIONS) {
+		verbose(VERB_ALGO, "nsec3 provenods: reached "
+			"MAX_NSEC3_CALCULATIONS (%d) while finding a "
+			"matching NSEC3, unchecked still",
+			MAX_NSEC3_CALCULATIONS);
+		return sec_status_unchecked;
+	}
 
 	/* Otherwise, we are probably in the opt-out case. */
-	if(nsec3_prove_closest_encloser(env, &flt, &ct, qinfo, 1, &ce)
-		!= sec_status_secure) {
+	sec = nsec3_prove_closest_encloser(env, &flt, ct, qinfo, 1, &ce, &calc);
+	if(sec == sec_status_unchecked) {
+		return sec_status_unchecked;
+	} else if(sec != sec_status_secure) {
 		/* an insecure delegation *above* the qname does not prove
 		 * anything about this qname exactly, and bogus is bogus */
 		verbose(VERB_ALGO, "nsec3 provenods: did not match qname, "
@@ -1407,17 +1580,16 @@ nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 
 enum sec_status
 nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
-	struct ub_packed_rrset_key** list, size_t num, 
-	struct query_info* qinfo, struct key_entry_key* kkey, int* nodata)
+	struct ub_packed_rrset_key** list, size_t num,
+	struct query_info* qinfo, struct key_entry_key* kkey, int* nodata,
+	struct  nsec3_cache_table* ct, int* calc)
 {
 	enum sec_status sec, secnx;
-	rbtree_type ct;
 	struct nsec3_filter flt;
 	*nodata = 0;
 
 	if(!list || num == 0 || !kkey || !key_entry_isgood(kkey))
 		return sec_status_bogus; /* no valid NSEC3s, bogus */
-	rbtree_init(&ct, &nsec3_hash_cmp); /* init names-to-hash cache */
 	filter_init(&flt, list, num, qinfo); /* init RR iterator */
 	if(!flt.zone)
 		return sec_status_bogus; /* no RRs */
@@ -1427,16 +1599,20 @@ nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
 	/* try nxdomain and nodata after another, while keeping the
 	 * hash cache intact */
 
-	secnx = nsec3_do_prove_nameerror(env, &flt, &ct, qinfo);
+	secnx = nsec3_do_prove_nameerror(env, &flt, ct, qinfo, calc);
 	if(secnx==sec_status_secure)
 		return sec_status_secure;
-	sec = nsec3_do_prove_nodata(env, &flt, &ct, qinfo);
+	else if(secnx == sec_status_unchecked)
+		return sec_status_unchecked;
+	sec = nsec3_do_prove_nodata(env, &flt, ct, qinfo, calc);
 	if(sec==sec_status_secure) {
 		*nodata = 1;
 	} else if(sec == sec_status_insecure) {
 		*nodata = 1;
 	} else if(secnx == sec_status_insecure) {
 		sec = sec_status_insecure;
+	} else if(sec == sec_status_unchecked) {
+		return sec_status_unchecked;
 	}
 	return sec;
 }
diff --git a/validator/val_nsec3.h b/validator/val_nsec3.h
index 7676fc8b..8ca91293 100644
--- a/validator/val_nsec3.h
+++ b/validator/val_nsec3.h
@@ -98,6 +98,15 @@ struct sldns_buffer;
 /** The SHA1 hash algorithm for NSEC3 */
 #define NSEC3_HASH_SHA1	0x01
 
+/**
+* Cache table for NSEC3 hashes.
+* It keeps a *pointer* to the region its items are allocated.
+*/
+struct nsec3_cache_table {
+	rbtree_type* ct;
+	struct regional* region;
+};
+
 /**
  * Determine if the set of NSEC3 records provided with a response prove NAME
  * ERROR. This means that the NSEC3s prove a) the closest encloser exists,
@@ -110,14 +119,18 @@ struct sldns_buffer;
  * @param num: number of RRsets in the array to examine.
  * @param qinfo: query that is verified for.
  * @param kkey: key entry that signed the NSEC3s.
+ * @param ct: cached hashes table.
+ * @param calc: current hash calculations.
  * @return:
  * 	sec_status SECURE of the Name Error is proven by the NSEC3 RRs, 
- * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
+ * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored,
+ * 	UNCHECKED if no more hash calculations are allowed at this point.
  */
 enum sec_status
 nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num, 
-	struct query_info* qinfo, struct key_entry_key* kkey);
+	struct query_info* qinfo, struct key_entry_key* kkey,
+	struct nsec3_cache_table* ct, int* calc);
 
 /**
  * Determine if the NSEC3s provided in a response prove the NOERROR/NODATA
@@ -144,15 +157,18 @@ nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
  * @param num: number of RRsets in the array to examine.
  * @param qinfo: query that is verified for.
  * @param kkey: key entry that signed the NSEC3s.
+ * @param ct: cached hashes table.
+ * @param calc: current hash calculations.
  * @return:
  * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs, 
- * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
+ * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored,
+ * 	UNCHECKED if no more hash calculations are allowed at this point.
  */
 enum sec_status
 nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num, 
-	struct query_info* qinfo, struct key_entry_key* kkey);
-
+	struct query_info* qinfo, struct key_entry_key* kkey,
+	struct nsec3_cache_table* ct, int* calc);
 
 /**
  * Prove that a positive wildcard match was appropriate (no direct match
@@ -166,14 +182,18 @@ nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
  * @param kkey: key entry that signed the NSEC3s.
  * @param wc: The purported wildcard that matched. This is the wildcard name
  * 	as *.wildcard.name., with the *. label already removed.
+ * @param ct: cached hashes table.
+ * @param calc: current hash calculations.
  * @return:
  * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs, 
- * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
+ * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored,
+ * 	UNCHECKED if no more hash calculations are allowed at this point.
  */
 enum sec_status
 nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num, 
-	struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc);
+	struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc,
+	struct nsec3_cache_table* ct, int* calc);
 
 /**
  * Prove that a DS response either had no DS, or wasn't a delegation point.
@@ -189,17 +209,20 @@ nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
  * @param reason: string for bogus result.
  * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure.
  * @param qstate: qstate with region.
+ * @param ct: cached hashes table.
  * @return:
  * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs, 
  * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
  * 	or if there was no DS in an insecure (i.e., opt-in) way,
- * 	INDETERMINATE if it was clear that this wasn't a delegation point.
+ * 	INDETERMINATE if it was clear that this wasn't a delegation point,
+ * 	UNCHECKED if no more hash calculations are allowed at this point.
  */
 enum sec_status
 nsec3_prove_nods(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num, 
 	struct query_info* qinfo, struct key_entry_key* kkey, char** reason,
-	sldns_ede_code* reason_bogus, struct module_qstate* qstate);
+	sldns_ede_code* reason_bogus, struct module_qstate* qstate,
+	struct nsec3_cache_table* ct);
 
 /**
  * Prove NXDOMAIN or NODATA.
@@ -212,14 +235,18 @@ nsec3_prove_nods(struct module_env* env, struct val_env* ve,
  * @param kkey: key entry that signed the NSEC3s.
  * @param nodata: if return value is secure, this indicates if nodata or
  * 	nxdomain was proven.
+ * @param ct: cached hashes table.
+ * @param calc: current hash calculations.
  * @return:
  * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs, 
- * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
+ * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored,
+ * 	UNCHECKED if no more hash calculations are allowed at this point.
  */
 enum sec_status
 nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key** list, size_t num, 
-	struct query_info* qinfo, struct key_entry_key* kkey, int* nodata);
+	struct query_info* qinfo, struct key_entry_key* kkey, int* nodata,
+	struct nsec3_cache_table* ct, int* calc);
 
 /**
  * The NSEC3 hash result storage.
@@ -256,6 +283,14 @@ struct nsec3_cached_hash {
  */
 int nsec3_hash_cmp(const void* c1, const void* c2);
 
+/**
+ * Initialise the NSEC3 cache table.
+ * @param ct: the nsec3 cache table.
+ * @param region: the region where allocations for the table will happen.
+ * @return true on success, false on malloc error.
+ */
+int nsec3_cache_table_init(struct nsec3_cache_table* ct, struct regional* region);
+
 /**
  * Obtain the hash of an owner name.
  * Used internally by the nsec3 proof functions in this file.
@@ -272,7 +307,8 @@ int nsec3_hash_cmp(const void* c1, const void* c2);
  * @param dname_len: the length of the name.
  * @param hash: the hash node is returned on success.
  * @return:
- * 	1 on success, either from cache or newly hashed hash is returned.
+ * 	2 on success, hash from cache is returned.
+ * 	1 on success, newly computed hash is returned.
  * 	0 on a malloc failure.
  * 	-1 if the NSEC3 rr was badly formatted (i.e. formerr).
  */
diff --git a/validator/val_sigcrypt.c b/validator/val_sigcrypt.c
index 5ab21e20..8600a682 100644
--- a/validator/val_sigcrypt.c
+++ b/validator/val_sigcrypt.c
@@ -78,6 +78,9 @@
 #include <openssl/engine.h>
 #endif
 
+/** Maximum number of RRSIG validations for an RRset. */
+#define MAX_VALIDATE_RRSIGS 8
+
 /** return number of rrs in an rrset */
 static size_t
 rrset_get_count(struct ub_packed_rrset_key* rrset)
@@ -541,6 +544,8 @@ int algo_needs_missing(struct algo_needs* n)
  * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure.
  * @param section: section of packet where this rrset comes from.
  * @param qstate: qstate with region.
+ * @param numverified: incremented when the number of RRSIG validations
+ * 	increases.
  * @return secure if any key signs *this* signature. bogus if no key signs it,
  *	unchecked on error, or indeterminate if all keys are not supported by
  *	the crypto library (openssl3+ only).
@@ -551,7 +556,8 @@ dnskeyset_verify_rrset_sig(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key* dnskey, size_t sig_idx,
 	struct rbtree_type** sortree,
 	char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate)
+	sldns_pkt_section section, struct module_qstate* qstate,
+	int* numverified)
 {
 	/* find matching keys and check them */
 	enum sec_status sec = sec_status_bogus;
@@ -575,6 +581,7 @@ dnskeyset_verify_rrset_sig(struct module_env* env, struct val_env* ve,
 			tag != dnskey_calc_keytag(dnskey, i))
 			continue;
 		numchecked ++;
+		(*numverified)++;
 
 		/* see if key verifies */
 		sec = dnskey_verify_rrset_sig(env->scratch,
@@ -585,6 +592,13 @@ dnskeyset_verify_rrset_sig(struct module_env* env, struct val_env* ve,
 			return sec;
 		else if(sec == sec_status_indeterminate)
 			numindeterminate ++;
+		if(*numverified > MAX_VALIDATE_RRSIGS) {
+			*reason = "too many RRSIG validations";
+			if(reason_bogus)
+				*reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
+			verbose(VERB_ALGO, "verify sig: too many RRSIG validations");
+			return sec_status_bogus;
+		}
 	}
 	if(numchecked == 0) {
 		*reason = "signatures from unknown keys";
@@ -608,7 +622,7 @@ enum sec_status
 dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
 	struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
 	uint8_t* sigalg, char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate)
+	sldns_pkt_section section, struct module_qstate* qstate, int* verified)
 {
 	enum sec_status sec;
 	size_t i, num;
@@ -616,6 +630,7 @@ dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
 	/* make sure that for all DNSKEY algorithms there are valid sigs */
 	struct algo_needs needs;
 	int alg;
+	*verified = 0;
 
 	num = rrset_get_sigcount(rrset);
 	if(num == 0) {
@@ -640,7 +655,7 @@ dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
 	for(i=0; i<num; i++) {
 		sec = dnskeyset_verify_rrset_sig(env, ve, *env->now, rrset, 
 			dnskey, i, &sortree, reason, reason_bogus,
-			section, qstate);
+			section, qstate, verified);
 		/* see which algorithm has been fixed up */
 		if(sec == sec_status_secure) {
 			if(!sigalg)
@@ -652,6 +667,13 @@ dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
 			algo_needs_set_bogus(&needs,
 				(uint8_t)rrset_get_sig_algo(rrset, i));
 		}
+		if(*verified > MAX_VALIDATE_RRSIGS) {
+			verbose(VERB_QUERY, "rrset failed to verify, too many RRSIG validations");
+			*reason = "too many RRSIG validations";
+			if(reason_bogus)
+				*reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
+			return sec_status_bogus;
+		}
 	}
 	if(sigalg && (alg=algo_needs_missing(&needs)) != 0) {
 		verbose(VERB_ALGO, "rrset failed to verify: "
@@ -690,6 +712,7 @@ dnskey_verify_rrset(struct module_env* env, struct val_env* ve,
 	int buf_canon = 0;
 	uint16_t tag = dnskey_calc_keytag(dnskey, dnskey_idx);
 	int algo = dnskey_get_algo(dnskey, dnskey_idx);
+	int numverified = 0;
 
 	num = rrset_get_sigcount(rrset);
 	if(num == 0) {
@@ -713,8 +736,16 @@ dnskey_verify_rrset(struct module_env* env, struct val_env* ve,
 		if(sec == sec_status_secure)
 			return sec;
 		numchecked ++;
+		numverified ++;
 		if(sec == sec_status_indeterminate)
 			numindeterminate ++;
+		if(numverified > MAX_VALIDATE_RRSIGS) {
+			verbose(VERB_QUERY, "rrset failed to verify, too many RRSIG validations");
+			*reason = "too many RRSIG validations";
+			if(reason_bogus)
+				*reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
+			return sec_status_bogus;
+		}
 	}
 	verbose(VERB_ALGO, "rrset failed to verify: all signatures are bogus");
 	if(!numchecked) {
diff --git a/validator/val_sigcrypt.h b/validator/val_sigcrypt.h
index 7f52b71e..1a3d8fcb 100644
--- a/validator/val_sigcrypt.h
+++ b/validator/val_sigcrypt.h
@@ -260,6 +260,7 @@ uint16_t dnskey_get_flags(struct ub_packed_rrset_key* k, size_t idx);
  * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure.
  * @param section: section of packet where this rrset comes from.
  * @param qstate: qstate with region.
+ * @param verified: if not NULL the number of RRSIG validations is returned.
  * @return SECURE if one key in the set verifies one rrsig.
  *	UNCHECKED on allocation errors, unsupported algorithms, malformed data,
  *	and BOGUS on verification failures (no keys match any signatures).
@@ -268,7 +269,7 @@ enum sec_status dnskeyset_verify_rrset(struct module_env* env,
 	struct val_env* ve, struct ub_packed_rrset_key* rrset, 
 	struct ub_packed_rrset_key* dnskey, uint8_t* sigalg,
 	char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate);
+	sldns_pkt_section section, struct module_qstate* qstate, int* verified);
 
 
 /** 
diff --git a/validator/val_utils.c b/validator/val_utils.c
index e2319ee2..cb37ea00 100644
--- a/validator/val_utils.c
+++ b/validator/val_utils.c
@@ -58,6 +58,10 @@
 #include "sldns/wire2str.h"
 #include "sldns/parseutil.h"
 
+/** Maximum allowed digest match failures per DS, for DNSKEYs with the same
+ *  properties */
+#define MAX_DS_MATCH_FAILURES 4
+
 enum val_classification 
 val_classify_response(uint16_t query_flags, struct query_info* origqinf,
 	struct query_info* qinf, struct reply_info* rep, size_t skip)
@@ -336,7 +340,8 @@ static enum sec_status
 val_verify_rrset(struct module_env* env, struct val_env* ve,
         struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* keys,
 	uint8_t* sigalg, char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate)
+	sldns_pkt_section section, struct module_qstate* qstate,
+	int *verified)
 {
 	enum sec_status sec;
 	struct packed_rrset_data* d = (struct packed_rrset_data*)rrset->
@@ -346,6 +351,7 @@ val_verify_rrset(struct module_env* env, struct val_env* ve,
 		log_nametypeclass(VERB_ALGO, "verify rrset cached", 
 			rrset->rk.dname, ntohs(rrset->rk.type), 
 			ntohs(rrset->rk.rrset_class));
+		*verified = 0;
 		return d->security;
 	}
 	/* check in the cache if verification has already been done */
@@ -354,12 +360,13 @@ val_verify_rrset(struct module_env* env, struct val_env* ve,
 		log_nametypeclass(VERB_ALGO, "verify rrset from cache", 
 			rrset->rk.dname, ntohs(rrset->rk.type), 
 			ntohs(rrset->rk.rrset_class));
+		*verified = 0;
 		return d->security;
 	}
 	log_nametypeclass(VERB_ALGO, "verify rrset", rrset->rk.dname,
 		ntohs(rrset->rk.type), ntohs(rrset->rk.rrset_class));
 	sec = dnskeyset_verify_rrset(env, ve, rrset, keys, sigalg, reason,
-		reason_bogus, section, qstate);
+		reason_bogus, section, qstate, verified);
 	verbose(VERB_ALGO, "verify result: %s", sec_status_to_string(sec));
 	regional_free_all(env->scratch);
 
@@ -393,7 +400,8 @@ enum sec_status
 val_verify_rrset_entry(struct module_env* env, struct val_env* ve,
         struct ub_packed_rrset_key* rrset, struct key_entry_key* kkey,
 	char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate)
+	sldns_pkt_section section, struct module_qstate* qstate,
+	int* verified)
 {
 	/* temporary dnskey rrset-key */
 	struct ub_packed_rrset_key dnskey;
@@ -407,7 +415,7 @@ val_verify_rrset_entry(struct module_env* env, struct val_env* ve,
 	dnskey.entry.key = &dnskey;
 	dnskey.entry.data = kd->rrset_data;
 	sec = val_verify_rrset(env, ve, rrset, &dnskey, kd->algo, reason,
-		reason_bogus, section, qstate);
+		reason_bogus, section, qstate, verified);
 	return sec;
 }
 
@@ -439,6 +447,12 @@ verify_dnskeys_with_ds_rr(struct module_env* env, struct val_env* ve,
 		if(!ds_digest_match_dnskey(env, dnskey_rrset, i, ds_rrset, 
 			ds_idx)) {
 			verbose(VERB_ALGO, "DS match attempt failed");
+			if(numchecked > numhashok + MAX_DS_MATCH_FAILURES) {
+				verbose(VERB_ALGO, "DS match attempt reached "
+					"MAX_DS_MATCH_FAILURES (%d); bogus",
+					MAX_DS_MATCH_FAILURES);
+				return sec_status_bogus;
+			}
 			continue;
 		}
 		numhashok++;
diff --git a/validator/val_utils.h b/validator/val_utils.h
index 83e3d0ad..e8cdcefa 100644
--- a/validator/val_utils.h
+++ b/validator/val_utils.h
@@ -124,12 +124,14 @@ void val_find_signer(enum val_classification subtype,
  * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure.
  * @param section: section of packet where this rrset comes from.
  * @param qstate: qstate with region.
+ * @param verified: if not NULL, the number of RRSIG validations is returned.
  * @return security status of verification.
  */
 enum sec_status val_verify_rrset_entry(struct module_env* env, 
 	struct val_env* ve, struct ub_packed_rrset_key* rrset, 
 	struct key_entry_key* kkey, char** reason, sldns_ede_code *reason_bogus,
-	sldns_pkt_section section, struct module_qstate* qstate);
+	sldns_pkt_section section, struct module_qstate* qstate,
+	int* verified);
 
 /**
  * Verify DNSKEYs with DS rrset. Like val_verify_new_DNSKEYs but
diff --git a/validator/validator.c b/validator/validator.c
index 1723afef..f1f7be34 100644
--- a/validator/validator.c
+++ b/validator/validator.c
@@ -64,10 +64,15 @@
 #include "sldns/wire2str.h"
 #include "sldns/str2wire.h"
 
+/** Max number of RRSIGs to validate at once, suspend query for later. */
+#define MAX_VALIDATE_AT_ONCE 8
+/** Max number of validation suspends allowed, error out otherwise. */
+#define MAX_VALIDATION_SUSPENDS 16
+
 /* forward decl for cache response and normal super inform calls of a DS */
 static void process_ds_response(struct module_qstate* qstate, 
 	struct val_qstate* vq, int id, int rcode, struct dns_msg* msg, 
-	struct query_info* qinfo, struct sock_list* origin);
+	struct query_info* qinfo, struct sock_list* origin, int* suspend);
 
 
 /* Updates the suplied EDE (RFC8914) code selectively so we don't loose
@@ -281,6 +286,21 @@ val_new(struct module_qstate* qstate, int id)
 	return val_new_getmsg(qstate, vq);
 }
 
+/** reset validator query state for query restart */
+static void
+val_restart(struct val_qstate* vq)
+{
+	struct comm_timer* temp_timer;
+	int restart_count;
+	if(!vq) return;
+	temp_timer = vq->suspend_timer;
+	restart_count = vq->restart_count+1;
+	memset(vq, 0, sizeof(*vq));
+	vq->suspend_timer = temp_timer;
+	vq->restart_count = restart_count;
+	vq->state = VAL_INIT_STATE;
+}
+
 /**
  * Exit validation with an error status
  * 
@@ -587,30 +607,42 @@ prime_trust_anchor(struct module_qstate* qstate, struct val_qstate* vq,
  * completed.
  * 
  * @param qstate: query state.
+ * @param vq: validator query state.
  * @param env: module env for verify.
  * @param ve: validator env for verify.
  * @param qchase: query that was made.
  * @param chase_reply: answer to validate.
  * @param key_entry: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  * @return false if any of the rrsets in the an or ns sections of the message 
  * 	fail to verify. The message is then set to bogus.
  */
 static int
-validate_msg_signatures(struct module_qstate* qstate, struct module_env* env,
-	struct val_env* ve, struct query_info* qchase,
-	struct reply_info* chase_reply, struct key_entry_key* key_entry)
+validate_msg_signatures(struct module_qstate* qstate, struct val_qstate* vq,
+	struct module_env* env, struct val_env* ve, struct query_info* qchase,
+	struct reply_info* chase_reply, struct key_entry_key* key_entry,
+	int* suspend)
 {
 	uint8_t* sname;
 	size_t i, slen;
 	struct ub_packed_rrset_key* s;
 	enum sec_status sec;
-	int dname_seen = 0;
+	int dname_seen = 0, num_verifies = 0, verified, have_state = 0;
 	char* reason = NULL;
 	sldns_ede_code reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
+	*suspend = 0;
+	if(vq->msg_signatures_state) {
+		/* Pick up the state, and reset it, may not be needed now. */
+		vq->msg_signatures_state = 0;
+		have_state = 1;
+	}
 
 	/* validate the ANSWER section */
 	for(i=0; i<chase_reply->an_numrrsets; i++) {
+		if(have_state && i <= vq->msg_signatures_index)
+			continue;
 		s = chase_reply->rrsets[i];
 		/* Skip the CNAME following a (validated) DNAME.
 		 * Because of the normalization routines in the iterator, 
@@ -629,7 +661,7 @@ validate_msg_signatures(struct module_qstate* qstate, struct module_env* env,
 
 		/* Verify the answer rrset */
 		sec = val_verify_rrset_entry(env, ve, s, key_entry, &reason,
-			&reason_bogus, LDNS_SECTION_ANSWER, qstate);
+			&reason_bogus, LDNS_SECTION_ANSWER, qstate, &verified);
 		/* If the (answer) rrset failed to validate, then this 
 		 * message is BAD. */
 		if(sec != sec_status_secure) {
@@ -654,14 +686,33 @@ validate_msg_signatures(struct module_qstate* qstate, struct module_env* env,
 			ntohs(s->rk.type) == LDNS_RR_TYPE_DNAME) {
 			dname_seen = 1;
 		}
+		num_verifies += verified;
+		if(num_verifies > MAX_VALIDATE_AT_ONCE &&
+			i+1 < (env->cfg->val_clean_additional?
+			chase_reply->an_numrrsets+chase_reply->ns_numrrsets:
+			chase_reply->rrset_count)) {
+			/* If the number of RRSIGs exceeds the maximum in
+			 * one go, suspend. Only suspend if there is a next
+			 * rrset to verify, i+1<loopmax. Store where to
+			 * continue later. */
+			*suspend = 1;
+			vq->msg_signatures_state = 1;
+			vq->msg_signatures_index = i;
+			verbose(VERB_ALGO, "msg signature validation "
+				"suspended");
+			return 0;
+		}
 	}
 
 	/* validate the AUTHORITY section */
 	for(i=chase_reply->an_numrrsets; i<chase_reply->an_numrrsets+
 		chase_reply->ns_numrrsets; i++) {
+		if(have_state && i <= vq->msg_signatures_index)
+			continue;
 		s = chase_reply->rrsets[i];
 		sec = val_verify_rrset_entry(env, ve, s, key_entry, &reason,
-			&reason_bogus, LDNS_SECTION_AUTHORITY, qstate);
+			&reason_bogus, LDNS_SECTION_AUTHORITY, qstate,
+			&verified);
 		/* If anything in the authority section fails to be secure, 
 		 * we have a bad message. */
 		if(sec != sec_status_secure) {
@@ -675,6 +726,18 @@ validate_msg_signatures(struct module_qstate* qstate, struct module_env* env,
 			update_reason_bogus(chase_reply, reason_bogus);
 			return 0;
 		}
+		num_verifies += verified;
+		if(num_verifies > MAX_VALIDATE_AT_ONCE &&
+			i+1 < (env->cfg->val_clean_additional?
+			chase_reply->an_numrrsets+chase_reply->ns_numrrsets:
+			chase_reply->rrset_count)) {
+			*suspend = 1;
+			vq->msg_signatures_state = 1;
+			vq->msg_signatures_index = i;
+			verbose(VERB_ALGO, "msg signature validation "
+				"suspended");
+			return 0;
+		}
 	}
 
 	/* If set, the validator should clean the additional section of
@@ -684,22 +747,103 @@ validate_msg_signatures(struct module_qstate* qstate, struct module_env* env,
 	/* attempt to validate the ADDITIONAL section rrsets */
 	for(i=chase_reply->an_numrrsets+chase_reply->ns_numrrsets; 
 		i<chase_reply->rrset_count; i++) {
+		if(have_state && i <= vq->msg_signatures_index)
+			continue;
 		s = chase_reply->rrsets[i];
 		/* only validate rrs that have signatures with the key */
 		/* leave others unchecked, those get removed later on too */
 		val_find_rrset_signer(s, &sname, &slen);
 
+		verified = 0;
 		if(sname && query_dname_compare(sname, key_entry->name)==0)
 			(void)val_verify_rrset_entry(env, ve, s, key_entry,
-				&reason, NULL, LDNS_SECTION_ADDITIONAL, qstate);
+				&reason, NULL, LDNS_SECTION_ADDITIONAL, qstate,
+				&verified);
 		/* the additional section can fail to be secure, 
 		 * it is optional, check signature in case we need
 		 * to clean the additional section later. */
+		num_verifies += verified;
+		if(num_verifies > MAX_VALIDATE_AT_ONCE &&
+			i+1 < chase_reply->rrset_count) {
+			*suspend = 1;
+			vq->msg_signatures_state = 1;
+			vq->msg_signatures_index = i;
+			verbose(VERB_ALGO, "msg signature validation "
+				"suspended");
+			return 0;
+		}
 	}
 
 	return 1;
 }
 
+void
+validate_suspend_timer_cb(void* arg)
+{
+	struct module_qstate* qstate = (struct module_qstate*)arg;
+	verbose(VERB_ALGO, "validate_suspend timer, continue");
+	mesh_run(qstate->env->mesh, qstate->mesh_info, module_event_pass,
+		NULL);
+}
+
+/** Setup timer to continue validation of msg signatures later */
+static int
+validate_suspend_setup_timer(struct module_qstate* qstate,
+	struct val_qstate* vq, int id, enum val_state resume_state)
+{
+	struct timeval tv;
+	int usec, slack, base;
+	if(vq->suspend_count >= MAX_VALIDATION_SUSPENDS) {
+		verbose(VERB_ALGO, "validate_suspend timer: "
+			"reached MAX_VALIDATION_SUSPENDS (%d); error out",
+			MAX_VALIDATION_SUSPENDS);
+		errinf(qstate, "max validation suspends reached, "
+			"too many RRSIG validations");
+		return 0;
+	}
+	verbose(VERB_ALGO, "validate_suspend timer, set for suspend");
+	vq->state = resume_state;
+	qstate->ext_state[id] = module_wait_reply;
+	if(!vq->suspend_timer) {
+		vq->suspend_timer = comm_timer_create(
+			qstate->env->worker_base,
+			validate_suspend_timer_cb, qstate);
+		if(!vq->suspend_timer) {
+			log_err("validate_suspend_setup_timer: "
+				"out of memory for comm_timer_create");
+			return 0;
+		}
+	}
+	/* The timer is activated later, after other events in the event
+	 * loop have been processed. The query state can also be deleted,
+	 * when the list is full and query states are dropped. */
+	/* Extend wait time if there are a lot of queries or if this one
+	 * is taking long, to keep around cpu time for ordinary queries. */
+	usec = 50000; /* 50 msec */
+	slack = 0;
+	if(qstate->env->mesh->all.count >= qstate->env->mesh->max_reply_states)
+		slack += 3;
+	else if(qstate->env->mesh->all.count >= qstate->env->mesh->max_reply_states/2)
+		slack += 2;
+	else if(qstate->env->mesh->all.count >= qstate->env->mesh->max_reply_states/4)
+		slack += 1;
+	if(vq->suspend_count > 3)
+		slack += 3;
+	else if(vq->suspend_count > 0)
+		slack += vq->suspend_count;
+	if(slack != 0 && slack <= 12 /* No numeric overflow. */) {
+		usec = usec << slack;
+	}
+	/* Spread such timeouts within 90%-100% of the original timer. */
+	base = usec * 9/10;
+	usec = base + ub_random_max(qstate->env->rnd, usec-base);
+	tv.tv_usec = (usec % 1000000);
+	tv.tv_sec = (usec / 1000000);
+	vq->suspend_count ++;
+	comm_timer_set(vq->suspend_timer, &tv);
+	return 1;
+}
+
 /**
  * Detect wrong truncated response (say from BIND 9.6.1 that is forwarding
  * and saw the NS record without signatures from a referral).
@@ -798,11 +942,17 @@ remove_spurious_authority(struct reply_info* chase_reply,
  * @param chase_reply: answer to that query to validate.
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_positive_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey)
+	struct key_entry_key* kkey, struct module_qstate* qstate,
+	struct val_qstate* vq, int* nsec3_calculations, int* suspend)
 {
 	uint8_t* wc = NULL;
 	size_t wl;
@@ -811,6 +961,7 @@ validate_positive_response(struct module_env* env, struct val_env* ve,
 	int nsec3s_seen = 0;
 	size_t i;
 	struct ub_packed_rrset_key* s;
+	*suspend = 0;
 
 	/* validate the ANSWER section - this will be the answer itself */
 	for(i=0; i<chase_reply->an_numrrsets; i++) {
@@ -862,17 +1013,23 @@ validate_positive_response(struct module_env* env, struct val_env* ve,
 	/* If this was a positive wildcard response that we haven't already
 	 * proven, and we have NSEC3 records, try to prove it using the NSEC3
 	 * records. */
-	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen) {
-		enum sec_status sec = nsec3_prove_wildcard(env, ve, 
+	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
+		enum sec_status sec = nsec3_prove_wildcard(env, ve,
 			chase_reply->rrsets+chase_reply->an_numrrsets,
-			chase_reply->ns_numrrsets, qchase, kkey, wc);
+			chase_reply->ns_numrrsets, qchase, kkey, wc,
+			&vq->nsec3_cache_table, nsec3_calculations);
 		if(sec == sec_status_insecure) {
 			verbose(VERB_ALGO, "Positive wildcard response is "
 				"insecure");
 			chase_reply->security = sec_status_insecure;
 			return;
-		} else if(sec == sec_status_secure)
+		} else if(sec == sec_status_secure) {
 			wc_NSEC_ok = 1;
+		} else if(sec == sec_status_unchecked) {
+			*suspend = 1;
+			return;
+		}
 	}
 
 	/* If after all this, we still haven't proven the positive wildcard
@@ -904,11 +1061,17 @@ validate_positive_response(struct module_env* env, struct val_env* ve,
  * @param chase_reply: answer to that query to validate.
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_nodata_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey)
+	struct key_entry_key* kkey, struct module_qstate* qstate,
+	struct val_qstate* vq, int* nsec3_calculations, int* suspend)
 {
 	/* Since we are here, there must be nothing in the ANSWER section to
 	 * validate. */
@@ -925,6 +1088,7 @@ validate_nodata_response(struct module_env* env, struct val_env* ve,
 	int nsec3s_seen = 0; /* nsec3s seen */
 	struct ub_packed_rrset_key* s; 
 	size_t i;
+	*suspend = 0;
 
 	for(i=chase_reply->an_numrrsets; i<chase_reply->an_numrrsets+
 		chase_reply->ns_numrrsets; i++) {
@@ -963,16 +1127,23 @@ validate_nodata_response(struct module_env* env, struct val_env* ve,
 		}
 	}
 	
-	if(!has_valid_nsec && nsec3s_seen) {
+	if(!has_valid_nsec && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
 		enum sec_status sec = nsec3_prove_nodata(env, ve, 
 			chase_reply->rrsets+chase_reply->an_numrrsets,
-			chase_reply->ns_numrrsets, qchase, kkey);
+			chase_reply->ns_numrrsets, qchase, kkey,
+			&vq->nsec3_cache_table, nsec3_calculations);
 		if(sec == sec_status_insecure) {
 			verbose(VERB_ALGO, "NODATA response is insecure");
 			chase_reply->security = sec_status_insecure;
 			return;
-		} else if(sec == sec_status_secure)
+		} else if(sec == sec_status_secure) {
 			has_valid_nsec = 1;
+		} else if(sec == sec_status_unchecked) {
+			/* check is incomplete; suspend */
+			*suspend = 1;
+			return;
+		}
 	}
 
 	if(!has_valid_nsec) {
@@ -1004,11 +1175,18 @@ validate_nodata_response(struct module_env* env, struct val_env* ve,
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
  * @param rcode: adjusted RCODE, in case of RCODE/proof mismatch leniency.
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_nameerror_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey, int* rcode)
+	struct key_entry_key* kkey, int* rcode,
+	struct module_qstate* qstate, struct val_qstate* vq,
+	int* nsec3_calculations, int* suspend)
 {
 	int has_valid_nsec = 0;
 	int has_valid_wnsec = 0;
@@ -1018,6 +1196,7 @@ validate_nameerror_response(struct module_env* env, struct val_env* ve,
 	uint8_t* ce;
 	int ce_labs = 0;
 	int prev_ce_labs = 0;
+	*suspend = 0;
 
 	for(i=chase_reply->an_numrrsets; i<chase_reply->an_numrrsets+
 		chase_reply->ns_numrrsets; i++) {
@@ -1047,13 +1226,18 @@ validate_nameerror_response(struct module_env* env, struct val_env* ve,
 			nsec3s_seen = 1;
 	}
 
-	if((!has_valid_nsec || !has_valid_wnsec) && nsec3s_seen) {
+	if((!has_valid_nsec || !has_valid_wnsec) && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
 		/* use NSEC3 proof, both answer and auth rrsets, in case
 		 * NSEC3s end up in the answer (due to qtype=NSEC3 or so) */
 		chase_reply->security = nsec3_prove_nameerror(env, ve,
 			chase_reply->rrsets, chase_reply->an_numrrsets+
-			chase_reply->ns_numrrsets, qchase, kkey);
-		if(chase_reply->security != sec_status_secure) {
+			chase_reply->ns_numrrsets, qchase, kkey,
+			&vq->nsec3_cache_table, nsec3_calculations);
+		if(chase_reply->security == sec_status_unchecked) {
+			*suspend = 1;
+			return;
+		} else if(chase_reply->security != sec_status_secure) {
 			verbose(VERB_QUERY, "NameError response failed nsec, "
 				"nsec3 proof was %s", sec_status_to_string(
 				chase_reply->security));
@@ -1065,26 +1249,34 @@ validate_nameerror_response(struct module_env* env, struct val_env* ve,
 
 	/* If the message fails to prove either condition, it is bogus. */
 	if(!has_valid_nsec) {
+		validate_nodata_response(env, ve, qchase, chase_reply, kkey,
+			qstate, vq, nsec3_calculations, suspend);
+		if(*suspend) return;
 		verbose(VERB_QUERY, "NameError response has failed to prove: "
 		          "qname does not exist");
-		chase_reply->security = sec_status_bogus;
-		update_reason_bogus(chase_reply, LDNS_EDE_DNSSEC_BOGUS);
 		/* Be lenient with RCODE in NSEC NameError responses */
-		validate_nodata_response(env, ve, qchase, chase_reply, kkey);
-		if (chase_reply->security == sec_status_secure)
+		if(chase_reply->security == sec_status_secure) {
 			*rcode = LDNS_RCODE_NOERROR;
+		} else {
+			chase_reply->security = sec_status_bogus;
+			update_reason_bogus(chase_reply, LDNS_EDE_DNSSEC_BOGUS);
+		}
 		return;
 	}
 
 	if(!has_valid_wnsec) {
+		validate_nodata_response(env, ve, qchase, chase_reply, kkey,
+			qstate, vq, nsec3_calculations, suspend);
+		if(*suspend) return;
 		verbose(VERB_QUERY, "NameError response has failed to prove: "
 		          "covering wildcard does not exist");
-		chase_reply->security = sec_status_bogus;
-		update_reason_bogus(chase_reply, LDNS_EDE_DNSSEC_BOGUS);
 		/* Be lenient with RCODE in NSEC NameError responses */
-		validate_nodata_response(env, ve, qchase, chase_reply, kkey);
-		if (chase_reply->security == sec_status_secure)
+		if (chase_reply->security == sec_status_secure) {
 			*rcode = LDNS_RCODE_NOERROR;
+		} else {
+			chase_reply->security = sec_status_bogus;
+			update_reason_bogus(chase_reply, LDNS_EDE_DNSSEC_BOGUS);
+		}
 		return;
 	}
 
@@ -1144,11 +1336,17 @@ validate_referral_response(struct reply_info* chase_reply)
  * @param chase_reply: answer to that query to validate.
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_any_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey)
+	struct key_entry_key* kkey, struct module_qstate* qstate,
+	struct val_qstate* vq, int* nsec3_calculations, int* suspend)
 {
 	/* all answer and auth rrsets already verified */
 	/* but check if a wildcard response is given, then check NSEC/NSEC3
@@ -1159,6 +1357,7 @@ validate_any_response(struct module_env* env, struct val_env* ve,
 	int nsec3s_seen = 0;
 	size_t i;
 	struct ub_packed_rrset_key* s;
+	*suspend = 0;
 
 	if(qchase->qtype != LDNS_RR_TYPE_ANY) {
 		log_err("internal error: ANY validation called for non-ANY");
@@ -1213,19 +1412,25 @@ validate_any_response(struct module_env* env, struct val_env* ve,
 	/* If this was a positive wildcard response that we haven't already
 	 * proven, and we have NSEC3 records, try to prove it using the NSEC3
 	 * records. */
-	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen) {
+	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
 		/* look both in answer and auth section for NSEC3s */
-		enum sec_status sec = nsec3_prove_wildcard(env, ve, 
+		enum sec_status sec = nsec3_prove_wildcard(env, ve,
 			chase_reply->rrsets,
-			chase_reply->an_numrrsets+chase_reply->ns_numrrsets, 
-			qchase, kkey, wc);
+			chase_reply->an_numrrsets+chase_reply->ns_numrrsets,
+			qchase, kkey, wc, &vq->nsec3_cache_table,
+			nsec3_calculations);
 		if(sec == sec_status_insecure) {
 			verbose(VERB_ALGO, "Positive ANY wildcard response is "
 				"insecure");
 			chase_reply->security = sec_status_insecure;
 			return;
-		} else if(sec == sec_status_secure)
+		} else if(sec == sec_status_secure) {
 			wc_NSEC_ok = 1;
+		} else if(sec == sec_status_unchecked) {
+			*suspend = 1;
+			return;
+		}
 	}
 
 	/* If after all this, we still haven't proven the positive wildcard
@@ -1258,11 +1463,17 @@ validate_any_response(struct module_env* env, struct val_env* ve,
  * @param chase_reply: answer to that query to validate.
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_cname_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey)
+	struct key_entry_key* kkey, struct module_qstate* qstate,
+	struct val_qstate* vq, int* nsec3_calculations, int* suspend)
 {
 	uint8_t* wc = NULL;
 	size_t wl;
@@ -1270,6 +1481,7 @@ validate_cname_response(struct module_env* env, struct val_env* ve,
 	int nsec3s_seen = 0;
 	size_t i;
 	struct ub_packed_rrset_key* s;
+	*suspend = 0;
 
 	/* validate the ANSWER section - this will be the CNAME (+DNAME) */
 	for(i=0; i<chase_reply->an_numrrsets; i++) {
@@ -1334,17 +1546,23 @@ validate_cname_response(struct module_env* env, struct val_env* ve,
 	/* If this was a positive wildcard response that we haven't already
 	 * proven, and we have NSEC3 records, try to prove it using the NSEC3
 	 * records. */
-	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen) {
-		enum sec_status sec = nsec3_prove_wildcard(env, ve, 
+	if(wc != NULL && !wc_NSEC_ok && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
+		enum sec_status sec = nsec3_prove_wildcard(env, ve,
 			chase_reply->rrsets+chase_reply->an_numrrsets,
-			chase_reply->ns_numrrsets, qchase, kkey, wc);
+			chase_reply->ns_numrrsets, qchase, kkey, wc,
+			&vq->nsec3_cache_table, nsec3_calculations);
 		if(sec == sec_status_insecure) {
 			verbose(VERB_ALGO, "wildcard CNAME response is "
 				"insecure");
 			chase_reply->security = sec_status_insecure;
 			return;
-		} else if(sec == sec_status_secure)
+		} else if(sec == sec_status_secure) {
 			wc_NSEC_ok = 1;
+		} else if(sec == sec_status_unchecked) {
+			*suspend = 1;
+			return;
+		}
 	}
 
 	/* If after all this, we still haven't proven the positive wildcard
@@ -1375,11 +1593,17 @@ validate_cname_response(struct module_env* env, struct val_env* ve,
  * @param chase_reply: answer to that query to validate.
  * @param kkey: the key entry, which is trusted, and which matches
  * 	the signer of the answer. The key entry isgood().
+ * @param qstate: query state for the region.
+ * @param vq: validator state for the nsec3 cache table.
+ * @param nsec3_calculations: current nsec3 hash calculations.
+ * @param suspend: returned true if the task takes too long and needs to
+ * 	suspend to continue the effort later.
  */
 static void
 validate_cname_noanswer_response(struct module_env* env, struct val_env* ve,
 	struct query_info* qchase, struct reply_info* chase_reply,
-	struct key_entry_key* kkey)
+	struct key_entry_key* kkey, struct module_qstate* qstate,
+	struct val_qstate* vq, int* nsec3_calculations, int* suspend)
 {
 	int nodata_valid_nsec = 0; /* If true, then NODATA has been proven.*/
 	uint8_t* ce = NULL; /* for wildcard nodata responses. This is the 
@@ -1393,6 +1617,7 @@ validate_cname_noanswer_response(struct module_env* env, struct val_env* ve,
 	uint8_t* nsec_ce; /* Used to find the NSEC with the longest ce */
 	int ce_labs = 0;
 	int prev_ce_labs = 0;
+	*suspend = 0;
 
 	/* the AUTHORITY section */
 	for(i=chase_reply->an_numrrsets; i<chase_reply->an_numrrsets+
@@ -1458,11 +1683,13 @@ validate_cname_noanswer_response(struct module_env* env, struct val_env* ve,
 		update_reason_bogus(chase_reply, LDNS_EDE_DNSSEC_BOGUS);
 		return;
 	}
-	if(!nodata_valid_nsec && !nxdomain_valid_nsec && nsec3s_seen) {
+	if(!nodata_valid_nsec && !nxdomain_valid_nsec && nsec3s_seen &&
+		nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
 		int nodata;
 		enum sec_status sec = nsec3_prove_nxornodata(env, ve, 
 			chase_reply->rrsets+chase_reply->an_numrrsets,
-			chase_reply->ns_numrrsets, qchase, kkey, &nodata);
+			chase_reply->ns_numrrsets, qchase, kkey, &nodata,
+			&vq->nsec3_cache_table, nsec3_calculations);
 		if(sec == sec_status_insecure) {
 			verbose(VERB_ALGO, "CNAMEchain to noanswer response "
 				"is insecure");
@@ -1472,6 +1699,9 @@ validate_cname_noanswer_response(struct module_env* env, struct val_env* ve,
 			if(nodata)
 				nodata_valid_nsec = 1;
 			else	nxdomain_valid_nsec = 1;
+		} else if(sec == sec_status_unchecked) {
+			*suspend = 1;
+			return;
 		}
 	}
 
@@ -1822,13 +2052,37 @@ processFindKey(struct module_qstate* qstate, struct val_qstate* vq, int id)
 		 * Uses negative cache for NSEC3 lookup of DS responses. */
 		/* only if cache not blacklisted, of course */
 		struct dns_msg* msg;
-		if(!qstate->blacklist && !vq->chain_blacklist &&
+		int suspend;
+		if(vq->sub_ds_msg) {
+			/* We have a suspended DS reply from a sub-query;
+			 * process it. */
+			verbose(VERB_ALGO, "Process suspended sub DS response");
+			msg = vq->sub_ds_msg;
+			process_ds_response(qstate, vq, id, LDNS_RCODE_NOERROR,
+				msg, &msg->qinfo, NULL, &suspend);
+			if(suspend) {
+				/* we'll come back here later to continue */
+				if(!validate_suspend_setup_timer(qstate, vq,
+					id, VAL_FINDKEY_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
+			vq->sub_ds_msg = NULL;
+			return 1; /* continue processing ds-response results */
+		} else if(!qstate->blacklist && !vq->chain_blacklist &&
 			(msg=val_find_DS(qstate->env, target_key_name, 
 			target_key_len, vq->qchase.qclass, qstate->region,
 			vq->key_entry->name)) ) {
 			verbose(VERB_ALGO, "Process cached DS response");
 			process_ds_response(qstate, vq, id, LDNS_RCODE_NOERROR,
-				msg, &msg->qinfo, NULL);
+				msg, &msg->qinfo, NULL, &suspend);
+			if(suspend) {
+				/* we'll come back here later to continue */
+				if(!validate_suspend_setup_timer(qstate, vq,
+					id, VAL_FINDKEY_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			return 1; /* continue processing ds-response results */
 		}
 		if(!generate_request(qstate, id, target_key_name, 
@@ -1871,7 +2125,7 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 	struct val_env* ve, int id)
 {
 	enum val_classification subtype;
-	int rcode;
+	int rcode, suspend, nsec3_calculations = 0;
 
 	if(!vq->key_entry) {
 		verbose(VERB_ALGO, "validate: no key entry, failed");
@@ -1926,8 +2180,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 
 	/* check signatures in the message; 
 	 * answer and authority must be valid, additional is only checked. */
-	if(!validate_msg_signatures(qstate, qstate->env, ve, &vq->qchase, 
-		vq->chase_reply, vq->key_entry)) {
+	if(!validate_msg_signatures(qstate, vq, qstate->env, ve, &vq->qchase,
+		vq->chase_reply, vq->key_entry, &suspend)) {
+		if(suspend) {
+			if(!validate_suspend_setup_timer(qstate, vq,
+				id, VAL_VALIDATE_STATE))
+				return val_error(qstate, id);
+			return 0;
+		}
 		/* workaround bad recursor out there that truncates (even
 		 * with EDNS4k) to 512 by removing RRSIG from auth section
 		 * for positive replies*/
@@ -1956,7 +2216,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 		case VAL_CLASS_POSITIVE:
 			verbose(VERB_ALGO, "Validating a positive response");
 			validate_positive_response(qstate->env, ve,
-				&vq->qchase, vq->chase_reply, vq->key_entry);
+				&vq->qchase, vq->chase_reply, vq->key_entry,
+				qstate, vq, &nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(positive): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -1965,7 +2232,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 		case VAL_CLASS_NODATA:
 			verbose(VERB_ALGO, "Validating a nodata response");
 			validate_nodata_response(qstate->env, ve,
-				&vq->qchase, vq->chase_reply, vq->key_entry);
+				&vq->qchase, vq->chase_reply, vq->key_entry,
+				qstate, vq, &nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(nodata): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -1975,7 +2249,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 			rcode = (int)FLAGS_GET_RCODE(vq->orig_msg->rep->flags);
 			verbose(VERB_ALGO, "Validating a nxdomain response");
 			validate_nameerror_response(qstate->env, ve, 
-				&vq->qchase, vq->chase_reply, vq->key_entry, &rcode);
+				&vq->qchase, vq->chase_reply, vq->key_entry, &rcode,
+				qstate, vq, &nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(nxdomain): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -1986,7 +2267,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 		case VAL_CLASS_CNAME:
 			verbose(VERB_ALGO, "Validating a cname response");
 			validate_cname_response(qstate->env, ve,
-				&vq->qchase, vq->chase_reply, vq->key_entry);
+				&vq->qchase, vq->chase_reply, vq->key_entry,
+				qstate, vq, &nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(cname): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -1996,7 +2284,14 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 			verbose(VERB_ALGO, "Validating a cname noanswer "
 				"response");
 			validate_cname_noanswer_response(qstate->env, ve,
-				&vq->qchase, vq->chase_reply, vq->key_entry);
+				&vq->qchase, vq->chase_reply, vq->key_entry,
+				qstate, vq, &nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(cname_noanswer): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -2013,8 +2308,15 @@ processValidate(struct module_qstate* qstate, struct val_qstate* vq,
 		case VAL_CLASS_ANY:
 			verbose(VERB_ALGO, "Validating a positive ANY "
 				"response");
-			validate_any_response(qstate->env, ve, &vq->qchase, 
-				vq->chase_reply, vq->key_entry);
+			validate_any_response(qstate->env, ve, &vq->qchase,
+				vq->chase_reply, vq->key_entry, qstate, vq,
+				&nsec3_calculations, &suspend);
+			if(suspend) {
+				if(!validate_suspend_setup_timer(qstate,
+					vq, id, VAL_VALIDATE_STATE))
+					return val_error(qstate, id);
+				return 0;
+			}
 			verbose(VERB_DETAIL, "validate(positive_any): %s",
 			  	sec_status_to_string(
 				vq->chase_reply->security));
@@ -2123,16 +2425,13 @@ processFinished(struct module_qstate* qstate, struct val_qstate* vq,
 	if(vq->orig_msg->rep->security == sec_status_bogus) {
 		/* see if we can try again to fetch data */
 		if(vq->restart_count < ve->max_restart) {
-			int restart_count = vq->restart_count+1;
 			verbose(VERB_ALGO, "validation failed, "
 				"blacklist and retry to fetch data");
 			val_blacklist(&qstate->blacklist, qstate->region, 
 				qstate->reply_origin, 0);
 			qstate->reply_origin = NULL;
 			qstate->errinf = NULL;
-			memset(vq, 0, sizeof(*vq));
-			vq->restart_count = restart_count;
-			vq->state = VAL_INIT_STATE;
+			val_restart(vq);
 			verbose(VERB_ALGO, "pass back to next module");
 			qstate->ext_state[id] = module_restart_next;
 			return 0;
@@ -2440,7 +2739,10 @@ primeResponseToKE(struct ub_packed_rrset_key* dnskey_rrset,
  *	DS response indicated an end to secure space, is_good if the DS
  *	validated. It returns ke=NULL if the DS response indicated that the
  *	request wasn't a delegation point.
- * @return 0 on servfail error (malloc failure).
+ * @return
+ *	0 on success,
+ *	1 on servfail error (malloc failure),
+ *	2 on NSEC3 suspend.
  */
 static int
 ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
@@ -2451,6 +2753,7 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 	char* reason = NULL;
 	sldns_ede_code reason_bogus = LDNS_EDE_DNSSEC_BOGUS;
 	enum val_classification subtype;
+	int verified;
 	if(rcode != LDNS_RCODE_NOERROR) {
 		char rc[16];
 		rc[0]=0;
@@ -2479,7 +2782,7 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 		/* Verify only returns BOGUS or SECURE. If the rrset is 
 		 * bogus, then we are done. */
 		sec = val_verify_rrset_entry(qstate->env, ve, ds,
-			vq->key_entry, &reason, &reason_bogus, LDNS_SECTION_ANSWER, qstate);
+			vq->key_entry, &reason, &reason_bogus, LDNS_SECTION_ANSWER, qstate, &verified);
 		if(sec != sec_status_secure) {
 			verbose(VERB_DETAIL, "DS rrset in DS response did "
 				"not verify");
@@ -2499,7 +2802,7 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 			*ke = key_entry_create_null(qstate->region, 
 				qinfo->qname, qinfo->qname_len, qinfo->qclass, 
 				ub_packed_rrset_ttl(ds), *qstate->env->now);
-			return (*ke) != NULL;
+			return (*ke) == NULL;
 		}
 
 		/* Otherwise, we return the positive response. */
@@ -2507,7 +2810,7 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 		*ke = key_entry_create_rrset(qstate->region,
 			qinfo->qname, qinfo->qname_len, qinfo->qclass, ds,
 			NULL, *qstate->env->now);
-		return (*ke) != NULL;
+		return (*ke) == NULL;
 	} else if(subtype == VAL_CLASS_NODATA || 
 		subtype == VAL_CLASS_NAMEERROR) {
 		/* NODATA means that the qname exists, but that there was 
@@ -2539,12 +2842,12 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 					qinfo->qname, qinfo->qname_len, 
 					qinfo->qclass, proof_ttl,
 					*qstate->env->now);
-				return (*ke) != NULL;
+				return (*ke) == NULL;
 			case sec_status_insecure:
 				verbose(VERB_DETAIL, "NSEC RRset for the "
 				  "referral proved not a delegation point");
 				*ke = NULL;
-				return 1;
+				return 0;
 			case sec_status_bogus:
 				verbose(VERB_DETAIL, "NSEC RRset for the "
 					"referral did not prove no DS.");
@@ -2556,10 +2859,17 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 				break;
 		}
 
+		if(!nsec3_cache_table_init(&vq->nsec3_cache_table, qstate->region)) {
+			log_err("malloc failure in ds_response_to_ke for "
+				"NSEC3 cache");
+			reason = "malloc failure";
+			errinf_ede(qstate, reason, 0);
+			goto return_bogus;
+		}
 		sec = nsec3_prove_nods(qstate->env, ve, 
 			msg->rep->rrsets + msg->rep->an_numrrsets,
 			msg->rep->ns_numrrsets, qinfo, vq->key_entry, &reason,
-			&reason_bogus, qstate);
+			&reason_bogus, qstate, &vq->nsec3_cache_table);
 		switch(sec) {
 			case sec_status_insecure:
 				/* case insecure also continues to unsigned
@@ -2572,18 +2882,19 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 					qinfo->qname, qinfo->qname_len, 
 					qinfo->qclass, proof_ttl,
 					*qstate->env->now);
-				return (*ke) != NULL;
+				return (*ke) == NULL;
 			case sec_status_indeterminate:
 				verbose(VERB_DETAIL, "NSEC3s for the "
 				  "referral proved no delegation");
 				*ke = NULL;
-				return 1;
+				return 0;
 			case sec_status_bogus:
 				verbose(VERB_DETAIL, "NSEC3s for the "
 					"referral did not prove no DS.");
 				errinf_ede(qstate, reason, reason_bogus);
 				goto return_bogus;
 			case sec_status_unchecked:
+				return 2;
 			default:
 				/* NSEC3 proof did not work */
 				break;
@@ -2620,13 +2931,14 @@ ds_response_to_ke(struct module_qstate* qstate, struct val_qstate* vq,
 			goto return_bogus;
 		}
 		sec = val_verify_rrset_entry(qstate->env, ve, cname, 
-			vq->key_entry, &reason, NULL, LDNS_SECTION_ANSWER, qstate);
+			vq->key_entry, &reason, NULL, LDNS_SECTION_ANSWER,
+			qstate, &verified);
 		if(sec == sec_status_secure) {
 			verbose(VERB_ALGO, "CNAME validated, "
 				"proof that DS does not exist");
 			/* and that it is not a referral point */
 			*ke = NULL;
-			return 1;
+			return 0;
 		}
 		errinf(qstate, "CNAME in DS response was not secure.");
 		errinf(qstate, reason);
@@ -2649,7 +2961,7 @@ return_bogus:
 	*ke = key_entry_create_bad(qstate->region, qinfo->qname,
 		qinfo->qname_len, qinfo->qclass, 
 		BOGUS_KEY_TTL, *qstate->env->now);
-	return (*ke) != NULL;
+	return (*ke) == NULL;
 }
 
 /**
@@ -2670,17 +2982,31 @@ return_bogus:
 static void
 process_ds_response(struct module_qstate* qstate, struct val_qstate* vq,
 	int id, int rcode, struct dns_msg* msg, struct query_info* qinfo,
-	struct sock_list* origin)
+	struct sock_list* origin, int* suspend)
 {
 	struct val_env* ve = (struct val_env*)qstate->env->modinfo[id];
 	struct key_entry_key* dske = NULL;
 	uint8_t* olds = vq->empty_DS_name;
+	int ret;
+	*suspend = 0;
 	vq->empty_DS_name = NULL;
-	if(!ds_response_to_ke(qstate, vq, id, rcode, msg, qinfo, &dske)) {
+	ret = ds_response_to_ke(qstate, vq, id, rcode, msg, qinfo, &dske);
+	if(ret != 0) {
+		switch(ret) {
+		case 1:
 			log_err("malloc failure in process_ds_response");
 			vq->key_entry = NULL; /* make it error */
 			vq->state = VAL_VALIDATE_STATE;
 			return;
+		case 2:
+			*suspend = 1;
+			return;
+		default:
+			log_err("unhandled error value for ds_response_to_ke");
+			vq->key_entry = NULL; /* make it error */
+			vq->state = VAL_VALIDATE_STATE;
+			return;
+		}
 	}
 	if(dske == NULL) {
 		vq->empty_DS_name = regional_alloc_init(qstate->region,
@@ -2927,9 +3253,26 @@ val_inform_super(struct module_qstate* qstate, int id,
 		return;
 	}
 	if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS) {
+		int suspend;
 		process_ds_response(super, vq, id, qstate->return_rcode,
-			qstate->return_msg, &qstate->qinfo, 
-			qstate->reply_origin);
+			qstate->return_msg, &qstate->qinfo,
+			qstate->reply_origin, &suspend);
+		/* If NSEC3 was needed during validation, NULL the NSEC3 cache;
+		 * it will be re-initiated if needed later on.
+		 * Validation (and the cache table) are happening/allocated in
+		 * the super qstate whilst the RRs are allocated (and pointed
+		 * to) in this sub qstate. */
+		if(vq->nsec3_cache_table.ct) {
+			vq->nsec3_cache_table.ct = NULL;
+		}
+		if(suspend) {
+			/* deep copy the return_msg to vq->sub_ds_msg; it will
+			 * be resumed later in the super state with the caveat
+			 * that the initial calculations will be re-caclulated
+			 * and re-suspended there before continuing. */
+			vq->sub_ds_msg = dns_msg_deepcopy_region(
+				qstate->return_msg, super->region);
+		}
 		return;
 	} else if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY) {
 		process_dnskey_response(super, vq, id, qstate->return_rcode,
@@ -2943,8 +3286,15 @@ val_inform_super(struct module_qstate* qstate, int id,
 void
 val_clear(struct module_qstate* qstate, int id)
 {
+	struct val_qstate* vq;
 	if(!qstate)
 		return;
+	vq = (struct val_qstate*)qstate->minfo[id];
+	if(vq) {
+		if(vq->suspend_timer) {
+			comm_timer_delete(vq->suspend_timer);
+		}
+	}
 	/* everything is allocated in the region, so assign NULL */
 	qstate->minfo[id] = NULL;
 }
diff --git a/validator/validator.h b/validator/validator.h
index 694e4c89..72f44b16 100644
--- a/validator/validator.h
+++ b/validator/validator.h
@@ -45,11 +45,13 @@
 #include "util/module.h"
 #include "util/data/msgreply.h"
 #include "validator/val_utils.h"
+#include "validator/val_nsec3.h"
 struct val_anchors;
 struct key_cache;
 struct key_entry_key;
 struct val_neg_cache;
 struct config_strlist;
+struct comm_timer;
 
 /**
  * This is the TTL to use when a trust anchor fails to prime. A trust anchor
@@ -215,6 +217,19 @@ struct val_qstate {
 
 	/** true if this state is waiting to prime a trust anchor */
 	int wait_prime_ta;
+
+	/** State to continue with RRSIG validation in a message later */
+	int msg_signatures_state;
+	/** The rrset index for the msg signatures to continue from */
+	size_t msg_signatures_index;
+	/** Cache table for NSEC3 hashes */
+	struct nsec3_cache_table nsec3_cache_table;
+	/** DS message from sub if it got suspended from NSEC3 calculations */
+	struct dns_msg* sub_ds_msg;
+	/** The timer to resume processing msg signatures */
+	struct comm_timer* suspend_timer;
+	/** Number of suspends */
+	int suspend_count;
 };
 
 /**
@@ -262,4 +277,7 @@ void val_clear(struct module_qstate* qstate, int id);
  */
 size_t val_get_mem(struct module_env* env, int id);
 
+/** Timer callback for msg signatures continue timer */
+void validate_suspend_timer_cb(void* arg);
+
 #endif /* VALIDATOR_VALIDATOR_H */
