Adding upstream version 1:9.18.19.upstream/1%9.18.19

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3394 insertions, 0 deletions

diff --git a/lib/dns/validator.c b/lib/dns/validator.c
new file mode 100644
index 0000000..56a0ced
--- /dev/null
+++ b/lib/dns/validator.c
@@ -0,0 +1,3394 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include <isc/base32.h>
+#include <isc/md.h>
+#include <isc/mem.h>
+#include <isc/print.h>
+#include <isc/result.h>
+#include <isc/string.h>
+#include <isc/task.h>
+#include <isc/util.h>
+
+#include <dns/client.h>
+#include <dns/db.h>
+#include <dns/dnssec.h>
+#include <dns/ds.h>
+#include <dns/events.h>
+#include <dns/keytable.h>
+#include <dns/keyvalues.h>
+#include <dns/log.h>
+#include <dns/message.h>
+#include <dns/ncache.h>
+#include <dns/nsec.h>
+#include <dns/nsec3.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+#include <dns/rdatatype.h>
+#include <dns/resolver.h>
+#include <dns/validator.h>
+#include <dns/view.h>
+
+/*! \file
+ * \brief
+ * Basic processing sequences:
+ *
+ * \li When called with rdataset and sigrdataset:
+ *     validator_start -> validate_answer -> proveunsecure
+ *     validator_start -> validate_answer -> validate_nx (if secure wildcard)
+ *
+ * \li When called with rdataset but no sigrdataset:
+ *     validator_start -> proveunsecure
+ *
+ * \li When called with no rdataset or sigrdataset:
+ *     validator_start -> validate_nx-> proveunsecure
+ *
+ * validator_start:   determine what type of validation to do.
+ * validate_answer:   attempt to perform a positive validation.
+ * proveunsecure:     attempt to prove the answer comes from an unsecure zone.
+ * validate_nx:       attempt to prove a negative response.
+ */
+
+#define VALIDATOR_MAGIC	   ISC_MAGIC('V', 'a', 'l', '?')
+#define VALID_VALIDATOR(v) ISC_MAGIC_VALID(v, VALIDATOR_MAGIC)
+
+#define VALATTR_SHUTDOWN 0x0001 /*%< Shutting down. */
+#define VALATTR_CANCELED 0x0002 /*%< Canceled. */
+#define VALATTR_TRIEDVERIFY                                    \
+	0x0004			  /*%< We have found a key and \
+				   * have attempted a verify. */
+#define VALATTR_INSECURITY 0x0010 /*%< Attempting proveunsecure. */
+
+/*!
+ * NSEC proofs to be looked for.
+ */
+#define VALATTR_NEEDNOQNAME    0x00000100
+#define VALATTR_NEEDNOWILDCARD 0x00000200
+#define VALATTR_NEEDNODATA     0x00000400
+
+/*!
+ * NSEC proofs that have been found.
+ */
+#define VALATTR_FOUNDNOQNAME	0x00001000
+#define VALATTR_FOUNDNOWILDCARD 0x00002000
+#define VALATTR_FOUNDNODATA	0x00004000
+#define VALATTR_FOUNDCLOSEST	0x00008000
+#define VALATTR_FOUNDOPTOUT	0x00010000
+#define VALATTR_FOUNDUNKNOWN	0x00020000
+
+#define NEEDNODATA(val)	     ((val->attributes & VALATTR_NEEDNODATA) != 0)
+#define NEEDNOQNAME(val)     ((val->attributes & VALATTR_NEEDNOQNAME) != 0)
+#define NEEDNOWILDCARD(val)  ((val->attributes & VALATTR_NEEDNOWILDCARD) != 0)
+#define FOUNDNODATA(val)     ((val->attributes & VALATTR_FOUNDNODATA) != 0)
+#define FOUNDNOQNAME(val)    ((val->attributes & VALATTR_FOUNDNOQNAME) != 0)
+#define FOUNDNOWILDCARD(val) ((val->attributes & VALATTR_FOUNDNOWILDCARD) != 0)
+#define FOUNDCLOSEST(val)    ((val->attributes & VALATTR_FOUNDCLOSEST) != 0)
+#define FOUNDOPTOUT(val)     ((val->attributes & VALATTR_FOUNDOPTOUT) != 0)
+
+#define SHUTDOWN(v) (((v)->attributes & VALATTR_SHUTDOWN) != 0)
+#define CANCELED(v) (((v)->attributes & VALATTR_CANCELED) != 0)
+
+#define NEGATIVE(r) (((r)->attributes & DNS_RDATASETATTR_NEGATIVE) != 0)
+#define NXDOMAIN(r) (((r)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)
+
+static void
+destroy(dns_validator_t *val);
+
+static isc_result_t
+select_signing_key(dns_validator_t *val, dns_rdataset_t *rdataset);
+
+static isc_result_t
+validate_answer(dns_validator_t *val, bool resume);
+
+static isc_result_t
+validate_dnskey(dns_validator_t *val);
+
+static isc_result_t
+validate_nx(dns_validator_t *val, bool resume);
+
+static isc_result_t
+proveunsecure(dns_validator_t *val, bool have_ds, bool resume);
+
+static void
+validator_logv(dns_validator_t *val, isc_logcategory_t *category,
+	       isc_logmodule_t *module, int level, const char *fmt, va_list ap)
+	ISC_FORMAT_PRINTF(5, 0);
+
+static void
+validator_log(void *val, int level, const char *fmt, ...)
+	ISC_FORMAT_PRINTF(3, 4);
+
+static void
+validator_logcreate(dns_validator_t *val, dns_name_t *name,
+		    dns_rdatatype_t type, const char *caller,
+		    const char *operation);
+
+/*%
+ * Ensure the validator's rdatasets are marked as expired.
+ */
+static void
+expire_rdatasets(dns_validator_t *val) {
+	if (dns_rdataset_isassociated(&val->frdataset)) {
+		dns_rdataset_expire(&val->frdataset);
+	}
+	if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+		dns_rdataset_expire(&val->fsigrdataset);
+	}
+}
+
+/*%
+ * Ensure the validator's rdatasets are disassociated.
+ */
+static void
+disassociate_rdatasets(dns_validator_t *val) {
+	if (dns_rdataset_isassociated(&val->fdsset)) {
+		dns_rdataset_disassociate(&val->fdsset);
+	}
+	if (dns_rdataset_isassociated(&val->frdataset)) {
+		dns_rdataset_disassociate(&val->frdataset);
+	}
+	if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+		dns_rdataset_disassociate(&val->fsigrdataset);
+	}
+}
+
+/*%
+ * Mark the rdatasets in val->event with trust level "answer",
+ * indicating that they did not validate, but could be cached as insecure.
+ *
+ * If we are validating a name that is marked as "must be secure", log a
+ * warning and return DNS_R_MUSTBESECURE instead.
+ */
+static isc_result_t
+markanswer(dns_validator_t *val, const char *where, const char *mbstext) {
+	if (val->mustbesecure && mbstext != NULL) {
+		validator_log(val, ISC_LOG_WARNING,
+			      "must be secure failure, %s", mbstext);
+		return (DNS_R_MUSTBESECURE);
+	}
+
+	validator_log(val, ISC_LOG_DEBUG(3), "marking as answer (%s)", where);
+	if (val->event->rdataset != NULL) {
+		dns_rdataset_settrust(val->event->rdataset, dns_trust_answer);
+	}
+	if (val->event->sigrdataset != NULL) {
+		dns_rdataset_settrust(val->event->sigrdataset,
+				      dns_trust_answer);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+/*%
+ * Mark the RRsets in val->event with trust level secure.
+ */
+static void
+marksecure(dns_validatorevent_t *event) {
+	dns_rdataset_settrust(event->rdataset, dns_trust_secure);
+	if (event->sigrdataset != NULL) {
+		dns_rdataset_settrust(event->sigrdataset, dns_trust_secure);
+	}
+	event->secure = true;
+}
+
+/*
+ * Validator 'val' is finished; send the completion event to the task
+ * that called dns_validator_create(), with result `result`.
+ */
+static void
+validator_done(dns_validator_t *val, isc_result_t result) {
+	isc_task_t *task;
+
+	if (val->event == NULL) {
+		return;
+	}
+
+	/*
+	 * Caller must be holding the lock.
+	 */
+
+	val->event->result = result;
+	task = val->event->ev_sender;
+	val->event->ev_sender = val;
+	val->event->ev_type = DNS_EVENT_VALIDATORDONE;
+	val->event->ev_action = val->action;
+	val->event->ev_arg = val->arg;
+	isc_task_sendanddetach(&task, (isc_event_t **)&val->event);
+}
+
+/*
+ * Called when deciding whether to destroy validator 'val'.
+ */
+static bool
+exit_check(dns_validator_t *val) {
+	/*
+	 * Caller must be holding the lock.
+	 */
+	if (!SHUTDOWN(val)) {
+		return (false);
+	}
+
+	INSIST(val->event == NULL);
+
+	if (val->fetch != NULL || val->subvalidator != NULL) {
+		return (false);
+	}
+
+	return (true);
+}
+
+/*%
+ * Look in the NSEC record returned from a DS query to see if there is
+ * a NS RRset at this name.  If it is found we are at a delegation point.
+ */
+static bool
+isdelegation(dns_name_t *name, dns_rdataset_t *rdataset,
+	     isc_result_t dbresult) {
+	dns_fixedname_t fixed;
+	dns_label_t hashlabel;
+	dns_name_t nsec3name;
+	dns_rdata_nsec3_t nsec3;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	dns_rdataset_t set;
+	int order;
+	int scope;
+	bool found;
+	isc_buffer_t buffer;
+	isc_result_t result;
+	unsigned char hash[NSEC3_MAX_HASH_LENGTH];
+	unsigned char owner[NSEC3_MAX_HASH_LENGTH];
+	unsigned int length;
+
+	REQUIRE(dbresult == DNS_R_NXRRSET || dbresult == DNS_R_NCACHENXRRSET);
+
+	dns_rdataset_init(&set);
+	if (dbresult == DNS_R_NXRRSET) {
+		dns_rdataset_clone(rdataset, &set);
+	} else {
+		result = dns_ncache_getrdataset(rdataset, name,
+						dns_rdatatype_nsec, &set);
+		if (result == ISC_R_NOTFOUND) {
+			goto trynsec3;
+		}
+		if (result != ISC_R_SUCCESS) {
+			return (false);
+		}
+	}
+
+	INSIST(set.type == dns_rdatatype_nsec);
+
+	found = false;
+	result = dns_rdataset_first(&set);
+	if (result == ISC_R_SUCCESS) {
+		dns_rdataset_current(&set, &rdata);
+		found = dns_nsec_typepresent(&rdata, dns_rdatatype_ns);
+		dns_rdata_reset(&rdata);
+	}
+	dns_rdataset_disassociate(&set);
+	return (found);
+
+trynsec3:
+	/*
+	 * Iterate over the ncache entry.
+	 */
+	found = false;
+	dns_name_init(&nsec3name, NULL);
+	dns_fixedname_init(&fixed);
+	dns_name_downcase(name, dns_fixedname_name(&fixed), NULL);
+	name = dns_fixedname_name(&fixed);
+	for (result = dns_rdataset_first(rdataset); result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(rdataset))
+	{
+		dns_ncache_current(rdataset, &nsec3name, &set);
+		if (set.type != dns_rdatatype_nsec3) {
+			dns_rdataset_disassociate(&set);
+			continue;
+		}
+		dns_name_getlabel(&nsec3name, 0, &hashlabel);
+		isc_region_consume(&hashlabel, 1);
+		isc_buffer_init(&buffer, owner, sizeof(owner));
+		result = isc_base32hexnp_decoderegion(&hashlabel, &buffer);
+		if (result != ISC_R_SUCCESS) {
+			dns_rdataset_disassociate(&set);
+			continue;
+		}
+		for (result = dns_rdataset_first(&set); result == ISC_R_SUCCESS;
+		     result = dns_rdataset_next(&set))
+		{
+			dns_rdata_reset(&rdata);
+			dns_rdataset_current(&set, &rdata);
+			(void)dns_rdata_tostruct(&rdata, &nsec3, NULL);
+			if (nsec3.hash != 1) {
+				continue;
+			}
+			length = isc_iterated_hash(
+				hash, nsec3.hash, nsec3.iterations, nsec3.salt,
+				nsec3.salt_length, name->ndata, name->length);
+			if (length != isc_buffer_usedlength(&buffer)) {
+				continue;
+			}
+			order = memcmp(hash, owner, length);
+			if (order == 0) {
+				found = dns_nsec3_typepresent(&rdata,
+							      dns_rdatatype_ns);
+				dns_rdataset_disassociate(&set);
+				return (found);
+			}
+			if ((nsec3.flags & DNS_NSEC3FLAG_OPTOUT) == 0) {
+				continue;
+			}
+			/*
+			 * Does this optout span cover the name?
+			 */
+			scope = memcmp(owner, nsec3.next, nsec3.next_length);
+			if ((scope < 0 && order > 0 &&
+			     memcmp(hash, nsec3.next, length) < 0) ||
+			    (scope >= 0 &&
+			     (order > 0 ||
+			      memcmp(hash, nsec3.next, length) < 0)))
+			{
+				dns_rdataset_disassociate(&set);
+				return (true);
+			}
+		}
+		dns_rdataset_disassociate(&set);
+	}
+	return (found);
+}
+
+/*%
+ * We have been asked to look for a key.
+ * If found, resume the validation process.
+ * If not found, fail the validation process.
+ */
+static void
+fetch_callback_dnskey(isc_task_t *task, isc_event_t *event) {
+	dns_fetchevent_t *devent;
+	dns_validator_t *val;
+	dns_rdataset_t *rdataset;
+	bool want_destroy;
+	isc_result_t result;
+	isc_result_t eresult;
+	isc_result_t saved_result;
+	dns_fetch_t *fetch;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
+	devent = (dns_fetchevent_t *)event;
+	val = devent->ev_arg;
+	rdataset = &val->frdataset;
+	eresult = devent->result;
+
+	/* Free resources which are not of interest. */
+	if (devent->node != NULL) {
+		dns_db_detachnode(devent->db, &devent->node);
+	}
+	if (devent->db != NULL) {
+		dns_db_detach(&devent->db);
+	}
+	if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+		dns_rdataset_disassociate(&val->fsigrdataset);
+	}
+	isc_event_free(&event);
+
+	INSIST(val->event != NULL);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in fetch_callback_dnskey");
+	LOCK(&val->lock);
+	fetch = val->fetch;
+	val->fetch = NULL;
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+	} else if (eresult == ISC_R_SUCCESS || eresult == DNS_R_NCACHENXRRSET) {
+		/*
+		 * We have an answer to our DNSKEY query.  Either the DNSKEY
+		 * RRset or a NODATA response.
+		 */
+		validator_log(val, ISC_LOG_DEBUG(3), "%s with trust %s",
+			      eresult == ISC_R_SUCCESS ? "keyset"
+						       : "NCACHENXRRSET",
+			      dns_trust_totext(rdataset->trust));
+		/*
+		 * Only extract the dst key if the keyset exists and is secure.
+		 */
+		if (eresult == ISC_R_SUCCESS &&
+		    rdataset->trust >= dns_trust_secure)
+		{
+			result = select_signing_key(val, rdataset);
+			if (result == ISC_R_SUCCESS) {
+				val->keyset = &val->frdataset;
+			}
+		}
+		result = validate_answer(val, true);
+		if (result == DNS_R_NOVALIDSIG &&
+		    (val->attributes & VALATTR_TRIEDVERIFY) == 0)
+		{
+			saved_result = result;
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "falling back to insecurity proof");
+			result = proveunsecure(val, false, false);
+			if (result == DNS_R_NOTINSECURE) {
+				result = saved_result;
+			}
+		}
+		if (result != DNS_R_WAIT) {
+			validator_done(val, result);
+		}
+	} else {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "fetch_callback_dnskey: got %s",
+			      isc_result_totext(eresult));
+		if (eresult == ISC_R_CANCELED) {
+			validator_done(val, eresult);
+		} else {
+			validator_done(val, DNS_R_BROKENCHAIN);
+		}
+	}
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+
+	if (fetch != NULL) {
+		dns_resolver_destroyfetch(&fetch);
+	}
+
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+/*%
+ * We have been asked to look for a DS. This may be part of
+ * walking a trust chain, or an insecurity proof.
+ */
+static void
+fetch_callback_ds(isc_task_t *task, isc_event_t *event) {
+	dns_fetchevent_t *devent;
+	dns_validator_t *val;
+	dns_rdataset_t *rdataset;
+	bool want_destroy, trustchain;
+	isc_result_t result;
+	isc_result_t eresult;
+	dns_fetch_t *fetch;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
+	devent = (dns_fetchevent_t *)event;
+	val = devent->ev_arg;
+	rdataset = &val->frdataset;
+	eresult = devent->result;
+
+	/*
+	 * Set 'trustchain' to true if we're walking a chain of
+	 * trust; false if we're attempting to prove insecurity.
+	 */
+	trustchain = ((val->attributes & VALATTR_INSECURITY) == 0);
+
+	/* Free resources which are not of interest. */
+	if (devent->node != NULL) {
+		dns_db_detachnode(devent->db, &devent->node);
+	}
+	if (devent->db != NULL) {
+		dns_db_detach(&devent->db);
+	}
+	if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+		dns_rdataset_disassociate(&val->fsigrdataset);
+	}
+
+	INSIST(val->event != NULL);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in fetch_callback_ds");
+	LOCK(&val->lock);
+	fetch = val->fetch;
+	val->fetch = NULL;
+
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+		goto done;
+	}
+
+	switch (eresult) {
+	case DNS_R_NXDOMAIN:
+	case DNS_R_NCACHENXDOMAIN:
+		/*
+		 * These results only make sense if we're attempting
+		 * an insecurity proof, not when walking a chain of trust.
+		 */
+		if (trustchain) {
+			goto unexpected;
+		}
+
+		FALLTHROUGH;
+	case ISC_R_SUCCESS:
+		if (trustchain) {
+			/*
+			 * We looked for a DS record as part of
+			 * following a key chain upwards; resume following
+			 * the chain.
+			 */
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "dsset with trust %s",
+				      dns_trust_totext(rdataset->trust));
+			val->dsset = &val->frdataset;
+			result = validate_dnskey(val);
+			if (result != DNS_R_WAIT) {
+				validator_done(val, result);
+			}
+		} else {
+			/*
+			 * There is a DS which may or may not be a zone cut.
+			 * In either case we are still in a secure zone,
+			 * so keep looking for the break in the chain
+			 * of trust.
+			 */
+			result = proveunsecure(val, (eresult == ISC_R_SUCCESS),
+					       true);
+			if (result != DNS_R_WAIT) {
+				validator_done(val, result);
+			}
+		}
+		break;
+	case DNS_R_CNAME:
+	case DNS_R_NXRRSET:
+	case DNS_R_NCACHENXRRSET:
+	case DNS_R_SERVFAIL: /* RFC 1034 parent? */
+		if (trustchain) {
+			/*
+			 * Failed to find a DS while following the
+			 * chain of trust; now we need to prove insecurity.
+			 */
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "falling back to insecurity proof (%s)",
+				      isc_result_totext(eresult));
+			result = proveunsecure(val, false, false);
+			if (result != DNS_R_WAIT) {
+				validator_done(val, result);
+			}
+		} else if (eresult == DNS_R_SERVFAIL) {
+			goto unexpected;
+		} else if (eresult != DNS_R_CNAME &&
+			   isdelegation(devent->foundname, &val->frdataset,
+					eresult))
+		{
+			/*
+			 * Failed to find a DS while trying to prove
+			 * insecurity. If this is a zone cut, that
+			 * means we're insecure.
+			 */
+			result = markanswer(val, "fetch_callback_ds",
+					    "no DS and this is a delegation");
+			validator_done(val, result);
+		} else {
+			/*
+			 * Not a zone cut, so we have to keep looking for
+			 * the break point in the chain of trust.
+			 */
+			result = proveunsecure(val, false, true);
+			if (result != DNS_R_WAIT) {
+				validator_done(val, result);
+			}
+		}
+		break;
+
+	default:
+	unexpected:
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "fetch_callback_ds: got %s",
+			      isc_result_totext(eresult));
+		if (eresult == ISC_R_CANCELED) {
+			validator_done(val, eresult);
+		} else {
+			validator_done(val, DNS_R_BROKENCHAIN);
+		}
+	}
+done:
+
+	isc_event_free(&event);
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+
+	if (fetch != NULL) {
+		dns_resolver_destroyfetch(&fetch);
+	}
+
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+/*%
+ * Callback from when a DNSKEY RRset has been validated.
+ *
+ * Resumes the stalled validation process.
+ */
+static void
+validator_callback_dnskey(isc_task_t *task, isc_event_t *event) {
+	dns_validatorevent_t *devent;
+	dns_validator_t *val;
+	bool want_destroy;
+	isc_result_t result;
+	isc_result_t eresult;
+	isc_result_t saved_result;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);
+
+	devent = (dns_validatorevent_t *)event;
+	val = devent->ev_arg;
+	eresult = devent->result;
+
+	isc_event_free(&event);
+	dns_validator_destroy(&val->subvalidator);
+
+	INSIST(val->event != NULL);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in validator_callback_dnskey");
+	LOCK(&val->lock);
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+	} else if (eresult == ISC_R_SUCCESS) {
+		validator_log(val, ISC_LOG_DEBUG(3), "keyset with trust %s",
+			      dns_trust_totext(val->frdataset.trust));
+		/*
+		 * Only extract the dst key if the keyset is secure.
+		 */
+		if (val->frdataset.trust >= dns_trust_secure) {
+			(void)select_signing_key(val, &val->frdataset);
+		}
+		result = validate_answer(val, true);
+		if (result == DNS_R_NOVALIDSIG &&
+		    (val->attributes & VALATTR_TRIEDVERIFY) == 0)
+		{
+			saved_result = result;
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "falling back to insecurity proof");
+			result = proveunsecure(val, false, false);
+			if (result == DNS_R_NOTINSECURE) {
+				result = saved_result;
+			}
+		}
+		if (result != DNS_R_WAIT) {
+			validator_done(val, result);
+		}
+	} else {
+		if (eresult != DNS_R_BROKENCHAIN) {
+			expire_rdatasets(val);
+		}
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "validator_callback_dnskey: got %s",
+			      isc_result_totext(eresult));
+		validator_done(val, DNS_R_BROKENCHAIN);
+	}
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+/*%
+ * Callback when the DS record has been validated.
+ *
+ * Resumes validation of the zone key or the unsecure zone proof.
+ */
+static void
+validator_callback_ds(isc_task_t *task, isc_event_t *event) {
+	dns_validatorevent_t *devent;
+	dns_validator_t *val;
+	bool want_destroy;
+	isc_result_t result;
+	isc_result_t eresult;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);
+
+	devent = (dns_validatorevent_t *)event;
+	val = devent->ev_arg;
+	eresult = devent->result;
+
+	isc_event_free(&event);
+	dns_validator_destroy(&val->subvalidator);
+
+	INSIST(val->event != NULL);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in validator_callback_ds");
+	LOCK(&val->lock);
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+	} else if (eresult == ISC_R_SUCCESS) {
+		bool have_dsset;
+		dns_name_t *name;
+		validator_log(val, ISC_LOG_DEBUG(3), "%s with trust %s",
+			      val->frdataset.type == dns_rdatatype_ds ? "dsset"
+								      : "ds "
+									"non-"
+									"existe"
+									"nce",
+			      dns_trust_totext(val->frdataset.trust));
+		have_dsset = (val->frdataset.type == dns_rdatatype_ds);
+		name = dns_fixedname_name(&val->fname);
+		if ((val->attributes & VALATTR_INSECURITY) != 0 &&
+		    val->frdataset.covers == dns_rdatatype_ds &&
+		    NEGATIVE(&val->frdataset) &&
+		    isdelegation(name, &val->frdataset, DNS_R_NCACHENXRRSET))
+		{
+			result = markanswer(val, "validator_callback_ds",
+					    "no DS and this is a delegation");
+		} else if ((val->attributes & VALATTR_INSECURITY) != 0) {
+			result = proveunsecure(val, have_dsset, true);
+		} else {
+			result = validate_dnskey(val);
+		}
+		if (result != DNS_R_WAIT) {
+			validator_done(val, result);
+		}
+	} else {
+		if (eresult != DNS_R_BROKENCHAIN) {
+			expire_rdatasets(val);
+		}
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "validator_callback_ds: got %s",
+			      isc_result_totext(eresult));
+		validator_done(val, DNS_R_BROKENCHAIN);
+	}
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+/*%
+ * Callback when the CNAME record has been validated.
+ *
+ * Resumes validation of the unsecure zone proof.
+ */
+static void
+validator_callback_cname(isc_task_t *task, isc_event_t *event) {
+	dns_validatorevent_t *devent;
+	dns_validator_t *val;
+	bool want_destroy;
+	isc_result_t result;
+	isc_result_t eresult;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);
+
+	devent = (dns_validatorevent_t *)event;
+	val = devent->ev_arg;
+	eresult = devent->result;
+
+	isc_event_free(&event);
+	dns_validator_destroy(&val->subvalidator);
+
+	INSIST(val->event != NULL);
+	INSIST((val->attributes & VALATTR_INSECURITY) != 0);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in validator_callback_cname");
+	LOCK(&val->lock);
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+	} else if (eresult == ISC_R_SUCCESS) {
+		validator_log(val, ISC_LOG_DEBUG(3), "cname with trust %s",
+			      dns_trust_totext(val->frdataset.trust));
+		result = proveunsecure(val, false, true);
+		if (result != DNS_R_WAIT) {
+			validator_done(val, result);
+		}
+	} else {
+		if (eresult != DNS_R_BROKENCHAIN) {
+			expire_rdatasets(val);
+		}
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "validator_callback_cname: got %s",
+			      isc_result_totext(eresult));
+		validator_done(val, DNS_R_BROKENCHAIN);
+	}
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+/*%
+ * Callback for when NSEC records have been validated.
+ *
+ * Looks for NOQNAME, NODATA and OPTOUT proofs.
+ *
+ * Resumes the negative response validation by calling validate_nx().
+ */
+static void
+validator_callback_nsec(isc_task_t *task, isc_event_t *event) {
+	dns_validatorevent_t *devent;
+	dns_validator_t *val;
+	dns_rdataset_t *rdataset;
+	bool want_destroy;
+	isc_result_t result;
+	bool exists, data;
+
+	UNUSED(task);
+	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);
+
+	devent = (dns_validatorevent_t *)event;
+	rdataset = devent->rdataset;
+	val = devent->ev_arg;
+	result = devent->result;
+	dns_validator_destroy(&val->subvalidator);
+
+	INSIST(val->event != NULL);
+
+	validator_log(val, ISC_LOG_DEBUG(3), "in validator_callback_nsec");
+	LOCK(&val->lock);
+	if (CANCELED(val)) {
+		validator_done(val, ISC_R_CANCELED);
+	} else if (result != ISC_R_SUCCESS) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "validator_callback_nsec: got %s",
+			      isc_result_totext(result));
+		if (result == DNS_R_BROKENCHAIN) {
+			val->authfail++;
+		}
+		if (result == ISC_R_CANCELED) {
+			validator_done(val, result);
+		} else {
+			result = validate_nx(val, true);
+			if (result != DNS_R_WAIT) {
+				validator_done(val, result);
+			}
+		}
+	} else {
+		dns_name_t **proofs = val->event->proofs;
+		dns_name_t *wild = dns_fixedname_name(&val->wild);
+
+		if (rdataset->type == dns_rdatatype_nsec &&
+		    rdataset->trust == dns_trust_secure &&
+		    (NEEDNODATA(val) || NEEDNOQNAME(val)) &&
+		    !FOUNDNODATA(val) && !FOUNDNOQNAME(val) &&
+		    dns_nsec_noexistnodata(val->event->type, val->event->name,
+					   devent->name, rdataset, &exists,
+					   &data, wild, validator_log,
+					   val) == ISC_R_SUCCESS)
+		{
+			if (exists && !data) {
+				val->attributes |= VALATTR_FOUNDNODATA;
+				if (NEEDNODATA(val)) {
+					proofs[DNS_VALIDATOR_NODATAPROOF] =
+						devent->name;
+				}
+			}
+			if (!exists) {
+				dns_name_t *closest;
+				unsigned int clabels;
+
+				val->attributes |= VALATTR_FOUNDNOQNAME;
+
+				closest = dns_fixedname_name(&val->closest);
+				clabels = dns_name_countlabels(closest);
+				/*
+				 * If we are validating a wildcard response
+				 * clabels will not be zero.  We then need
+				 * to check if the generated wildcard from
+				 * dns_nsec_noexistnodata is consistent with
+				 * the wildcard used to generate the response.
+				 */
+				if (clabels == 0 ||
+				    dns_name_countlabels(wild) == clabels + 1)
+				{
+					val->attributes |= VALATTR_FOUNDCLOSEST;
+				}
+				/*
+				 * The NSEC noqname proof also contains
+				 * the closest encloser.
+				 */
+				if (NEEDNOQNAME(val)) {
+					proofs[DNS_VALIDATOR_NOQNAMEPROOF] =
+						devent->name;
+				}
+			}
+		}
+
+		result = validate_nx(val, true);
+		if (result != DNS_R_WAIT) {
+			validator_done(val, result);
+		}
+	}
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+
+	/*
+	 * Free stuff from the event.
+	 */
+	isc_event_free(&event);
+}
+
+/*%
+ * Looks for the requested name and type in the view (zones and cache).
+ *
+ * Returns:
+ * \li	ISC_R_SUCCESS
+ * \li	ISC_R_NOTFOUND
+ * \li	DNS_R_NCACHENXDOMAIN
+ * \li	DNS_R_NCACHENXRRSET
+ * \li	DNS_R_NXRRSET
+ * \li	DNS_R_NXDOMAIN
+ * \li	DNS_R_BROKENCHAIN
+ */
+static isc_result_t
+view_find(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type) {
+	dns_fixedname_t fixedname;
+	dns_name_t *foundname;
+	isc_result_t result;
+	unsigned int options;
+	isc_time_t now;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	char typebuf[DNS_RDATATYPE_FORMATSIZE];
+
+	disassociate_rdatasets(val);
+
+	if (isc_time_now(&now) == ISC_R_SUCCESS &&
+	    dns_resolver_getbadcache(val->view->resolver, name, type, &now))
+	{
+		dns_name_format(name, namebuf, sizeof(namebuf));
+		dns_rdatatype_format(type, typebuf, sizeof(typebuf));
+		validator_log(val, ISC_LOG_INFO, "bad cache hit (%s/%s)",
+			      namebuf, typebuf);
+		return (DNS_R_BROKENCHAIN);
+	}
+
+	options = DNS_DBFIND_PENDINGOK;
+	foundname = dns_fixedname_initname(&fixedname);
+	result = dns_view_find(val->view, name, type, 0, options, false, false,
+			       NULL, NULL, foundname, &val->frdataset,
+			       &val->fsigrdataset);
+
+	if (result == DNS_R_NXDOMAIN) {
+		goto notfound;
+	} else if (result != ISC_R_SUCCESS && result != DNS_R_NCACHENXDOMAIN &&
+		   result != DNS_R_NCACHENXRRSET && result != DNS_R_EMPTYNAME &&
+		   result != DNS_R_NXRRSET && result != ISC_R_NOTFOUND)
+	{
+		result = ISC_R_NOTFOUND;
+		goto notfound;
+	}
+
+	return (result);
+
+notfound:
+	disassociate_rdatasets(val);
+
+	return (result);
+}
+
+/*%
+ * Checks to make sure we are not going to loop.  As we use a SHARED fetch
+ * the validation process will stall if looping was to occur.
+ */
+static bool
+check_deadlock(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
+	       dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset) {
+	dns_validator_t *parent;
+
+	for (parent = val; parent != NULL; parent = parent->parent) {
+		if (parent->event != NULL && parent->event->type == type &&
+		    dns_name_equal(parent->event->name, name) &&
+		    /*
+		     * As NSEC3 records are meta data you sometimes
+		     * need to prove a NSEC3 record which says that
+		     * itself doesn't exist.
+		     */
+		    (parent->event->type != dns_rdatatype_nsec3 ||
+		     rdataset == NULL || sigrdataset == NULL ||
+		     parent->event->message == NULL ||
+		     parent->event->rdataset != NULL ||
+		     parent->event->sigrdataset != NULL))
+		{
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "continuing validation would lead to "
+				      "deadlock: aborting validation");
+			return (true);
+		}
+	}
+	return (false);
+}
+
+/*%
+ * Start a fetch for the requested name and type.
+ */
+static isc_result_t
+create_fetch(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
+	     isc_taskaction_t callback, const char *caller) {
+	unsigned int fopts = 0;
+
+	disassociate_rdatasets(val);
+
+	if (check_deadlock(val, name, type, NULL, NULL)) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "deadlock found (create_fetch)");
+		return (DNS_R_NOVALIDSIG);
+	}
+
+	if ((val->options & DNS_VALIDATOR_NOCDFLAG) != 0) {
+		fopts |= DNS_FETCHOPT_NOCDFLAG;
+	}
+
+	if ((val->options & DNS_VALIDATOR_NONTA) != 0) {
+		fopts |= DNS_FETCHOPT_NONTA;
+	}
+
+	validator_logcreate(val, name, type, caller, "fetch");
+	return (dns_resolver_createfetch(
+		val->view->resolver, name, type, NULL, NULL, NULL, NULL, 0,
+		fopts, 0, NULL, val->event->ev_sender, callback, val,
+		&val->frdataset, &val->fsigrdataset, &val->fetch));
+}
+
+/*%
+ * Start a subvalidation process.
+ */
+static isc_result_t
+create_validator(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
+		 dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
+		 isc_taskaction_t action, const char *caller) {
+	isc_result_t result;
+	unsigned int vopts = 0;
+	dns_rdataset_t *sig = NULL;
+
+	if (sigrdataset != NULL && dns_rdataset_isassociated(sigrdataset)) {
+		sig = sigrdataset;
+	}
+
+	if (check_deadlock(val, name, type, rdataset, sig)) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "deadlock found (create_validator)");
+		return (DNS_R_NOVALIDSIG);
+	}
+
+	/* OK to clear other options, but preserve NOCDFLAG and NONTA. */
+	vopts |= (val->options &
+		  (DNS_VALIDATOR_NOCDFLAG | DNS_VALIDATOR_NONTA));
+
+	validator_logcreate(val, name, type, caller, "validator");
+	result = dns_validator_create(val->view, name, type, rdataset, sig,
+				      NULL, vopts, val->task, action, val,
+				      &val->subvalidator);
+	if (result == ISC_R_SUCCESS) {
+		val->subvalidator->parent = val;
+		val->subvalidator->depth = val->depth + 1;
+	}
+	return (result);
+}
+
+/*%
+ * Try to find a key that could have signed val->siginfo among those in
+ * 'rdataset'.  If found, build a dst_key_t for it and point val->key at
+ * it.
+ *
+ * If val->key is already non-NULL, locate it in the rdataset and then
+ * search past it for the *next* key that could have signed 'siginfo', then
+ * set val->key to that.
+ *
+ * Returns ISC_R_SUCCESS if a possible matching key has been found,
+ * ISC_R_NOTFOUND if not. Any other value indicates error.
+ */
+static isc_result_t
+select_signing_key(dns_validator_t *val, dns_rdataset_t *rdataset) {
+	isc_result_t result;
+	dns_rdata_rrsig_t *siginfo = val->siginfo;
+	isc_buffer_t b;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	dst_key_t *oldkey = val->key;
+	bool foundold;
+
+	if (oldkey == NULL) {
+		foundold = true;
+	} else {
+		foundold = false;
+		val->key = NULL;
+	}
+
+	result = dns_rdataset_first(rdataset);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+	do {
+		dns_rdataset_current(rdataset, &rdata);
+
+		isc_buffer_init(&b, rdata.data, rdata.length);
+		isc_buffer_add(&b, rdata.length);
+		INSIST(val->key == NULL);
+		result = dst_key_fromdns(&siginfo->signer, rdata.rdclass, &b,
+					 val->view->mctx, &val->key);
+		if (result == ISC_R_SUCCESS) {
+			if (siginfo->algorithm ==
+				    (dns_secalg_t)dst_key_alg(val->key) &&
+			    siginfo->keyid ==
+				    (dns_keytag_t)dst_key_id(val->key) &&
+			    dst_key_iszonekey(val->key))
+			{
+				if (foundold) {
+					/*
+					 * This is the key we're looking for.
+					 */
+					return (ISC_R_SUCCESS);
+				} else if (dst_key_compare(oldkey, val->key)) {
+					foundold = true;
+					dst_key_free(&oldkey);
+				}
+			}
+			dst_key_free(&val->key);
+		}
+		dns_rdata_reset(&rdata);
+		result = dns_rdataset_next(rdataset);
+	} while (result == ISC_R_SUCCESS);
+
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_NOTFOUND;
+	}
+
+failure:
+	if (oldkey != NULL) {
+		dst_key_free(&oldkey);
+	}
+
+	return (result);
+}
+
+/*%
+ * Get the key that generated the signature in val->siginfo.
+ */
+static isc_result_t
+seek_dnskey(dns_validator_t *val) {
+	isc_result_t result;
+	dns_rdata_rrsig_t *siginfo = val->siginfo;
+	unsigned int nlabels;
+	int order;
+	dns_namereln_t namereln;
+
+	/*
+	 * Is the signer name appropriate for this signature?
+	 *
+	 * The signer name must be at the same level as the owner name
+	 * or closer to the DNS root.
+	 */
+	namereln = dns_name_fullcompare(val->event->name, &siginfo->signer,
+					&order, &nlabels);
+	if (namereln != dns_namereln_subdomain &&
+	    namereln != dns_namereln_equal)
+	{
+		return (DNS_R_CONTINUE);
+	}
+
+	if (namereln == dns_namereln_equal) {
+		/*
+		 * If this is a self-signed keyset, it must not be a zone key
+		 * (since seek_dnskey is not called from validate_dnskey).
+		 */
+		if (val->event->rdataset->type == dns_rdatatype_dnskey) {
+			return (DNS_R_CONTINUE);
+		}
+
+		/*
+		 * Records appearing in the parent zone at delegation
+		 * points cannot be self-signed.
+		 */
+		if (dns_rdatatype_atparent(val->event->rdataset->type)) {
+			return (DNS_R_CONTINUE);
+		}
+	} else {
+		/*
+		 * SOA and NS RRsets can only be signed by a key with
+		 * the same name.
+		 */
+		if (val->event->rdataset->type == dns_rdatatype_soa ||
+		    val->event->rdataset->type == dns_rdatatype_ns)
+		{
+			const char *type;
+
+			if (val->event->rdataset->type == dns_rdatatype_soa) {
+				type = "SOA";
+			} else {
+				type = "NS";
+			}
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "%s signer mismatch", type);
+			return (DNS_R_CONTINUE);
+		}
+	}
+
+	/*
+	 * Do we know about this key?
+	 */
+	result = view_find(val, &siginfo->signer, dns_rdatatype_dnskey);
+	switch (result) {
+	case ISC_R_SUCCESS:
+		/*
+		 * We have an rrset for the given keyname.
+		 */
+		val->keyset = &val->frdataset;
+		if ((DNS_TRUST_PENDING(val->frdataset.trust) ||
+		     DNS_TRUST_ANSWER(val->frdataset.trust)) &&
+		    dns_rdataset_isassociated(&val->fsigrdataset))
+		{
+			/*
+			 * We know the key but haven't validated it yet or
+			 * we have a key of trust answer but a DS
+			 * record for the zone may have been added.
+			 */
+			result = create_validator(
+				val, &siginfo->signer, dns_rdatatype_dnskey,
+				&val->frdataset, &val->fsigrdataset,
+				validator_callback_dnskey, "seek_dnskey");
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+			return (DNS_R_WAIT);
+		} else if (DNS_TRUST_PENDING(val->frdataset.trust)) {
+			/*
+			 * Having a pending key with no signature means that
+			 * something is broken.
+			 */
+			result = DNS_R_CONTINUE;
+		} else if (val->frdataset.trust < dns_trust_secure) {
+			/*
+			 * The key is legitimately insecure.  There's no
+			 * point in even attempting verification.
+			 */
+			val->key = NULL;
+			result = ISC_R_SUCCESS;
+		} else {
+			/*
+			 * See if we've got the key used in the signature.
+			 */
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "keyset with trust %s",
+				      dns_trust_totext(val->frdataset.trust));
+			result = select_signing_key(val, val->keyset);
+			if (result != ISC_R_SUCCESS) {
+				/*
+				 * Either the key we're looking for is not
+				 * in the rrset, or something bad happened.
+				 * Give up.
+				 */
+				result = DNS_R_CONTINUE;
+			}
+		}
+		break;
+
+	case ISC_R_NOTFOUND:
+		/*
+		 * We don't know anything about this key.
+		 */
+		result = create_fetch(val, &siginfo->signer,
+				      dns_rdatatype_dnskey,
+				      fetch_callback_dnskey, "seek_dnskey");
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		return (DNS_R_WAIT);
+
+	case DNS_R_NCACHENXDOMAIN:
+	case DNS_R_NCACHENXRRSET:
+	case DNS_R_EMPTYNAME:
+	case DNS_R_NXDOMAIN:
+	case DNS_R_NXRRSET:
+		/*
+		 * This key doesn't exist.
+		 */
+		result = DNS_R_CONTINUE;
+		break;
+
+	case DNS_R_BROKENCHAIN:
+		return (result);
+
+	default:
+		break;
+	}
+
+	if (dns_rdataset_isassociated(&val->frdataset) &&
+	    val->keyset != &val->frdataset)
+	{
+		dns_rdataset_disassociate(&val->frdataset);
+	}
+	if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+		dns_rdataset_disassociate(&val->fsigrdataset);
+	}
+
+	return (result);
+}
+
+/*
+ * Compute the tag for a key represented in a DNSKEY rdata.
+ */
+static dns_keytag_t
+compute_keytag(dns_rdata_t *rdata) {
+	isc_region_t r;
+
+	dns_rdata_toregion(rdata, &r);
+	return (dst_region_computeid(&r));
+}
+
+/*%
+ * Is the DNSKEY rrset in val->event->rdataset self-signed?
+ */
+static bool
+selfsigned_dnskey(dns_validator_t *val) {
+	dns_rdataset_t *rdataset = val->event->rdataset;
+	dns_rdataset_t *sigrdataset = val->event->sigrdataset;
+	dns_name_t *name = val->event->name;
+	isc_result_t result;
+	isc_mem_t *mctx = val->view->mctx;
+	bool answer = false;
+
+	if (rdataset->type != dns_rdatatype_dnskey) {
+		return (false);
+	}
+
+	for (result = dns_rdataset_first(rdataset); result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(rdataset))
+	{
+		dns_rdata_t keyrdata = DNS_RDATA_INIT;
+		dns_rdata_t sigrdata = DNS_RDATA_INIT;
+		dns_rdata_dnskey_t key;
+		dns_rdata_rrsig_t sig;
+		dns_keytag_t keytag;
+
+		dns_rdata_reset(&keyrdata);
+		dns_rdataset_current(rdataset, &keyrdata);
+		result = dns_rdata_tostruct(&keyrdata, &key, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+		keytag = compute_keytag(&keyrdata);
+
+		for (result = dns_rdataset_first(sigrdataset);
+		     result == ISC_R_SUCCESS;
+		     result = dns_rdataset_next(sigrdataset))
+		{
+			dst_key_t *dstkey = NULL;
+
+			dns_rdata_reset(&sigrdata);
+			dns_rdataset_current(sigrdataset, &sigrdata);
+			result = dns_rdata_tostruct(&sigrdata, &sig, NULL);
+			RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+			if (sig.algorithm != key.algorithm ||
+			    sig.keyid != keytag ||
+			    !dns_name_equal(name, &sig.signer))
+			{
+				continue;
+			}
+
+			/*
+			 * If the REVOKE bit is not set we have a
+			 * theoretically self signed DNSKEY RRset.
+			 * This will be verified later.
+			 */
+			if ((key.flags & DNS_KEYFLAG_REVOKE) == 0) {
+				answer = true;
+				continue;
+			}
+
+			result = dns_dnssec_keyfromrdata(name, &keyrdata, mctx,
+							 &dstkey);
+			if (result != ISC_R_SUCCESS) {
+				continue;
+			}
+
+			/*
+			 * If this RRset is pending and it is trusted,
+			 * see if it was self signed by this DNSKEY.
+			 */
+			if (DNS_TRUST_PENDING(rdataset->trust) &&
+			    dns_view_istrusted(val->view, name, &key))
+			{
+				result = dns_dnssec_verify(
+					name, rdataset, dstkey, true,
+					val->view->maxbits, mctx, &sigrdata,
+					NULL);
+				if (result == ISC_R_SUCCESS) {
+					/*
+					 * The key with the REVOKE flag has
+					 * self signed the RRset so it is no
+					 * good.
+					 */
+					dns_view_untrust(val->view, name, &key);
+				}
+			} else if (rdataset->trust >= dns_trust_secure) {
+				/*
+				 * We trust this RRset so if the key is
+				 * marked revoked remove it.
+				 */
+				dns_view_untrust(val->view, name, &key);
+			}
+
+			dst_key_free(&dstkey);
+		}
+	}
+
+	return (answer);
+}
+
+/*%
+ * Attempt to verify the rdataset using the given key and rdata (RRSIG).
+ * The signature was good and from a wildcard record and the QNAME does
+ * not match the wildcard we need to look for a NOQNAME proof.
+ *
+ * Returns:
+ * \li	ISC_R_SUCCESS if the verification succeeds.
+ * \li	Others if the verification fails.
+ */
+static isc_result_t
+verify(dns_validator_t *val, dst_key_t *key, dns_rdata_t *rdata,
+       uint16_t keyid) {
+	isc_result_t result;
+	dns_fixedname_t fixed;
+	bool ignore = false;
+	dns_name_t *wild;
+
+	val->attributes |= VALATTR_TRIEDVERIFY;
+	wild = dns_fixedname_initname(&fixed);
+again:
+	result = dns_dnssec_verify(val->event->name, val->event->rdataset, key,
+				   ignore, val->view->maxbits, val->view->mctx,
+				   rdata, wild);
+	if ((result == DNS_R_SIGEXPIRED || result == DNS_R_SIGFUTURE) &&
+	    val->view->acceptexpired)
+	{
+		ignore = true;
+		goto again;
+	}
+
+	if (ignore && (result == ISC_R_SUCCESS || result == DNS_R_FROMWILDCARD))
+	{
+		validator_log(val, ISC_LOG_INFO,
+			      "accepted expired %sRRSIG (keyid=%u)",
+			      (result == DNS_R_FROMWILDCARD) ? "wildcard " : "",
+			      keyid);
+	} else if (result == DNS_R_SIGEXPIRED || result == DNS_R_SIGFUTURE) {
+		validator_log(val, ISC_LOG_INFO,
+			      "verify failed due to bad signature (keyid=%u): "
+			      "%s",
+			      keyid, isc_result_totext(result));
+	} else {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "verify rdataset (keyid=%u): %s", keyid,
+			      isc_result_totext(result));
+	}
+	if (result == DNS_R_FROMWILDCARD) {
+		if (!dns_name_equal(val->event->name, wild)) {
+			dns_name_t *closest;
+			unsigned int labels;
+
+			/*
+			 * Compute the closest encloser in case we need it
+			 * for the NSEC3 NOQNAME proof.
+			 */
+			closest = dns_fixedname_name(&val->closest);
+			dns_name_copy(wild, closest);
+			labels = dns_name_countlabels(closest) - 1;
+			dns_name_getlabelsequence(closest, 1, labels, closest);
+			val->attributes |= VALATTR_NEEDNOQNAME;
+		}
+		result = ISC_R_SUCCESS;
+	}
+	return (result);
+}
+
+/*%
+ * Attempts positive response validation of a normal RRset.
+ *
+ * Returns:
+ * \li	ISC_R_SUCCESS	Validation completed successfully
+ * \li	DNS_R_WAIT	Validation has started but is waiting
+ *			for an event.
+ * \li	Other return codes are possible and all indicate failure.
+ */
+static isc_result_t
+validate_answer(dns_validator_t *val, bool resume) {
+	isc_result_t result, vresult = DNS_R_NOVALIDSIG;
+	dns_validatorevent_t *event;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+
+	/*
+	 * Caller must be holding the validator lock.
+	 */
+
+	event = val->event;
+
+	if (resume) {
+		/*
+		 * We already have a sigrdataset.
+		 */
+		result = ISC_R_SUCCESS;
+		validator_log(val, ISC_LOG_DEBUG(3), "resuming validate");
+	} else {
+		result = dns_rdataset_first(event->sigrdataset);
+	}
+
+	for (; result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(event->sigrdataset))
+	{
+		dns_rdata_reset(&rdata);
+		dns_rdataset_current(event->sigrdataset, &rdata);
+		if (val->siginfo == NULL) {
+			val->siginfo = isc_mem_get(val->view->mctx,
+						   sizeof(*val->siginfo));
+		}
+		result = dns_rdata_tostruct(&rdata, val->siginfo, NULL);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+
+		/*
+		 * At this point we could check that the signature algorithm
+		 * was known and "sufficiently good".
+		 */
+		if (!dns_resolver_algorithm_supported(val->view->resolver,
+						      event->name,
+						      val->siginfo->algorithm))
+		{
+			resume = false;
+			continue;
+		}
+
+		if (!resume) {
+			result = seek_dnskey(val);
+			if (result == DNS_R_CONTINUE) {
+				continue; /* Try the next SIG RR. */
+			}
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+		}
+
+		/*
+		 * There isn't a secure DNSKEY for this signature so move
+		 * onto the next RRSIG.
+		 */
+		if (val->key == NULL) {
+			resume = false;
+			continue;
+		}
+
+		do {
+			isc_result_t tresult;
+			vresult = verify(val, val->key, &rdata,
+					 val->siginfo->keyid);
+			if (vresult == ISC_R_SUCCESS) {
+				break;
+			}
+
+			tresult = select_signing_key(val, val->keyset);
+			if (tresult != ISC_R_SUCCESS) {
+				break;
+			}
+		} while (1);
+		if (vresult != ISC_R_SUCCESS) {
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "failed to verify rdataset");
+		} else {
+			dns_rdataset_trimttl(event->rdataset,
+					     event->sigrdataset, val->siginfo,
+					     val->start,
+					     val->view->acceptexpired);
+		}
+
+		if (val->key != NULL) {
+			dst_key_free(&val->key);
+		}
+		if (val->keyset != NULL) {
+			dns_rdataset_disassociate(val->keyset);
+			val->keyset = NULL;
+		}
+		val->key = NULL;
+		if (NEEDNOQNAME(val)) {
+			if (val->event->message == NULL) {
+				validator_log(val, ISC_LOG_DEBUG(3),
+					      "no message available "
+					      "for noqname proof");
+				return (DNS_R_NOVALIDSIG);
+			}
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "looking for noqname proof");
+			return (validate_nx(val, false));
+		} else if (vresult == ISC_R_SUCCESS) {
+			marksecure(event);
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "marking as secure, "
+				      "noqname proof not needed");
+			return (ISC_R_SUCCESS);
+		} else {
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "verify failure: %s",
+				      isc_result_totext(result));
+			resume = false;
+		}
+	}
+	if (result != ISC_R_NOMORE) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "failed to iterate signatures: %s",
+			      isc_result_totext(result));
+		return (result);
+	}
+
+	validator_log(val, ISC_LOG_INFO, "no valid signature found");
+	return (vresult);
+}
+
+/*%
+ * Check whether this DNSKEY (keyrdata) signed the DNSKEY RRset
+ * (val->event->rdataset).
+ */
+static isc_result_t
+check_signer(dns_validator_t *val, dns_rdata_t *keyrdata, uint16_t keyid,
+	     dns_secalg_t algorithm) {
+	dns_rdata_rrsig_t sig;
+	dst_key_t *dstkey = NULL;
+	isc_result_t result;
+
+	for (result = dns_rdataset_first(val->event->sigrdataset);
+	     result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(val->event->sigrdataset))
+	{
+		dns_rdata_t rdata = DNS_RDATA_INIT;
+
+		dns_rdataset_current(val->event->sigrdataset, &rdata);
+		result = dns_rdata_tostruct(&rdata, &sig, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+		if (keyid != sig.keyid || algorithm != sig.algorithm) {
+			continue;
+		}
+		if (dstkey == NULL) {
+			result = dns_dnssec_keyfromrdata(
+				val->event->name, keyrdata, val->view->mctx,
+				&dstkey);
+			if (result != ISC_R_SUCCESS) {
+				/*
+				 * This really shouldn't happen, but...
+				 */
+				continue;
+			}
+		}
+		result = verify(val, dstkey, &rdata, sig.keyid);
+		if (result == ISC_R_SUCCESS) {
+			break;
+		}
+	}
+
+	if (dstkey != NULL) {
+		dst_key_free(&dstkey);
+	}
+
+	return (result);
+}
+
+/*
+ * get_dsset() is called to look up a DS RRset corresponding to the name
+ * of a DNSKEY record, either in the cache or, if necessary, by starting a
+ * fetch. This is done in the context of validating a zone key to build a
+ * trust chain.
+ *
+ * Returns:
+ * \li	ISC_R_COMPLETE		a DS has not been found; the caller should
+ *				stop trying to validate the zone key and
+ *				return the result code in '*resp'.
+ * \li	DNS_R_CONTINUE		a DS has been found and the caller may
+ * 				continue the zone key validation.
+ */
+static isc_result_t
+get_dsset(dns_validator_t *val, dns_name_t *tname, isc_result_t *resp) {
+	isc_result_t result;
+
+	result = view_find(val, tname, dns_rdatatype_ds);
+	switch (result) {
+	case ISC_R_SUCCESS:
+		/*
+		 * We have a DS RRset.
+		 */
+		val->dsset = &val->frdataset;
+		if ((DNS_TRUST_PENDING(val->frdataset.trust) ||
+		     DNS_TRUST_ANSWER(val->frdataset.trust)) &&
+		    dns_rdataset_isassociated(&val->fsigrdataset))
+		{
+			/*
+			 * ... which is signed but not yet validated.
+			 */
+			result = create_validator(
+				val, tname, dns_rdatatype_ds, &val->frdataset,
+				&val->fsigrdataset, validator_callback_ds,
+				"validate_dnskey");
+			*resp = DNS_R_WAIT;
+			if (result != ISC_R_SUCCESS) {
+				*resp = result;
+			}
+			return (ISC_R_COMPLETE);
+		} else if (DNS_TRUST_PENDING(val->frdataset.trust)) {
+			/*
+			 * There should never be an unsigned DS.
+			 */
+			disassociate_rdatasets(val);
+			validator_log(val, ISC_LOG_DEBUG(2),
+				      "unsigned DS record");
+			*resp = DNS_R_NOVALIDSIG;
+			return (ISC_R_COMPLETE);
+		}
+		break;
+
+	case ISC_R_NOTFOUND:
+		/*
+		 * We don't have the DS.  Find it.
+		 */
+		result = create_fetch(val, tname, dns_rdatatype_ds,
+				      fetch_callback_ds, "validate_dnskey");
+		*resp = DNS_R_WAIT;
+		if (result != ISC_R_SUCCESS) {
+			*resp = result;
+		}
+		return (ISC_R_COMPLETE);
+
+	case DNS_R_NCACHENXDOMAIN:
+	case DNS_R_NCACHENXRRSET:
+	case DNS_R_EMPTYNAME:
+	case DNS_R_NXDOMAIN:
+	case DNS_R_NXRRSET:
+	case DNS_R_CNAME:
+		/*
+		 * The DS does not exist.
+		 */
+		disassociate_rdatasets(val);
+		validator_log(val, ISC_LOG_DEBUG(2), "no DS record");
+		*resp = DNS_R_NOVALIDSIG;
+		return (ISC_R_COMPLETE);
+
+	case DNS_R_BROKENCHAIN:
+		*resp = result;
+		return (ISC_R_COMPLETE);
+
+	default:
+		break;
+	}
+
+	return (DNS_R_CONTINUE);
+}
+
+/*%
+ * Attempts positive response validation of an RRset containing zone keys
+ * (i.e. a DNSKEY rrset).
+ *
+ * Caller must be holding the validator lock.
+ *
+ * Returns:
+ * \li	ISC_R_SUCCESS	Validation completed successfully
+ * \li	DNS_R_WAIT	Validation has started but is waiting
+ *			for an event.
+ * \li	Other return codes are possible and all indicate failure.
+ */
+static isc_result_t
+validate_dnskey(dns_validator_t *val) {
+	isc_result_t result;
+	dns_rdata_t dsrdata = DNS_RDATA_INIT;
+	dns_rdata_t keyrdata = DNS_RDATA_INIT;
+	dns_keynode_t *keynode = NULL;
+	dns_rdata_ds_t ds;
+	bool supported_algorithm;
+	char digest_types[256];
+
+	/*
+	 * If we don't already have a DS RRset, check to see if there's
+	 * a DS style trust anchor configured for this key.
+	 */
+	if (val->dsset == NULL) {
+		result = dns_keytable_find(val->keytable, val->event->name,
+					   &keynode);
+		if (result == ISC_R_SUCCESS) {
+			if (dns_keynode_dsset(keynode, &val->fdsset)) {
+				val->dsset = &val->fdsset;
+			}
+			dns_keytable_detachkeynode(val->keytable, &keynode);
+		}
+	}
+
+	/*
+	 * No trust anchor for this name, so we look up the DS at the parent.
+	 */
+	if (val->dsset == NULL) {
+		isc_result_t tresult = ISC_R_SUCCESS;
+
+		/*
+		 * If this is the root name and there was no trust anchor,
+		 * we can give up now, since there's no DS at the root.
+		 */
+		if (dns_name_equal(val->event->name, dns_rootname)) {
+			if ((val->attributes & VALATTR_TRIEDVERIFY) != 0) {
+				validator_log(val, ISC_LOG_DEBUG(3),
+					      "root key failed to validate");
+			} else {
+				validator_log(val, ISC_LOG_DEBUG(3),
+					      "no trusted root key");
+			}
+			result = DNS_R_NOVALIDSIG;
+			goto cleanup;
+		}
+
+		/*
+		 * Look up the DS RRset for this name.
+		 */
+		result = get_dsset(val, val->event->name, &tresult);
+		if (result == ISC_R_COMPLETE) {
+			result = tresult;
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * We have a DS set.
+	 */
+	INSIST(val->dsset != NULL);
+
+	if (val->dsset->trust < dns_trust_secure) {
+		result = markanswer(val, "validate_dnskey (2)", "insecure DS");
+		goto cleanup;
+	}
+
+	/*
+	 * Look through the DS record and find the keys that can sign the
+	 * key set and the matching signature.  For each such key, attempt
+	 * verification.
+	 */
+
+	supported_algorithm = false;
+
+	/*
+	 * If DNS_DSDIGEST_SHA256 or DNS_DSDIGEST_SHA384 is present we
+	 * are required to prefer it over DNS_DSDIGEST_SHA1.  This in
+	 * practice means that we need to ignore DNS_DSDIGEST_SHA1 if a
+	 * DNS_DSDIGEST_SHA256 or DNS_DSDIGEST_SHA384 is present.
+	 */
+	memset(digest_types, 1, sizeof(digest_types));
+	for (result = dns_rdataset_first(val->dsset); result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(val->dsset))
+	{
+		dns_rdata_reset(&dsrdata);
+		dns_rdataset_current(val->dsset, &dsrdata);
+		result = dns_rdata_tostruct(&dsrdata, &ds, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+		if (!dns_resolver_ds_digest_supported(val->view->resolver,
+						      val->event->name,
+						      ds.digest_type))
+		{
+			continue;
+		}
+
+		if (!dns_resolver_algorithm_supported(val->view->resolver,
+						      val->event->name,
+						      ds.algorithm))
+		{
+			continue;
+		}
+
+		if ((ds.digest_type == DNS_DSDIGEST_SHA256 &&
+		     ds.length == ISC_SHA256_DIGESTLENGTH) ||
+		    (ds.digest_type == DNS_DSDIGEST_SHA384 &&
+		     ds.length == ISC_SHA384_DIGESTLENGTH))
+		{
+			digest_types[DNS_DSDIGEST_SHA1] = 0;
+			break;
+		}
+	}
+
+	for (result = dns_rdataset_first(val->dsset); result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(val->dsset))
+	{
+		dns_rdata_reset(&dsrdata);
+		dns_rdataset_current(val->dsset, &dsrdata);
+		result = dns_rdata_tostruct(&dsrdata, &ds, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+		if (digest_types[ds.digest_type] == 0) {
+			continue;
+		}
+
+		if (!dns_resolver_ds_digest_supported(val->view->resolver,
+						      val->event->name,
+						      ds.digest_type))
+		{
+			continue;
+		}
+
+		if (!dns_resolver_algorithm_supported(val->view->resolver,
+						      val->event->name,
+						      ds.algorithm))
+		{
+			continue;
+		}
+
+		supported_algorithm = true;
+
+		/*
+		 * Find the DNSKEY matching the DS...
+		 */
+		result = dns_dnssec_matchdskey(val->event->name, &dsrdata,
+					       val->event->rdataset, &keyrdata);
+		if (result != ISC_R_SUCCESS) {
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "no DNSKEY matching DS");
+			continue;
+		}
+
+		/*
+		 * ... and check that it signed the DNSKEY RRset.
+		 */
+		result = check_signer(val, &keyrdata, ds.key_tag, ds.algorithm);
+		if (result == ISC_R_SUCCESS) {
+			break;
+		}
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "no RRSIG matching DS key");
+	}
+
+	if (result == ISC_R_SUCCESS) {
+		marksecure(val->event);
+		validator_log(val, ISC_LOG_DEBUG(3), "marking as secure (DS)");
+	} else if (result == ISC_R_NOMORE && !supported_algorithm) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "no supported algorithm/digest (DS)");
+		result = markanswer(val, "validate_dnskey (3)",
+				    "no supported algorithm/digest (DS)");
+	} else {
+		validator_log(val, ISC_LOG_INFO,
+			      "no valid signature found (DS)");
+		result = DNS_R_NOVALIDSIG;
+	}
+
+cleanup:
+	if (val->dsset == &val->fdsset) {
+		val->dsset = NULL;
+		dns_rdataset_disassociate(&val->fdsset);
+	}
+
+	return (result);
+}
+
+/*%
+ * val_rdataset_first and val_rdataset_next provide iteration methods
+ * that hide whether we are iterating across the AUTHORITY section of
+ * a message, or a negative cache rdataset.
+ */
+static isc_result_t
+val_rdataset_first(dns_validator_t *val, dns_name_t **namep,
+		   dns_rdataset_t **rdatasetp) {
+	dns_message_t *message = val->event->message;
+	isc_result_t result;
+
+	REQUIRE(rdatasetp != NULL);
+	REQUIRE(namep != NULL);
+	if (message == NULL) {
+		REQUIRE(*rdatasetp != NULL);
+		REQUIRE(*namep != NULL);
+	} else {
+		REQUIRE(*rdatasetp == NULL);
+		REQUIRE(*namep == NULL);
+	}
+
+	if (message != NULL) {
+		result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		dns_message_currentname(message, DNS_SECTION_AUTHORITY, namep);
+		*rdatasetp = ISC_LIST_HEAD((*namep)->list);
+		INSIST(*rdatasetp != NULL);
+	} else {
+		result = dns_rdataset_first(val->event->rdataset);
+		if (result == ISC_R_SUCCESS) {
+			dns_ncache_current(val->event->rdataset, *namep,
+					   *rdatasetp);
+		}
+	}
+	return (result);
+}
+
+static isc_result_t
+val_rdataset_next(dns_validator_t *val, dns_name_t **namep,
+		  dns_rdataset_t **rdatasetp) {
+	dns_message_t *message = val->event->message;
+	isc_result_t result = ISC_R_SUCCESS;
+
+	REQUIRE(rdatasetp != NULL && *rdatasetp != NULL);
+	REQUIRE(namep != NULL && *namep != NULL);
+
+	if (message != NULL) {
+		dns_rdataset_t *rdataset = *rdatasetp;
+		rdataset = ISC_LIST_NEXT(rdataset, link);
+		if (rdataset == NULL) {
+			*namep = NULL;
+			result = dns_message_nextname(message,
+						      DNS_SECTION_AUTHORITY);
+			if (result == ISC_R_SUCCESS) {
+				dns_message_currentname(
+					message, DNS_SECTION_AUTHORITY, namep);
+				rdataset = ISC_LIST_HEAD((*namep)->list);
+				INSIST(rdataset != NULL);
+			}
+		}
+		*rdatasetp = rdataset;
+	} else {
+		dns_rdataset_disassociate(*rdatasetp);
+		result = dns_rdataset_next(val->event->rdataset);
+		if (result == ISC_R_SUCCESS) {
+			dns_ncache_current(val->event->rdataset, *namep,
+					   *rdatasetp);
+		}
+	}
+	return (result);
+}
+
+/*%
+ * Look for NODATA at the wildcard and NOWILDCARD proofs in the
+ * previously validated NSEC records.  As these proofs are mutually
+ * exclusive we stop when one is found.
+ *
+ * Returns
+ * \li	ISC_R_SUCCESS
+ */
+static isc_result_t
+checkwildcard(dns_validator_t *val, dns_rdatatype_t type,
+	      dns_name_t *zonename) {
+	dns_name_t *name, *wild, tname;
+	isc_result_t result;
+	bool exists, data;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	dns_rdataset_t *rdataset, trdataset;
+
+	dns_name_init(&tname, NULL);
+	dns_rdataset_init(&trdataset);
+	wild = dns_fixedname_name(&val->wild);
+
+	if (dns_name_countlabels(wild) == 0) {
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "in checkwildcard: no wildcard to check");
+		return (ISC_R_SUCCESS);
+	}
+
+	dns_name_format(wild, namebuf, sizeof(namebuf));
+	validator_log(val, ISC_LOG_DEBUG(3), "in checkwildcard: %s", namebuf);
+
+	if (val->event->message == NULL) {
+		name = &tname;
+		rdataset = &trdataset;
+	} else {
+		name = NULL;
+		rdataset = NULL;
+	}
+
+	for (result = val_rdataset_first(val, &name, &rdataset);
+	     result == ISC_R_SUCCESS;
+	     result = val_rdataset_next(val, &name, &rdataset))
+	{
+		if (rdataset->type != type ||
+		    rdataset->trust != dns_trust_secure)
+		{
+			continue;
+		}
+
+		if (rdataset->type == dns_rdatatype_nsec &&
+		    (NEEDNODATA(val) || NEEDNOWILDCARD(val)) &&
+		    !FOUNDNODATA(val) && !FOUNDNOWILDCARD(val) &&
+		    dns_nsec_noexistnodata(val->event->type, wild, name,
+					   rdataset, &exists, &data, NULL,
+					   validator_log, val) == ISC_R_SUCCESS)
+		{
+			dns_name_t **proofs = val->event->proofs;
+			if (exists && !data) {
+				val->attributes |= VALATTR_FOUNDNODATA;
+			}
+			if (exists && !data && NEEDNODATA(val)) {
+				proofs[DNS_VALIDATOR_NODATAPROOF] = name;
+			}
+			if (!exists) {
+				val->attributes |= VALATTR_FOUNDNOWILDCARD;
+			}
+			if (!exists && NEEDNOQNAME(val)) {
+				proofs[DNS_VALIDATOR_NOWILDCARDPROOF] = name;
+			}
+			if (dns_rdataset_isassociated(&trdataset)) {
+				dns_rdataset_disassociate(&trdataset);
+			}
+			return (ISC_R_SUCCESS);
+		}
+
+		if (rdataset->type == dns_rdatatype_nsec3 &&
+		    (NEEDNODATA(val) || NEEDNOWILDCARD(val)) &&
+		    !FOUNDNODATA(val) && !FOUNDNOWILDCARD(val) &&
+		    dns_nsec3_noexistnodata(
+			    val->event->type, wild, name, rdataset, zonename,
+			    &exists, &data, NULL, NULL, NULL, NULL, NULL, NULL,
+			    validator_log, val) == ISC_R_SUCCESS)
+		{
+			dns_name_t **proofs = val->event->proofs;
+			if (exists && !data) {
+				val->attributes |= VALATTR_FOUNDNODATA;
+			}
+			if (exists && !data && NEEDNODATA(val)) {
+				proofs[DNS_VALIDATOR_NODATAPROOF] = name;
+			}
+			if (!exists) {
+				val->attributes |= VALATTR_FOUNDNOWILDCARD;
+			}
+			if (!exists && NEEDNOQNAME(val)) {
+				proofs[DNS_VALIDATOR_NOWILDCARDPROOF] = name;
+			}
+			if (dns_rdataset_isassociated(&trdataset)) {
+				dns_rdataset_disassociate(&trdataset);
+			}
+			return (ISC_R_SUCCESS);
+		}
+	}
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+	if (dns_rdataset_isassociated(&trdataset)) {
+		dns_rdataset_disassociate(&trdataset);
+	}
+	return (result);
+}
+
+/*
+ * Look for the needed proofs for a negative or wildcard response
+ * from a zone using NSEC3, and set flags in the validator as they
+ * are found.
+ */
+static isc_result_t
+findnsec3proofs(dns_validator_t *val) {
+	dns_name_t *name, tname;
+	isc_result_t result;
+	bool exists, data, optout, unknown;
+	bool setclosest, setnearest, *setclosestp;
+	dns_fixedname_t fclosest, fnearest, fzonename;
+	dns_name_t *closest, *nearest, *zonename, *closestp;
+	dns_name_t **proofs = val->event->proofs;
+	dns_rdataset_t *rdataset, trdataset;
+
+	dns_name_init(&tname, NULL);
+	dns_rdataset_init(&trdataset);
+	closest = dns_fixedname_initname(&fclosest);
+	nearest = dns_fixedname_initname(&fnearest);
+	zonename = dns_fixedname_initname(&fzonename);
+
+	if (val->event->message == NULL) {
+		name = &tname;
+		rdataset = &trdataset;
+	} else {
+		name = NULL;
+		rdataset = NULL;
+	}
+
+	for (result = val_rdataset_first(val, &name, &rdataset);
+	     result == ISC_R_SUCCESS;
+	     result = val_rdataset_next(val, &name, &rdataset))
+	{
+		if (rdataset->type != dns_rdatatype_nsec3 ||
+		    rdataset->trust != dns_trust_secure)
+		{
+			continue;
+		}
+
+		result = dns_nsec3_noexistnodata(
+			val->event->type, val->event->name, name, rdataset,
+			zonename, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+			NULL, validator_log, val);
+		if (result != ISC_R_IGNORE && result != ISC_R_SUCCESS) {
+			if (dns_rdataset_isassociated(&trdataset)) {
+				dns_rdataset_disassociate(&trdataset);
+			}
+			return (result);
+		}
+	}
+	if (result != ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+	POST(result);
+
+	if (dns_name_countlabels(zonename) == 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	/*
+	 * If the val->closest is set then we want to use it otherwise
+	 * we need to discover it.
+	 */
+	if (dns_name_countlabels(dns_fixedname_name(&val->closest)) != 0) {
+		char namebuf[DNS_NAME_FORMATSIZE];
+
+		dns_name_format(dns_fixedname_name(&val->closest), namebuf,
+				sizeof(namebuf));
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "closest encloser from wildcard signature '%s'",
+			      namebuf);
+		dns_name_copy(dns_fixedname_name(&val->closest), closest);
+		closestp = NULL;
+		setclosestp = NULL;
+	} else {
+		closestp = closest;
+		setclosestp = &setclosest;
+	}
+
+	for (result = val_rdataset_first(val, &name, &rdataset);
+	     result == ISC_R_SUCCESS;
+	     result = val_rdataset_next(val, &name, &rdataset))
+	{
+		if (rdataset->type != dns_rdatatype_nsec3 ||
+		    rdataset->trust != dns_trust_secure)
+		{
+			continue;
+		}
+
+		/*
+		 * We process all NSEC3 records to find the closest
+		 * encloser and nearest name to the closest encloser.
+		 */
+		setclosest = setnearest = false;
+		optout = false;
+		unknown = false;
+		result = dns_nsec3_noexistnodata(
+			val->event->type, val->event->name, name, rdataset,
+			zonename, &exists, &data, &optout, &unknown,
+			setclosestp, &setnearest, closestp, nearest,
+			validator_log, val);
+		if (unknown) {
+			val->attributes |= VALATTR_FOUNDUNKNOWN;
+		}
+		if (result == DNS_R_NSEC3ITERRANGE) {
+			/*
+			 * We don't really know which NSEC3 record provides
+			 * which proof.  Just populate them.
+			 */
+			if (NEEDNOQNAME(val) &&
+			    proofs[DNS_VALIDATOR_NOQNAMEPROOF] == NULL)
+			{
+				proofs[DNS_VALIDATOR_NOQNAMEPROOF] = name;
+			} else if (setclosest) {
+				proofs[DNS_VALIDATOR_CLOSESTENCLOSER] = name;
+			} else if (NEEDNODATA(val) &&
+				   proofs[DNS_VALIDATOR_NODATAPROOF] == NULL)
+			{
+				proofs[DNS_VALIDATOR_NODATAPROOF] = name;
+			} else if (NEEDNOWILDCARD(val) &&
+				   proofs[DNS_VALIDATOR_NOWILDCARDPROOF] ==
+					   NULL)
+			{
+				proofs[DNS_VALIDATOR_NOWILDCARDPROOF] = name;
+			}
+			return (result);
+		}
+		if (result != ISC_R_SUCCESS) {
+			continue;
+		}
+		if (setclosest) {
+			proofs[DNS_VALIDATOR_CLOSESTENCLOSER] = name;
+		}
+		if (exists && !data && NEEDNODATA(val)) {
+			val->attributes |= VALATTR_FOUNDNODATA;
+			proofs[DNS_VALIDATOR_NODATAPROOF] = name;
+		}
+		if (!exists && setnearest) {
+			val->attributes |= VALATTR_FOUNDNOQNAME;
+			proofs[DNS_VALIDATOR_NOQNAMEPROOF] = name;
+			if (optout) {
+				val->attributes |= VALATTR_FOUNDOPTOUT;
+			}
+		}
+	}
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+
+	/*
+	 * To know we have a valid noqname and optout proofs we need to also
+	 * have a valid closest encloser.  Otherwise we could still be looking
+	 * at proofs from the parent zone.
+	 */
+	if (dns_name_countlabels(closest) > 0 &&
+	    dns_name_countlabels(nearest) ==
+		    dns_name_countlabels(closest) + 1 &&
+	    dns_name_issubdomain(nearest, closest))
+	{
+		val->attributes |= VALATTR_FOUNDCLOSEST;
+		result = dns_name_concatenate(dns_wildcardname, closest,
+					      dns_fixedname_name(&val->wild),
+					      NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	} else {
+		val->attributes &= ~VALATTR_FOUNDNOQNAME;
+		val->attributes &= ~VALATTR_FOUNDOPTOUT;
+		proofs[DNS_VALIDATOR_NOQNAMEPROOF] = NULL;
+	}
+
+	/*
+	 * Do we need to check for the wildcard?
+	 */
+	if (FOUNDNOQNAME(val) && FOUNDCLOSEST(val) &&
+	    ((NEEDNODATA(val) && !FOUNDNODATA(val)) || NEEDNOWILDCARD(val)))
+	{
+		result = checkwildcard(val, dns_rdatatype_nsec3, zonename);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+	return (result);
+}
+
+/*
+ * Start a validator for negative response data.
+ *
+ * Returns:
+ * \li	DNS_R_CONTINUE	Validation skipped, continue
+ * \li	DNS_R_WAIT	Validation is in progress
+ *
+ * \li	Other return codes indicate failure.
+ */
+static isc_result_t
+validate_neg_rrset(dns_validator_t *val, dns_name_t *name,
+		   dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset) {
+	isc_result_t result;
+
+	/*
+	 * If a signed zone is missing the zone key, bad
+	 * things could happen.  A query for data in the zone
+	 * would lead to a query for the zone key, which
+	 * would return a negative answer, which would contain
+	 * an SOA and an NSEC signed by the missing key, which
+	 * would trigger another query for the DNSKEY (since
+	 * the first one is still in progress), and go into an
+	 * infinite loop.  Avoid that.
+	 */
+	if (val->event->type == dns_rdatatype_dnskey &&
+	    rdataset->type == dns_rdatatype_nsec &&
+	    dns_name_equal(name, val->event->name))
+	{
+		dns_rdata_t nsec = DNS_RDATA_INIT;
+
+		result = dns_rdataset_first(rdataset);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+		dns_rdataset_current(rdataset, &nsec);
+		if (dns_nsec_typepresent(&nsec, dns_rdatatype_soa)) {
+			return (DNS_R_CONTINUE);
+		}
+	}
+
+	val->currentset = rdataset;
+	result = create_validator(val, name, rdataset->type, rdataset,
+				  sigrdataset, validator_callback_nsec,
+				  "validate_neg_rrset");
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	val->authcount++;
+	return (DNS_R_WAIT);
+}
+
+/*%
+ * Validate the authority section records.
+ */
+static isc_result_t
+validate_authority(dns_validator_t *val, bool resume) {
+	dns_name_t *name;
+	dns_message_t *message = val->event->message;
+	isc_result_t result;
+
+	if (!resume) {
+		result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
+	} else {
+		result = ISC_R_SUCCESS;
+	}
+
+	for (; result == ISC_R_SUCCESS;
+	     result = dns_message_nextname(message, DNS_SECTION_AUTHORITY))
+	{
+		dns_rdataset_t *rdataset = NULL, *sigrdataset = NULL;
+
+		name = NULL;
+		dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
+		if (resume) {
+			rdataset = ISC_LIST_NEXT(val->currentset, link);
+			val->currentset = NULL;
+			resume = false;
+		} else {
+			rdataset = ISC_LIST_HEAD(name->list);
+		}
+
+		for (; rdataset != NULL;
+		     rdataset = ISC_LIST_NEXT(rdataset, link))
+		{
+			if (rdataset->type == dns_rdatatype_rrsig) {
+				continue;
+			}
+
+			for (sigrdataset = ISC_LIST_HEAD(name->list);
+			     sigrdataset != NULL;
+			     sigrdataset = ISC_LIST_NEXT(sigrdataset, link))
+			{
+				if (sigrdataset->type == dns_rdatatype_rrsig &&
+				    sigrdataset->covers == rdataset->type)
+				{
+					break;
+				}
+			}
+
+			result = validate_neg_rrset(val, name, rdataset,
+						    sigrdataset);
+			if (result != DNS_R_CONTINUE) {
+				return (result);
+			}
+		}
+	}
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+	return (result);
+}
+
+/*%
+ * Validate negative cache elements.
+ */
+static isc_result_t
+validate_ncache(dns_validator_t *val, bool resume) {
+	dns_name_t *name;
+	isc_result_t result;
+
+	if (!resume) {
+		result = dns_rdataset_first(val->event->rdataset);
+	} else {
+		result = dns_rdataset_next(val->event->rdataset);
+	}
+
+	for (; result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(val->event->rdataset))
+	{
+		dns_rdataset_t *rdataset, *sigrdataset = NULL;
+
+		disassociate_rdatasets(val);
+
+		name = dns_fixedname_initname(&val->fname);
+		rdataset = &val->frdataset;
+		dns_ncache_current(val->event->rdataset, name, rdataset);
+
+		if (val->frdataset.type == dns_rdatatype_rrsig) {
+			continue;
+		}
+
+		result = dns_ncache_getsigrdataset(val->event->rdataset, name,
+						   rdataset->type,
+						   &val->fsigrdataset);
+		if (result == ISC_R_SUCCESS) {
+			sigrdataset = &val->fsigrdataset;
+		}
+
+		result = validate_neg_rrset(val, name, rdataset, sigrdataset);
+		if (result == DNS_R_CONTINUE) {
+			continue;
+		}
+
+		return (result);
+	}
+	if (result == ISC_R_NOMORE) {
+		result = ISC_R_SUCCESS;
+	}
+
+	return (result);
+}
+
+/*%
+ * Prove a negative answer is good or that there is a NOQNAME when the
+ * answer is from a wildcard.
+ *
+ * Loop through the authority section looking for NODATA, NOWILDCARD
+ * and NOQNAME proofs in the NSEC records by calling
+ * validator_callback_nsec().
+ *
+ * If the required proofs are found we are done.
+ *
+ * If the proofs are not found attempt to prove this is an unsecure
+ * response.
+ */
+static isc_result_t
+validate_nx(dns_validator_t *val, bool resume) {
+	isc_result_t result;
+
+	if (resume) {
+		validator_log(val, ISC_LOG_DEBUG(3), "resuming validate_nx");
+	}
+
+	if (val->event->message == NULL) {
+		result = validate_ncache(val, resume);
+	} else {
+		result = validate_authority(val, resume);
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	/*
+	 * Do we only need to check for NOQNAME?  To get here we must have
+	 * had a secure wildcard answer.
+	 */
+	if (!NEEDNODATA(val) && !NEEDNOWILDCARD(val) && NEEDNOQNAME(val)) {
+		if (!FOUNDNOQNAME(val)) {
+			result = findnsec3proofs(val);
+			if (result == DNS_R_NSEC3ITERRANGE) {
+				validator_log(val, ISC_LOG_DEBUG(3),
+					      "too many iterations");
+				markanswer(val, "validate_nx (3)", NULL);
+				return (ISC_R_SUCCESS);
+			}
+		}
+
+		if (FOUNDNOQNAME(val) && FOUNDCLOSEST(val) && !FOUNDOPTOUT(val))
+		{
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "marking as secure, noqname proof found");
+			marksecure(val->event);
+			return (ISC_R_SUCCESS);
+		} else if (FOUNDOPTOUT(val) &&
+			   dns_name_countlabels(
+				   dns_fixedname_name(&val->wild)) != 0)
+		{
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "optout proof found");
+			val->event->optout = true;
+			markanswer(val, "validate_nx (1)", NULL);
+			return (ISC_R_SUCCESS);
+		} else if ((val->attributes & VALATTR_FOUNDUNKNOWN) != 0) {
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "unknown NSEC3 hash algorithm found");
+			markanswer(val, "validate_nx (2)", NULL);
+			return (ISC_R_SUCCESS);
+		}
+
+		validator_log(val, ISC_LOG_DEBUG(3), "noqname proof not found");
+		return (DNS_R_NOVALIDNSEC);
+	}
+
+	if (!FOUNDNOQNAME(val) && !FOUNDNODATA(val)) {
+		result = findnsec3proofs(val);
+		if (result == DNS_R_NSEC3ITERRANGE) {
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "too many iterations");
+			markanswer(val, "validate_nx (4)", NULL);
+			return (ISC_R_SUCCESS);
+		}
+	}
+
+	/*
+	 * Do we need to check for the wildcard?
+	 */
+	if (FOUNDNOQNAME(val) && FOUNDCLOSEST(val) &&
+	    ((NEEDNODATA(val) && !FOUNDNODATA(val)) || NEEDNOWILDCARD(val)))
+	{
+		result = checkwildcard(val, dns_rdatatype_nsec, NULL);
+		if (result != ISC_R_SUCCESS) {
+			return (result);
+		}
+	}
+
+	if ((NEEDNODATA(val) && (FOUNDNODATA(val) || FOUNDOPTOUT(val))) ||
+	    (NEEDNOQNAME(val) && FOUNDNOQNAME(val) && NEEDNOWILDCARD(val) &&
+	     FOUNDNOWILDCARD(val) && FOUNDCLOSEST(val)))
+	{
+		if ((val->attributes & VALATTR_FOUNDOPTOUT) != 0) {
+			val->event->optout = true;
+		}
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "nonexistence proof(s) found");
+		if (val->event->message == NULL) {
+			marksecure(val->event);
+		} else {
+			val->event->secure = true;
+		}
+		return (ISC_R_SUCCESS);
+	}
+
+	if (val->authfail != 0 && val->authcount == val->authfail) {
+		return (DNS_R_BROKENCHAIN);
+	}
+
+	validator_log(val, ISC_LOG_DEBUG(3), "nonexistence proof(s) not found");
+	return (proveunsecure(val, false, false));
+}
+
+/*%
+ * Check that DS rdataset has at least one record with
+ * a supported algorithm and digest.
+ */
+static bool
+check_ds_algs(dns_validator_t *val, dns_name_t *name,
+	      dns_rdataset_t *rdataset) {
+	dns_rdata_t dsrdata = DNS_RDATA_INIT;
+	dns_rdata_ds_t ds;
+	isc_result_t result;
+
+	for (result = dns_rdataset_first(rdataset); result == ISC_R_SUCCESS;
+	     result = dns_rdataset_next(rdataset))
+	{
+		dns_rdataset_current(rdataset, &dsrdata);
+		result = dns_rdata_tostruct(&dsrdata, &ds, NULL);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+		if (dns_resolver_ds_digest_supported(val->view->resolver, name,
+						     ds.digest_type) &&
+		    dns_resolver_algorithm_supported(val->view->resolver, name,
+						     ds.algorithm))
+		{
+			dns_rdata_reset(&dsrdata);
+			return (true);
+		}
+		dns_rdata_reset(&dsrdata);
+	}
+	return (false);
+}
+
+/*%
+ * seek_ds is called to look up DS rrsets at the label of val->event->name
+ * indicated by val->labels. This is done while building an insecurity
+ * proof, and so it will attempt validation of NXDOMAIN, NXRRSET or CNAME
+ * responses.
+ *
+ * Returns:
+ * \li	ISC_R_COMPLETE		a result has been determined and copied
+ * 				into `*resp`; ISC_R_SUCCESS indicates that
+ * 				the name has been proven insecure and any
+ * 				other result indicates failure.
+ * \li	DNS_R_CONTINUE		result is indeterminate; caller should
+ * 				continue walking down labels.
+ */
+static isc_result_t
+seek_ds(dns_validator_t *val, isc_result_t *resp) {
+	isc_result_t result;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	dns_fixedname_t fixedfound;
+	dns_name_t *found = dns_fixedname_initname(&fixedfound);
+	dns_name_t *tname = dns_fixedname_initname(&val->fname);
+
+	if (val->labels == dns_name_countlabels(val->event->name)) {
+		dns_name_copy(val->event->name, tname);
+	} else {
+		dns_name_split(val->event->name, val->labels, NULL, tname);
+	}
+
+	dns_name_format(tname, namebuf, sizeof(namebuf));
+	validator_log(val, ISC_LOG_DEBUG(3), "checking existence of DS at '%s'",
+		      namebuf);
+
+	result = view_find(val, tname, dns_rdatatype_ds);
+	switch (result) {
+	case ISC_R_SUCCESS:
+		/*
+		 * There is a DS here.  If it's already been
+		 * validated, continue walking down labels.
+		 */
+		if (val->frdataset.trust >= dns_trust_secure) {
+			if (!check_ds_algs(val, tname, &val->frdataset)) {
+				validator_log(val, ISC_LOG_DEBUG(3),
+					      "no supported algorithm/"
+					      "digest (%s/DS)",
+					      namebuf);
+				*resp = markanswer(val, "proveunsecure (5)",
+						   "no supported "
+						   "algorithm/digest (DS)");
+				return (ISC_R_COMPLETE);
+			}
+
+			break;
+		}
+
+		/*
+		 * Otherwise, try to validate it now.
+		 */
+		if (dns_rdataset_isassociated(&val->fsigrdataset)) {
+			result = create_validator(
+				val, tname, dns_rdatatype_ds, &val->frdataset,
+				&val->fsigrdataset, validator_callback_ds,
+				"proveunsecure");
+			*resp = DNS_R_WAIT;
+			if (result != ISC_R_SUCCESS) {
+				*resp = result;
+			}
+		} else {
+			/*
+			 * There should never be an unsigned DS.
+			 */
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "unsigned DS record");
+			*resp = DNS_R_NOVALIDSIG;
+		}
+
+		return (ISC_R_COMPLETE);
+
+	case ISC_R_NOTFOUND:
+		/*
+		 * We don't know anything about the DS.  Find it.
+		 */
+		*resp = DNS_R_WAIT;
+		result = create_fetch(val, tname, dns_rdatatype_ds,
+				      fetch_callback_ds, "proveunsecure");
+		if (result != ISC_R_SUCCESS) {
+			*resp = result;
+		}
+		return (ISC_R_COMPLETE);
+
+	case DNS_R_NXRRSET:
+	case DNS_R_NCACHENXRRSET:
+		/*
+		 * There is no DS.  If this is a delegation,
+		 * we may be done.
+		 *
+		 * If we have "trust == answer" then this namespace
+		 * has switched from insecure to should be secure.
+		 */
+		if (DNS_TRUST_PENDING(val->frdataset.trust) ||
+		    DNS_TRUST_ANSWER(val->frdataset.trust))
+		{
+			result = create_validator(
+				val, tname, dns_rdatatype_ds, &val->frdataset,
+				&val->fsigrdataset, validator_callback_ds,
+				"proveunsecure");
+			*resp = DNS_R_WAIT;
+			if (result != ISC_R_SUCCESS) {
+				*resp = result;
+			}
+			return (ISC_R_COMPLETE);
+		}
+
+		/*
+		 * Zones using NSEC3 don't return a NSEC RRset so
+		 * we need to use dns_view_findzonecut2 to find
+		 * the zone cut.
+		 */
+		if (result == DNS_R_NXRRSET &&
+		    !dns_rdataset_isassociated(&val->frdataset) &&
+		    dns_view_findzonecut(val->view, tname, found, NULL, 0, 0,
+					 false, false, NULL,
+					 NULL) == ISC_R_SUCCESS &&
+		    dns_name_equal(tname, found))
+		{
+			*resp = markanswer(val, "proveunsecure (3)",
+					   "no DS at zone cut");
+			return (ISC_R_COMPLETE);
+		}
+
+		if (val->frdataset.trust < dns_trust_secure) {
+			/*
+			 * This shouldn't happen, since the negative
+			 * response should have been validated.  Since
+			 * there's no way of validating existing
+			 * negative response blobs, give up.
+			 */
+			validator_log(val, ISC_LOG_WARNING,
+				      "can't validate existing "
+				      "negative responses (no DS)");
+			*resp = DNS_R_MUSTBESECURE;
+			return (ISC_R_COMPLETE);
+		}
+
+		if (isdelegation(tname, &val->frdataset, result)) {
+			*resp = markanswer(val, "proveunsecure (4)",
+					   "this is a delegation");
+			return (ISC_R_COMPLETE);
+		}
+
+		break;
+
+	case DNS_R_NXDOMAIN:
+	case DNS_R_NCACHENXDOMAIN:
+		/*
+		 * This is not a zone cut. Assuming things are
+		 * as expected, continue.
+		 */
+		if (!dns_rdataset_isassociated(&val->frdataset)) {
+			/*
+			 * There should be an NSEC here, since we
+			 * are still in a secure zone.
+			 */
+			*resp = DNS_R_NOVALIDNSEC;
+			return (ISC_R_COMPLETE);
+		} else if (DNS_TRUST_PENDING(val->frdataset.trust) ||
+			   DNS_TRUST_ANSWER(val->frdataset.trust))
+		{
+			/*
+			 * If we have "trust == answer" then this
+			 * namespace has switched from insecure to
+			 * should be secure.
+			 */
+			*resp = DNS_R_WAIT;
+			result = create_validator(
+				val, tname, dns_rdatatype_ds, &val->frdataset,
+				&val->fsigrdataset, validator_callback_ds,
+				"proveunsecure");
+			if (result != ISC_R_SUCCESS) {
+				*resp = result;
+			}
+			return (ISC_R_COMPLETE);
+		} else if (val->frdataset.trust < dns_trust_secure) {
+			/*
+			 * This shouldn't happen, since the negative
+			 * response should have been validated.  Since
+			 * there's no way of validating existing
+			 * negative response blobs, give up.
+			 */
+			validator_log(val, ISC_LOG_WARNING,
+				      "can't validate existing "
+				      "negative responses "
+				      "(not a zone cut)");
+			*resp = DNS_R_NOVALIDSIG;
+			return (ISC_R_COMPLETE);
+		}
+
+		break;
+
+	case DNS_R_CNAME:
+		if (DNS_TRUST_PENDING(val->frdataset.trust) ||
+		    DNS_TRUST_ANSWER(val->frdataset.trust))
+		{
+			result = create_validator(
+				val, tname, dns_rdatatype_cname,
+				&val->frdataset, &val->fsigrdataset,
+				validator_callback_cname,
+				"proveunsecure "
+				"(cname)");
+			*resp = DNS_R_WAIT;
+			if (result != ISC_R_SUCCESS) {
+				*resp = result;
+			}
+			return (ISC_R_COMPLETE);
+		}
+
+		break;
+
+	default:
+		*resp = result;
+		return (ISC_R_COMPLETE);
+	}
+
+	/*
+	 * No definite answer yet; continue walking down labels.
+	 */
+	return (DNS_R_CONTINUE);
+}
+
+/*%
+ * proveunsecure walks down, label by label, from the closest enclosing
+ * trust anchor to the name that is being validated, looking for an
+ * endpoint in the chain of trust.  That occurs when we can prove that
+ * a DS record does not exist at a delegation point, or that a DS exists
+ * at a delegation point but we don't support its algorithm/digest.  If
+ * no such endpoint is found, then the response should have been secure.
+ *
+ * Returns:
+ * \li	ISC_R_SUCCESS		val->event->name is in an unsecure zone
+ * \li	DNS_R_WAIT		validation is in progress.
+ * \li	DNS_R_MUSTBESECURE	val->event->name is supposed to be secure
+ *				(policy) but we proved that it is unsecure.
+ * \li	DNS_R_NOVALIDSIG
+ * \li	DNS_R_NOVALIDNSEC
+ * \li	DNS_R_NOTINSECURE
+ * \li	DNS_R_BROKENCHAIN
+ */
+static isc_result_t
+proveunsecure(dns_validator_t *val, bool have_ds, bool resume) {
+	isc_result_t result;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	dns_fixedname_t fixedsecroot;
+	dns_name_t *secroot = dns_fixedname_initname(&fixedsecroot);
+	unsigned int labels;
+
+	/*
+	 * We're attempting to prove insecurity.
+	 */
+	val->attributes |= VALATTR_INSECURITY;
+
+	dns_name_copy(val->event->name, secroot);
+
+	/*
+	 * If this is a response to a DS query, we need to look in
+	 * the parent zone for the trust anchor.
+	 */
+	labels = dns_name_countlabels(secroot);
+	if (val->event->type == dns_rdatatype_ds && labels > 1U) {
+		dns_name_getlabelsequence(secroot, 1, labels - 1, secroot);
+	}
+
+	result = dns_keytable_finddeepestmatch(val->keytable, secroot, secroot);
+	if (result == ISC_R_NOTFOUND) {
+		validator_log(val, ISC_LOG_DEBUG(3), "not beneath secure root");
+		return (markanswer(val, "proveunsecure (1)",
+				   "not beneath secure root"));
+	} else if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	if (!resume) {
+		/*
+		 * We are looking for interruptions in the chain of trust.
+		 * That can only happen *below* the trust anchor, so we
+		 * start looking at the next label down.
+		 */
+		val->labels = dns_name_countlabels(secroot) + 1;
+	} else {
+		validator_log(val, ISC_LOG_DEBUG(3), "resuming proveunsecure");
+
+		/*
+		 * If we have a DS rdataset and it is secure, check whether
+		 * it has a supported algorithm combination.  If not, this is
+		 * an insecure delegation as far as this resolver is concerned.
+		 */
+		if (have_ds && val->frdataset.trust >= dns_trust_secure &&
+		    !check_ds_algs(val, dns_fixedname_name(&val->fname),
+				   &val->frdataset))
+		{
+			dns_name_format(dns_fixedname_name(&val->fname),
+					namebuf, sizeof(namebuf));
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "no supported algorithm/digest (%s/DS)",
+				      namebuf);
+			result = markanswer(val, "proveunsecure (2)", namebuf);
+			goto out;
+		}
+		val->labels++;
+	}
+
+	/*
+	 * Walk down through each of the remaining labels in the name,
+	 * looking for DS records.
+	 */
+	while (val->labels <= dns_name_countlabels(val->event->name)) {
+		isc_result_t tresult;
+
+		result = seek_ds(val, &tresult);
+		if (result == ISC_R_COMPLETE) {
+			result = tresult;
+			goto out;
+		}
+
+		INSIST(result == DNS_R_CONTINUE);
+		val->labels++;
+	}
+
+	/* Couldn't complete insecurity proof. */
+	validator_log(val, ISC_LOG_DEBUG(3), "insecurity proof failed: %s",
+		      isc_result_totext(result));
+	return (DNS_R_NOTINSECURE);
+
+out:
+	if (result != DNS_R_WAIT) {
+		disassociate_rdatasets(val);
+	}
+	return (result);
+}
+
+/*%
+ * Start the validation process.
+ *
+ * Attempt to validate the answer based on the category it appears to
+ * fall in.
+ * \li	1. secure positive answer.
+ * \li	2. unsecure positive answer.
+ * \li	3. a negative answer (secure or unsecure).
+ *
+ * Note an answer that appears to be a secure positive answer may actually
+ * be an unsecure positive answer.
+ */
+static void
+validator_start(isc_task_t *task, isc_event_t *event) {
+	dns_validator_t *val;
+	dns_validatorevent_t *vevent;
+	bool want_destroy = false;
+	isc_result_t result = ISC_R_FAILURE;
+
+	UNUSED(task);
+	REQUIRE(event->ev_type == DNS_EVENT_VALIDATORSTART);
+	vevent = (dns_validatorevent_t *)event;
+	val = vevent->validator;
+
+	/* If the validator has been canceled, val->event == NULL */
+	if (val->event == NULL) {
+		return;
+	}
+
+	validator_log(val, ISC_LOG_DEBUG(3), "starting");
+
+	LOCK(&val->lock);
+
+	if (val->event->rdataset != NULL && val->event->sigrdataset != NULL) {
+		isc_result_t saved_result;
+
+		/*
+		 * This looks like a simple validation.  We say "looks like"
+		 * because it might end up requiring an insecurity proof.
+		 */
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "attempting positive response validation");
+
+		INSIST(dns_rdataset_isassociated(val->event->rdataset));
+		INSIST(dns_rdataset_isassociated(val->event->sigrdataset));
+		if (selfsigned_dnskey(val)) {
+			result = validate_dnskey(val);
+		} else {
+			result = validate_answer(val, false);
+		}
+		if (result == DNS_R_NOVALIDSIG &&
+		    (val->attributes & VALATTR_TRIEDVERIFY) == 0)
+		{
+			saved_result = result;
+			validator_log(val, ISC_LOG_DEBUG(3),
+				      "falling back to insecurity proof");
+			result = proveunsecure(val, false, false);
+			if (result == DNS_R_NOTINSECURE) {
+				result = saved_result;
+			}
+		}
+	} else if (val->event->rdataset != NULL &&
+		   val->event->rdataset->type != 0)
+	{
+		/*
+		 * This is either an unsecure subdomain or a response
+		 * from a broken server.
+		 */
+		INSIST(dns_rdataset_isassociated(val->event->rdataset));
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "attempting insecurity proof");
+
+		result = proveunsecure(val, false, false);
+		if (result == DNS_R_NOTINSECURE) {
+			validator_log(val, ISC_LOG_INFO,
+				      "got insecure response; "
+				      "parent indicates it should be secure");
+		}
+	} else if ((val->event->rdataset == NULL &&
+		    val->event->sigrdataset == NULL))
+	{
+		/*
+		 * This is a validation of a negative response.
+		 */
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "attempting negative response validation "
+			      "from message");
+
+		if (val->event->message->rcode == dns_rcode_nxdomain) {
+			val->attributes |= VALATTR_NEEDNOQNAME;
+			val->attributes |= VALATTR_NEEDNOWILDCARD;
+		} else {
+			val->attributes |= VALATTR_NEEDNODATA;
+		}
+
+		result = validate_nx(val, false);
+	} else if ((val->event->rdataset != NULL &&
+		    NEGATIVE(val->event->rdataset)))
+	{
+		/*
+		 * This is a delayed validation of a negative cache entry.
+		 */
+		validator_log(val, ISC_LOG_DEBUG(3),
+			      "attempting negative response validation "
+			      "from cache");
+
+		if (NXDOMAIN(val->event->rdataset)) {
+			val->attributes |= VALATTR_NEEDNOQNAME;
+			val->attributes |= VALATTR_NEEDNOWILDCARD;
+		} else {
+			val->attributes |= VALATTR_NEEDNODATA;
+		}
+
+		result = validate_nx(val, false);
+	} else {
+		UNREACHABLE();
+	}
+
+	if (result != DNS_R_WAIT) {
+		want_destroy = exit_check(val);
+		validator_done(val, result);
+	}
+
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+isc_result_t
+dns_validator_create(dns_view_t *view, dns_name_t *name, dns_rdatatype_t type,
+		     dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
+		     dns_message_t *message, unsigned int options,
+		     isc_task_t *task, isc_taskaction_t action, void *arg,
+		     dns_validator_t **validatorp) {
+	isc_result_t result = ISC_R_FAILURE;
+	dns_validator_t *val;
+	isc_task_t *tclone = NULL;
+	dns_validatorevent_t *event;
+
+	REQUIRE(name != NULL);
+	REQUIRE(rdataset != NULL ||
+		(rdataset == NULL && sigrdataset == NULL && message != NULL));
+	REQUIRE(validatorp != NULL && *validatorp == NULL);
+
+	event = (dns_validatorevent_t *)isc_event_allocate(
+		view->mctx, task, DNS_EVENT_VALIDATORSTART, validator_start,
+		NULL, sizeof(dns_validatorevent_t));
+
+	isc_task_attach(task, &tclone);
+	event->result = ISC_R_FAILURE;
+	event->name = name;
+	event->type = type;
+	event->rdataset = rdataset;
+	event->sigrdataset = sigrdataset;
+	event->message = message;
+	memset(event->proofs, 0, sizeof(event->proofs));
+	event->optout = false;
+	event->secure = false;
+
+	val = isc_mem_get(view->mctx, sizeof(*val));
+	*val = (dns_validator_t){ .event = event,
+				  .options = options,
+				  .task = task,
+				  .action = action,
+				  .arg = arg };
+
+	dns_view_weakattach(view, &val->view);
+	isc_mutex_init(&val->lock);
+
+	result = dns_view_getsecroots(val->view, &val->keytable);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	val->mustbesecure = dns_resolver_getmustbesecure(view->resolver, name);
+	dns_rdataset_init(&val->fdsset);
+	dns_rdataset_init(&val->frdataset);
+	dns_rdataset_init(&val->fsigrdataset);
+	dns_fixedname_init(&val->wild);
+	dns_fixedname_init(&val->closest);
+	isc_stdtime_get(&val->start);
+	ISC_LINK_INIT(val, link);
+	val->magic = VALIDATOR_MAGIC;
+
+	event->validator = val;
+
+	if ((options & DNS_VALIDATOR_DEFER) == 0) {
+		isc_task_send(task, ISC_EVENT_PTR(&event));
+	}
+
+	*validatorp = val;
+
+	return (ISC_R_SUCCESS);
+
+cleanup:
+	isc_mutex_destroy(&val->lock);
+
+	isc_task_detach(&tclone);
+	isc_event_free(ISC_EVENT_PTR(&event));
+
+	dns_view_weakdetach(&val->view);
+	isc_mem_put(view->mctx, val, sizeof(*val));
+
+	return (result);
+}
+
+void
+dns_validator_send(dns_validator_t *validator) {
+	isc_event_t *event;
+	REQUIRE(VALID_VALIDATOR(validator));
+
+	LOCK(&validator->lock);
+
+	INSIST((validator->options & DNS_VALIDATOR_DEFER) != 0);
+	event = (isc_event_t *)validator->event;
+	validator->options &= ~DNS_VALIDATOR_DEFER;
+	UNLOCK(&validator->lock);
+
+	isc_task_send(validator->task, ISC_EVENT_PTR(&event));
+}
+
+void
+dns_validator_cancel(dns_validator_t *validator) {
+	dns_fetch_t *fetch = NULL;
+
+	REQUIRE(VALID_VALIDATOR(validator));
+
+	LOCK(&validator->lock);
+
+	validator_log(validator, ISC_LOG_DEBUG(3), "dns_validator_cancel");
+
+	if ((validator->attributes & VALATTR_CANCELED) == 0) {
+		validator->attributes |= VALATTR_CANCELED;
+		if (validator->event != NULL) {
+			fetch = validator->fetch;
+			validator->fetch = NULL;
+
+			if (validator->subvalidator != NULL) {
+				dns_validator_cancel(validator->subvalidator);
+			}
+			if ((validator->options & DNS_VALIDATOR_DEFER) != 0) {
+				validator->options &= ~DNS_VALIDATOR_DEFER;
+				validator_done(validator, ISC_R_CANCELED);
+			}
+		}
+	}
+	UNLOCK(&validator->lock);
+
+	/* Need to cancel and destroy the fetch outside validator lock */
+	if (fetch != NULL) {
+		dns_resolver_cancelfetch(fetch);
+		dns_resolver_destroyfetch(&fetch);
+	}
+}
+
+static void
+destroy(dns_validator_t *val) {
+	isc_mem_t *mctx;
+
+	REQUIRE(SHUTDOWN(val));
+	REQUIRE(val->event == NULL);
+	REQUIRE(val->fetch == NULL);
+
+	val->magic = 0;
+	if (val->key != NULL) {
+		dst_key_free(&val->key);
+	}
+	if (val->keytable != NULL) {
+		dns_keytable_detach(&val->keytable);
+	}
+	if (val->subvalidator != NULL) {
+		dns_validator_destroy(&val->subvalidator);
+	}
+	disassociate_rdatasets(val);
+	mctx = val->view->mctx;
+	if (val->siginfo != NULL) {
+		isc_mem_put(mctx, val->siginfo, sizeof(*val->siginfo));
+	}
+	isc_mutex_destroy(&val->lock);
+	dns_view_weakdetach(&val->view);
+	isc_mem_put(mctx, val, sizeof(*val));
+}
+
+void
+dns_validator_destroy(dns_validator_t **validatorp) {
+	dns_validator_t *val;
+	bool want_destroy = false;
+
+	REQUIRE(validatorp != NULL);
+	val = *validatorp;
+	*validatorp = NULL;
+	REQUIRE(VALID_VALIDATOR(val));
+
+	LOCK(&val->lock);
+
+	val->attributes |= VALATTR_SHUTDOWN;
+	validator_log(val, ISC_LOG_DEBUG(4), "dns_validator_destroy");
+
+	want_destroy = exit_check(val);
+	UNLOCK(&val->lock);
+	if (want_destroy) {
+		destroy(val);
+	}
+}
+
+static void
+validator_logv(dns_validator_t *val, isc_logcategory_t *category,
+	       isc_logmodule_t *module, int level, const char *fmt,
+	       va_list ap) {
+	char msgbuf[2048];
+	static const char spaces[] = "        *";
+	int depth = val->depth * 2;
+	const char *viewname, *sep1, *sep2;
+
+	vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
+
+	if ((unsigned int)depth >= sizeof spaces) {
+		depth = sizeof spaces - 1;
+	}
+
+	/*
+	 * Log the view name unless it's:
+	 * * "_default/IN" (which means there's only one view
+	 *   configured in the server), or
+	 * * "_dnsclient/IN" (which means this is being called
+	 *   from an application using dns/client.c).
+	 */
+	if (val->view->rdclass == dns_rdataclass_in &&
+	    (strcmp(val->view->name, "_default") == 0 ||
+	     strcmp(val->view->name, DNS_CLIENTVIEW_NAME) == 0))
+	{
+		sep1 = viewname = sep2 = "";
+	} else {
+		sep1 = "view ";
+		viewname = val->view->name;
+		sep2 = ": ";
+	}
+
+	if (val->event != NULL && val->event->name != NULL) {
+		char namebuf[DNS_NAME_FORMATSIZE];
+		char typebuf[DNS_RDATATYPE_FORMATSIZE];
+
+		dns_name_format(val->event->name, namebuf, sizeof(namebuf));
+		dns_rdatatype_format(val->event->type, typebuf,
+				     sizeof(typebuf));
+		isc_log_write(dns_lctx, category, module, level,
+			      "%s%s%s%.*svalidating %s/%s: %s", sep1, viewname,
+			      sep2, depth, spaces, namebuf, typebuf, msgbuf);
+	} else {
+		isc_log_write(dns_lctx, category, module, level,
+			      "%s%s%s%.*svalidator @%p: %s", sep1, viewname,
+			      sep2, depth, spaces, val, msgbuf);
+	}
+}
+
+static void
+validator_log(void *val, int level, const char *fmt, ...) {
+	va_list ap;
+
+	if (!isc_log_wouldlog(dns_lctx, level)) {
+		return;
+	}
+
+	va_start(ap, fmt);
+
+	validator_logv(val, DNS_LOGCATEGORY_DNSSEC, DNS_LOGMODULE_VALIDATOR,
+		       level, fmt, ap);
+	va_end(ap);
+}
+
+static void
+validator_logcreate(dns_validator_t *val, dns_name_t *name,
+		    dns_rdatatype_t type, const char *caller,
+		    const char *operation) {
+	char namestr[DNS_NAME_FORMATSIZE];
+	char typestr[DNS_RDATATYPE_FORMATSIZE];
+
+	dns_name_format(name, namestr, sizeof(namestr));
+	dns_rdatatype_format(type, typestr, sizeof(typestr));
+	validator_log(val, ISC_LOG_DEBUG(9), "%s: creating %s for %s %s",
+		      caller, operation, namestr, typestr);
+}