validator.c

非常好的dns解析软件

	 * is present.
	 */
	digest_type = DNS_DSDIGEST_SHA1;
	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);
		dns_rdata_tostruct(&dsrdata, &ds, NULL);

		if (!dns_resolver_algorithm_supported(val->view->resolver,
						      val->event->name,
						      ds.algorithm))
			continue;

		if (ds.digest_type == DNS_DSDIGEST_SHA256) {
			digest_type = DNS_DSDIGEST_SHA256;
			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);
		(void)dns_rdata_tostruct(&dsrdata, &ds, NULL);

		if (!dns_resolver_digest_supported(val->view->resolver,
						   ds.digest_type))
			continue;

		if (ds.digest_type != digest_type)
			continue;

		if (!dns_resolver_algorithm_supported(val->view->resolver,
						      val->event->name,
						      ds.algorithm))
			continue;

		supported_algorithm = ISC_TRUE;

		dns_rdataset_init(&trdataset);
		dns_rdataset_clone(val->event->rdataset, &trdataset);

		/*
		 * Look for the KEY that matches the DS record.
		 */
		for (result = dns_rdataset_first(&trdataset);
		     result == ISC_R_SUCCESS;
		     result = dns_rdataset_next(&trdataset))
		{
			dns_rdata_reset(&keyrdata);
			dns_rdataset_current(&trdataset, &keyrdata);
			(void)dns_rdata_tostruct(&keyrdata, &key, NULL);
			keytag = compute_keytag(&keyrdata, &key);
			if (ds.key_tag != keytag ||
			    ds.algorithm != key.algorithm)
				continue;
			dns_rdata_reset(&newdsrdata);
			result = dns_ds_buildrdata(val->event->name,
						   &keyrdata, ds.digest_type,
						   dsbuf, &newdsrdata);
			if (result != ISC_R_SUCCESS)
				continue;
			if (dns_rdata_compare(&dsrdata, &newdsrdata) == 0)
				break;
		}
		if (result != ISC_R_SUCCESS) {
			validator_log(val, ISC_LOG_DEBUG(3),
				      "no DNSKEY matching DS");
			continue;
		}
		
		for (result = dns_rdataset_first(val->event->sigrdataset);
		     result == ISC_R_SUCCESS;
		     result = dns_rdataset_next(val->event->sigrdataset))
		{
			dns_rdata_reset(&sigrdata);
			dns_rdataset_current(val->event->sigrdataset,
					     &sigrdata);
			(void)dns_rdata_tostruct(&sigrdata, &sig, NULL);
			if (ds.key_tag != sig.keyid ||
			    ds.algorithm != sig.algorithm)
				continue;

			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, &sigrdata, sig.keyid);
			dst_key_free(&dstkey);
			if (result == ISC_R_SUCCESS)
				break;
		}
		dns_rdataset_disassociate(&trdataset);
		if (result == ISC_R_SUCCESS)
			break;
		validator_log(val, ISC_LOG_DEBUG(3),
			      "no RRSIG matching DS key");
	}
	if (result == ISC_R_SUCCESS) {
		event->rdataset->trust = dns_trust_secure;
		event->sigrdataset->trust = dns_trust_secure;
		validator_log(val, ISC_LOG_DEBUG(3), "marking as secure");
		return (result);
	} else if (result == ISC_R_NOMORE && !supported_algorithm) {
		if (val->mustbesecure) {
			validator_log(val, ISC_LOG_WARNING,
				      "must be secure failure");
			return (DNS_R_MUSTBESECURE);
		}
		validator_log(val, ISC_LOG_DEBUG(3),
			      "no supported algorithm/digest (DS)");
		markanswer(val);
		return (ISC_R_SUCCESS);
	} else
		return (DNS_R_NOVALIDSIG);
}

/*%
 * Starts a positive response validation.
 *
 * 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
start_positive_validation(dns_validator_t *val) {
	/*
	 * If this is not a key, go straight into validate().
	 */
	if (val->event->type != dns_rdatatype_dnskey || !isselfsigned(val))
		return (validate(val, ISC_FALSE));

	return (validatezonekey(val));
}

/*%
 * 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_name_t *name, *wild;
	dns_message_t *message = val->event->message;
	isc_result_t result;
	isc_boolean_t exists, data;
	char namebuf[DNS_NAME_FORMATSIZE];

	wild = dns_fixedname_name(&val->wild);
	dns_name_format(wild, namebuf, sizeof(namebuf));
	validator_log(val, ISC_LOG_DEBUG(3), "in checkwildcard: %s", namebuf);

	for (result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
	     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);

		for (rdataset = ISC_LIST_HEAD(name->list);
		     rdataset != NULL;
		     rdataset = ISC_LIST_NEXT(rdataset, link))
		{
			if (rdataset->type != dns_rdatatype_nsec)
				continue;
			val->nsecset = rdataset;

			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;
			}
			if (sigrdataset == NULL)
				continue;

			if (rdataset->trust != dns_trust_secure)
				continue;

			if (((val->attributes & VALATTR_NEEDNODATA) != 0 ||
			     (val->attributes & VALATTR_NEEDNOWILDCARD) != 0) &&
			    (val->attributes & VALATTR_FOUNDNODATA) == 0 &&
			    (val->attributes & VALATTR_FOUNDNOWILDCARD) == 0 &&
			    nsecnoexistnodata(val, wild, name, rdataset,
					      &exists, &data, NULL)
					       == 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;
				return (ISC_R_SUCCESS);
			}
		}
	}
	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 authvalidated().
 *
 * If the required proofs are found we are done.
 *
 * If the proofs are not found attempt to prove this is a unsecure
 * response.
 */
static isc_result_t
nsecvalidate(dns_validator_t *val, isc_boolean_t 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;
		validator_log(val, ISC_LOG_DEBUG(3), "resuming nsecvalidate");
	}

	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 = ISC_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;
			}
			/*
			 * 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 &&
			    dns_name_equal(name, val->event->name))
			{
				dns_rdata_t nsec = DNS_RDATA_INIT;

				if (rdataset->type != dns_rdatatype_nsec)
					continue;

				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))
					continue;
			}
			val->currentset = rdataset;
			result = create_validator(val, name, rdataset->type,
						  rdataset, sigrdataset,
						  authvalidated,
						  "nsecvalidate");
			if (result != ISC_R_SUCCESS)
				return (result);
			return (DNS_R_WAIT);

		}
	}
	if (result == ISC_R_NOMORE)
		result = ISC_R_SUCCESS;
	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 ((val->attributes & VALATTR_NEEDNODATA) == 0 &&
	    (val->attributes & VALATTR_NEEDNOWILDCARD) == 0 &&
	    (val->attributes & VALATTR_NEEDNOQNAME) != 0) {
		if ((val->attributes & VALATTR_FOUNDNOQNAME) != 0) {
			validator_log(val, ISC_LOG_DEBUG(3),
				      "noqname proof found");
			validator_log(val, ISC_LOG_DEBUG(3),
				      "marking as secure");
			val->event->rdataset->trust = dns_trust_secure;
			val->event->sigrdataset->trust = dns_trust_secure;
			return (ISC_R_SUCCESS);
		}
		validator_log(val, ISC_LOG_DEBUG(3),
			      "noqname proof not found");
		return (DNS_R_NOVALIDNSEC);
	}

	/*
	 * Do we need to check for the wildcard?
	 */
	if ((val->attributes & VALATTR_FOUNDNOQNAME) != 0 &&
	    (((val->attributes & VALATTR_NEEDNODATA) != 0 &&
	      (val->attributes & VALATTR_FOUNDNODATA) == 0) ||
	     (val->attributes & VALATTR_NEEDNOWILDCARD) != 0)) {
		result = checkwildcard(val);
		if (result != ISC_R_SUCCESS)
			return (result);
	}

	if (((val->attributes & VALATTR_NEEDNODATA) != 0 &&
	     (val->attributes & VALATTR_FOUNDNODATA) != 0) ||
	    ((val->attributes & VALATTR_NEEDNOQNAME) != 0 &&
	     (val->attributes & VALATTR_FOUNDNOQNAME) != 0 &&
	     (val->attributes & VALATTR_NEEDNOWILDCARD) != 0 &&
	     (val->attributes & VALATTR_FOUNDNOWILDCARD) != 0)) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "nonexistence proof(s) found");
		return (ISC_R_SUCCESS);
	}

	validator_log(val, ISC_LOG_DEBUG(3),
		      "nonexistence proof(s) not found");
	val->attributes |= VALATTR_INSECURITY;
	return (proveunsecure(val, ISC_FALSE));
}

static isc_boolean_t
check_ds(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);
		(void)dns_rdata_tostruct(&dsrdata, &ds, NULL);

		if (dns_resolver_digest_supported(val->view->resolver,
						  ds.digest_type) &&
		    dns_resolver_algorithm_supported(val->view->resolver,
						     name, ds.algorithm)) {
			dns_rdata_reset(&dsrdata);
			return (ISC_TRUE);
		}
		dns_rdata_reset(&dsrdata);
	}
	return (ISC_FALSE);
}

/*%
 * Callback from fetching a DLV record.
 * 
 * Resumes the DLV lookup process.
 */
static void
dlvfetched(isc_task_t *task, isc_event_t *event) {
	char namebuf[DNS_NAME_FORMATSIZE];
	dns_fetchevent_t *devent;
	dns_validator_t *val;
	isc_boolean_t want_destroy;
	isc_result_t eresult;
	isc_result_t result;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
	devent = (dns_fetchevent_t *)event;
	val = devent->ev_arg;
	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);
	dns_resolver_destroyfetch(&val->fetch);

	INSIST(val->event != NULL);
	validator_log(val, ISC_LOG_DEBUG(3), "in dlvfetched: %s",
		      dns_result_totext(eresult));

	LOCK(&val->lock);
	if (eresult == ISC_R_SUCCESS) {
		dns_name_format(dns_fixedname_name(&val->dlvsep), namebuf,
				sizeof(namebuf));
		dns_rdataset_clone(&val->frdataset, &val->dlv);
		val->havedlvsep = ISC_TRUE;
		validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found", namebuf);
		dlv_validator_start(val);
	} else if (eresult == DNS_R_NXRRSET ||
		   eresult == DNS_R_NXDOMAIN ||
		   eresult == DNS_R_NCACHENXRRSET ||
		   eresult == DNS_R_NCACHENXDOMAIN) {
		   result = finddlvsep(val, ISC_TRUE);
		if (result == ISC_R_SUCCESS) {
			dns_name_format(dns_fixedname_name(&val->dlvsep),
					namebuf, sizeof(namebuf));
			validator_log(val, ISC_LOG_DEBUG(3), "DLV %s found",
				      namebuf);
			dlv_validator_start(val);
		} else if (result == ISC_R_NOTFOUND) {
			validator_log(val, ISC_LOG_DEBUG(3), "DLV not found");
			markanswer(val);
			validator_done(va