validator.c

bind-3.2.

		validator_log(val, ISC_LOG_DEBUG(3),
			      "negauthvalidated: got %s",
			      dns_result_totext(eresult));
		validator_done(val, eresult);
	}
	UNLOCK(&val->lock);

	/*
	 * Free stuff from the event.
	 */
	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
}

static void
nullkeyvalidated(isc_task_t *task, isc_event_t *event) {
	dns_validatorevent_t *devent;
	dns_validator_t *val;
	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;

	dns_name_free(devent->name, val->view->mctx);
	isc_mem_put(val->view->mctx, devent->name, sizeof(dns_name_t));
	dns_validator_destroy(&val->keyvalidator);
	isc_event_free(&event);

	if (SHUTDOWN(val)) {
		dns_validator_destroy(&val);
		return;
	}

	if (val->event == NULL)
		return;

	validator_log(val, ISC_LOG_DEBUG(3), "in nullkeyvalidated");
	LOCK(&val->lock);
	if (eresult == ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "proved that name is in an unsecure domain");
		validator_log(val, ISC_LOG_DEBUG(3), "marking as answer");
		val->event->rdataset->trust = dns_trust_answer;
		validator_done(val, ISC_R_SUCCESS);
	} else {
		result = proveunsecure(val, ISC_TRUE);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	}
	UNLOCK(&val->lock);

	/*
	 * Free stuff from the event.
	 */
	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
}

/*
 * Try to find a null zone key among those in 'rdataset'.  If found, build
 * a dst_key_t for it and point val->key at it.
 */
static inline isc_boolean_t
containsnullkey(dns_validator_t *val, dns_rdataset_t *rdataset) {
	isc_result_t result;
	dst_key_t *key = NULL;
	isc_buffer_t b;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	isc_boolean_t found = ISC_FALSE;

	result = dns_rdataset_first(rdataset);
	if (result != ISC_R_SUCCESS)
		return (ISC_FALSE);
	while (result == ISC_R_SUCCESS && !found) {
		dns_rdataset_current(rdataset, &rdata);
		isc_buffer_init(&b, rdata.data, rdata.length);
		isc_buffer_add(&b, rdata.length);
		key = NULL;
		/*
		 * The key name is unimportant, so we can avoid any name/text
		 * conversion.
		 */
		result = dst_key_fromdns(dns_rootname, rdata.rdclass, &b,
					 val->view->mctx, &key);
		if (result != ISC_R_SUCCESS)
			continue;
		if (dst_key_isnullkey(key))
			found = ISC_TRUE;
		dst_key_free(&key);
		dns_rdata_reset(&rdata);
		result = dns_rdataset_next(rdataset);
	}
	return (found);
}

/*
 * Try to find a key that could have signed 'siginfo' among those
 * in 'rdataset'.  If found, build a dst_key_t for it and point
 * val->key at it.
 *
 * If val->key is non-NULL, this returns the next matching key.
 */
static inline isc_result_t
get_dst_key(dns_validator_t *val, dns_rdata_sig_t *siginfo,
	    dns_rdataset_t *rdataset)
{
	isc_result_t result;
	isc_buffer_t b;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	dst_key_t *oldkey = val->key;
	isc_boolean_t foundold;

	if (oldkey == NULL)
		foundold = ISC_TRUE;
	else {
		foundold = ISC_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)
			goto failure;
		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) == ISC_TRUE)
			{
				foundold = ISC_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);
}

static inline isc_result_t
get_key(dns_validator_t *val, dns_rdata_sig_t *siginfo) {
	isc_result_t result;
	dns_validatorevent_t *event;
	unsigned int nbits, nlabels;
	int order;
	dns_namereln_t namereln;

	event = val->event;

	/*
	 * Is the key name appropriate for this signature?
	 * This previously checked for self-signed keys.  Now, if the key
	 * is self signed with a preconfigured key, it's ok.
	 */
	namereln = dns_name_fullcompare(event->name, &siginfo->signer,
					&order, &nlabels, &nbits);
	if (namereln != dns_namereln_subdomain &&
	    namereln != dns_namereln_equal) {
		/*
		 * The key name is not at the same level
		 * as 'rdataset', nor is it closer to the
		 * DNS root.
		 */
		return (DNS_R_CONTINUE);
	}

	/*
	 * Is the key used for the signature a security root?
	 */
	INSIST(val->keynode == NULL);
	val->keytable = val->view->secroots;
	result = dns_keytable_findkeynode(val->view->secroots,
					  &siginfo->signer,
					  siginfo->algorithm, siginfo->keyid,
					  &val->keynode);
	if (result == ISC_R_SUCCESS) {
		/*
		 * The key is a security root.
		 */
		val->key = dns_keynode_key(val->keynode);
		return (ISC_R_SUCCESS);
	}

	/*
	 * A key set may not be self-signed unless the signing key is a
	 * security root.  We don't want a KEY RR to authenticate
	 * itself, so we ignore the signature if it was not made by
	 * an ancestor of the KEY or a preconfigured key.
	 */
	if (event->rdataset->type == dns_rdatatype_key &&
	    namereln == dns_namereln_equal)
	{
		validator_log(val, ISC_LOG_DEBUG(3),
			      "keyset was self-signed but not preconfigured");
		return (DNS_R_CONTINUE);
	}

	/*
	 * Do we know about this key?
	 */
	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
	result = dns_view_simplefind(val->view, &siginfo->signer,
				     dns_rdatatype_key, 0,
				     DNS_DBFIND_PENDINGOK, ISC_FALSE,
				     &val->frdataset, &val->fsigrdataset);
	if (result == ISC_R_SUCCESS) {
		/*
		 * We have an rrset for the given keyname.
		 */
		val->keyset = &val->frdataset;
		if (val->frdataset.trust == dns_trust_pending &&
		    dns_rdataset_isassociated(&val->fsigrdataset))
		{
			/*
			 * We know the key but haven't validated it yet.
			 */
			result = dns_validator_create(val->view,
						      &siginfo->signer,
						      dns_rdatatype_key,
						      &val->frdataset,
						      &val->fsigrdataset,
						      NULL,
						      0,
						      val->task,
						      keyvalidated,
						      val,
						      &val->keyvalidator);
			if (result != ISC_R_SUCCESS)
				return (result);
			return (DNS_R_WAIT);
		} else if (val->frdataset.trust == dns_trust_pending) {
			/*
			 * 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 %d",
				      val->frdataset.trust);
			result = get_dst_key(val, siginfo, 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;
			}
		}
	} else if (result == ISC_R_NOTFOUND) {
		/*
		 * We don't know anything about this key.
		 */
		val->fetch = NULL;
		result = dns_resolver_createfetch(val->view->resolver,
						  &siginfo->signer,
						  dns_rdatatype_key,
						  NULL, NULL, NULL, 0,
						  val->event->ev_sender,
						  fetch_callback_validator,
						  val,
						  &val->frdataset,
						  &val->fsigrdataset,
						  &val->fetch);
		if (result != ISC_R_SUCCESS)
			return (result);
		return (DNS_R_WAIT);
	} else if (result ==  DNS_R_NCACHENXDOMAIN ||
		   result == DNS_R_NCACHENXRRSET ||
		   result == DNS_R_NXDOMAIN ||
		   result == DNS_R_NXRRSET)
	{
		/*
		 * This key doesn't exist.
		 */
		result = DNS_R_CONTINUE;
	}

	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);
}

/*
 * If the rdataset being validated is a key set, is each key a security root?
 */
static isc_boolean_t
issecurityroot(dns_validator_t *val) {
	dns_name_t *name;
	dns_rdataset_t *rdataset;
	isc_mem_t *mctx;
	dns_keytable_t *secroots;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	isc_result_t result;
	dns_keynode_t *keynode, *nextnode;
	dst_key_t *key, *secrootkey;
	isc_boolean_t match = ISC_FALSE;

	name = val->event->name;
	rdataset = val->event->rdataset;
	mctx = val->view->mctx;
	secroots = val->view->secroots;

	for (result = dns_rdataset_first(rdataset);
	     result == ISC_R_SUCCESS;
	     result = dns_rdataset_next(rdataset))
	{
		dns_rdataset_current(rdataset, &rdata);
		key = NULL;
		result = dns_dnssec_keyfromrdata(name, &rdata, mctx, &key);
		dns_rdata_reset(&rdata);
		if (result != ISC_R_SUCCESS)
			 continue;
		keynode = NULL;
		result = dns_keytable_findkeynode(
						secroots, name,
						(dns_secalg_t)dst_key_alg(key),
						dst_key_id(key),
						&keynode);

		match = ISC_FALSE;
		while (result == ISC_R_SUCCESS) {
			secrootkey = dns_keynode_key(keynode);
			if (dst_key_compare(key, secrootkey)) {
				match = ISC_TRUE;
				dns_keytable_detachkeynode(secroots, &keynode);
				break;
			}
			nextnode = NULL;
			result = dns_keytable_findnextkeynode(secroots,
							      keynode,
							      &nextnode);
			dns_keytable_detachkeynode(secroots, &keynode);
		}

		dst_key_free(&key);
		if (!match)
			return (ISC_FALSE);
	}
	return (match);
}

/*
 * Attempts positive response validation.
 *
 * Returns:
 *	ISC_R_SUCCESS	Validation completed successfully
 *	DNS_R_WAIT	Validation has started but is waiting
 *			for an event.
 *	Other return codes are possible and all indicate failure.
 */
static inline isc_result_t
validate(dns_validator_t *val, isc_boolean_t resume) {
	isc_result_t result;
	dns_validatorevent_t *event;
	dns_rdata_t rdata = DNS_RDATA_INIT;

	/*
	 * Caller must be holding the validator lock.
	 */

	event = val->event;

	/*
	 * If this is a security root, it's ok.
	 */
	if (!resume) {
		dns_fixedname_t fsecroot;
		dns_name_t *secroot;

		dns_fixedname_init(&fsecroot);
		secroot = dns_fixedname_name(&fsecroot);
		result = dns_keytable_finddeepestmatch(val->view->secroots,
						       val->event->name,
						       secroot);
		if (result == ISC_R_SUCCESS &&
		    val->event->type == dns_rdatatype_key &&
		    dns_name_equal(val->event->name, secroot) &&
		    issecurityroot(val))
		{
			val->event->rdataset->trust = dns_trust_secure;
			return (ISC_R_SUCCESS);
		}
	}

	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)
			isc_mem_put(val->view->mctx, val->siginfo,
				    sizeof *val->siginfo);
		val->siginfo = isc_mem_get(val->view->mctx,
					   sizeof *val->siginfo);
		if (val->siginfo == NULL)
			return (ISC_R_NOMEMORY);
		dns_rdata_tostruct(&rdata, val->siginfo, NULL);

		/*
		 * At this point we could check that the signature algorithm
		 * was known and "sufficiently good".  For now, any algorithm
		 * is acceptable.
		 */

		if (!resume) {
			result = get_key(val, val->siginfo);
			if (result == DNS_R_CONTINUE)
				continue; /* Try the next SIG RR. */
			if (result != ISC_R_SUCCESS)
				return (result);
		}

		if (val->key == NULL) {
			event->rdataset->trust = dns_trust_answer;
			event->sigrdataset->trust = dns_trust_answer;
			validator_log(val, ISC_LOG_DEBUG(3),
				      "marking as answer");
			return (ISC_R_SUCCESS);

		}

		do {
			val->attributes |= VALATTR_TRIEDVERIFY;
			result = dns_dnssec_verify(event->name,
						   event->rdataset,
						   val->key, ISC_FALSE,
						   val->view->mctx, &rdata);
			validator_log(val, ISC_LOG_DEBUG(3),
				      "verify rdataset: %s",
				      isc_result_totext(result));
			if (result == ISC_R_SUCCESS)
				break;
			if (val->keynode != NULL) {
				dns_keynode_t *nextnode = NULL;
				result = dns_keytable_findnextkeynode(
							val->keytable,
							val->keynode,
							&nextnode);
				dns_keytable_detachkeynode(val->keytable,
							   &val->keynode);
				val->keynode = nextnode;
				if (result != ISC_R_SUCCESS) {
					val->key = NULL;
					break;
				}
				val->key = dns_keynode_key(val->keynode);
			} else {
				if (get_dst_key(val, val->siginfo, val->keyset)
				    != ISC_R_SUCCESS)
					break;
			}
		} while (1);
		if (result != ISC_R_SUCCESS)
			validator_log(val, ISC_LOG_DEBUG(3),
				      "failed to verify rdataset");
		else {
			isc_uint32_t ttl;
			isc_stdtime_t now;

			isc_stdtime_get(&now);
			ttl = ISC_MIN(event->rdataset->ttl,
				      val->siginfo->timeexpire - now);
			if (val->keyset != NULL)
				ttl = ISC_MIN(ttl, val->keyset->ttl);
			event->rdataset->ttl = ttl;
			event->sigrdataset->ttl = ttl;
		}

		if (val->keynode != NULL)
			dns_keytable_detachkeynode(val->keytable,
						   &val->keynode);
		else {
			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 (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 {
			validator_log(val, ISC_LOG_DEBUG(3),
				      "verify failure: %s",
				      isc_result_totext(result));
			resume = ISC_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 (DNS_R_NOVALIDSIG);
}