1 /***************************** -*- Java -*- ********************************\
3 * Copyright (c) 2009 VeriSign, Inc. All rights reserved. *
5 * This software is provided solely in connection with the terms of the *
6 * license agreement. Any other use without the prior express written *
7 * permission of VeriSign is completely prohibited. The software and *
8 * documentation are "Commercial Items", as that term is defined in 48 *
9 * C.F.R. section 2.101, consisting of "Commercial Computer Software" and *
10 * "Commercial Computer Software Documentation" as such terms are defined *
11 * in 48 C.F.R. section 252.227-7014(a)(5) and 48 C.F.R. section *
12 * 252.227-7014(a)(1), and used in 48 C.F.R. section 12.212 and 48 C.F.R. *
13 * section 227.7202, as applicable. Pursuant to the above and other *
14 * relevant sections of the Code of Federal Regulations, as applicable, *
15 * VeriSign's publications, commercial computer software, and commercial *
16 * computer software documentation are distributed and licensed to United *
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22 \***************************************************************************/
24 package com.verisign.tat.dnssec;
26 import com.verisign.tat.dnssec.SignUtils.ByteArrayComparator;
28 import org.apache.log4j.Logger;
30 import org.xbill.DNS.*;
31 import org.xbill.DNS.utils.base32;
33 import java.security.NoSuchAlgorithmException;
38 public class NSEC3ValUtils {
39 // FIXME: should probably refactor to handle different NSEC3 parameters more
41 // Given a list of NSEC3 RRs, they should be grouped according to
42 // parameters. The idea is to hash and compare for each group independently,
43 // instead of having to skip NSEC3 RRs with the wrong parameters.
44 private static Name asterisk_label = Name.fromConstantString("*");
45 private static Logger st_log = Logger.getLogger(NSEC3ValUtils.class);
46 private static final base32 b32 = new base32(base32.Alphabet.BASE32HEX,
49 public static boolean supportsHashAlgorithm(int alg) {
50 if (alg == NSEC3Record.SHA1_DIGEST_ID) {
57 public static void stripUnknownAlgNSEC3s(List<NSEC3Record> nsec3s) {
62 for (ListIterator<NSEC3Record> i = nsec3s.listIterator(); i.hasNext();) {
63 NSEC3Record nsec3 = i.next();
65 if (!supportsHashAlgorithm(nsec3.getHashAlgorithm())) {
71 public static boolean isOptOut(NSEC3Record nsec3) {
72 return (nsec3.getFlags() & NSEC3Record.Flags.OPT_OUT) == NSEC3Record.Flags.OPT_OUT;
76 * Given a list of NSEC3Records that are part of a message, determine the
77 * NSEC3 parameters (hash algorithm, iterations, and salt) present. If there
78 * is more than one distinct grouping, return null;
81 * A list of NSEC3Record object.
82 * @return A set containing a number of objects (NSEC3Parameter objects)
83 * that correspond to each distinct set of parameters, or null if
84 * the nsec3s list was empty.
86 public static NSEC3Parameters nsec3Parameters(List<NSEC3Record> nsec3s) {
87 if ((nsec3s == null) || (nsec3s.size() == 0)) {
91 NSEC3Parameters params = new NSEC3Parameters((NSEC3Record) nsec3s.get(
93 ByteArrayComparator bac = new ByteArrayComparator();
95 for (NSEC3Record nsec3 : nsec3s) {
96 if (!params.match(nsec3, bac)) {
105 * Given a hash and an a zone name, construct an NSEC3 ownername.
108 * The hash of an original name.
110 * The zone to use in constructing the NSEC3 name.
111 * @return The NSEC3 name.
113 private static Name hashName(byte [] hash, Name zonename) {
115 return new Name(b32.toString(hash).toLowerCase(), zonename);
116 } catch (TextParseException e) {
117 // Note, this should never happen.
123 * Given a set of NSEC3 parameters, hash a name.
128 * The parameters to hash with.
131 private static byte [] hash(Name name, NSEC3Parameters params) {
133 return params.hash(name);
134 } catch (NoSuchAlgorithmException e) {
135 st_log.warn("Did not recognize hash algorithm: " + params.alg);
141 private static byte[] hash(Name name, NSEC3Record nsec3) {
143 return nsec3.hashName(name);
144 } catch (NoSuchAlgorithmException e) {
145 st_log.warn("Did not recognize hash algorithm: " + nsec3.getHashAlgorithm());
152 * Given the name of a closest encloser, return the name *.closest_encloser.
154 * @param closestEncloser
155 * The name to start with.
156 * @return The wildcard name.
158 private static Name ceWildcard(Name closestEncloser) {
160 Name wc = Name.concatenate(asterisk_label, closestEncloser);
163 } catch (NameTooLongException e) {
169 * Given a qname and its proven closest encloser, calculate the "next
170 * closest" name. Basically, this is the name that is one label longer than
171 * the closest encloser that is still a subdomain of qname.
175 * @param closestEncloser
176 * The closest encloser name.
177 * @return The next closer name.
179 private static Name nextClosest(Name qname, Name closestEncloser) {
180 int strip = qname.labels() - closestEncloser.labels() - 1;
182 return (strip > 0) ? new Name(qname, strip) : qname;
186 * Find the NSEC3Record that matches a hash of a name.
189 * The pre-calculated hash of a name.
191 * The name of the zone that the NSEC3s are from.
193 * A list of NSEC3Records from a given message.
195 * The parameters used for calculating the hash.
197 * An already allocated ByteArrayComparator, for reuse. This may
200 * @return The matching NSEC3Record, if one is present.
202 private static NSEC3Record findMatchingNSEC3(byte [] hash, Name zonename,
203 List<NSEC3Record> nsec3s, NSEC3Parameters params,
204 ByteArrayComparator bac) {
205 Name n = hashName(hash, zonename);
207 for (NSEC3Record nsec3 : nsec3s) {
208 // Skip nsec3 records that are using different parameters.
209 if (!params.match(nsec3, bac)) {
213 if (n.equals(nsec3.getName())) {
222 * Given a hash and a candidate NSEC3Record, determine if that NSEC3Record
223 * covers the hash. Covers specifically means that the hash is in between
224 * the owner and next hashes and does not equal either.
227 * The candidate NSEC3Record.
229 * The precalculated hash.
231 * An already allocated comparator. This may be null.
232 * @return True if the NSEC3Record covers the hash.
234 private static boolean nsec3Covers(NSEC3Record nsec3, byte [] hash,
235 ByteArrayComparator bac) {
236 Name ownerName = nsec3.getName();
237 byte [] owner = b32.fromString(ownerName.getLabelString(0));
238 byte [] next = nsec3.getNext();
240 // This is the "normal case: owner < next and owner < hash < next
241 if ((bac.compare(owner, hash) < 0) && (bac.compare(hash, next) < 0)) {
244 // this is the end of zone case: next < owner && hash > owner || hash <
246 if ((bac.compare(next, owner) <= 0) &&
247 ((bac.compare(hash, next) < 0) ||
248 (bac.compare(owner, hash) < 0))) {
252 // Otherwise, the NSEC3 does not cover the hash.
257 * Given a pre-hashed name, find a covering NSEC3 from among a list of
261 * The hash to consider.
263 * The name of the zone.
265 * The list of NSEC3s present in a message.
267 * The NSEC3 parameters used to generate the hash -- NSEC3s that
268 * do not use those parameters will be skipped.
270 * @return A covering NSEC3 if one is present, null otherwise.
272 private static NSEC3Record findCoveringNSEC3(byte [] hash, Name zonename,
273 List<NSEC3Record> nsec3s, NSEC3Parameters params,
274 ByteArrayComparator bac) {
275 ByteArrayComparator comparator = new ByteArrayComparator();
277 for (NSEC3Record nsec3 : nsec3s) {
278 if (!params.match(nsec3, bac)) {
282 if (nsec3Covers(nsec3, hash, comparator)) {
291 * Given a name and a list of NSEC3s, find the candidate closest encloser.
292 * This will be the first ancestor of 'name' (including itself) to have a
296 * The name the start with.
298 * The name of the zone that the NSEC3s came from.
300 * The list of NSEC3s.
302 * The NSEC3 parameters.
304 * A pre-allocated comparator. May be null.
306 * @return A CEResponse containing the closest encloser name and the NSEC3
307 * RR that matched it, or null if there wasn't one.
309 private static CEResponse findClosestEncloser(Name name, Name zonename,
310 List<NSEC3Record> nsec3s, NSEC3Parameters params,
311 ByteArrayComparator bac) {
316 // This scans from longest name to shortest, so the first match we find
317 // is the only viable candidate.
318 // FIXME: modify so that the NSEC3 matching the zone apex need not be
320 while (n.labels() >= zonename.labels()) {
321 nsec3 = findMatchingNSEC3(hash(n, params), zonename,
322 nsec3s, params, bac);
325 return new CEResponse(n, nsec3);
335 * Given a List of nsec3 RRs, find and prove the closest encloser to qname.
338 * The qname in question.
340 * The name of the zone that the NSEC3 RRs come from.
342 * The list of NSEC3s found the this response (already verified).
344 * The NSEC3 parameters found in the response.
346 * A pre-allocated comparator. May be null.
347 * @param proveDoesNotExist
348 * If true, then if the closest encloser turns out to be qname,
349 * then null is returned.
350 * @return null if the proof isn't completed. Otherwise, return a CEResponse
351 * object which contains the closest encloser name and the NSEC3
354 private static CEResponse proveClosestEncloser(Name qname, Name zonename,
355 List<NSEC3Record> nsec3s, NSEC3Parameters params,
356 ByteArrayComparator bac, boolean proveDoesNotExist, List<String> errorList) {
357 CEResponse candidate = findClosestEncloser(qname, zonename, nsec3s,
360 if (candidate == null) {
361 errorList.add("Could not find a candidate for the closest encloser");
362 st_log.debug("proveClosestEncloser: could not find a " +
363 "candidate for the closest encloser.");
368 if (candidate.closestEncloser.equals(qname)) {
369 if (proveDoesNotExist) {
370 errorList.add("Proven closest encloser proved that the qname existed and should not have");
371 st_log.debug("proveClosestEncloser: proved that qname existed!");
376 // otherwise, we need to nothing else to prove that qname is its own
381 // If the closest encloser is actually a delegation, then the response
382 // should have been a referral. If it is a DNAME, then it should have
385 if (candidate.ce_nsec3.hasType(Type.NS) &&
386 !candidate.ce_nsec3.hasType(Type.SOA)) {
387 errorList.add("Proven closest encloser was a delegation");
388 st_log.debug("proveClosestEncloser: closest encloser " +
389 "was a delegation!");
394 if (candidate.ce_nsec3.hasType(Type.DNAME)) {
395 errorList.add("Proven closest encloser was a DNAME");
396 st_log.debug("proveClosestEncloser: closest encloser was a DNAME!");
401 // Otherwise, we need to show that the next closer name is covered.
402 Name nextClosest = nextClosest(qname, candidate.closestEncloser);
404 byte [] nc_hash = hash(nextClosest, params);
405 candidate.nc_nsec3 = findCoveringNSEC3(nc_hash, zonename, nsec3s,
408 if (candidate.nc_nsec3 == null) {
409 errorList.add("Could not find proof that the closest encloser was the closest encloser");
410 errorList.add("hash " + hashName(nc_hash, zonename) + " is not covered by any NSEC3 RRs");
411 st_log.debug("Could not find proof that the " +
412 "closest encloser was the closest encloser");
420 private static int maxIterations(int baseAlg, int keysize) {
422 case DnsSecVerifier.RSA:
425 return 2500; // the max at 4096
428 if (keysize > 2048) {
432 if (keysize > 1024) {
442 case DnsSecVerifier.DSA:
445 return 5000; // the max at 2048;
448 if (keysize > 1024) {
462 @SuppressWarnings("unchecked")
463 private static boolean validIterations(NSEC3Parameters nsec3params,
464 RRset dnskey_rrset, DnsSecVerifier verifier) {
465 // for now, we return the maximum iterations based simply on the key
466 // algorithms that may have been used to sign the NSEC3 RRsets.
467 int max_iterations = 0;
469 for (Iterator i = dnskey_rrset.rrs(); i.hasNext();) {
470 DNSKEYRecord dnskey = (DNSKEYRecord) i.next();
471 int baseAlg = verifier.baseAlgorithm(dnskey.getAlgorithm());
472 int iters = maxIterations(baseAlg, 0);
473 max_iterations = (max_iterations < iters) ? iters
477 if (nsec3params.iterations > max_iterations) {
485 * Determine if all of the NSEC3s in a response are legally ignoreable
486 * (i.e., their presence should lead to an INSECURE result). Currently, this
487 * is solely based on iterations.
490 * The list of NSEC3s. If there is more than one set of NSEC3
491 * parameters present, this test will not be performed.
492 * @param dnskey_rrset
493 * The set of validating DNSKEYs.
495 * The verifier used to verify the NSEC3 RRsets. This is solely
496 * used to map algorithm aliases.
497 * @return true if all of the NSEC3s can be legally ignored, false if not.
499 public static boolean allNSEC3sIgnoreable(List<NSEC3Record> nsec3s,
500 RRset dnskey_rrset, DnsSecVerifier verifier) {
501 NSEC3Parameters params = nsec3Parameters(nsec3s);
503 if (params == null) {
507 return !validIterations(params, dnskey_rrset, verifier);
511 * Determine if the set of NSEC3 records provided with a response prove NAME
512 * ERROR. This means that the NSEC3s prove a) the closest encloser exists,
513 * b) the direct child of the closest encloser towards qname doesn't exist,
514 * and c) *.closest encloser does not exist.
517 * The list of NSEC3s.
519 * The query name to check against.
521 * This is the name of the zone that the NSEC3s belong to. This
522 * may be discovered in any number of ways. A good one is to use
523 * the signerName from the NSEC3 record's RRSIG.
524 * @return SecurityStatus.SECURE of the Name Error is proven by the NSEC3
525 * RRs, BOGUS if not, INSECURE if all of the NSEC3s could be validly
528 public static boolean proveNameError(List<NSEC3Record> nsec3s, Name qname,
529 Name zonename, List<String> errorList) {
530 if ((nsec3s == null) || (nsec3s.size() == 0)) {
534 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
536 if (nsec3params == null) {
537 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present");
538 st_log.debug("Could not find a single set of " +
539 "NSEC3 parameters (multiple parameters present).");
544 ByteArrayComparator bac = new ByteArrayComparator();
546 // First locate and prove the closest encloser to qname. We will use the
547 // variant that fails if the closest encloser turns out to be qname.
548 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
549 nsec3params, bac, true, errorList);
552 errorList.add("Failed to find the closest encloser as part of the NSEC3 proof");
553 st_log.debug("proveNameError: failed to prove a closest encloser.");
558 // At this point, we know that qname does not exist. Now we need to
560 // that the wildcard does not exist.
561 Name wc = ceWildcard(ce.closestEncloser);
562 byte [] wc_hash = hash(wc, nsec3params);
563 NSEC3Record nsec3 = findCoveringNSEC3(wc_hash, zonename, nsec3s,
567 errorList.add("Failed to prove that the applicable wildcard did not exist");
568 st_log.debug("proveNameError: could not prove that the " +
569 "applicable wildcard did not exist.");
578 * Determine if the NSEC3s provided in a response prove the NOERROR/NODATA
579 * status. There are a number of different variants to this:
581 * 1) Normal NODATA -- qname is matched to an NSEC3 record, type is not
584 * 2) ENT NODATA -- because there must be NSEC3 record for
585 * empty-non-terminals, this is the same as #1.
587 * 3) NSEC3 ownername NODATA -- qname matched an existing, lone NSEC3
588 * ownername, but qtype was not NSEC3. NOTE: as of nsec-05, this case no
591 * 4) Wildcard NODATA -- A wildcard matched the name, but not the type.
593 * 5) Opt-In DS NODATA -- the qname is covered by an opt-in span and qtype
594 * == DS. (or maybe some future record with the same parent-side-only
598 * The NSEC3Records to consider.
600 * The qname in question.
602 * The qtype in question.
604 * The name of the zone that the NSEC3s came from.
605 * @return true if the NSEC3s prove the proposition.
607 public static boolean proveNodata(List<NSEC3Record> nsec3s, Name qname,
608 int qtype, Name zonename, List<String> errorList) {
609 if ((nsec3s == null) || (nsec3s.size() == 0)) {
613 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
615 if (nsec3params == null) {
616 st_log.debug("could not find a single set of " +
617 "NSEC3 parameters (multiple parameters present)");
622 ByteArrayComparator bac = new ByteArrayComparator();
624 NSEC3Record nsec3 = findMatchingNSEC3(hash(qname, nsec3params),
625 zonename, nsec3s, nsec3params, bac);
629 if (nsec3.hasType(qtype)) {
631 "proveNodata: Matching NSEC3 proved that type existed!");
636 if (nsec3.hasType(Type.CNAME)) {
637 st_log.debug("proveNodata: Matching NSEC3 proved " +
638 "that a CNAME existed!");
646 // For cases 3 - 5, we need the proven closest encloser, and it can't
647 // match qname. Although, at this point, we know that it won't since we
648 // just checked that.
649 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
650 nsec3params, bac, true, errorList);
652 // At this point, not finding a match or a proven closest encloser is a
655 st_log.debug("proveNodata: did not match qname, " +
656 "nor found a proven closest encloser.");
664 Name wc = ceWildcard(ce.closestEncloser);
665 nsec3 = findMatchingNSEC3(hash(wc, nsec3params), zonename, nsec3s,
669 if (nsec3.hasType(qtype)) {
670 st_log.debug("proveNodata: matching wildcard had qtype!");
679 if (qtype != Type.DS) {
680 st_log.debug("proveNodata: could not find matching NSEC3, " +
681 "nor matching wildcard, and qtype is not DS -- no more options.");
686 // We need to make sure that the covering NSEC3 is opt-in.
687 if (!isOptOut(ce.nc_nsec3)) {
688 st_log.debug("proveNodata: covering NSEC3 was not " +
689 "opt-in in an opt-in DS NOERROR/NODATA case.");
698 * Prove that a positive wildcard match was appropriate (no direct match
702 * The NSEC3 records to work with.
704 * The qname that was matched to the wildcard
706 * The name of the zone that the NSEC3s come from.
708 * The purported wildcard that matched.
709 * @return true if the NSEC3 records prove this case.
711 public static boolean proveWildcard(List<NSEC3Record> nsec3s, Name qname,
712 Name zonename, Name wildcard, List<String> errorList) {
713 if ((nsec3s == null) || (nsec3s.size() == 0)) {
717 if ((qname == null) || (wildcard == null)) {
721 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
723 if (nsec3params == null) {
724 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present)");
726 "couldn't find a single set of NSEC3 parameters (multiple parameters present).");
731 ByteArrayComparator bac = new ByteArrayComparator();
733 // We know what the (purported) closest encloser is by just looking at
735 // supposed generating wildcard.
736 CEResponse candidate = new CEResponse(new Name(wildcard, 1), null);
738 // Now we still need to prove that the original data did not exist.
739 // Otherwise, we need to show that the next closer name is covered.
740 Name nextClosest = nextClosest(qname, candidate.closestEncloser);
741 candidate.nc_nsec3 = findCoveringNSEC3(hash(nextClosest, nsec3params),
742 zonename, nsec3s, nsec3params, bac);
744 if (candidate.nc_nsec3 == null) {
745 errorList.add("Did not find a NSEC3 that covered the next closer name to '" +
746 qname + "' from '" + candidate.closestEncloser + "' (derived from the wildcard: " +
748 st_log.debug("proveWildcard: did not find a covering NSEC3 " +
749 "that covered the next closer name to " + qname + " from " +
750 candidate.closestEncloser + " (derived from wildcard " +
760 * Prove that a DS response either had no DS, or wasn't a delegation point.
762 * Fundamentally there are two cases here: normal NODATA and Opt-In NODATA.
765 * The NSEC3 RRs to examine.
767 * The name of the DS in question.
769 * The name of the zone that the NSEC3 RRs come from.
771 * @return SecurityStatus.SECURE if it was proven that there is no DS in a
772 * secure (i.e., not opt-in) way, SecurityStatus.INSECURE if there
773 * was no DS in an insecure (i.e., opt-in) way,
774 * SecurityStatus.INDETERMINATE if it was clear that this wasn't a
775 * delegation point, and SecurityStatus.BOGUS if the proofs don't
778 public static byte proveNoDS(List<NSEC3Record> nsec3s, Name qname,
779 Name zonename, List<String> errorList) {
780 if ((nsec3s == null) || (nsec3s.size() == 0)) {
781 return SecurityStatus.BOGUS;
784 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
786 if (nsec3params == null) {
787 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present)");
788 st_log.debug("couldn't find a single set of " +
789 "NSEC3 parameters (multiple parameters present).");
791 return SecurityStatus.BOGUS;
794 ByteArrayComparator bac = new ByteArrayComparator();
796 // Look for a matching NSEC3 to qname -- this is the normal NODATA case.
797 NSEC3Record nsec3 = findMatchingNSEC3(hash(qname, nsec3params),
798 zonename, nsec3s, nsec3params, bac);
801 // If the matching NSEC3 has the SOA bit set, it is from the wrong
802 // zone (the child instead of the parent). If it has the DS bit set,
803 // then we were lied to.
804 if (nsec3.hasType(Type.SOA) || nsec3.hasType(Type.DS)) {
805 errorList.add("Matching NSEC3 is incorrectly from the child instead of the parent (SOA or DS bit set)");
806 return SecurityStatus.BOGUS;
809 // If the NSEC3 RR doesn't have the NS bit set, then this wasn't a
811 if (!nsec3.hasType(Type.NS)) {
812 return SecurityStatus.INDETERMINATE;
815 // Otherwise, this proves no DS.
816 return SecurityStatus.SECURE;
819 // Otherwise, we are probably in the opt-in case.
820 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
821 nsec3params, bac, true, errorList);
824 errorList.add("Failed to prove the closest encloser as part of a 'No DS' proof");
825 return SecurityStatus.BOGUS;
828 // If we had the closest encloser proof, then we need to check that the
829 // covering NSEC3 was opt-in -- the proveClosestEncloser step already
830 // checked to see if the closest encloser was a delegation or DNAME.
831 if (isOptOut(ce.nc_nsec3)) {
832 return SecurityStatus.SECURE;
835 errorList.add("Failed to find a covering NSEC3 for 'No DS' proof");
836 return SecurityStatus.BOGUS;
840 * This is a class to encapsulate a unique set of NSEC3 parameters:
841 * algorithm, iterations, and salt.
843 private static class NSEC3Parameters {
846 public int iterations;
847 private NSEC3PARAMRecord nsec3paramrec;
849 public NSEC3Parameters(NSEC3Record r) {
850 alg = r.getHashAlgorithm();
852 iterations = r.getIterations();
854 nsec3paramrec = new NSEC3PARAMRecord(Name.root, DClass.IN, 0,
855 alg, 0, iterations, salt);
858 public boolean match(NSEC3Record r, ByteArrayComparator bac) {
859 if (r.getHashAlgorithm() != alg) {
863 if (r.getIterations() != iterations) {
867 if ((salt == null) && (r.getSalt() != null)) {
876 bac = new ByteArrayComparator();
879 return bac.compare(r.getSalt(), salt) == 0;
882 public byte[] hash(Name name) throws NoSuchAlgorithmException {
883 return nsec3paramrec.hashName(name);
888 * This is just a simple class to encapsulate the response to a closest
891 private static class CEResponse {
892 public Name closestEncloser;
893 public NSEC3Record ce_nsec3;
894 public NSEC3Record nc_nsec3;
896 public CEResponse(Name ce, NSEC3Record nsec3) {
897 this.closestEncloser = ce;
898 this.ce_nsec3 = nsec3;