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;
37 public class NSEC3ValUtils {
38 // FIXME: should probably refactor to handle different NSEC3 parameters more
40 // Given a list of NSEC3 RRs, they should be grouped according to
41 // parameters. The idea is to hash and compare for each group independently,
42 // instead of having to skip NSEC3 RRs with the wrong parameters.
43 private static Name asterisk_label = Name.fromConstantString("*");
44 private static Logger st_log = Logger.getLogger(NSEC3ValUtils.class);
45 private static final base32 b32 = new base32(base32.Alphabet.BASE32HEX,
48 public static boolean supportsHashAlgorithm(int alg) {
49 if (alg == NSEC3Record.SHA1_DIGEST_ID) {
56 public static void stripUnknownAlgNSEC3s(List<NSEC3Record> nsec3s) {
61 for (ListIterator<NSEC3Record> i = nsec3s.listIterator(); i.hasNext();) {
62 NSEC3Record nsec3 = i.next();
64 if (!supportsHashAlgorithm(nsec3.getHashAlgorithm())) {
70 public static boolean isOptOut(NSEC3Record nsec3) {
71 return (nsec3.getFlags() & NSEC3Record.Flags.OPT_OUT) == NSEC3Record.Flags.OPT_OUT;
75 * Given a list of NSEC3Records that are part of a message, determine the
76 * NSEC3 parameters (hash algorithm, iterations, and salt) present. If there
77 * is more than one distinct grouping, return null;
80 * A list of NSEC3Record object.
81 * @return A set containing a number of objects (NSEC3Parameter objects)
82 * that correspond to each distinct set of parameters, or null if
83 * the nsec3s list was empty.
85 public static NSEC3Parameters nsec3Parameters(List<NSEC3Record> nsec3s) {
86 if ((nsec3s == null) || (nsec3s.size() == 0)) {
90 NSEC3Parameters params = new NSEC3Parameters((NSEC3Record) nsec3s
92 ByteArrayComparator bac = new ByteArrayComparator();
94 for (NSEC3Record nsec3 : nsec3s) {
95 if (!params.match(nsec3, bac)) {
104 * Given a hash and an a zone name, construct an NSEC3 ownername.
107 * The hash of an original name.
109 * The zone to use in constructing the NSEC3 name.
110 * @return The NSEC3 name.
112 private static Name hashName(byte[] hash, Name zonename) {
114 return new Name(b32.toString(hash).toLowerCase(), zonename);
115 } catch (TextParseException e) {
116 // Note, this should never happen.
122 * Given a set of NSEC3 parameters, hash a name.
127 * The parameters to hash with.
130 private static byte[] hash(Name name, NSEC3Parameters params) {
132 return params.hash(name);
133 } catch (NoSuchAlgorithmException e) {
134 st_log.warn("Did not recognize hash algorithm: " + params.alg);
141 * Given the name of a closest encloser, return the name *.closest_encloser.
143 * @param closestEncloser
144 * The name to start with.
145 * @return The wildcard name.
147 private static Name ceWildcard(Name closestEncloser) {
149 Name wc = Name.concatenate(asterisk_label, closestEncloser);
152 } catch (NameTooLongException e) {
158 * Given a qname and its proven closest encloser, calculate the "next
159 * closest" name. Basically, this is the name that is one label longer than
160 * the closest encloser that is still a subdomain of qname.
164 * @param closestEncloser
165 * The closest encloser name.
166 * @return The next closer name.
168 private static Name nextClosest(Name qname, Name closestEncloser) {
169 int strip = qname.labels() - closestEncloser.labels() - 1;
171 return (strip > 0) ? new Name(qname, strip) : qname;
175 * Find the NSEC3Record that matches a hash of a name.
178 * The pre-calculated hash of a name.
180 * The name of the zone that the NSEC3s are from.
182 * A list of NSEC3Records from a given message.
184 * The parameters used for calculating the hash.
186 * An already allocated ByteArrayComparator, for reuse. This may
189 * @return The matching NSEC3Record, if one is present.
191 private static NSEC3Record findMatchingNSEC3(byte[] hash, Name zonename,
192 List<NSEC3Record> nsec3s, NSEC3Parameters params,
193 ByteArrayComparator bac) {
194 Name n = hashName(hash, zonename);
196 for (NSEC3Record nsec3 : nsec3s) {
197 // Skip nsec3 records that are using different parameters.
198 if (!params.match(nsec3, bac)) {
202 if (n.equals(nsec3.getName())) {
211 * Given a hash and a candidate NSEC3Record, determine if that NSEC3Record
212 * covers the hash. Covers specifically means that the hash is in between
213 * the owner and next hashes and does not equal either.
216 * The candidate NSEC3Record.
218 * The precalculated hash.
220 * An already allocated comparator. This may be null.
221 * @return True if the NSEC3Record covers the hash.
223 private static boolean nsec3Covers(NSEC3Record nsec3, byte [] hash,
224 ByteArrayComparator bac) {
225 Name ownerName = nsec3.getName();
226 byte [] owner = b32.fromString(ownerName.getLabelString(0));
227 byte [] next = nsec3.getNext();
229 // This is the "normal case: owner < next and owner < hash < next
230 if ((bac.compare(owner, hash) < 0) && (bac.compare(hash, next) < 0)) {
233 // this is the end of zone case: next < owner && hash > owner || hash <
235 if ((bac.compare(next, owner) <= 0)
236 && ((bac.compare(hash, next) < 0) || (bac.compare(owner, hash) < 0))) {
240 // Otherwise, the NSEC3 does not cover the hash.
245 * Given a pre-hashed name, find a covering NSEC3 from among a list of
249 * The hash to consider.
251 * The name of the zone.
253 * The list of NSEC3s present in a message.
255 * The NSEC3 parameters used to generate the hash -- NSEC3s that
256 * do not use those parameters will be skipped.
258 * @return A covering NSEC3 if one is present, null otherwise.
260 private static NSEC3Record findCoveringNSEC3(byte[] hash, Name zonename,
261 List<NSEC3Record> nsec3s, NSEC3Parameters params,
262 ByteArrayComparator bac) {
263 ByteArrayComparator comparator = new ByteArrayComparator();
265 for (NSEC3Record nsec3 : nsec3s) {
266 if (!params.match(nsec3, bac)) {
270 if (nsec3Covers(nsec3, hash, comparator)) {
279 * Given a name and a list of NSEC3s, find the candidate closest encloser.
280 * This will be the first ancestor of 'name' (including itself) to have a
284 * The name the start with.
286 * The name of the zone that the NSEC3s came from.
288 * The list of NSEC3s.
290 * The NSEC3 parameters.
292 * A pre-allocated comparator. May be null.
294 * @return A CEResponse containing the closest encloser name and the NSEC3
295 * RR that matched it, or null if there wasn't one.
297 private static CEResponse findClosestEncloser(Name name, Name zonename,
298 List<NSEC3Record> nsec3s, NSEC3Parameters params,
299 ByteArrayComparator bac) {
304 // This scans from longest name to shortest, so the first match we find
305 // is the only viable candidate.
306 // FIXME: modify so that the NSEC3 matching the zone apex need not be
308 while (n.labels() >= zonename.labels()) {
309 nsec3 = findMatchingNSEC3(hash(n, params), zonename,
310 nsec3s, params, bac);
313 return new CEResponse(n, nsec3);
323 * Given a List of nsec3 RRs, find and prove the closest encloser to qname.
326 * The qname in question.
328 * The name of the zone that the NSEC3 RRs come from.
330 * The list of NSEC3s found the this response (already verified).
332 * The NSEC3 parameters found in the response.
334 * A pre-allocated comparator. May be null.
335 * @param proveDoesNotExist
336 * If true, then if the closest encloser turns out to be qname,
337 * then null is returned.
338 * @return null if the proof isn't completed. Otherwise, return a CEResponse
339 * object which contains the closest encloser name and the NSEC3
342 private static CEResponse proveClosestEncloser(Name qname, Name zonename,
343 List<NSEC3Record> nsec3s, NSEC3Parameters params,
344 ByteArrayComparator bac, boolean proveDoesNotExist, List<String> errorList) {
345 CEResponse candidate = findClosestEncloser(qname, zonename, nsec3s,
348 if (candidate == null) {
349 errorList.add("Could not find a candidate for the closest encloser");
350 st_log.debug("proveClosestEncloser: could not find a " +
351 "candidate for the closest encloser.");
356 if (candidate.closestEncloser.equals(qname)) {
357 if (proveDoesNotExist) {
358 errorList.add("Proven closest encloser proved that the qname existed and should not have");
359 st_log.debug("proveClosestEncloser: proved that qname existed!");
364 // otherwise, we need to nothing else to prove that qname is its own
369 // If the closest encloser is actually a delegation, then the response
370 // should have been a referral. If it is a DNAME, then it should have
373 if (candidate.ce_nsec3.hasType(Type.NS) &&
374 !candidate.ce_nsec3.hasType(Type.SOA)) {
375 errorList.add("Proven closest encloser was a delegation");
376 st_log.debug("proveClosestEncloser: closest encloser " +
377 "was a delegation!");
382 if (candidate.ce_nsec3.hasType(Type.DNAME)) {
383 errorList.add("Proven closest encloser was a DNAME");
384 st_log.debug("proveClosestEncloser: closest encloser was a DNAME!");
389 // Otherwise, we need to show that the next closer name is covered.
390 Name nextClosest = nextClosest(qname, candidate.closestEncloser);
392 byte[] nc_hash = hash(nextClosest, params);
393 candidate.nc_nsec3 = findCoveringNSEC3(nc_hash, zonename, nsec3s,
396 if (candidate.nc_nsec3 == null) {
397 errorList.add("Could not find proof that the closest encloser was the closest encloser");
398 errorList.add("hash " + hashName(nc_hash, zonename) + " is not covered by any NSEC3 RRs");
399 st_log.debug("Could not find proof that the " +
400 "closest encloser was the closest encloser");
408 private static int maxIterations(int baseAlg, int keysize) {
410 case DnsSecVerifier.RSA:
413 return 2500; // the max at 4096
416 if (keysize > 2048) {
420 if (keysize > 1024) {
430 case DnsSecVerifier.DSA:
433 return 5000; // the max at 2048;
436 if (keysize > 1024) {
450 @SuppressWarnings("rawtypes")
451 private static boolean validIterations(NSEC3Parameters nsec3params,
452 RRset dnskey_rrset, DnsSecVerifier verifier) {
453 // for now, we return the maximum iterations based simply on the key
454 // algorithms that may have been used to sign the NSEC3 RRsets.
455 int max_iterations = 0;
457 for (Iterator i = dnskey_rrset.rrs(); i.hasNext();) {
458 DNSKEYRecord dnskey = (DNSKEYRecord) i.next();
459 int baseAlg = verifier.baseAlgorithm(dnskey.getAlgorithm());
460 int iters = maxIterations(baseAlg, 0);
461 max_iterations = (max_iterations < iters) ? iters : max_iterations;
464 if (nsec3params.iterations > max_iterations) {
472 * Determine if all of the NSEC3s in a response are legally ignoreable
473 * (i.e., their presence should lead to an INSECURE result). Currently, this
474 * is solely based on iterations.
477 * The list of NSEC3s. If there is more than one set of NSEC3
478 * parameters present, this test will not be performed.
479 * @param dnskey_rrset
480 * The set of validating DNSKEYs.
482 * The verifier used to verify the NSEC3 RRsets. This is solely
483 * used to map algorithm aliases.
484 * @return true if all of the NSEC3s can be legally ignored, false if not.
486 public static boolean allNSEC3sIgnoreable(List<NSEC3Record> nsec3s,
487 RRset dnskey_rrset, DnsSecVerifier verifier) {
488 NSEC3Parameters params = nsec3Parameters(nsec3s);
490 if (params == null) {
494 return !validIterations(params, dnskey_rrset, verifier);
498 * Determine if the set of NSEC3 records provided with a response prove NAME
499 * ERROR. This means that the NSEC3s prove a) the closest encloser exists,
500 * b) the direct child of the closest encloser towards qname doesn't exist,
501 * and c) *.closest encloser does not exist.
504 * The list of NSEC3s.
506 * The query name to check against.
508 * This is the name of the zone that the NSEC3s belong to. This
509 * may be discovered in any number of ways. A good one is to use
510 * the signerName from the NSEC3 record's RRSIG.
511 * @return SecurityStatus.SECURE of the Name Error is proven by the NSEC3
512 * RRs, BOGUS if not, INSECURE if all of the NSEC3s could be validly
515 public static boolean proveNameError(List<NSEC3Record> nsec3s, Name qname,
516 Name zonename, List<String> errorList) {
517 if ((nsec3s == null) || (nsec3s.size() == 0)) {
521 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
523 if (nsec3params == null) {
524 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present");
525 st_log.debug("Could not find a single set of " +
526 "NSEC3 parameters (multiple parameters present).");
531 ByteArrayComparator bac = new ByteArrayComparator();
533 // First locate and prove the closest encloser to qname. We will use the
534 // variant that fails if the closest encloser turns out to be qname.
535 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
536 nsec3params, bac, true, errorList);
539 errorList.add("Failed to find the closest encloser as part of the NSEC3 proof");
540 st_log.debug("proveNameError: failed to prove a closest encloser.");
545 // At this point, we know that qname does not exist. Now we need to
547 // that the wildcard does not exist.
548 Name wc = ceWildcard(ce.closestEncloser);
549 byte[] wc_hash = hash(wc, nsec3params);
550 NSEC3Record nsec3 = findCoveringNSEC3(wc_hash, zonename, nsec3s,
554 errorList.add("Failed to prove that the applicable wildcard did not exist");
555 st_log.debug("proveNameError: could not prove that the " +
556 "applicable wildcard did not exist.");
565 * Determine if the NSEC3s provided in a response prove the NOERROR/NODATA
566 * status. There are a number of different variants to this:
568 * 1) Normal NODATA -- qname is matched to an NSEC3 record, type is not
571 * 2) ENT NODATA -- because there must be NSEC3 record for
572 * empty-non-terminals, this is the same as #1.
574 * 3) NSEC3 ownername NODATA -- qname matched an existing, lone NSEC3
575 * ownername, but qtype was not NSEC3. NOTE: as of nsec-05, this case no
578 * 4) Wildcard NODATA -- A wildcard matched the name, but not the type.
580 * 5) Opt-In DS NODATA -- the qname is covered by an opt-in span and qtype
581 * == DS. (or maybe some future record with the same parent-side-only
585 * The NSEC3Records to consider.
587 * The qname in question.
589 * The qtype in question.
591 * The name of the zone that the NSEC3s came from.
592 * @return true if the NSEC3s prove the proposition.
594 public static boolean proveNodata(List<NSEC3Record> nsec3s, Name qname,
595 int qtype, Name zonename, List<String> errorList) {
596 if ((nsec3s == null) || (nsec3s.size() == 0)) {
600 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
602 if (nsec3params == null) {
603 st_log.debug("could not find a single set of "
604 + "NSEC3 parameters (multiple parameters present)");
609 ByteArrayComparator bac = new ByteArrayComparator();
611 NSEC3Record nsec3 = findMatchingNSEC3(hash(qname, nsec3params),
612 zonename, nsec3s, nsec3params, bac);
616 if (nsec3.hasType(qtype)) {
618 .debug("proveNodata: Matching NSEC3 proved that type existed!");
623 if (nsec3.hasType(Type.CNAME)) {
624 st_log.debug("proveNodata: Matching NSEC3 proved "
625 + "that a CNAME existed!");
633 // For cases 3 - 5, we need the proven closest encloser, and it can't
634 // match qname. Although, at this point, we know that it won't since we
635 // just checked that.
636 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
637 nsec3params, bac, true, errorList);
639 // At this point, not finding a match or a proven closest encloser is a
642 st_log.debug("proveNodata: did not match qname, "
643 + "nor found a proven closest encloser.");
651 Name wc = ceWildcard(ce.closestEncloser);
652 nsec3 = findMatchingNSEC3(hash(wc, nsec3params), zonename, nsec3s,
656 if (nsec3.hasType(qtype)) {
657 st_log.debug("proveNodata: matching wildcard had qtype!");
666 if (qtype != Type.DS) {
668 .debug("proveNodata: could not find matching NSEC3, "
669 + "nor matching wildcard, and qtype is not DS -- no more options.");
674 // We need to make sure that the covering NSEC3 is opt-in.
675 if (!isOptOut(ce.nc_nsec3)) {
676 st_log.debug("proveNodata: covering NSEC3 was not "
677 + "opt-in in an opt-in DS NOERROR/NODATA case.");
686 * Prove that a positive wildcard match was appropriate (no direct match
690 * The NSEC3 records to work with.
692 * The qname that was matched to the wildcard
694 * The name of the zone that the NSEC3s come from.
696 * The purported wildcard that matched.
697 * @return true if the NSEC3 records prove this case.
699 public static boolean proveWildcard(List<NSEC3Record> nsec3s, Name qname,
700 Name zonename, Name wildcard, List<String> errorList) {
701 if ((nsec3s == null) || (nsec3s.size() == 0)) {
705 if ((qname == null) || (wildcard == null)) {
709 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
711 if (nsec3params == null) {
712 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present)");
714 "couldn't find a single set of NSEC3 parameters (multiple parameters present).");
719 ByteArrayComparator bac = new ByteArrayComparator();
721 // We know what the (purported) closest encloser is by just looking at
723 // supposed generating wildcard.
724 CEResponse candidate = new CEResponse(new Name(wildcard, 1), null);
726 // Now we still need to prove that the original data did not exist.
727 // Otherwise, we need to show that the next closer name is covered.
728 Name nextClosest = nextClosest(qname, candidate.closestEncloser);
729 candidate.nc_nsec3 = findCoveringNSEC3(hash(nextClosest, nsec3params),
730 zonename, nsec3s, nsec3params, bac);
732 if (candidate.nc_nsec3 == null) {
733 errorList.add("Did not find a NSEC3 that covered the next closer name to '" +
734 qname + "' from '" + candidate.closestEncloser + "' (derived from the wildcard: " +
736 st_log.debug("proveWildcard: did not find a covering NSEC3 " +
737 "that covered the next closer name to " + qname + " from " +
738 candidate.closestEncloser + " (derived from wildcard " +
748 * Prove that a DS response either had no DS, or wasn't a delegation point.
750 * Fundamentally there are two cases here: normal NODATA and Opt-In NODATA.
753 * The NSEC3 RRs to examine.
755 * The name of the DS in question.
757 * The name of the zone that the NSEC3 RRs come from.
759 * @return SecurityStatus.SECURE if it was proven that there is no DS in a
760 * secure (i.e., not opt-in) way, SecurityStatus.INSECURE if there
761 * was no DS in an insecure (i.e., opt-in) way,
762 * SecurityStatus.INDETERMINATE if it was clear that this wasn't a
763 * delegation point, and SecurityStatus.BOGUS if the proofs don't
766 public static byte proveNoDS(List<NSEC3Record> nsec3s, Name qname,
767 Name zonename, List<String> errorList) {
768 if ((nsec3s == null) || (nsec3s.size() == 0)) {
769 return SecurityStatus.BOGUS;
772 NSEC3Parameters nsec3params = nsec3Parameters(nsec3s);
774 if (nsec3params == null) {
775 errorList.add("Could not find a single set of NSEC3 parameters (multiple parameters present)");
776 st_log.debug("couldn't find a single set of " +
777 "NSEC3 parameters (multiple parameters present).");
779 return SecurityStatus.BOGUS;
782 ByteArrayComparator bac = new ByteArrayComparator();
784 // Look for a matching NSEC3 to qname -- this is the normal NODATA case.
785 NSEC3Record nsec3 = findMatchingNSEC3(hash(qname, nsec3params),
786 zonename, nsec3s, nsec3params, bac);
789 // If the matching NSEC3 has the SOA bit set, it is from the wrong
790 // zone (the child instead of the parent). If it has the DS bit set,
791 // then we were lied to.
792 if (nsec3.hasType(Type.SOA) || nsec3.hasType(Type.DS)) {
793 errorList.add("Matching NSEC3 is incorrectly from the child instead of the parent (SOA or DS bit set)");
794 return SecurityStatus.BOGUS;
797 // If the NSEC3 RR doesn't have the NS bit set, then this wasn't a
799 if (!nsec3.hasType(Type.NS)) {
800 return SecurityStatus.INDETERMINATE;
803 // Otherwise, this proves no DS.
804 return SecurityStatus.SECURE;
807 // Otherwise, we are probably in the opt-in case.
808 CEResponse ce = proveClosestEncloser(qname, zonename, nsec3s,
809 nsec3params, bac, true, errorList);
812 errorList.add("Failed to prove the closest encloser as part of a 'No DS' proof");
813 return SecurityStatus.BOGUS;
816 // If we had the closest encloser proof, then we need to check that the
817 // covering NSEC3 was opt-in -- the proveClosestEncloser step already
818 // checked to see if the closest encloser was a delegation or DNAME.
819 if (isOptOut(ce.nc_nsec3)) {
820 return SecurityStatus.SECURE;
823 errorList.add("Failed to find a covering NSEC3 for 'No DS' proof");
824 return SecurityStatus.BOGUS;
828 * This is a class to encapsulate a unique set of NSEC3 parameters:
829 * algorithm, iterations, and salt.
831 private static class NSEC3Parameters {
834 public int iterations;
835 private NSEC3PARAMRecord nsec3paramrec;
837 public NSEC3Parameters(NSEC3Record r) {
838 alg = r.getHashAlgorithm();
840 iterations = r.getIterations();
842 nsec3paramrec = new NSEC3PARAMRecord(Name.root, DClass.IN, 0, alg,
843 0, iterations, salt);
846 public boolean match(NSEC3Record r, ByteArrayComparator bac) {
847 if (r.getHashAlgorithm() != alg) {
851 if (r.getIterations() != iterations) {
855 if ((salt == null) && (r.getSalt() != null)) {
864 bac = new ByteArrayComparator();
867 return bac.compare(r.getSalt(), salt) == 0;
870 public byte[] hash(Name name) throws NoSuchAlgorithmException {
871 return nsec3paramrec.hashName(name);
876 * This is just a simple class to encapsulate the response to a closest
879 private static class CEResponse {
880 public Name closestEncloser;
881 public NSEC3Record ce_nsec3;
882 public NSEC3Record nc_nsec3;
884 public CEResponse(Name ce, NSEC3Record nsec3) {
885 this.closestEncloser = ce;
886 this.ce_nsec3 = nsec3;