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, *
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22 \***************************************************************************/
24 package com.verisign.tat.dnssec;
26 import org.apache.log4j.Logger;
28 import org.xbill.DNS.*;
30 import java.security.MessageDigest;
31 import java.security.NoSuchAlgorithmException;
33 import java.util.Iterator;
37 * This is a collection of routines encompassing the logic of validating
38 * different message types.
40 public class ValUtils {
41 private static Logger st_log = Logger.getLogger(ValUtils.class);
42 private Logger log = Logger.getLogger(this.getClass());
44 /** A local copy of the verifier object. */
45 private DnsSecVerifier mVerifier;
47 public ValUtils(DnsSecVerifier verifier) {
52 * Given a response, classify ANSWER responses into a subtype.
55 * The response to classify.
57 * @return A subtype ranging from UNKNOWN to NAMEERROR.
59 public static ResponseType classifyResponse(SMessage m, Name zone) {
62 // Normal Name Error's are easy to detect -- but don't mistake a CNAME
63 // chain ending in NXDOMAIN.
64 if ((m.getRcode() == Rcode.NXDOMAIN) &&
65 (m.getCount(Section.ANSWER) == 0)) {
66 return ResponseType.NAMEERROR;
69 // If rcode isn't NXDOMAIN or NOERROR, it is a throwaway response.
70 if (m.getRcode() != Rcode.NOERROR) {
71 return ResponseType.THROWAWAY;
74 // Next is REFERRAL. These are distinguished by having:
75 // 1) nothing in the ANSWER section
76 // 2) an NS RRset in the AUTHORITY section that is a strict subdomain of
77 // 'zone' (the presumed queried zone).
78 if ((zone != null) && (m.getCount(Section.ANSWER) == 0) &&
79 (m.getCount(Section.AUTHORITY) > 0)) {
80 rrsets = m.getSectionRRsets(Section.AUTHORITY);
82 for (int i = 0; i < rrsets.length; ++i) {
83 if ((rrsets[i].getType() == Type.NS) &&
84 strictSubdomain(rrsets[i].getName(), zone)) {
85 return ResponseType.REFERRAL;
91 if (m.getCount(Section.ANSWER) == 0) {
92 return ResponseType.NODATA;
95 // We distinguish between CNAME response and other positive/negative
96 // responses because CNAME answers require extra processing.
97 int qtype = m.getQuestion().getType();
99 // We distinguish between ANY and CNAME or POSITIVE because ANY
100 // responses are validated differently.
101 if (qtype == Type.ANY) {
102 return ResponseType.ANY;
105 rrsets = m.getSectionRRsets(Section.ANSWER);
107 // Note that DNAMEs will be ignored here, unless qtype=DNAME. Unless
108 // qtype=CNAME, this will yield a CNAME response.
109 for (int i = 0; i < rrsets.length; i++) {
110 if (rrsets[i].getType() == qtype) {
111 return ResponseType.POSITIVE;
114 if (rrsets[i].getType() == Type.CNAME) {
115 return ResponseType.CNAME;
119 st_log.warn("Failed to classify response message:\n" + m);
121 return ResponseType.UNKNOWN;
125 * Given a response, determine the name of the "signer". This is primarily
126 * to determine if the response is, in fact, signed at all, and, if so, what
127 * is the name of the most pertinent keyset.
130 * The response to analyze.
131 * @return a signer name, if the response is signed (even partially), or
132 * null if the response isn't signed.
134 public Name findSigner(SMessage m) {
135 // FIXME: this used to classify the message, then look in the pertinent
136 // section. Now we just find the first RRSIG in the ANSWER and AUTHORIY
138 for (int section = Section.ANSWER; section < Section.ADDITIONAL;
140 SRRset [] rrsets = m.getSectionRRsets(section);
142 for (int i = 0; i < rrsets.length; ++i) {
143 Name signerName = rrsets[i].getSignerName();
145 if (signerName != null) {
155 * Given a DNSKEY record, generate the DS record from it.
158 * the DNSKEY record in question.
160 * The DS digest algorithm in use.
161 * @return the corresponding {@link org.xbill.DNS.DSRecord}
163 public static byte [] calculateDSHash(DNSKEYRecord keyrec, int ds_alg) {
164 DNSOutput os = new DNSOutput();
166 os.writeByteArray(keyrec.getName().toWireCanonical());
167 os.writeByteArray(keyrec.rdataToWireCanonical());
170 MessageDigest md = null;
173 case DSRecord.SHA1_DIGEST_ID:
174 md = MessageDigest.getInstance("SHA");
176 return md.digest(os.toByteArray());
178 case DSRecord.SHA256_DIGEST_ID:
179 md = MessageDigest.getInstance("SHA256");
181 return md.digest(os.toByteArray());
184 st_log.warn("Unknown DS algorithm: " + ds_alg);
188 } catch (NoSuchAlgorithmException e) {
189 st_log.error("Error using DS algorithm: " + ds_alg, e);
195 public static boolean supportsDigestID(int digest_id) {
196 if (digest_id == DSRecord.SHA1_DIGEST_ID) {
200 if (digest_id == DSRecord.SHA256_DIGEST_ID) {
208 * Check to see if a type is a special DNSSEC type.
213 * @return true if the type is one of the special DNSSEC types.
215 public static boolean isDNSSECType(int type) {
230 * Set the security status of a particular RRset. This will only upgrade the
234 * The SRRset to update.
236 * The security status.
238 public static void setRRsetSecurity(SRRset rrset, byte security) {
243 int cur_sec = rrset.getSecurityStatus();
245 if ((cur_sec == SecurityStatus.UNCHECKED) || (security > cur_sec)) {
246 rrset.setSecurityStatus(security);
251 * Set the security status of a message and all of its RRsets. This will
252 * only upgrade the status of the message (i.e., set to more secure, not
253 * less) and all of the RRsets.
259 * SMessage m = response.getSMessage(); SRRset ans_rrset =
260 * m.findAnswerRRset(qname, qtype, qclass);
262 * ke = verifySRRset(ans_rrset, key_rrset); if
263 * (ans_rrset.getSecurityStatus() != SecurityStatus.SECURE) {
264 * return; } key_rrset = ke.getRRset();
266 public static void setMessageSecurity(SMessage m, byte security) {
271 int cur_sec = m.getStatus();
273 if ((cur_sec == SecurityStatus.UNCHECKED) || (security > cur_sec)) {
274 m.setStatus(security);
277 for (int section = Section.ANSWER; section <= Section.ADDITIONAL;
279 SRRset [] rrsets = m.getSectionRRsets(section);
281 for (int i = 0; i < rrsets.length; i++) {
282 setRRsetSecurity(rrsets[i], security);
288 * Given an SRRset that is signed by a DNSKEY found in the key_rrset, verify
289 * it. This will return the status (either BOGUS or SECURE) and set that
293 * The SRRset to verify.
295 * The set of keys to verify against.
296 * @return The status (BOGUS or SECURE).
298 public byte verifySRRset(SRRset rrset, SRRset key_rrset) {
299 String rrset_name = rrset.getName() + "/" +
300 Type.string(rrset.getType()) + "/" +
301 DClass.string(rrset.getDClass());
303 if (rrset.getSecurityStatus() == SecurityStatus.SECURE) {
304 log.trace("verifySRRset: rrset <" + rrset_name +
305 "> previously found to be SECURE");
307 return SecurityStatus.SECURE;
310 byte status = mVerifier.verify(rrset, key_rrset);
312 if (status != SecurityStatus.SECURE) {
313 log.debug("verifySRRset: rrset <" + rrset_name +
314 "> found to be BAD");
315 status = SecurityStatus.BOGUS;
317 log.trace("verifySRRset: rrset <" + rrset_name +
318 "> found to be SECURE");
321 rrset.setSecurityStatus(status);
327 * Determine if a given type map has a given type.
330 * The type map from the NSEC record.
332 * The type to look for.
333 * @return true if the type is present in the type map, false otherwise.
335 public static boolean typeMapHasType(int [] types, int type) {
336 for (int i = 0; i < types.length; i++) {
337 if (types[i] == type) {
345 @SuppressWarnings("unchecked")
346 public static RRSIGRecord rrsetFirstSig(RRset rrset) {
347 for (Iterator i = rrset.sigs(); i.hasNext();) {
348 return (RRSIGRecord) i.next();
355 * Finds the longest common name between two domain names.
361 public static Name longestCommonName(Name domain1, Name domain2) {
362 if ((domain1 == null) || (domain2 == null)) {
366 // for now, do this in a a fairly brute force way
367 // FIXME: convert this to direct operations on the byte[]
368 int d1_labels = domain1.labels();
369 int d2_labels = domain2.labels();
371 int l = (d1_labels < d2_labels) ? d1_labels : d2_labels;
373 for (int i = l; i > 0; i--) {
374 Name n1 = new Name(domain1, d1_labels - i);
375 Name n2 = new Name(domain2, d2_labels - i);
385 public static boolean strictSubdomain(Name child, Name parent) {
386 int clabels = child.labels();
387 int plabels = parent.labels();
389 if (plabels >= clabels) {
393 Name n = new Name(child, clabels - plabels);
395 return parent.equals(n);
399 * Determine by looking at a signed RRset whether or not the rrset name was
400 * the result of a wildcard expansion.
403 * The rrset to examine.
404 * @return true if the rrset is a wildcard expansion. This will return false
405 * for all unsigned rrsets.
407 public static boolean rrsetIsWildcardExpansion(RRset rrset) {
412 RRSIGRecord rrsig = rrsetFirstSig(rrset);
414 if ((rrset.getName().labels() - 1) > rrsig.getLabels()) {
422 * Determine by looking at a signed RRset whether or not the RRset name was
423 * the result of a wildcard expansion. If so, return the name of the
424 * generating wildcard.
427 * The rrset to check.
428 * @return the wildcard name, if the rrset was synthesized from a wildcard.
431 public static Name rrsetWildcard(RRset rrset) {
436 RRSIGRecord rrsig = rrsetFirstSig(rrset);
438 // if the RRSIG label count is shorter than the number of actual labels,
439 // then this rrset was synthesized from a wildcard.
440 // Note that the RRSIG label count doesn't count the root label.
441 int label_diff = (rrset.getName().labels() - 1) - rrsig.getLabels();
443 if (label_diff > 0) {
444 return rrset.getName().wild(label_diff);
450 public static Name closestEncloser(Name domain, NSECRecord nsec) {
451 Name n1 = longestCommonName(domain, nsec.getName());
452 Name n2 = longestCommonName(domain, nsec.getNext());
454 return (n1.labels() > n2.labels()) ? n1 : n2;
457 public static Name nsecWildcard(Name domain, NSECRecord nsec) {
459 return new Name("*", closestEncloser(domain, nsec));
460 } catch (TextParseException e) {
461 // this should never happen.
467 * Determine if the given NSEC proves a NameError (NXDOMAIN) for a given
473 * The qname to check against.
475 * The signer name of the NSEC record, which is used as the zone
476 * name, for a more precise (but perhaps more brittle) check for
477 * the last NSEC in a zone.
478 * @return true if the NSEC proves the condition.
480 public static boolean nsecProvesNameError(NSECRecord nsec, Name qname,
482 Name owner = nsec.getName();
483 Name next = nsec.getNext();
485 // If NSEC owner == qname, then this NSEC proves that qname exists.
486 if (qname.equals(owner)) {
490 // If NSEC is a parent of qname, we need to check the type map
491 // If the parent name has a DNAME or is a delegation point, then this
492 // NSEC is being misused.
493 boolean hasBadType = typeMapHasType(nsec.getTypes(), Type.DNAME) ||
494 (typeMapHasType(nsec.getTypes(), Type.NS) &&
495 !typeMapHasType(nsec.getTypes(), Type.SOA));
497 if (qname.subdomain(owner) && hasBadType) {
501 if (((qname.compareTo(owner) > 0) && (qname.compareTo(next) < 0)) ||
502 signerName.equals(next)) {
510 * Determine if a NSEC record proves the non-existence of a wildcard that
511 * could have produced qname.
516 * The qname to check against.
518 * The signer name for the NSEC rrset, used as the zone name.
519 * @return true if the NSEC proves the condition.
521 public static boolean nsecProvesNoWC(NSECRecord nsec, Name qname,
523 Name owner = nsec.getName();
524 Name next = nsec.getNext();
526 int qname_labels = qname.labels();
527 int signer_labels = signerName.labels();
529 for (int i = qname_labels - signer_labels; i > 0; i--) {
530 Name wc_name = qname.wild(i);
532 if ((wc_name.compareTo(owner) > 0) &&
533 ((wc_name.compareTo(next) < 0) || signerName.equals(next))) {
542 * Determine if a NSEC proves the NOERROR/NODATA conditions. This will also
543 * handle the empty non-terminal (ENT) case and partially handle the
544 * wildcard case. If the ownername of 'nsec' is a wildcard, the validator
545 * must still be provided proof that qname did not directly exist and that
546 * the wildcard is, in fact, *.closest_encloser.
551 * The query name to check against.
553 * The query type to check against.
554 * @return true if the NSEC proves the condition.
556 public static boolean nsecProvesNodata(NSECRecord nsec, Name qname,
558 if (!nsec.getName().equals(qname)) {
559 // wildcard checking.
561 // If this is a wildcard NSEC, make sure that a) it was possible to
563 // generated qname from the wildcard and b) the type map does not
564 // contain qtype. Note that this does NOT prove that this wildcard
566 // the applicable wildcard.
567 if (nsec.getName().isWild()) {
568 // the is the purported closest encloser.
569 Name ce = new Name(nsec.getName(), 1);
571 // The qname must be a strict subdomain of the closest encloser,
573 // the qtype must be absent from the type map.
574 if (!strictSubdomain(qname, ce) ||
575 typeMapHasType(nsec.getTypes(), qtype)) {
582 // empty-non-terminal checking.
584 // If the nsec is proving that qname is an ENT, the nsec owner will
586 // less than qname, and the next name will be a child domain of the
588 if (strictSubdomain(nsec.getNext(), qname) &&
589 (qname.compareTo(nsec.getName()) > 0)) {
593 // Otherwise, this NSEC does not prove ENT, so it does not prove
598 // If the qtype exists, then we should have gotten it.
599 if (typeMapHasType(nsec.getTypes(), qtype)) {
603 // if the name is a CNAME node, then we should have gotten the CNAME
604 if (typeMapHasType(nsec.getTypes(), Type.CNAME)) {
608 // If an NS set exists at this name, and NOT a SOA (so this is a zone
610 // not a zone apex), then we should have gotten a referral (or we just
613 if (typeMapHasType(nsec.getTypes(), Type.NS) &&
614 !typeMapHasType(nsec.getTypes(), Type.SOA)) {
621 public static byte nsecProvesNoDS(NSECRecord nsec, Name qname) {
622 // Could check to make sure the qname is a subdomain of nsec
623 int [] types = nsec.getTypes();
625 if (typeMapHasType(types, Type.SOA) || typeMapHasType(types, Type.DS)) {
626 // SOA present means that this is the NSEC from the child, not the
627 // parent (so it is the wrong one)
628 // DS present means that there should have been a positive response
630 // the DS query, so there is something wrong.
631 return SecurityStatus.BOGUS;
634 if (!typeMapHasType(types, Type.NS)) {
635 // If there is no NS at this point at all, then this doesn't prove
636 // anything one way or the other.
637 return SecurityStatus.INSECURE;
640 // Otherwise, this proves no DS.
641 return SecurityStatus.SECURE;
644 // These are response subtypes. They are necessary for determining the
645 // validation strategy. They have no bearing on the iterative resolution
646 // algorithm, so they are confined here.
647 public enum ResponseType {UNTYPED, UNKNOWN, POSITIVE, CNAME, NODATA,
648 NAMEERROR, ANY, REFERRAL,
649 // a referral response
651 // a throwaway response (i.e., an error)