Class Dnsruby::Dnssec
In: lib/Dnsruby/dnssec.rb
Parent: Object
ResolvError EncodeError OtherResolvError ServFail FormErr DecodeError NXRRSet YXDomain NotImp NXDomain VerifyError NotAuth YXRRSet NotZone Refused TsigError Message Update CodeMapper Types MetaTypes QTypes Nsec3HashAlgorithms Algorithms OpCode Classes ExtendedRCode RCode Modes Comparable Name RRSet Resolver SingleResolver StandardError TimeoutError ResolvTimeout DNS Dnssec Hosts SelectThread\n[lib/Dnsruby/select_thread.rb\nlib/Dnsruby/select_thread.rb.michael.rb] Recursor IPv6 IPv4 ZoneTransfer MessageDecoder MessageEncoder Question Header TheLog RR\n[lib/Dnsruby/resource/A.rb\nlib/Dnsruby/resource/AAAA.rb\nlib/Dnsruby/resource/AFSDB.rb\nlib/Dnsruby/resource/CERT.rb\nlib/Dnsruby/resource/DLV.rb\nlib/Dnsruby/resource/DNSKEY.rb\nlib/Dnsruby/resource/DS.rb\nlib/Dnsruby/resource/HINFO.rb\nlib/Dnsruby/resource/IN.rb\nlib/Dnsruby/resource/ISDN.rb\nlib/Dnsruby/resource/LOC.rb\nlib/Dnsruby/resource/MINFO.rb\nlib/Dnsruby/resource/MX.rb\nlib/Dnsruby/resource/NAPTR.rb\nlib/Dnsruby/resource/NSAP.rb\nlib/Dnsruby/resource/NSEC.rb\nlib/Dnsruby/resource/NSEC3.rb\nlib/Dnsruby/resource/NSEC3PARAM.rb\nlib/Dnsruby/resource/OPT.rb\nlib/Dnsruby/resource/PX.rb\nlib/Dnsruby/resource/RP.rb\nlib/Dnsruby/resource/RRSIG.rb\nlib/Dnsruby/resource/RT.rb\nlib/Dnsruby/resource/SOA.rb\nlib/Dnsruby/resource/SPF.rb\nlib/Dnsruby/resource/SRV.rb\nlib/Dnsruby/resource/TKEY.rb\nlib/Dnsruby/resource/TSIG.rb\nlib/Dnsruby/resource/TXT.rb\nlib/Dnsruby/resource/X25.rb\nlib/Dnsruby/resource/domain_name.rb\nlib/Dnsruby/resource/generic.rb\nlib/Dnsruby/resource/resource.rb] ValidatorThread PacketSender ResolverRuby Config KeyCache Cache SingleVerifier Resolv Iana lib/Dnsruby/DNS.rb lib/Dnsruby/dnssec.rb lib/Dnsruby/Hosts.rb lib/Dnsruby/select_thread.rb.michael.rb lib/Dnsruby/Recursor.rb lib/Dnsruby/update.rb lib/Dnsruby/ipv6.rb lib/Dnsruby/ipv4.rb lib/Dnsruby/code_mapper.rb lib/Dnsruby/zone_transfer.rb lib/Dnsruby/message.rb lib/Dnsruby/TheLog.rb lib/Dnsruby/resource/resource.rb lib/Dnsruby/validator_thread.rb lib/Dnsruby/PacketSender.rb lib/Dnsruby/Resolver.rb lib/Dnsruby/Config.rb lib/Dnsruby/key_cache.rb lib/Dnsruby/Cache.rb lib/Dnsruby/single_verifier.rb lib/Dnsruby/SingleResolver.rb lib/Dnsruby/name.rb lib/dnsruby.rb lib/Dnsruby/resource/TKEY.rb lib/Dnsruby/iana_ports.rb Dnsruby dot/m_56_0.png

RFC4033, section 7

  "There is one more step that a security-aware stub resolver can take
  if, for whatever reason, it is not able to establish a useful trust
  relationship with the recursive name servers that it uses: it can
  perform its own signature validation by setting the Checking Disabled
  (CD) bit in its query messages.  A validating stub resolver is thus
  able to treat the DNSSEC signatures as trust relationships between
  the zone administrators and the stub resolver itself. "

Dnsruby is configured to validate responses by default. However, it is not configured with any trusted keys by default. Applications may use the verify() method to perform verification with of RRSets of Messages with given keys. Alternatively, trusted keys may be added to this class (either directly, or by loading the IANA TAR or the DLV ISC ZSK). Validation will then be performed from these keys (or the DLV registry, if configured). Negative and positive responses are validation.

Messages are tagged with the current security_level (Message::SecurityLevel). UNCHECKED means Dnsruby has not attempted to validate the response. BOGUS means the response has been checked, and is bogus. INSECURE means the response has been validated to be insecure (e.g. in an unsigned zone) SECURE means that the response has been verfied to be correct.

Several validators are provided, with each maintaining its own cache of trusted keys. If validators are added or removed, the caches of the other validators are not affected.

Methods

Classes and Modules

Class Dnsruby::Dnssec::ValidationPolicy

Public Class methods

Add a trusted Key Signing Key for the ISC DLV registry.

[Source]

    # File lib/Dnsruby/dnssec.rb, line 88
88:     def Dnssec.add_dlv_key(dlv_key)
89:       @@dlv_verifier.add_dlv_key(dlv_key)
90:     end

Add a new trust anchor

[Source]

    # File lib/Dnsruby/dnssec.rb, line 92
92:     def Dnssec.add_trust_anchor(t)
93:       # @TODO@ Create a new verifier?
94:       @@anchor_verifier.add_trust_anchor(t)
95:     end

Add the trusted key with the given expiration time

[Source]

     # File lib/Dnsruby/dnssec.rb, line 97
 97:     def self.add_trust_anchor_with_expiration(k, expiration)
 98:       # Create a new verifier?
 99:       @@anchor_verifier.add_trust_anchor_with_expiration(k, expiration)
100:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 301
301:     def self.anchor_verifier
302:       return @@anchor_verifier
303:     end

Wipes the cache of trusted keys

[Source]

     # File lib/Dnsruby/dnssec.rb, line 106
106:     def self.clear_trust_anchors
107:       @@anchor_verifier.clear_trust_anchors
108:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 114
114:     def self.clear_trusted_keys
115:       [@@anchor_verifier, @@root_verifier, @@dlv_verifier].each {|v|
116:         v.clear_trusted_keys
117:       }
118:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 181
181:     def self.default_resolver
182:       return @@default_resolver
183:     end

This method overrides the system default resolver configuration for validation If default_resolver is set, then it will be used to follow the chain of trust. If it is not, then the default system resolver will be used (unless do_validation_with_recursor is set.

[Source]

     # File lib/Dnsruby/dnssec.rb, line 178
178:     def self.default_resolver=(res)
179:       @@default_resolver = res
180:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 304
304:     def self.dlv_verifier
305:       return @@dlv_verifier
306:     end

This method defines the choice of Resolver or Recursor, when the validator is checking responses. If set to true, then a Recursor will be used to query for the DNSSEC records. Otherwise, the default system resolver will be used.

[Source]

     # File lib/Dnsruby/dnssec.rb, line 168
168:     def self.do_validation_with_recursor(on)
169:       @@do_validation_with_recursor = on
170:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 171
171:     def self.do_validation_with_recursor?
172:       return @@do_validation_with_recursor
173:     end

Load the IANA TAR. THIS METHOD IS NOT SECURE!!!

[Source]

     # File lib/Dnsruby/dnssec.rb, line 132
132:     def self.load_itar
133:       # @TODO@ THIS IS VERY INSECURE!! WRITE THIS PROPERLY!!
134:       # Should really check the signatures here to make sure the keys are good!
135:       Net::FTP::open("ftp.iana.org") { |ftp|
136:         ftp.login("anonymous")
137:         ftp.passive = true
138:         ftp.chdir("/itar")
139:         lastname=nil
140:         ftp.gettextfile("anchors.mf") {|line|
141:           next if (line.strip.length == 0)
142:           first = line[0]
143:           if (first.class == String)
144:             first = first.getbyte(0) # Ruby 1.9
145:           end
146: #            print "Reading ITAR : #{line}, first : #{first}\n"
147:           next if (first==59) # ";")
148:           if (line.strip=~(/^DS /) || line.strip=~(/^DNSKEY /))
149:             line = lastname.to_s + ((lastname.absolute?)?".":"") + " " + line
150:           end
151:           ds = RR.create(line)
152:           if ((ds.type == Types::DS) || (ds.type == Types::DNSKEY))
153:             #            assert(ds.name.absolute?)
154:             Dnssec.add_trust_anchor(ds)
155:           end
156:           lastname = ds.name
157:         }
158:       }
159:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 120
120:     def self.no_keys?
121:       no_keys = true
122:       [@@anchor_verifier, @@root_verifier, @@dlv_verifier].each {|v|
123:         if (v.trusted_keys.length() > 0 ||
124:             v.trust_anchors.length() > 0)
125:           no_keys = false
126:         end
127:       }
128:       return no_keys
129:     end

Remove the trusted key

[Source]

     # File lib/Dnsruby/dnssec.rb, line 102
102:     def Dnssec.remove_trust_anchor(t)
103:       @@anchor_verifier.remove_trust_anchor(t)
104:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 307
307:     def self.root_verifier
308:       return @@root_verifier
309:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 110
110:     def self.trust_anchors
111:       return @@anchor_verifier.trust_anchors
112:     end

Returns true for secure/insecure, false otherwise This method will set the security_level on msg to the appropriate value. Could be : secure, insecure, bogus or indeterminate If an error is encountered during verification, then the thrown exception will define the error.

[Source]

     # File lib/Dnsruby/dnssec.rb, line 190
190:     def self.validate(msg)
191:       query = Message.new()
192:       query.header.cd=true
193:       return self.validate_with_query(query, msg)
194:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 277
277:     def self.validate_with_anchors(msg, query)
278:       return @@anchor_verifier.validate(msg, query)
279:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 285
285:     def self.validate_with_dlv(msg, query)
286:       return @@dlv_verifier.validate(msg, query)
287:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 196
196:     def self.validate_with_query(query, msg)
197:       if (!msg)
198:         return false
199:       end
200:       # First, just check there is something to validate!
201:       found_sigs = false
202:       msg.each_resource {|rr|
203:         if (rr.type == Types::RRSIG)
204:           found_sigs = true
205:         end
206:       }
207:       if (found_sigs)
208:         begin
209:           if (verify(msg))
210:             msg.security_level = Message::SecurityLevel.SECURE
211:             return true
212:           end
213:         rescue VerifyError
214:         end
215:       end
216: 
217:       # SHOULD ALWAYS VERIFY DNSSEC-SIGNED RESPONSES?
218:       # Yes - if a trust anchor is configured. Otherwise, act on CD bit (in query)
219:       TheLog.debug("Checking whether to validate, query.cd = #{query.header.cd}")
220:       if (((@@validation_policy > ValidationPolicy::ALWAYS_ROOT_ONLY) && (self.trust_anchors().length > 0)) ||
221:             # Check query here, and validate if CD is true
222:           (query.header.cd == true))
223:         TheLog.debug("Starting validation")
224: 
225:         # Validate!
226:         # Need to think about trapping/storing exceptions and security_levels here
227:         last_error = ""
228:         last_level = Message::SecurityLevel.BOGUS
229:         last_error_level = Message::SecurityLevel.BOGUS
230:         if (@@validation_policy == ValidationPolicy::ALWAYS_LOCAL_ANCHORS_ONLY)
231:           last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level,
232:             Proc.new{|m, q| validate_with_anchors(m, q)}, msg, query)
233:         elsif (@@validation_policy == ValidationPolicy::ALWAYS_ROOT_ONLY)
234:           last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level,
235:             Proc.new{|m, q| validate_with_root(m, q)}, msg, query)
236:         elsif (@@validation_policy == ValidationPolicy::LOCAL_ANCHORS_THEN_ROOT)
237:           last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level, 
238:             Proc.new{|m, q| validate_with_anchors(m, q)}, msg, query)
239:           if (last_level != Message::SecurityLevel.SECURE)
240:             last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level,
241:               Proc.new{|m, q| validate_with_root(m, q)}, msg, query)
242:           end
243:         elsif (@@validation_policy == ValidationPolicy::ROOT_THEN_LOCAL_ANCHORS)
244:           last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level,
245:             Proc.new{|m, q| validate_with_root(m, q)}, msg, query)
246:           if (last_level != Message::SecurityLevel.SECURE)
247:             last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level,
248:               Proc.new{|m, q| validate_with_anchors(m, q)}, msg, query)
249:           end
250:         end
251:         if (last_level != Message::SecurityLevel.SECURE)
252:           last_level, last_error, last_error_level = try_validation(last_level, last_error, last_error_level, 
253:             Proc.new{|m, q| validate_with_dlv(m, q)}, msg, query)
254:         end
255:         # Set the message security level!
256:         msg.security_level = last_level
257:         raise VerifyError.new(last_error) if (last_level < 0)
258:         return (msg.security_level.code > Message::SecurityLevel::UNCHECKED)
259:       end
260:       msg.security_level = Message::SecurityLevel.UNCHECKED
261:       return true
262:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 281
281:     def self.validate_with_root(msg, query)
282:       return @@root_verifier.validate(msg, query)
283:     end

[Source]

    # File lib/Dnsruby/dnssec.rb, line 74
74:     def Dnssec.validation_policy
75:       @@validation_policy
76:     end

[Source]

    # File lib/Dnsruby/dnssec.rb, line 68
68:     def Dnssec.validation_policy=(p)
69:       if ((p >= ALWAYS_ROOT_ONY) && (p <= ALWAYS_LOCAL_ANCHORS))
70:         @@validation_policy = p
71:         # @TODO@ Should we be clearing the trusted keys now?
72:       end
73:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 289
289:     def self.verify(msg)
290:       begin
291:         return true if @@anchor_verifier.verify(msg)
292:       rescue VerifyError
293:         begin
294:           return true if @@root_verifier.verify(msg)
295:         rescue VerifyError
296:           return true if @@dlv_verifier.verify(msg) # Will carry error to client
297:         end
298:       end
299:     end

[Source]

     # File lib/Dnsruby/dnssec.rb, line 314
314:     def self.verify_rrset(rrset, keys = nil)
315:       return ((@@anchor_verifier.verify_rrset(rrset, keys) ||
316:             @@root_verifier.verify_rrset(rrset, keys) ||
317:             @@dlv_verifier.verify_rrset(rrset, keys)))
318:     end

[Validate]