5 verify - Utility to verify certificates.
10 [B<-CApath directory>]
29 [B<-attime timestamp>]
37 The B<verify> command verifies certificate chains.
39 =head1 COMMAND OPTIONS
43 =item B<-CApath directory>
45 A directory of trusted certificates. The certificates should have names
46 of the form: hash.0 or have symbolic links to them of this
47 form ("hash" is the hashed certificate subject name: see the B<-hash> option
48 of the B<x509> utility). Under Unix the B<c_rehash> script will automatically
49 create symbolic links to a directory of certificates.
53 A file of trusted certificates. The file should contain multiple certificates
54 in PEM format concatenated together.
56 =item B<-untrusted file>
58 A file of untrusted certificates. The file should contain multiple certificates
59 in PEM format concatenated together.
61 =item B<-trusted_first>
63 Use certificates in CA file or CA directory before certificates in untrusted
64 file when building the trust chain to verify certificates.
65 This is mainly useful in environments with Bridge CA or Cross-Certified CAs.
67 =item B<-purpose purpose>
69 The intended use for the certificate. If this option is not specified,
70 B<verify> will not consider certificate purpose during chain verification.
71 Currently accepted uses are B<sslclient>, B<sslserver>, B<nssslserver>,
72 B<smimesign>, B<smimeencrypt>. See the B<VERIFY OPERATION> section for more
77 Print out a usage message.
81 Print extra information about the operations being performed.
83 =item B<-issuer_checks>
85 Print out diagnostics relating to searches for the issuer certificate of the
86 current certificate. This shows why each candidate issuer certificate was
87 rejected. The presence of rejection messages does not itself imply that
88 anything is wrong; during the normal verification process, several
89 rejections may take place.
91 =item B<-attime timestamp>
93 Perform validation checks using time specified by B<timestamp> and not
94 current system time. B<timestamp> is the number of seconds since
95 01.01.1970 (UNIX time).
99 Enable policy processing and add B<arg> to the user-initial-policy-set (see
100 RFC5280). The policy B<arg> can be an object name an OID in numeric form.
101 This argument can appear more than once.
103 =item B<-policy_check>
105 Enables certificate policy processing.
107 =item B<-explicit_policy>
109 Set policy variable require-explicit-policy (see RFC5280).
111 =item B<-inhibit_any>
113 Set policy variable inhibit-any-policy (see RFC5280).
115 =item B<-inhibit_map>
117 Set policy variable inhibit-policy-mapping (see RFC5280).
119 =item B<-policy_print>
121 Print out diagnostics related to policy processing.
125 Checks end entity certificate validity by attempting to look up a valid CRL.
126 If a valid CRL cannot be found an error occurs.
128 =item B<-crl_check_all>
130 Checks the validity of B<all> certificates in the chain by attempting
131 to look up valid CRLs.
133 =item B<-ignore_critical>
135 Normally if an unhandled critical extension is present which is not
136 supported by OpenSSL the certificate is rejected (as required by RFC5280).
137 If this option is set critical extensions are ignored.
139 =item B<-x509_strict>
141 For strict X.509 compliance, disable non-compliant workarounds for broken
144 =item B<-extended_crl>
146 Enable extended CRL features such as indirect CRLs and alternate CRL
151 Enable support for delta CRLs.
153 =item B<-check_ss_sig>
155 Verify the signature on the self-signed root CA. This is disabled by default
156 because it doesn't add any security.
160 Indicates the last option. All arguments following this are assumed to be
161 certificate files. This is useful if the first certificate filename begins
164 =item B<certificates>
166 One or more certificates to verify. If no certificates are given, B<verify>
167 will attempt to read a certificate from standard input. Certificates must be
172 =head1 VERIFY OPERATION
174 The B<verify> program uses the same functions as the internal SSL and S/MIME
175 verification, therefore this description applies to these verify operations
178 There is one crucial difference between the verify operations performed
179 by the B<verify> program: wherever possible an attempt is made to continue
180 after an error whereas normally the verify operation would halt on the
181 first error. This allows all the problems with a certificate chain to be
184 The verify operation consists of a number of separate steps.
186 Firstly a certificate chain is built up starting from the supplied certificate
187 and ending in the root CA. It is an error if the whole chain cannot be built
188 up. The chain is built up by looking up the issuers certificate of the current
189 certificate. If a certificate is found which is its own issuer it is assumed
192 The process of 'looking up the issuers certificate' itself involves a number
193 of steps. In versions of OpenSSL before 0.9.5a the first certificate whose
194 subject name matched the issuer of the current certificate was assumed to be
195 the issuers certificate. In OpenSSL 0.9.6 and later all certificates
196 whose subject name matches the issuer name of the current certificate are
197 subject to further tests. The relevant authority key identifier components
198 of the current certificate (if present) must match the subject key identifier
199 (if present) and issuer and serial number of the candidate issuer, in addition
200 the keyUsage extension of the candidate issuer (if present) must permit
203 The lookup first looks in the list of untrusted certificates and if no match
204 is found the remaining lookups are from the trusted certificates. The root CA
205 is always looked up in the trusted certificate list: if the certificate to
206 verify is a root certificate then an exact match must be found in the trusted
209 The second operation is to check every untrusted certificate's extensions for
210 consistency with the supplied purpose. If the B<-purpose> option is not included
211 then no checks are done. The supplied or "leaf" certificate must have extensions
212 compatible with the supplied purpose and all other certificates must also be valid
213 CA certificates. The precise extensions required are described in more detail in
214 the B<CERTIFICATE EXTENSIONS> section of the B<x509> utility.
216 The third operation is to check the trust settings on the root CA. The root
217 CA should be trusted for the supplied purpose. For compatibility with previous
218 versions of SSLeay and OpenSSL a certificate with no trust settings is considered
219 to be valid for all purposes.
221 The final operation is to check the validity of the certificate chain. The validity
222 period is checked against the current system time and the notBefore and notAfter
223 dates in the certificate. The certificate signatures are also checked at this
226 If all operations complete successfully then certificate is considered valid. If
227 any operation fails then the certificate is not valid.
231 When a verify operation fails the output messages can be somewhat cryptic. The
232 general form of the error message is:
234 server.pem: /C=AU/ST=Queensland/O=CryptSoft Pty Ltd/CN=Test CA (1024 bit)
235 error 24 at 1 depth lookup:invalid CA certificate
237 The first line contains the name of the certificate being verified followed by
238 the subject name of the certificate. The second line contains the error number
239 and the depth. The depth is number of the certificate being verified when a
240 problem was detected starting with zero for the certificate being verified itself
241 then 1 for the CA that signed the certificate and so on. Finally a text version
242 of the error number is presented.
244 An exhaustive list of the error codes and messages is shown below, this also
245 includes the name of the error code as defined in the header file x509_vfy.h
246 Some of the error codes are defined but never returned: these are described
251 =item B<0 X509_V_OK: ok>
253 the operation was successful.
255 =item B<2 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get issuer certificate>
257 the issuer certificate of a looked up certificate could not be found. This
258 normally means the list of trusted certificates is not complete.
260 =item B<3 X509_V_ERR_UNABLE_TO_GET_CRL: unable to get certificate CRL>
262 the CRL of a certificate could not be found.
264 =item B<4 X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE: unable to decrypt certificate's signature>
266 the certificate signature could not be decrypted. This means that the actual signature value
267 could not be determined rather than it not matching the expected value, this is only
268 meaningful for RSA keys.
270 =item B<5 X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE: unable to decrypt CRL's signature>
272 the CRL signature could not be decrypted: this means that the actual signature value
273 could not be determined rather than it not matching the expected value. Unused.
275 =item B<6 X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: unable to decode issuer public key>
277 the public key in the certificate SubjectPublicKeyInfo could not be read.
279 =item B<7 X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature failure>
281 the signature of the certificate is invalid.
283 =item B<8 X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure>
285 the signature of the certificate is invalid.
287 =item B<9 X509_V_ERR_CERT_NOT_YET_VALID: certificate is not yet valid>
289 the certificate is not yet valid: the notBefore date is after the current time.
291 =item B<10 X509_V_ERR_CERT_HAS_EXPIRED: certificate has expired>
293 the certificate has expired: that is the notAfter date is before the current time.
295 =item B<11 X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid>
297 the CRL is not yet valid.
299 =item B<12 X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired>
303 =item B<13 X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD: format error in certificate's notBefore field>
305 the certificate notBefore field contains an invalid time.
307 =item B<14 X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD: format error in certificate's notAfter field>
309 the certificate notAfter field contains an invalid time.
311 =item B<15 X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD: format error in CRL's lastUpdate field>
313 the CRL lastUpdate field contains an invalid time.
315 =item B<16 X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD: format error in CRL's nextUpdate field>
317 the CRL nextUpdate field contains an invalid time.
319 =item B<17 X509_V_ERR_OUT_OF_MEM: out of memory>
321 an error occurred trying to allocate memory. This should never happen.
323 =item B<18 X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: self signed certificate>
325 the passed certificate is self signed and the same certificate cannot be found in the list of
326 trusted certificates.
328 =item B<19 X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in certificate chain>
330 the certificate chain could be built up using the untrusted certificates but the root could not
333 =item B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: unable to get local issuer certificate>
335 the issuer certificate could not be found: this occurs if the issuer
336 certificate of an untrusted certificate cannot be found.
338 =item B<21 X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE: unable to verify the first certificate>
340 no signatures could be verified because the chain contains only one certificate and it is not
343 =item B<22 X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long>
345 the certificate chain length is greater than the supplied maximum depth. Unused.
347 =item B<23 X509_V_ERR_CERT_REVOKED: certificate revoked>
349 the certificate has been revoked.
351 =item B<24 X509_V_ERR_INVALID_CA: invalid CA certificate>
353 a CA certificate is invalid. Either it is not a CA or its extensions are not consistent
354 with the supplied purpose.
356 =item B<25 X509_V_ERR_PATH_LENGTH_EXCEEDED: path length constraint exceeded>
358 the basicConstraints pathlength parameter has been exceeded.
360 =item B<26 X509_V_ERR_INVALID_PURPOSE: unsupported certificate purpose>
362 the supplied certificate cannot be used for the specified purpose.
364 =item B<27 X509_V_ERR_CERT_UNTRUSTED: certificate not trusted>
366 the root CA is not marked as trusted for the specified purpose.
368 =item B<28 X509_V_ERR_CERT_REJECTED: certificate rejected>
370 the root CA is marked to reject the specified purpose.
372 =item B<29 X509_V_ERR_SUBJECT_ISSUER_MISMATCH: subject issuer mismatch>
374 the current candidate issuer certificate was rejected because its subject name
375 did not match the issuer name of the current certificate. Only displayed when
376 the B<-issuer_checks> option is set.
378 =item B<30 X509_V_ERR_AKID_SKID_MISMATCH: authority and subject key identifier mismatch>
380 the current candidate issuer certificate was rejected because its subject key
381 identifier was present and did not match the authority key identifier current
382 certificate. Only displayed when the B<-issuer_checks> option is set.
384 =item B<31 X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH: authority and issuer serial number mismatch>
386 the current candidate issuer certificate was rejected because its issuer name
387 and serial number was present and did not match the authority key identifier
388 of the current certificate. Only displayed when the B<-issuer_checks> option is set.
390 =item B<32 X509_V_ERR_KEYUSAGE_NO_CERTSIGN:key usage does not include certificate signing>
392 the current candidate issuer certificate was rejected because its keyUsage extension
393 does not permit certificate signing.
395 =item B<50 X509_V_ERR_APPLICATION_VERIFICATION: application verification failure>
397 an application specific error. Unused.
403 Although the issuer checks are a considerable improvement over the old technique they still
404 suffer from limitations in the underlying X509_LOOKUP API. One consequence of this is that
405 trusted certificates with matching subject name must either appear in a file (as specified by the
406 B<-CAfile> option) or a directory (as specified by B<-CApath>. If they occur in both then only
407 the certificates in the file will be recognised.
409 Previous versions of OpenSSL assume certificates with matching subject name are identical and
412 Previous versions of this documentation swapped the meaning of the
413 B<X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT> and
414 B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY> error codes.