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