6 verify - Utility to verify certificates.
11 [B<-CApath directory>]
16 [B<-attime timestamp>]
31 [B<-allow_proxy_certs>]
43 The B<verify> command verifies certificate chains.
45 =head1 COMMAND OPTIONS
49 =item B<-CApath directory>
51 A directory of trusted certificates. The certificates should have names
52 of the form: hash.0 or have symbolic links to them of this
53 form ("hash" is the hashed certificate subject name: see the B<-hash> option
54 of the B<x509> utility). Under Unix the B<c_rehash> script will automatically
55 create symbolic links to a directory of certificates.
58 A file of trusted certificates. The file should contain multiple certificates
59 in PEM format concatenated together.
61 =item B<-attime timestamp>
63 Perform validation checks using time specified by B<timestamp> and not
64 current system time. B<timestamp> is the number of seconds since
65 01.01.1970 (UNIX time).
67 =item B<-check_ss_sig>
69 Verify the signature on the self-signed root CA. This is disabled by default
70 because it doesn't add any security.
72 =item B<-CRLfile file>
74 File containing one or more CRL's (in PEM format) to load.
76 =item B<-crl_download>
78 Attempt to download CRL information for this certificate.
82 Checks end entity certificate validity by attempting to look up a valid CRL.
83 If a valid CRL cannot be found an error occurs.
85 =item B<-untrusted file>
87 A file of untrusted certificates. The file should contain multiple certificates
88 in PEM format concatenated together.
90 =item B<-purpose purpose>
92 The intended use for the certificate. If this option is not specified,
93 B<verify> will not consider certificate purpose during chain verification.
94 Currently accepted uses are B<sslclient>, B<sslserver>, B<nssslserver>,
95 B<smimesign>, B<smimeencrypt>. See the B<VERIFY OPERATION> section for more
100 Print out a usage message.
104 Print extra information about the operations being performed.
106 =item B<-issuer_checks>
108 Print out diagnostics relating to searches for the issuer certificate of the
109 current certificate. This shows why each candidate issuer certificate was
110 rejected. The presence of rejection messages does not itself imply that
111 anything is wrong; during the normal verification process, several
112 rejections may take place.
116 Enable policy processing and add B<arg> to the user-initial-policy-set (see
117 RFC5280). The policy B<arg> can be an object name an OID in numeric form.
118 This argument can appear more than once.
120 =item B<-policy_check>
122 Enables certificate policy processing.
124 =item B<-explicit_policy>
126 Set policy variable require-explicit-policy (see RFC5280).
128 =item B<-inhibit_any>
130 Set policy variable inhibit-any-policy (see RFC5280).
132 =item B<-inhibit_map>
134 Set policy variable inhibit-policy-mapping (see RFC5280).
136 =item B<-no_alt_chains>
138 When building a certificate chain, if the first certificate chain found is not
139 trusted, then OpenSSL will continue to check to see if an alternative chain can
140 be found that is trusted. With this option that behaviour is suppressed so that
141 only the first chain found is ever used. Using this option will force the
142 behaviour to match that of previous OpenSSL versions.
144 =item B<-allow_proxy_certs>
146 Allow the verification of proxy certificates.
148 =item B<-trusted file>
150 A file of additional trusted certificates. The file should contain multiple
151 certificates in PEM format concatenated together.
153 =item B<-policy_print>
155 Print out diagnostics related to policy processing.
159 Checks end entity certificate validity by attempting to look up a valid CRL.
160 If a valid CRL cannot be found an error occurs.
162 =item B<-crl_check_all>
164 Checks the validity of B<all> certificates in the chain by attempting
165 to look up valid CRLs.
167 =item B<-ignore_critical>
169 Normally if an unhandled critical extension is present which is not
170 supported by OpenSSL the certificate is rejected (as required by RFC5280).
171 If this option is set critical extensions are ignored.
173 =item B<-x509_strict>
175 For strict X.509 compliance, disable non-compliant workarounds for broken
178 =item B<-extended_crl>
180 Enable extended CRL features such as indirect CRLs and alternate CRL
185 Enable support for delta CRLs.
187 =item B<-check_ss_sig>
189 Verify the signature on the self-signed root CA. This is disabled by default
190 because it doesn't add any security.
194 Indicates the last option. All arguments following this are assumed to be
195 certificate files. This is useful if the first certificate filename begins
198 =item B<certificates>
200 One or more certificates to verify. If no certificates are given, B<verify>
201 will attempt to read a certificate from standard input. Certificates must be
206 =head1 VERIFY OPERATION
208 The B<verify> program uses the same functions as the internal SSL and S/MIME
209 verification, therefore this description applies to these verify operations
212 There is one crucial difference between the verify operations performed
213 by the B<verify> program: wherever possible an attempt is made to continue
214 after an error whereas normally the verify operation would halt on the
215 first error. This allows all the problems with a certificate chain to be
218 The verify operation consists of a number of separate steps.
220 Firstly a certificate chain is built up starting from the supplied certificate
221 and ending in the root CA. It is an error if the whole chain cannot be built
222 up. The chain is built up by looking up the issuers certificate of the current
223 certificate. If a certificate is found which is its own issuer it is assumed
226 The process of 'looking up the issuers certificate' itself involves a number
227 of steps. In versions of OpenSSL before 0.9.5a the first certificate whose
228 subject name matched the issuer of the current certificate was assumed to be
229 the issuers certificate. In OpenSSL 0.9.6 and later all certificates
230 whose subject name matches the issuer name of the current certificate are
231 subject to further tests. The relevant authority key identifier components
232 of the current certificate (if present) must match the subject key identifier
233 (if present) and issuer and serial number of the candidate issuer, in addition
234 the keyUsage extension of the candidate issuer (if present) must permit
237 The lookup first looks in the list of untrusted certificates and if no match
238 is found the remaining lookups are from the trusted certificates. The root CA
239 is always looked up in the trusted certificate list: if the certificate to
240 verify is a root certificate then an exact match must be found in the trusted
243 The second operation is to check every untrusted certificate's extensions for
244 consistency with the supplied purpose. If the B<-purpose> option is not included
245 then no checks are done. The supplied or "leaf" certificate must have extensions
246 compatible with the supplied purpose and all other certificates must also be valid
247 CA certificates. The precise extensions required are described in more detail in
248 the B<CERTIFICATE EXTENSIONS> section of the B<x509> utility.
250 The third operation is to check the trust settings on the root CA. The root
251 CA should be trusted for the supplied purpose. For compatibility with previous
252 versions of SSLeay and OpenSSL a certificate with no trust settings is considered
253 to be valid for all purposes.
255 The final operation is to check the validity of the certificate chain. The validity
256 period is checked against the current system time and the notBefore and notAfter
257 dates in the certificate. The certificate signatures are also checked at this
260 If all operations complete successfully then certificate is considered valid. If
261 any operation fails then the certificate is not valid.
265 When a verify operation fails the output messages can be somewhat cryptic. The
266 general form of the error message is:
268 server.pem: /C=AU/ST=Queensland/O=CryptSoft Pty Ltd/CN=Test CA (1024 bit)
269 error 24 at 1 depth lookup:invalid CA certificate
271 The first line contains the name of the certificate being verified followed by
272 the subject name of the certificate. The second line contains the error number
273 and the depth. The depth is number of the certificate being verified when a
274 problem was detected starting with zero for the certificate being verified itself
275 then 1 for the CA that signed the certificate and so on. Finally a text version
276 of the error number is presented.
278 An exhaustive list of the error codes and messages is shown below, this also
279 includes the name of the error code as defined in the header file x509_vfy.h
280 Some of the error codes are defined but never returned: these are described
285 =item B<0 X509_V_OK: ok>
287 the operation was successful.
289 =item B<2 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get issuer certificate>
291 the issuer certificate of a looked up certificate could not be found. This
292 normally means the list of trusted certificates is not complete.
294 =item B<3 X509_V_ERR_UNABLE_TO_GET_CRL: unable to get certificate CRL>
296 the CRL of a certificate could not be found.
298 =item B<4 X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE: unable to decrypt certificate's signature>
300 the certificate signature could not be decrypted. This means that the actual signature value
301 could not be determined rather than it not matching the expected value, this is only
302 meaningful for RSA keys.
304 =item B<5 X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE: unable to decrypt CRL's signature>
306 the CRL signature could not be decrypted: this means that the actual signature value
307 could not be determined rather than it not matching the expected value. Unused.
309 =item B<6 X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: unable to decode issuer public key>
311 the public key in the certificate SubjectPublicKeyInfo could not be read.
313 =item B<7 X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature failure>
315 the signature of the certificate is invalid.
317 =item B<8 X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure>
319 the signature of the certificate is invalid.
321 =item B<9 X509_V_ERR_CERT_NOT_YET_VALID: certificate is not yet valid>
323 the certificate is not yet valid: the notBefore date is after the current time.
325 =item B<10 X509_V_ERR_CERT_HAS_EXPIRED: certificate has expired>
327 the certificate has expired: that is the notAfter date is before the current time.
329 =item B<11 X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid>
331 the CRL is not yet valid.
333 =item B<12 X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired>
337 =item B<13 X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD: format error in certificate's notBefore field>
339 the certificate notBefore field contains an invalid time.
341 =item B<14 X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD: format error in certificate's notAfter field>
343 the certificate notAfter field contains an invalid time.
345 =item B<15 X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD: format error in CRL's lastUpdate field>
347 the CRL lastUpdate field contains an invalid time.
349 =item B<16 X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD: format error in CRL's nextUpdate field>
351 the CRL nextUpdate field contains an invalid time.
353 =item B<17 X509_V_ERR_OUT_OF_MEM: out of memory>
355 an error occurred trying to allocate memory. This should never happen.
357 =item B<18 X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: self signed certificate>
359 the passed certificate is self signed and the same certificate cannot be found in the list of
360 trusted certificates.
362 =item B<19 X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in certificate chain>
364 the certificate chain could be built up using the untrusted certificates but the root could not
367 =item B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: unable to get local issuer certificate>
369 the issuer certificate could not be found: this occurs if the issuer
370 certificate of an untrusted certificate cannot be found.
372 =item B<21 X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE: unable to verify the first certificate>
374 no signatures could be verified because the chain contains only one certificate and it is not
377 =item B<22 X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long>
379 the certificate chain length is greater than the supplied maximum depth. Unused.
381 =item B<23 X509_V_ERR_CERT_REVOKED: certificate revoked>
383 the certificate has been revoked.
385 =item B<24 X509_V_ERR_INVALID_CA: invalid CA certificate>
387 a CA certificate is invalid. Either it is not a CA or its extensions are not consistent
388 with the supplied purpose.
390 =item B<25 X509_V_ERR_PATH_LENGTH_EXCEEDED: path length constraint exceeded>
392 the basicConstraints pathlength parameter has been exceeded.
394 =item B<26 X509_V_ERR_INVALID_PURPOSE: unsupported certificate purpose>
396 the supplied certificate cannot be used for the specified purpose.
398 =item B<27 X509_V_ERR_CERT_UNTRUSTED: certificate not trusted>
400 the root CA is not marked as trusted for the specified purpose.
402 =item B<28 X509_V_ERR_CERT_REJECTED: certificate rejected>
404 the root CA is marked to reject the specified purpose.
406 =item B<29 X509_V_ERR_SUBJECT_ISSUER_MISMATCH: subject issuer mismatch>
408 the current candidate issuer certificate was rejected because its subject name
409 did not match the issuer name of the current certificate. Only displayed when
410 the B<-issuer_checks> option is set.
412 =item B<30 X509_V_ERR_AKID_SKID_MISMATCH: authority and subject key identifier mismatch>
414 the current candidate issuer certificate was rejected because its subject key
415 identifier was present and did not match the authority key identifier current
416 certificate. Only displayed when the B<-issuer_checks> option is set.
418 =item B<31 X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH: authority and issuer serial number mismatch>
420 the current candidate issuer certificate was rejected because its issuer name
421 and serial number was present and did not match the authority key identifier
422 of the current certificate. Only displayed when the B<-issuer_checks> option is set.
424 =item B<32 X509_V_ERR_KEYUSAGE_NO_CERTSIGN:key usage does not include certificate signing>
426 the current candidate issuer certificate was rejected because its keyUsage extension
427 does not permit certificate signing.
429 =item B<50 X509_V_ERR_APPLICATION_VERIFICATION: application verification failure>
431 an application specific error. Unused.
437 Although the issuer checks are a considerable improvement over the old technique they still
438 suffer from limitations in the underlying X509_LOOKUP API. One consequence of this is that
439 trusted certificates with matching subject name must either appear in a file (as specified by the
440 B<-CAfile> option) or a directory (as specified by B<-CApath>. If they occur in both then only
441 the certificates in the file will be recognised.
443 Previous versions of OpenSSL assume certificates with matching subject name are identical and
446 Previous versions of this documentation swapped the meaning of the
447 B<X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT> and
448 B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY> error codes.
456 The -no_alt_chains options was first added to OpenSSL 1.0.2b.