| =pod |
| |
| =head1 NAME |
| |
| pkcs7 - PKCS#7 utility |
| |
| =head1 SYNOPSIS |
| |
| B<openssl> B<verify> |
| [B<-CApath directory>] |
| [B<-CAfile file>] |
| [B<-purpose purpose>] |
| [B<-untrusted file>] |
| [B<-help>] |
| [B<-verbose>] |
| [B<->] |
| [certificates] |
| |
| |
| =head1 DESCRIPTION |
| |
| The B<verify> command verifies certificate chains. |
| |
| =head1 COMMAND OPTIONS |
| |
| =over 4 |
| |
| =item B<-CApath directory> |
| |
| A directory of trusted certificates. The certificates should have names |
| of the form: hash.0 or have symbolic links to them of this |
| form ("hash" is the hashed certificate subject name: see the B<-hash> option |
| of the B<x509> utility). Under Unix the B<c_rehash> script will automatically |
| create symbolic links to a directory of certificates. |
| |
| =item B<-CAfile file> |
| |
| A file of trusted certificates. The file should contain multiple certificates |
| in PEM format concatenated together. |
| |
| =item B<-untrusted file> |
| |
| A file of untrusted certificates. The file should contain multiple certificates |
| |
| =item B<-purpose purpose> |
| |
| the intended use for the certificate. Without this option no chain verification |
| will be done. Currently accepted uses are B<sslclient>, B<sslserver>, |
| B<nssslserver>, B<smimesign>, B<smimeencrypt>. See the B<VERIFY OPERATION> |
| section for more information. |
| |
| =item B<-help> |
| |
| prints out a usage message. |
| |
| =item B<-verbose> |
| |
| print extra information about the operations being performed. |
| |
| =item B<-> |
| |
| marks the last option. All arguments following this are assumed to be |
| certificate files. This is useful if the first certificate filename begins |
| with a B<->. |
| |
| =item B<certificates> |
| |
| one or more certificates to verify. If no certificate filenames are included |
| then an attempt is made to read a certificate from standard input. They should |
| all be in PEM format. |
| |
| |
| =back |
| |
| =head1 VERIFY OPERATION |
| |
| The B<verify> program uses the same functions as the internal SSL and S/MIME |
| verification, therefore this description applies to these verify operations |
| too. |
| |
| There is one crucial difference between the verify operations performed |
| by the B<verify> program: wherever possible an attempt is made to continue |
| after an error whereas normally the verify operation would halt on the |
| first error. This allows all the problems with a certificate chain to be |
| determined. |
| |
| The verify operation consists of a number of separate steps. |
| |
| Firstly a certificate chain is built up starting from the supplied certificate |
| and ending in the root CA. It is an error if the whole chain cannot be built |
| up. The chain is built up by looking up a certificate whose subject name |
| matches the issuer name of the current certificate. If a certificate is found |
| whose subject and issuer names are identical it is assumed to be the root CA. |
| The lookup first looks in the list of untrusted certificates and if no match |
| is found the remaining lookups are from the trusted certificates. The root CA |
| is always looked up in the trusted certificate list: if the certificate to |
| verify is a root certificate then an exact match must be found in the trusted |
| list. |
| |
| The second operation is to check every untrusted certificate's extensions for |
| consistency with the supplied purpose. If the B<-purpose> option is not included |
| then no checks are done. The supplied or "leaf" certificate must have extensions |
| compatible with the supplied purpose and all other certificates must also be valid |
| CA certificates. The precise extensions required are described in more detail in |
| the B<CERTIFICATE EXTENSIONS> section of the B<x509> utility. |
| |
| The third operation is to check the trust settings on the root CA. The root |
| CA should be trusted for the supplied purpose. For compatibility with previous |
| versions of SSLeay and OpenSSL a certificate with no trust settings is considered |
| to be valid for all purposes. |
| |
| The final operation is to check the validity of the certificate chain. The validity |
| period is checked against the current system time and the notBefore and notAfter |
| dates in the certificate. The certificate signatures are also checked at this |
| point. |
| |
| If all operations complete successfully then certificate is considered valid. If |
| any operation fails then the certificate is not valid. |
| |
| =head1 DIAGNOSTICS |
| |
| When a verify operation fails the output messages can be somewhat cryptic. The |
| general form of the error message is: |
| |
| server.pem: /C=AU/ST=Queensland/O=CryptSoft Pty Ltd/CN=Test CA (1024 bit) |
| error 24 at 1 depth lookup:invalid CA certificate |
| |
| The first line contains the name of the certificate being verified followed by |
| the subject name of the certificate. The second line contains the error number |
| and the depth. The depth is number of the certificate being verified when a |
| problem was detected starting with zero for the certificate being verified itself |
| then 1 for the CA that signed the certificate and so on. Finally a text version |
| of the error number is presented. |
| |
| An exhaustive list of the error codes and messages is shown below, this also |
| includes the name of the error code as defined in the header file x509_vfy.h |
| Some of the error codes are defined but never returned: these are described |
| as "unused". |
| |
| =over 4 |
| |
| =item B<0 X509_V_OK: ok> |
| |
| the operation was successful. |
| |
| =item B<2 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get issuer certificate> |
| |
| the issuer certificate could not be found: this occurs if the issuer certificate |
| of an untrusted certificate cannot be found. |
| |
| =item B<3 X509_V_ERR_UNABLE_TO_GET_CRL unable to get certificate CRL> |
| |
| the CRL of a certificate could not be found. Unused. |
| |
| =item B<4 X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE: unable to decrypt certificate's signature> |
| |
| the certificate signature could not be decrypted. This means that the actual signature value |
| could not be determined rather than it not matching the expected value, this is only |
| meaningful for RSA keys. |
| |
| =item B<5 X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE: unable to decrypt CRL's signature> |
| |
| the CRL signature could not be decrypted: this means that the actual signature value |
| could not be determined rather than it not matching the expected value. Unused. |
| |
| =item B<6 X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: unable to decode issuer public key> |
| |
| the public key in the certificate SubjectPublicKeyInfo could not be read. |
| |
| =item B<7 X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature failure> |
| |
| the signature of the certificate is invalid. |
| |
| =item B<8 X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure> |
| |
| the signature of the certificate is invalid. Unused. |
| |
| =item B<9 X509_V_ERR_CERT_NOT_YET_VALID: certificate is not yet valid> |
| |
| the certificate is not yet valid: the notBefore date is after the current time. |
| |
| =item B<10 X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid> |
| |
| the CRL is not yet valid. Unused. |
| |
| =item B<11 X509_V_ERR_CERT_HAS_EXPIRED: Certificate has expired> |
| |
| the certificate has expired: that is the notAfter date is before the current time. |
| |
| =item B<12 X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired> |
| |
| the CRL has expired. Unused. |
| |
| =item B<13 X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD: format error in certificate's notBefore field> |
| |
| the certificate notBefore field contains an invalid time. |
| |
| =item B<14 X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD: format error in certificate's notAfter field> |
| |
| the certificate notAfter field contains an invalid time. |
| |
| =item B<15 X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD: format error in CRL's lastUpdate field> |
| |
| the CRL lastUpdate field contains an invalid time. Unused. |
| |
| =item B<16 X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD: format error in CRL's nextUpdate field> |
| |
| the CRL nextUpdate field contains an invalid time. Unused. |
| |
| =item B<17 X509_V_ERR_OUT_OF_MEM: out of memory> |
| |
| an error occurred trying to allocate memory. This should never happen. |
| |
| =item B<18 X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: self signed certificate> |
| |
| the passed certificate is self signed and the same certificate cannot be found in the list of |
| trusted certificates. |
| |
| =item B<19 X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in certificate chain> |
| |
| the certificate chain could be built up using the untrusted certificates but the root could not |
| be found locally. |
| |
| =item B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: unable to get local issuer certificate> |
| |
| the issuer certificate of a locally looked up certificate could not be found. This normally means |
| the list of trusted certificates is not complete. |
| |
| =item B<21 X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE: unable to verify the first certificate> |
| |
| no signatures could be verified because the chain contains only one certificate and it is not |
| self signed. |
| |
| =item B<22 X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long> |
| |
| the certificate chain length is greater than the supplied maximum depth. Unused. |
| |
| =item B<23 X509_V_ERR_CERT_REVOKED: certificate revoked> |
| |
| the certificate has been revoked. Unused. |
| |
| =item B<24 X509_V_ERR_INVALID_CA: invalid CA certificate> |
| |
| a CA certificate is invalid. Either it is not a CA or its extensions are not consistent |
| with the supplied purpose. |
| |
| =item B<25 X509_V_ERR_PATH_LENGTH_EXCEEDED: path length constraint exceeded> |
| |
| the basicConstraints pathlength parameter has been exceeded. |
| |
| =item B<26 X509_V_ERR_INVALID_PURPOSE: unsupported certificate purpose> |
| |
| the supplied certificate cannot be used for the specified purpose. |
| |
| =item B<27 X509_V_ERR_CERT_UNTRUSTED: certificate not trusted> |
| |
| the root CA is not marked as trusted for the specified purpose. |
| |
| =item B<28 X509_V_ERR_CERT_REJECTED: certificate rejected> |
| |
| the root CA is marked to reject the specified purpose. |
| |
| =item B<50 X509_V_ERR_APPLICATION_VERIFICATION: application verification failure> |
| |
| an application specific error. Unused. |
| |
| =back |
| |
| =head1 SEE ALSO |
| |
| L<x509(1)|x509(1)> |
| |
| =cut |
