verify - Utility to verify certificates.


SYNOPSIS

       openssl verify [-CApath directory] [-CAfile file]
       [-purpose purpose] [-untrusted file] [-help]
       [-issuer_checks] [-verbose] [-] [certificates]


DESCRIPTION

       The verify command verifies certificate chains.


COMMAND OPTIONS

       -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 -hash option of the
           x509 utility). Under Unix the c_rehash script will
           automatically create symbolic links to a directory of
           certificates.

       -CAfile file
           A file of trusted certificates. The file should
           contain multiple certificates in PEM format
           concatenated together.

       -untrusted file
           A file of untrusted certificates. The file should
           contain multiple certificates

       -purpose purpose
           the intended use for the certificate. Without this
           option no chain verification will be done. Currently
           accepted uses are sslclient, sslserver, nssslserver,
           smimesign, smimeencrypt. See the VERIFY OPERATION
           section for more information.

       -help
           prints out a usage message.

       -verbose
           print extra information about the operations being
           performed.

       -issuer_checks
           print out diagnostics relating to searches for the
           issuer certificate of the current certificate. This
           shows why each candidate issuer certificate was
           rejected. However the presence of rejection messages
           does not itself imply that anything is wrong: during
           the normal verify process several rejections may take
           place.

           are assumed to be certificate files. This is useful if
           the first certificate filename begins with a -.

       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.


VERIFY OPERATION

       The 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 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 the issuers certificate of the
       current certificate. If a certificate is found which is
       its own issuer it is assumed to be the root CA.

       The process of 'looking up the issuers certificate' itself
       involves a number of steps. In versions of OpenSSL before
       0.9.5a the first certificate whose subject name matched
       the issuer of the current certificate was assumed to be
       the issuers certificate. In OpenSSL 0.9.6 and later all
       certificates whose subject name matches the issuer name of
       the current certificate are subject to further tests. The
       relevant authority key identifier components of the
       current certificate (if present) must match the subject
       key identifier (if present) and issuer and serial number
       of the candidate issuer, in addition the keyUsage
       extension of the candidate issuer (if present) must permit
       certificate signing.

       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

       purpose. If the -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 CERTIFICATE EXTENSIONS section of the 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.


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".

       0 X509_V_OK: ok
           the operation was successful.

       2 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get
           issuer certificate
           the issuer certificate could not be found: this occurs

           cannot be found.

       3 X509_V_ERR_UNABLE_TO_GET_CRL unable to get certificate
           CRL
           the CRL of a certificate could not be found. Unused.

       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.

       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.

       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.

       7 X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature
           failure
           the signature of the certificate is invalid.

       8 X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure
           the signature of the certificate is invalid. Unused.

       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.

       10 X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid
           the CRL is not yet valid. Unused.

       11 X509_V_ERR_CERT_HAS_EXPIRED: Certificate has expired
           the certificate has expired: that is the notAfter date
           is before the current time.

       12 X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired
           the CRL has expired. Unused.

       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.

           in certificate's notAfter field
           the certificate notAfter field contains an invalid
           time.

       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.

       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.

       17 X509_V_ERR_OUT_OF_MEM: out of memory
           an error occurred trying to allocate memory. This
           should never happen.

       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.

       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.

       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.

       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.

       22 X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too
           long
           the certificate chain length is greater than the
           supplied maximum depth. Unused.

       23 X509_V_ERR_CERT_REVOKED: certificate revoked
           the certificate has been revoked. Unused.

       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


       25 X509_V_ERR_PATH_LENGTH_EXCEEDED: path length constraint
           exceeded
           the basicConstraints pathlength parameter has been
           exceeded.

       26 X509_V_ERR_INVALID_PURPOSE: unsupported certificate
           purpose
           the supplied certificate cannot be used for the
           specified purpose.

       27 X509_V_ERR_CERT_UNTRUSTED: certificate not trusted
           the root CA is not marked as trusted for the specified
           purpose.

       28 X509_V_ERR_CERT_REJECTED: certificate rejected
           the root CA is marked to reject the specified purpose.

       29 X509_V_ERR_SUBJECT_ISSUER_MISMATCH: subject issuer
           mismatch
           the current candidate issuer certificate was rejected
           because its subject name did not match the issuer name
           of the current certificate. Only displayed when the
           -issuer_checks option is set.

       30 X509_V_ERR_AKID_SKID_MISMATCH: authority and subject
           key identifier mismatch
           the current candidate issuer certificate was rejected
           because its subject key identifier was present and did
           not match the authority key identifier current
           certificate. Only displayed when the -issuer_checks
           option is set.

       31 X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH: authority and
           issuer serial number mismatch
           the current candidate issuer certificate was rejected
           because its issuer name and serial number was present
           and did not match the authority key identifier of the
           current certificate. Only displayed when the
           -issuer_checks option is set.

       32 X509_V_ERR_KEYUSAGE_NO_CERTSIGN:key usage does not
           include certificate signing
           the current candidate issuer certificate was rejected
           because its keyUsage extension does not permit
           certificate signing.

       50 X509_V_ERR_APPLICATION_VERIFICATION: application
           verification failure
           an application specific error. Unused.


BUGS

       Although the issuer checks are a considerably improvement

       in the underlying X509_LOOKUP API. One consequence of this
       is that trusted certificates with matching subject name
       must either appear in a file (as specified by the -CAfile
       option) or a directory (as specified by -CApath. If they
       occur in both then only the certificates in the file will
       be recognised.

       Previous versions of OpenSSL assume certificates with
       matching subject name are identical and mishandled them.


SEE ALSO

       x509(1)



Man(1) output converted with man2html