VERIFY(1)                   OpenSSL                   VERIFY(1)





NAME
       verify - Utility to verify certificates.

SYNOPSIS
       openssl verify [-CApath directory] [-CAfile file] [-pur-
       pose 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 certifi-
           cates 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 con-
           tain multiple certificates in PEM format concate-
           nated 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.

       -   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 -.

       certificates
           one or more certificates to verify. If no certifi-
           cate 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 inter-
       nal SSL and S/MIME verification, therefore this descrip-
       tion applies to these verify operations too.

       There is one crucial difference between the verify oper-
       ations performed by the verify program: wherever possi-
       ble 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 cer-
       tificate 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 sub-
       ject 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 candi-
       date issuer (if present) must permit certificate sign-
       ing.

       The lookup first looks in the list of untrusted certifi-
       cates 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 cer-
       tificate 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 cer-
       tificate's extensions for consistency with the supplied
       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 certifi-
       cates. 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 sup-
       plied purpose. For compatibility with previous versions
       of SSLeay and OpenSSL a certificate with no trust set-
       tings is considered to be valid for all purposes.

       The final operation is to check the validity of the cer-
       tificate 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 cer-
       tificate. 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 if the issuer certificate of an untrusted
           certificate 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 deter-
           mined 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 SubjectPublicKey-
           Info could not be read.

       7 X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signa-
       ture failure
           the signature of the certificate is invalid.

       8 X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature fail-
       ure
           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_CERT_HAS_EXPIRED: certificate has expired
           the certificate has expired: that is the notAfter
           date is before the current time.

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

       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.

       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.

       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 cer-
           tificate 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 sup-
           plied purpose.

       25 X509_V_ERR_PATH_LENGTH_EXCEEDED: path length con-
       straint 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 speci-
           fied purpose.

       28 X509_V_ERR_CERT_REJECTED: certificate rejected
           the root CA is marked to reject the specified pur-
           pose.

       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 dis-
           played 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 identi-
           fier 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 dis-
           played 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 ver-
       ification failure
           an application specific error. Unused.

BUGS
       Although the issuer checks are a considerably improve-
       ment over the old technique they still suffer from limi-
       tations in the underlying X509_LOOKUP API. One conse-
       quence of this is that trusted certificates with match-
       ing subject name must either appear in a file (as speci-
       fied by the -CAfile option) or a directory (as specified
       by -CApath. If they occur in both then only the certifi-
       cates 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)



0.9.7c                     2001-10-08                 VERIFY(1)
