--- /dev/null
+=pod
+
+=head1 NAME
+
+verify - Utility to verify certificates.
+
+=head1 SYNOPSIS
+
+B<openssl> B<verify>
+[B<-CApath directory>]
+[B<-CAfile file>]
+[B<-purpose purpose>]
+[B<-policy arg>]
+[B<-ignore_critical>]
+[B<-crl_check>]
+[B<-crl_check_all>]
+[B<-policy_check>]
+[B<-explicit_policy>]
+[B<-inhibit_any>]
+[B<-inhibit_map>]
+[B<-x509_strict>]
+[B<-extended_crl>]
+[B<-use_deltas>]
+[B<-policy_print>]
+[B<-untrusted file>]
+[B<-help>]
+[B<-issuer_checks>]
+[B<-attime timestamp>]
+[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
+in PEM format concatenated together.
+
+=item B<-purpose purpose>
+
+The intended use for the certificate. If this option is not specified,
+B<verify> will not consider certificate purpose during chain verification.
+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>
+
+Print out a usage message.
+
+=item B<-verbose>
+
+Print extra information about the operations being performed.
+
+=item B<-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. The presence of rejection messages does not itself imply that
+anything is wrong; during the normal verification process, several
+rejections may take place.
+
+=item B<-attime timestamp>
+
+Perform validation checks using time specified by B<timestamp> and not
+current system time. B<timestamp> is the number of seconds since
+01.01.1970 (UNIX time).
+
+=item B<-policy arg>
+
+Enable policy processing and add B<arg> to the user-initial-policy-set (see
+RFC5280). The policy B<arg> can be an object name an OID in numeric form.
+This argument can appear more than once.
+
+=item B<-policy_check>
+
+Enables certificate policy processing.
+
+=item B<-explicit_policy>
+
+Set policy variable require-explicit-policy (see RFC5280).
+
+=item B<-inhibit_any>
+
+Set policy variable inhibit-any-policy (see RFC5280).
+
+=item B<-inhibit_map>
+
+Set policy variable inhibit-policy-mapping (see RFC5280).
+
+=item B<-policy_print>
+
+Print out diagnostics related to policy processing.
+
+=item B<-crl_check>
+
+Checks end entity certificate validity by attempting to look up a valid CRL.
+If a valid CRL cannot be found an error occurs.
+
+=item B<-crl_check_all>
+
+Checks the validity of B<all> certificates in the chain by attempting
+to look up valid CRLs.
+
+=item B<-ignore_critical>
+
+Normally if an unhandled critical extension is present which is not
+supported by OpenSSL the certificate is rejected (as required by RFC5280).
+If this option is set critical extensions are ignored.
+
+=item B<-x509_strict>
+
+For strict X.509 compliance, disable non-compliant workarounds for broken
+certificates.
+
+=item B<-extended_crl>
+
+Enable extended CRL features such as indirect CRLs and alternate CRL
+signing keys.
+
+=item B<-use_deltas>
+
+Enable support for delta CRLs.
+
+=item B<-check_ss_sig>
+
+Verify the signature on the self-signed root CA. This is disabled by default
+because it doesn't add any security.
+
+=item B<->
+
+Indicates 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 certificates are given, B<verify>
+will attempt to read a certificate from standard input. Certificates must 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 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 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 of a looked up certificate could not be found. This
+normally means the list of trusted certificates is not complete.
+
+=item B<3 X509_V_ERR_UNABLE_TO_GET_CRL: unable to get certificate CRL>
+
+the CRL of a certificate could not be found.
+
+=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.
+
+=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_CERT_HAS_EXPIRED: certificate has expired>
+
+the certificate has expired: that is the notAfter date is before the current time.
+
+=item B<11 X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid>
+
+the CRL is not yet valid.
+
+=item B<12 X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired>
+
+the CRL has expired.
+
+=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.
+
+=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.
+
+=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 could not be found: this occurs if the issuer
+certificate of an untrusted certificate cannot be found.
+
+=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.
+
+=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<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 B<-issuer_checks> option is set.
+
+=item B<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 B<-issuer_checks> option is set.
+
+=item B<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 B<-issuer_checks> option is set.
+
+=item B<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.
+
+=item B<50 X509_V_ERR_APPLICATION_VERIFICATION: application verification failure>
+
+an application specific error. Unused.
+
+=back
+
+=head1 BUGS
+
+Although the issuer checks are a considerable improvement over the old technique they still
+suffer from limitations 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
+B<-CAfile> option) or a directory (as specified by B<-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.
+
+Previous versions of this documentation swapped the meaning of the
+B<X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT> and
+B<20 X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY> error codes.
+
+=head1 SEE ALSO
+
+L<x509(1)|x509(1)>
+
+=cut
projects / cassiopeia.git / blobdiff