X509_VERIFY_PARAM_set_purpose(3)

NAME

       X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags, X509_VER-
       IFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose, X509_VER-
       IFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth, X509_VER-
       IFY_PARAM_get_depth, X509_VERIFY_PARAM_set_time, X509_VER-
       IFY_PARAM_add0_policy, X509_VERIFY_PARAM_set1_policies, X509_VER-
       IFY_PARAM_set1_host, X509_VERIFY_PARAM_add1_host, X509_VER-
       IFY_PARAM_set_hostflags, X509_VERIFY_PARAM_get0_peername, X509_VER-
       IFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip, X509_VER-
       IFY_PARAM_set1_ip_asc - X509 verification parameters

SYNOPSIS

        #include <openssl/x509_vfy.h>

        int X509_VERIFY_PARAM_set_flags(X509_VERIFY_PARAM *param, unsigned long flags);
        int X509_VERIFY_PARAM_clear_flags(X509_VERIFY_PARAM *param,
                                                               unsigned long flags);
        unsigned long X509_VERIFY_PARAM_get_flags(X509_VERIFY_PARAM *param);

        int X509_VERIFY_PARAM_set_purpose(X509_VERIFY_PARAM *param, int purpose);
        int X509_VERIFY_PARAM_set_trust(X509_VERIFY_PARAM *param, int trust);

        void X509_VERIFY_PARAM_set_time(X509_VERIFY_PARAM *param, time_t t);

        int X509_VERIFY_PARAM_add0_policy(X509_VERIFY_PARAM *param,
                                                       ASN1_OBJECT *policy);
        int X509_VERIFY_PARAM_set1_policies(X509_VERIFY_PARAM *param,
                                               STACK_OF(ASN1_OBJECT) *policies);

        void X509_VERIFY_PARAM_set_depth(X509_VERIFY_PARAM *param, int depth);
        int X509_VERIFY_PARAM_get_depth(const X509_VERIFY_PARAM *param);

        int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
                                        const char *name, size_t namelen);
        int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
                                        const char *name, size_t namelen);
        void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,
                                             unsigned int flags);
        char *X509_VERIFY_PARAM_get0_peername(X509_VERIFY_PARAM *param);
        int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,
                                        const char *email, size_t emaillen);
        int X509_VERIFY_PARAM_set1_ip(X509_VERIFY_PARAM *param,
                                      const unsigned char *ip, size_t iplen);
        int X509_VERIFY_PARAM_set1_ip_asc(X509_VERIFY_PARAM *param, const char *ipasc);

DESCRIPTION

       These functions manipulate the X509_VERIFY_PARAM structure associated
       with a certificate verification operation.

       The X509_VERIFY_PARAM_set_flags() function sets the flags in param by
       oring it with flags. See the VERIFICATION FLAGS section for a complete
       description of values the flags parameter can take.

       X509_VERIFY_PARAM_get_flags() returns the flags in param.

       X509_VERIFY_PARAM_clear_flags() clears the flags flags in param.

       X509_VERIFY_PARAM_set_purpose() sets the verification purpose in param
       to purpose. This determines the acceptable purpose of the certificate
       chain, for example SSL client or SSL server.

       X509_VERIFY_PARAM_set_trust() sets the trust setting in param to trust.

       X509_VERIFY_PARAM_set_time() sets the verification time in param to t.
       Normally the current time is used.

       X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled
       by default) and adds policy to the acceptable policy set.

       X509_VERIFY_PARAM_set1_policies() enables policy checking (it is dis-
       abled by default) and sets the acceptable policy set to policies. Any
       existing policy set is cleared. The policies parameter can be NULL to
       clear an existing policy set.

       X509_VERIFY_PARAM_set_depth() sets the maximum verification depth to
       depth.  That is the maximum number of untrusted CA certificates that
       can appear in a chain.

       X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to name
       clearing any previously specified host name or names.  If name is NULL,
       or empty the list of hostnames is cleared, and name checks are not per-
       formed on the peer certificate.  If name is NUL-terminated, namelen may
       be zero, otherwise namelen must be set to the length of name.  When a
       hostname is specified, certificate verification automatically invokes
       X509_check_host(3) with flags equal to the flags argument given to
       XX550099_VVEERRIIFFYY_PPAARRAAMM_sseett_hhoossttffllaaggss(()) (default zero).  Applications are
       strongly advised to use this interface in preference to explicitly
       calling X509_check_host(3), hostname checks are out of scope with the
       DANE-EE(3) certificate usage, and the internal check will be suppressed
       as appropriate when DANE support is added to OpenSSL.

       X509_VERIFY_PARAM_add1_host() adds name as an additional reference
       identifer that can match the peer's certificate.  Any previous names
       set via X509_VERIFY_PARAM_set1_host() or X509_VERIFY_PARAM_add1_host()
       are retained, no change is made if name is NULL or empty.  When multi-
       ple names are configured, the peer is considered verified when any name
       matches.

       X509_VERIFY_PARAM_get0_peername() returns the DNS hostname or subject
       CommonName from the peer certificate that matched one of the reference
       identifiers.  When wildcard matching is not disabled, or when a refer-
       ence identifier specifies a parent domain (starts with ".")  rather
       than a hostname, the peer name may be a wildcard name or a sub-domain
       of the reference identifier respectively.  The return string is allo-
       cated by the library and is no longer valid once the associated param
       argument is freed.  Applications must not free the return value.

       X509_VERIFY_PARAM_set1_email() sets the expected RFC822 email address
       to email.  If email is NUL-terminated, emaillen may be zero, otherwise
       emaillen must be set to the length of email.  When an email address is
       specified, certificate verification automatically invokes
       X509_check_email(3).

       X509_VERIFY_PARAM_set1_ip() sets the expected IP address to ip.  The ip
       argument is in binary format, in network byte-order and iplen must be
       set to 4 for IPv4 and 16 for IPv6.  When an IP address is specified,
       certificate verification automatically invokes X509_check_ip(3).

       X509_VERIFY_PARAM_set1_ip_asc() sets the expected IP address to ipasc.
       The ipasc argument is a NUL-terminal ASCII string: dotted decimal quad
       for IPv4 and colon-separated hexadecimal for IPv6.  The condensed "::"
       notation is supported for IPv6 addresses.

       X509_VERIFY_PARAM_set_flags(), X509_VERIFY_PARAM_clear_flags(),
       X509_VERIFY_PARAM_set_purpose(), X509_VERIFY_PARAM_set_trust(),
       X509_VERIFY_PARAM_add0_policy() X509_VERIFY_PARAM_set1_policies(),
       X509_VERIFY_PARAM_set1_host(), X509_VERIFY_PARAM_set_hostflags(),
       X509_VERIFY_PARAM_set1_email(), X509_VERIFY_PARAM_set1_ip() and
       X509_VERIFY_PARAM_set1_ip_asc() return 1 for success and 0 for failure.

       X509_VERIFY_PARAM_get_flags() returns the current verification flags.

       X509_VERIFY_PARAM_set_time() and X509_VERIFY_PARAM_set_depth() do not
       return values.

       X509_VERIFY_PARAM_get_depth() returns the current verification depth.

       The verification flags consists of zero or more of the following flags
       ored together.

       X509_V_FLAG_CRL_CHECK enables CRL checking for the certificate chain
       leaf certificate. An error occurs if a suitable CRL cannot be found.

       X509_V_FLAG_CRL_CHECK_ALL enables CRL checking for the entire certifi-
       cate chain.

       X509_V_FLAG_IGNORE_CRITICAL disabled critical extension checking. By
       default any unhandled critical extensions in certificates or (if
       checked) CRLs results in a fatal error. If this flag is set unhandled
       critical extensions are ignored. WARNING setting this option for any-
       thing other than debugging purposes can be a security risk. Finer con-
       trol over which extensions are supported can be performed in the veri-
       fication callback.

       THe X509_V_FLAG_X509_STRICT flag disables workarounds for some broken
       certificates and makes the verification strictly apply X509 rules.

       X509_V_FLAG_ALLOW_PROXY_CERTS enables proxy certificate verification.

       X509_V_FLAG_POLICY_CHECK enables certificate policy checking, by
       default no policy checking is peformed. Additional information is sent
       to the verification callback relating to policy checking.

       X509_V_FLAG_EXPLICIT_POLICY, X509_V_FLAG_INHIBIT_ANY and
       X509_V_FLAG_INHIBIT_MAP set the require explicit policy, inhibit any
       policy and inhibit policy mapping flags respectively as defined in
       RFC3280. Policy checking is automatically enabled if any of these flags
       are set.

       If X509_V_FLAG_NOTIFY_POLICY is set and the policy checking is success-
       ful a special status code is set to the verification callback. This
       permits it to examine the valid policy tree and perform additional
       checks or simply log it for debugging purposes.

       By default some additional features such as indirect CRLs and CRLs
       signed by different keys are disabled. If X509_V_FLAG_EXTENDED_CRL_SUP-
       PORT is set they are enabled.

       If X509_V_FLAG_USE_DELTAS ise set delta CRLs (if present) are used to
       determine certificate status. If not set deltas are ignored.

       X509_V_FLAG_CHECK_SS_SIGNATURE enables checking of the root CA self
       signed cerificate signature. By default this check is disabled because
       it doesn't add any additional security but in some cases applications
       might want to check the signature anyway. A side effect of not checking
       the root CA signature is that disabled or unsupported message digests
       on the root CA are not treated as fatal errors.

       The X509_V_FLAG_CB_ISSUER_CHECK flag enables debugging of certificate
       issuer checks. It is not needed unless you are logging certificate ver-
       ification. If this flag is set then additional status codes will be
       sent to the verification callback and it must be prepared to handle
       such cases without assuming they are hard errors.

       The X509_V_FLAG_NO_ALT_CHAINS flag suppresses checking for alternative
       chains. By default, when building a certificate chain, if the first
       certificate chain found is not trusted, then OpenSSL will continue to
       check to see if an alternative chain can be found that is trusted. With
       this flag set the behaviour will match that of OpenSSL versions prior
       to 1.0.2b.

       The X509_V_FLAG_TRUSTED_FIRST flag causes chain construction to look
       for issuers in the trust store before looking at the untrusted certifi-
       cates provided as part of the the peer chain.  Though it is not on by
       default in OpenSSL 1.0.2, applications should generally set this flag.
       Local issuer certificates are often more likely to satisfy local secu-
       rity requirements and lead to a locally trusted root.  This is espe-
       cially important When some certificates in the trust store have
       explicit trust settings (see "TRUST SETTINGS" in x509(1)).

       The X509_V_FLAG_PARTIAL_CHAIN flag causes intermediate certificates in
       the trust store to be treated as trust-anchors, in the same way as the
       self-signed root CA certificates.  This makes it possible to trust cer-
       tificates issued by an intermediate CA without having to trust its
       ancestor root CA.  With OpenSSL 1.0.2, chain construction continues as
       long as there are additional trusted issuers in the trust store, and
       the last trusted issuer becomes the trust-anchor.  Thus, even when an
       intermediate certificate is found in the trust store, the verified
       chain passed to callbacks may still be anchored by a root CA.

       The above functions should be used to manipulate verification parame-
       ters instead of legacy functions which work in specific structures such
       as X509_STORE_CTX_set_flags().

       Delta CRL checking is currently primitive. Only a single delta can be
       used and (partly due to limitations of X509_STORE) constructed CRLs are
       not maintained.

       If CRLs checking is enable CRLs are expected to be available in the
       corresponding X509_STORE structure. No attempt is made to download CRLs
       from the CRL distribution points extension.

       Enable CRL checking when performing certificate verification during SSL
       connections associated with an SSL_CTX structure ctx:

         X509_VERIFY_PARAM *param;
         param = X509_VERIFY_PARAM_new();
         X509_VERIFY_PARAM_set_flags(param, X509_V_FLAG_CRL_CHECK);
         SSL_CTX_set1_param(ctx, param);
         X509_VERIFY_PARAM_free(param);

       X509_verify_cert(3), X509_check_host(3), X509_check_email(3),
       X509_check_ip(3), x509(1)

       The X509_V_FLAG_NO_ALT_CHAINS flag was added in OpenSSL 1.0.2b

1.0.2t                            2019-09-10    X509_VERIFY_PARAM_set_flags(3)