Updated: 2021/Apr/14

X509_VERIFY_PARAM_set_flags(3)      OpenSSL     X509_VERIFY_PARAM_set_flags(3)

       X509_VERIFY_PARAM_set_flags, X509_VERIFY_PARAM_clear_flags,
       X509_VERIFY_PARAM_get_flags, X509_VERIFY_PARAM_set_purpose,
       X509_VERIFY_PARAM_get_inh_flags, X509_VERIFY_PARAM_set_inh_flags,
       X509_VERIFY_PARAM_set_trust, X509_VERIFY_PARAM_set_depth,
       X509_VERIFY_PARAM_get_depth, X509_VERIFY_PARAM_set_auth_level,
       X509_VERIFY_PARAM_get_auth_level, X509_VERIFY_PARAM_set_time,
       X509_VERIFY_PARAM_get_time, X509_VERIFY_PARAM_add0_policy,
       X509_VERIFY_PARAM_set1_policies, X509_VERIFY_PARAM_set1_host,
       X509_VERIFY_PARAM_add1_host, X509_VERIFY_PARAM_set_hostflags,
       X509_VERIFY_PARAM_get_hostflags, X509_VERIFY_PARAM_get0_peername,
       X509_VERIFY_PARAM_set1_email, X509_VERIFY_PARAM_set1_ip,
       X509_VERIFY_PARAM_set1_ip_asc - X509 verification parameters

       libcrypto, -lcrypto

        #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_inh_flags(X509_VERIFY_PARAM *param,
                                            uint32_t flags);
        uint32_t X509_VERIFY_PARAM_get_inh_flags(const 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);
        time_t X509_VERIFY_PARAM_get_time(const X509_VERIFY_PARAM *param);

        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);

        void X509_VERIFY_PARAM_set_auth_level(X509_VERIFY_PARAM *param,
                                              int auth_level);
        int X509_VERIFY_PARAM_get_auth_level(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);
        unsigned int X509_VERIFY_PARAM_get_hostflags(const X509_VERIFY_PARAM *param);
        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);

       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_get_inh_flags() returns the inheritance flags in
       param which specifies how verification flags are copied from one
       structure to another. X509_VERIFY_PARAM_set_inh_flags() sets the
       inheritance flags.  See the INHERITANCE FLAGS section for a description
       of these bits.

       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
       disabled 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 intermediate CA certificates that
       can appear in a chain.  A maximal depth chain contains 2 more
       certificates than the limit, since neither the end-entity certificate
       nor the trust-anchor count against this limit.  Thus a depth limit of 0
       only allows the end-entity certificate to be signed directly by the
       trust-anchor, while with a depth limit of 1 there can be one
       intermediate CA certificate between the trust-anchor and the end-entity

       X509_VERIFY_PARAM_set_auth_level() sets the authentication security
       level to auth_level.  The authentication security level determines the
       acceptable signature and public key strength when verifying certificate
       chains.  For a certificate chain to validate, the public keys of all
       the certificates must meet the specified security level.  The signature
       algorithm security level is not enforced for the chain's trust anchor
       certificate, which is either directly trusted or validated by means
       other than its signature.  See SSL_CTX_set_security_level(3) for the
       definitions of the available levels.  The default security level is -1,
       or "not set".  At security level 0 or lower all algorithms are
       acceptable.  Security level 1 requires at least 80-bit-equivalent
       security and is broadly interoperable, though it will, for example,
       reject MD5 signatures or RSA keys shorter than 1024 bits.

       X509_VERIFY_PARAM_set1_host() sets the expected DNS hostname to name
       clearing any previously specified hostname or names.  If name is NULL,
       or empty the list of hostnames is cleared, and name checks are not
       performed 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 X509_VERIFY_PARAM_set_hostflags() (default zero).  Applications are
       strongly advised to use this interface in preference to explicitly
       calling X509_check_host(3), hostname checks may be out of scope with
       the DANE-EE(3) certificate usage, and the internal check will be
       suppressed as appropriate when DANE verification is enabled.

       When the subject CommonName will not be ignored, whether as a result of
       the X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT host flag, or because no DNS
       subject alternative names are present in the certificate, any DNS name
       constraints in issuer certificates apply to the subject CommonName as
       well as the subject alternative name extension.

       When the subject CommonName will be ignored, whether as a result of the
       X509_CHECK_FLAG_NEVER_CHECK_SUBJECT host flag, or because some DNS
       subject alternative names are present in the certificate, DNS name
       constraints in issuer certificates will not be applied to the subject
       DN. As described in X509_check_host(3) the
       X509_CHECK_FLAG_NEVER_CHECK_SUBJECT flag takes precedence over the

       X509_VERIFY_PARAM_get_hostflags() returns any host flags previously set
       via a call to X509_VERIFY_PARAM_set_hostflags().

       X509_VERIFY_PARAM_add1_host() adds name as an additional reference
       identifier 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
       multiple 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
       reference 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
       allocated 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_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_inh_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_add1_host(), 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_get_hostflags() returns any current host flags.

       X509_VERIFY_PARAM_get_inh_flags() returns the current inheritance

       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.

       X509_VERIFY_PARAM_get_auth_level() returns the current authentication
       security level.

       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
       certificate 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
       anything other than debugging purposes can be a security risk. Finer
       control over which extensions are supported can be performed in the
       verification 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 performed. Additional information is sent
       to the verification callback relating to policy checking.

       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
       successful 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_SUPPORT is set they are enabled.

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

       X509_V_FLAG_CHECK_SS_SIGNATURE requests checking the signature of the
       last certificate in a chain if the certificate is supposedly self-
       signed.  This is prohibited and will result in an error if it is a non-
       conforming CA certificate with key usage restrictions not including the
       keyCertSign bit.  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 self-
       signature of such a certificate is that disabled or unsupported message
       digests used for the signature are not treated as fatal errors.

       When X509_V_FLAG_TRUSTED_FIRST is set, construction of the certificate
       chain in X509_verify_cert(3) will search the trust store for issuer
       certificates before searching the provided untrusted certificates.
       Local issuer certificates are often more likely to satisfy local
       security requirements and lead to a locally trusted root.  This is
       especially important when some certificates in the trust store have
       explicit trust settings (see "TRUST SETTINGS" in x509(1)).  As of
       OpenSSL 1.1.0 this option is on by default.

       The X509_V_FLAG_NO_ALT_CHAINS flag suppresses checking for alternative
       chains.  By default, unless X509_V_FLAG_TRUSTED_FIRST is set, when
       building a certificate chain, if the first certificate chain found is
       not trusted, then OpenSSL will attempt to replace untrusted
       certificates supplied by the peer with certificates from the trust
       store to see if an alternative chain can be found that is trusted.  As
       of OpenSSL 1.1.0, with X509_V_FLAG_TRUSTED_FIRST always set, this
       option has no effect.

       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
       certificates issued by an intermediate CA without having to trust its
       ancestor root CA. With OpenSSL 1.1.0 and later and
       <X509_V_FLAG_PARTIAL_CHAIN> set, chain construction stops as soon as
       the first certificate from the trust store is added to the chain,
       whether that certificate is a self-signed "root" certificate or a not
       self-signed intermediate certificate.  Thus, when an intermediate
       certificate is found in the trust store, the verified chain passed to
       callbacks may be shorter than it otherwise would be without the
       X509_V_FLAG_PARTIAL_CHAIN flag.

       The X509_V_FLAG_NO_CHECK_TIME flag suppresses checking the validity
       period of certificates and CRLs against the current time. If
       X509_VERIFY_PARAM_set_time() is used to specify a verification time,
       the check is not suppressed.

       These flags specify how parameters are "inherited" from one structure
       to another.

       If X509_VP_FLAG_ONCE is set then the current setting is zeroed after
       the next call.

       If X509_VP_FLAG_LOCKED is set then no values are copied.  This
       overrides all of the following flags.

       If X509_VP_FLAG_DEFAULT is set then anything set in the source is
       copied to the destination. Effectively the values in "to" become
       default values which will be used only if nothing new is set in "from".
       This is the default.

       If X509_VP_FLAG_OVERWRITE is set then all value are copied across
       whether they are set or not. Flags is still Ored though.

       If X509_VP_FLAG_RESET_FLAGS is set then the flags value is copied
       instead of ORed.

       The above functions should be used to manipulate verification
       parameters instead of functions which work in specific structures such
       as X509_STORE_CTX_set_flags() which are likely to be deprecated in a
       future release.

       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_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 1.1.0.  The
       flag X509_V_FLAG_CB_ISSUER_CHECK was deprecated in OpenSSL 1.1.0 and
       has no effect.

       The X509_VERIFY_PARAM_get_hostflags() function was added in OpenSSL

       Copyright 2009-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

1.1.1i                            2020-12-10    X509_VERIFY_PARAM_set_flags(3)