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X509_get_extension_flags(3)         OpenSSL        X509_get_extension_flags(3)



NAME
       X509_get0_subject_key_id, X509_get0_authority_key_id, X509_get_pathlen,
       X509_get_extension_flags, X509_get_key_usage,
       X509_get_extended_key_usage, X509_set_proxy_flag,
       X509_set_proxy_pathlen, X509_get_proxy_pathlen - retrieve certificate
       extension data

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/x509v3.h>

        long X509_get_pathlen(X509 *x);
        uint32_t X509_get_extension_flags(X509 *x);
        uint32_t X509_get_key_usage(X509 *x);
        uint32_t X509_get_extended_key_usage(X509 *x);
        const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x);
        const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x);
        void X509_set_proxy_flag(X509 *x);
        void X509_set_proxy_pathlen(int l);
        long X509_get_proxy_pathlen(X509 *x);

DESCRIPTION
       These functions retrieve information related to commonly used
       certificate extensions.

       X509_get_pathlen() retrieves the path length extension from a
       certificate.  This extension is used to limit the length of a cert
       chain that may be issued from that CA.

       X509_get_extension_flags() retrieves general information about a
       certificate, it will return one or more of the following flags ored
       together.

       EXFLAG_V1
           The certificate is an obsolete version 1 certificate.

       EXFLAG_BCONS
           The certificate contains a basic constraints extension.

       EXFLAG_CA
           The certificate contains basic constraints and asserts the CA flag.

       EXFLAG_PROXY
           The certificate is a valid proxy certificate.

       EXFLAG_SI
           The certificate is self issued (that is subject and issuer names
           match).

       EXFLAG_SS
           The subject and issuer names match and extension values imply it is
           self signed.

       EXFLAG_FRESHEST
           The freshest CRL extension is present in the certificate.

       EXFLAG_CRITICAL
           The certificate contains an unhandled critical extension.

       EXFLAG_INVALID
           Some certificate extension values are invalid or inconsistent. The
           certificate should be rejected.

       EXFLAG_KUSAGE
           The certificate contains a key usage extension. The value can be
           retrieved using X509_get_key_usage().

       EXFLAG_XKUSAGE
           The certificate contains an extended key usage extension. The value
           can be retrieved using X509_get_extended_key_usage().

       X509_get_key_usage() returns the value of the key usage extension.  If
       key usage is present will return zero or more of the flags:
       KU_DIGITAL_SIGNATURE, KU_NON_REPUDIATION, KU_KEY_ENCIPHERMENT,
       KU_DATA_ENCIPHERMENT, KU_KEY_AGREEMENT, KU_KEY_CERT_SIGN, KU_CRL_SIGN,
       KU_ENCIPHER_ONLY or KU_DECIPHER_ONLY corresponding to individual key
       usage bits. If key usage is absent then UINT32_MAX is returned.

       X509_get_extended_key_usage() returns the value of the extended key
       usage extension. If extended key usage is present it will return zero
       or more of the flags: XKU_SSL_SERVER, XKU_SSL_CLIENT, XKU_SMIME,
       XKU_CODE_SIGN XKU_OCSP_SIGN, XKU_TIMESTAMP, XKU_DVCS or XKU_ANYEKU.
       These correspond to the OIDs id-kp-serverAuth, id-kp-clientAuth, id-kp-
       emailProtection, id-kp-codeSigning, id-kp-OCSPSigning, id-kp-
       timeStamping, id-kp-dvcs and anyExtendedKeyUsage respectively.
       Additionally XKU_SGC is set if either Netscape or Microsoft SGC OIDs
       are present.

       X509_get0_subject_key_id() returns an internal pointer to the subject
       key identifier of x as an ASN1_OCTET_STRING or NULL if the extension is
       not present or cannot be parsed.

       X509_get0_authority_key_id() returns an internal pointer to the
       authority key identifier of x as an ASN1_OCTET_STRING or NULL if the
       extension is not present or cannot be parsed.

       X509_set_proxy_flag() marks the certificate with the EXFLAG_PROXY flag.
       This is for the users who need to mark non-RFC3820 proxy certificates
       as such, as OpenSSL only detects RFC3820 compliant ones.

       X509_set_proxy_pathlen() sets the proxy certificate path length for the
       given certificate x.  This is for the users who need to mark
       non-RFC3820 proxy certificates as such, as OpenSSL only detects RFC3820
       compliant ones.

       X509_get_proxy_pathlen() returns the proxy certificate path length for
       the given certificate x if it is a proxy certificate.

NOTES
       The value of the flags correspond to extension values which are cached
       in the X509 structure. If the flags returned do not provide sufficient
       information an application should examine extension values directly for
       example using X509_get_ext_d2i().

       If the key usage or extended key usage extension is absent then
       typically usage is unrestricted. For this reason X509_get_key_usage()
       and X509_get_extended_key_usage() return UINT32_MAX when the
       corresponding extension is absent. Applications can additionally check
       the return value of X509_get_extension_flags() and take appropriate
       action is an extension is absent.

       If X509_get0_subject_key_id() returns NULL then the extension may be
       absent or malformed. Applications can determine the precise reason
       using X509_get_ext_d2i().

RETURN VALUES
       X509_get_pathlen() returns the path length value, or -1 if the
       extension is not present.

       X509_get_extension_flags(), X509_get_key_usage() and
       X509_get_extended_key_usage() return sets of flags corresponding to the
       certificate extension values.

       X509_get0_subject_key_id() returns the subject key identifier as a
       pointer to an ASN1_OCTET_STRING structure or NULL if the extension is
       absent or an error occurred during parsing.

       X509_get_proxy_pathlen() returns the path length value if the given
       certificate is a proxy one and has a path length set, and -1 otherwise.

SEE ALSO
       X509_check_purpose(3)

HISTORY
       X509_get_pathlen(), X509_set_proxy_flag(), X509_set_proxy_pathlen() and
       X509_get_proxy_pathlen() were added in OpenSSL 1.1.0.

COPYRIGHT
       Copyright 2015-2018 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
       <https://www.openssl.org/source/license.html>.



1.1.1                             2018-09-17       X509_get_extension_flags(3)