5 X509_get0_subject_key_id,
6 X509_get0_authority_key_id,
7 X509_get0_authority_issuer,
8 X509_get0_authority_serial,
10 X509_get_extension_flags,
12 X509_get_extended_key_usage,
14 X509_set_proxy_pathlen,
15 X509_get_proxy_pathlen - retrieve certificate extension data
19 #include <openssl/x509v3.h>
21 long X509_get_pathlen(X509 *x);
22 uint32_t X509_get_extension_flags(X509 *x);
23 uint32_t X509_get_key_usage(X509 *x);
24 uint32_t X509_get_extended_key_usage(X509 *x);
25 const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x);
26 const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x);
27 const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x);
28 const ASN1_INTEGER *X509_get0_authority_serial(X509 *x);
29 void X509_set_proxy_flag(X509 *x);
30 void X509_set_proxy_pathlen(int l);
31 long X509_get_proxy_pathlen(X509 *x);
35 These functions retrieve information related to commonly used certificate extensions.
37 X509_get_pathlen() retrieves the path length extension from a certificate.
38 This extension is used to limit the length of a cert chain that may be
41 X509_get_extension_flags() retrieves general information about a certificate,
42 it will return one or more of the following flags ored together.
48 The certificate is an obsolete version 1 certificate.
52 The certificate contains a basic constraints extension.
56 The certificate contains basic constraints and asserts the CA flag.
60 The certificate is a valid proxy certificate.
64 The certificate is self issued (that is subject and issuer names match).
68 The subject and issuer names match and extension values imply it is self
71 =item B<EXFLAG_FRESHEST>
73 The freshest CRL extension is present in the certificate.
75 =item B<EXFLAG_CRITICAL>
77 The certificate contains an unhandled critical extension.
79 =item B<EXFLAG_INVALID>
81 Some certificate extension values are invalid or inconsistent.
82 The certificate should be rejected.
83 This bit may also be raised after an out-of-memory error while
84 processing the X509 object, so it may not be related to the processed
87 =item B<EXFLAG_NO_FINGERPRINT>
89 Failed to compute the internal SHA1 hash value of the certificate or CRL.
90 This may be due to malloc failure or because no SHA1 implementation was found.
92 =item B<EXFLAG_INVALID_POLICY>
94 The NID_certificate_policies certificate extension is invalid or
95 inconsistent. The certificate should be rejected.
96 This bit may also be raised after an out-of-memory error while
97 processing the X509 object, so it may not be related to the processed
100 =item B<EXFLAG_KUSAGE>
102 The certificate contains a key usage extension. The value can be retrieved
103 using X509_get_key_usage().
105 =item B<EXFLAG_XKUSAGE>
107 The certificate contains an extended key usage extension. The value can be
108 retrieved using X509_get_extended_key_usage().
112 X509_get_key_usage() returns the value of the key usage extension. If key
113 usage is present will return zero or more of the flags:
114 B<KU_DIGITAL_SIGNATURE>, B<KU_NON_REPUDIATION>, B<KU_KEY_ENCIPHERMENT>,
115 B<KU_DATA_ENCIPHERMENT>, B<KU_KEY_AGREEMENT>, B<KU_KEY_CERT_SIGN>,
116 B<KU_CRL_SIGN>, B<KU_ENCIPHER_ONLY> or B<KU_DECIPHER_ONLY> corresponding to
117 individual key usage bits. If key usage is absent then B<UINT32_MAX> is
120 X509_get_extended_key_usage() returns the value of the extended key usage
121 extension. If extended key usage is present it will return zero or more of the
122 flags: B<XKU_SSL_SERVER>, B<XKU_SSL_CLIENT>, B<XKU_SMIME>, B<XKU_CODE_SIGN>
123 B<XKU_OCSP_SIGN>, B<XKU_TIMESTAMP>, B<XKU_DVCS> or B<XKU_ANYEKU>. These
124 correspond to the OIDs B<id-kp-serverAuth>, B<id-kp-clientAuth>,
125 B<id-kp-emailProtection>, B<id-kp-codeSigning>, B<id-kp-OCSPSigning>,
126 B<id-kp-timeStamping>, B<id-kp-dvcs> and B<anyExtendedKeyUsage> respectively.
127 Additionally B<XKU_SGC> is set if either Netscape or Microsoft SGC OIDs are
130 X509_get0_subject_key_id() returns an internal pointer to the subject key
131 identifier of B<x> as an B<ASN1_OCTET_STRING> or B<NULL> if the extension
132 is not present or cannot be parsed.
134 X509_get0_authority_key_id() returns an internal pointer to the authority key
135 identifier of B<x> as an B<ASN1_OCTET_STRING> or B<NULL> if the extension
136 is not present or cannot be parsed.
138 X509_get0_authority_issuer() returns an internal pointer to the authority
139 certificate issuer of B<x> as a stack of B<GENERAL_NAME> structures or
140 B<NULL> if the extension is not present or cannot be parsed.
142 X509_get0_authority_serial() returns an internal pointer to the authority
143 certificate serial number of B<x> as an B<ASN1_INTEGER> or B<NULL> if the
144 extension is not present or cannot be parsed.
146 X509_set_proxy_flag() marks the certificate with the B<EXFLAG_PROXY> flag.
147 This is for the users who need to mark non-RFC3820 proxy certificates as
148 such, as OpenSSL only detects RFC3820 compliant ones.
150 X509_set_proxy_pathlen() sets the proxy certificate path length for the given
151 certificate B<x>. This is for the users who need to mark non-RFC3820 proxy
152 certificates as such, as OpenSSL only detects RFC3820 compliant ones.
154 X509_get_proxy_pathlen() returns the proxy certificate path length for the
155 given certificate B<x> if it is a proxy certificate.
159 The value of the flags correspond to extension values which are cached
160 in the B<X509> structure. If the flags returned do not provide sufficient
161 information an application should examine extension values directly
162 for example using X509_get_ext_d2i().
164 If the key usage or extended key usage extension is absent then typically usage
165 is unrestricted. For this reason X509_get_key_usage() and
166 X509_get_extended_key_usage() return B<UINT32_MAX> when the corresponding
167 extension is absent. Applications can additionally check the return value of
168 X509_get_extension_flags() and take appropriate action is an extension is
171 If X509_get0_subject_key_id() returns B<NULL> then the extension may be
172 absent or malformed. Applications can determine the precise reason using
177 X509_get_pathlen() returns the path length value, or -1 if the extension
180 X509_get_extension_flags(), X509_get_key_usage() and
181 X509_get_extended_key_usage() return sets of flags corresponding to the
182 certificate extension values.
184 X509_get0_subject_key_id() returns the subject key identifier as a
185 pointer to an B<ASN1_OCTET_STRING> structure or B<NULL> if the extension
186 is absent or an error occurred during parsing.
188 X509_get_proxy_pathlen() returns the path length value if the given
189 certificate is a proxy one and has a path length set, and -1 otherwise.
193 L<X509_check_purpose(3)>
197 X509_get_pathlen(), X509_set_proxy_flag(), X509_set_proxy_pathlen() and
198 X509_get_proxy_pathlen() were added in OpenSSL 1.1.0.
202 Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.
204 Licensed under the Apache License 2.0 (the "License"). You may not use
205 this file except in compliance with the License. You can obtain a copy
206 in the file LICENSE in the source distribution or at
207 L<https://www.openssl.org/source/license.html>.