X509_get_key_usage(3ssl)

1X509_GET_EXTENSION_FLAGS(3)         OpenSSL        X509_GET_EXTENSION_FLAGS(3)
2
3
4

NAME

6       X509_get0_subject_key_id, X509_get0_authority_key_id,
7       X509_get0_authority_issuer, X509_get0_authority_serial,
8       X509_get_pathlen, X509_get_extension_flags, X509_get_key_usage,
9       X509_get_extended_key_usage, X509_set_proxy_flag,
10       X509_set_proxy_pathlen, X509_get_proxy_pathlen - retrieve certificate
11       extension data
12

SYNOPSIS

14        #include <openssl/x509v3.h>
15
16        long X509_get_pathlen(X509 *x);
17        uint32_t X509_get_extension_flags(X509 *x);
18        uint32_t X509_get_key_usage(X509 *x);
19        uint32_t X509_get_extended_key_usage(X509 *x);
20        const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x);
21        const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x);
22        const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x);
23        const ASN1_INTEGER *X509_get0_authority_serial(X509 *x);
24        void X509_set_proxy_flag(X509 *x);
25        void X509_set_proxy_pathlen(int l);
26        long X509_get_proxy_pathlen(X509 *x);
27

DESCRIPTION

29       These functions retrieve information related to commonly used
30       certificate extensions.
31
32       X509_get_pathlen() retrieves the path length extension from a
33       certificate.  This extension is used to limit the length of a cert
34       chain that may be issued from that CA.
35
36       X509_get_extension_flags() retrieves general information about a
37       certificate, it will return one or more of the following flags ored
38       together.
39
40       EXFLAG_V1
41           The certificate is an obsolete version 1 certificate.
42
43       EXFLAG_BCONS
44           The certificate contains a basic constraints extension.
45
46       EXFLAG_CA
47           The certificate contains basic constraints and asserts the CA flag.
48
49       EXFLAG_PROXY
50           The certificate is a valid proxy certificate.
51
52       EXFLAG_SI
53           The certificate is self issued (that is subject and issuer names
54           match).
55
56       EXFLAG_SS
57           The subject and issuer names match and extension values imply it is
58           self signed.
59
60       EXFLAG_FRESHEST
61           The freshest CRL extension is present in the certificate.
62
63       EXFLAG_CRITICAL
64           The certificate contains an unhandled critical extension.
65
66       EXFLAG_INVALID
67           Some certificate extension values are invalid or inconsistent. The
68           certificate should be rejected.
69
70       EXFLAG_KUSAGE
71           The certificate contains a key usage extension. The value can be
72           retrieved using X509_get_key_usage().
73
74       EXFLAG_XKUSAGE
75           The certificate contains an extended key usage extension. The value
76           can be retrieved using X509_get_extended_key_usage().
77
78       X509_get_key_usage() returns the value of the key usage extension.  If
79       key usage is present will return zero or more of the flags:
80       KU_DIGITAL_SIGNATURE, KU_NON_REPUDIATION, KU_KEY_ENCIPHERMENT,
81       KU_DATA_ENCIPHERMENT, KU_KEY_AGREEMENT, KU_KEY_CERT_SIGN, KU_CRL_SIGN,
82       KU_ENCIPHER_ONLY or KU_DECIPHER_ONLY corresponding to individual key
83       usage bits. If key usage is absent then UINT32_MAX is returned.
84
85       X509_get_extended_key_usage() returns the value of the extended key
86       usage extension. If extended key usage is present it will return zero
87       or more of the flags: XKU_SSL_SERVER, XKU_SSL_CLIENT, XKU_SMIME,
88       XKU_CODE_SIGN XKU_OCSP_SIGN, XKU_TIMESTAMP, XKU_DVCS or XKU_ANYEKU.
89       These correspond to the OIDs id-kp-serverAuth, id-kp-clientAuth, id-kp-
90       emailProtection, id-kp-codeSigning, id-kp-OCSPSigning, id-kp-
91       timeStamping, id-kp-dvcs and anyExtendedKeyUsage respectively.
92       Additionally XKU_SGC is set if either Netscape or Microsoft SGC OIDs
93       are present.
94
95       X509_get0_subject_key_id() returns an internal pointer to the subject
96       key identifier of x as an ASN1_OCTET_STRING or NULL if the extension is
97       not present or cannot be parsed.
98
99       X509_get0_authority_key_id() returns an internal pointer to the
100       authority key identifier of x as an ASN1_OCTET_STRING or NULL if the
101       extension is not present or cannot be parsed.
102
103       X509_get0_authority_issuer() returns an internal pointer to the
104       authority certificate issuer of x as a stack of GENERAL_NAME structures
105       or NULL if the extension is not present or cannot be parsed.
106
107       X509_get0_authority_serial() returns an internal pointer to the
108       authority certificate serial number of x as an ASN1_INTEGER or NULL if
109       the extension is not present or cannot be parsed.
110
111       X509_set_proxy_flag() marks the certificate with the EXFLAG_PROXY flag.
112       This is for the users who need to mark non-RFC3820 proxy certificates
113       as such, as OpenSSL only detects RFC3820 compliant ones.
114
115       X509_set_proxy_pathlen() sets the proxy certificate path length for the
116       given certificate x.  This is for the users who need to mark
117       non-RFC3820 proxy certificates as such, as OpenSSL only detects RFC3820
118       compliant ones.
119
120       X509_get_proxy_pathlen() returns the proxy certificate path length for
121       the given certificate x if it is a proxy certificate.
122

NOTES

124       The value of the flags correspond to extension values which are cached
125       in the X509 structure. If the flags returned do not provide sufficient
126       information an application should examine extension values directly for
127       example using X509_get_ext_d2i().
128
129       If the key usage or extended key usage extension is absent then
130       typically usage is unrestricted. For this reason X509_get_key_usage()
131       and X509_get_extended_key_usage() return UINT32_MAX when the
132       corresponding extension is absent. Applications can additionally check
133       the return value of X509_get_extension_flags() and take appropriate
134       action is an extension is absent.
135
136       If X509_get0_subject_key_id() returns NULL then the extension may be
137       absent or malformed. Applications can determine the precise reason
138       using X509_get_ext_d2i().
139

RETURN VALUES

141       X509_get_pathlen() returns the path length value, or -1 if the
142       extension is not present.
143
144       X509_get_extension_flags(), X509_get_key_usage() and
145       X509_get_extended_key_usage() return sets of flags corresponding to the
146       certificate extension values.
147
148       X509_get0_subject_key_id() returns the subject key identifier as a
149       pointer to an ASN1_OCTET_STRING structure or NULL if the extension is
150       absent or an error occurred during parsing.
151
152       X509_get_proxy_pathlen() returns the path length value if the given
153       certificate is a proxy one and has a path length set, and -1 otherwise.
154

HISTORY

159       X509_get_pathlen(), X509_set_proxy_flag(), X509_set_proxy_pathlen() and
160       X509_get_proxy_pathlen() were added in OpenSSL 1.1.0.
161

COPYRIGHT

163       Copyright 2015-2019 The OpenSSL Project Authors. All Rights Reserved.
164
165       Licensed under the OpenSSL license (the "License").  You may not use
166       this file except in compliance with the License.  You can obtain a copy
167       in the file LICENSE in the source distribution or at
168       <https://www.openssl.org/source/license.html>.
169
170
171
1721.1.1d                            2019-10-03       X509_GET_EXTENSION_FLAGS(3)