1X509_GET_EXTENSION_FLAGS(3)         OpenSSL        X509_GET_EXTENSION_FLAGS(3)
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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.
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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.  This bit may also be raised after
69           an out-of-memory error while processing the X509 object, so it may
70           not be related to the processed ASN1 object itself.
71
72       EXFLAG_NO_FINGERPRINT
73           Failed to compute the internal SHA1 hash value of the certificate.
74           This may be due to malloc failure or because no SHA1 implementation
75           was found.
76
77       EXFLAG_INVALID_POLICY
78           The NID_certificate_policies certificate extension is invalid or
79           inconsistent. The certificate should be rejected.  This bit may
80           also be raised after an out-of-memory error while processing the
81           X509 object, so it may not be related to the processed ASN1 object
82           itself.
83
84       EXFLAG_KUSAGE
85           The certificate contains a key usage extension. The value can be
86           retrieved using X509_get_key_usage().
87
88       EXFLAG_XKUSAGE
89           The certificate contains an extended key usage extension. The value
90           can be retrieved using X509_get_extended_key_usage().
91
92       X509_get_key_usage() returns the value of the key usage extension.  If
93       key usage is present will return zero or more of the flags:
94       KU_DIGITAL_SIGNATURE, KU_NON_REPUDIATION, KU_KEY_ENCIPHERMENT,
95       KU_DATA_ENCIPHERMENT, KU_KEY_AGREEMENT, KU_KEY_CERT_SIGN, KU_CRL_SIGN,
96       KU_ENCIPHER_ONLY or KU_DECIPHER_ONLY corresponding to individual key
97       usage bits. If key usage is absent then UINT32_MAX is returned.
98
99       X509_get_extended_key_usage() returns the value of the extended key
100       usage extension. If extended key usage is present it will return zero
101       or more of the flags: XKU_SSL_SERVER, XKU_SSL_CLIENT, XKU_SMIME,
102       XKU_CODE_SIGN XKU_OCSP_SIGN, XKU_TIMESTAMP, XKU_DVCS or XKU_ANYEKU.
103       These correspond to the OIDs id-kp-serverAuth, id-kp-clientAuth, id-kp-
104       emailProtection, id-kp-codeSigning, id-kp-OCSPSigning, id-kp-
105       timeStamping, id-kp-dvcs and anyExtendedKeyUsage respectively.
106       Additionally XKU_SGC is set if either Netscape or Microsoft SGC OIDs
107       are present.
108
109       X509_get0_subject_key_id() returns an internal pointer to the subject
110       key identifier of x as an ASN1_OCTET_STRING or NULL if the extension is
111       not present or cannot be parsed.
112
113       X509_get0_authority_key_id() returns an internal pointer to the
114       authority key identifier of x as an ASN1_OCTET_STRING or NULL if the
115       extension is not present or cannot be parsed.
116
117       X509_get0_authority_issuer() returns an internal pointer to the
118       authority certificate issuer of x as a stack of GENERAL_NAME structures
119       or NULL if the extension is not present or cannot be parsed.
120
121       X509_get0_authority_serial() returns an internal pointer to the
122       authority certificate serial number of x as an ASN1_INTEGER or NULL if
123       the extension is not present or cannot be parsed.
124
125       X509_set_proxy_flag() marks the certificate with the EXFLAG_PROXY flag.
126       This is for the users who need to mark non-RFC3820 proxy certificates
127       as such, as OpenSSL only detects RFC3820 compliant ones.
128
129       X509_set_proxy_pathlen() sets the proxy certificate path length for the
130       given certificate x.  This is for the users who need to mark
131       non-RFC3820 proxy certificates as such, as OpenSSL only detects RFC3820
132       compliant ones.
133
134       X509_get_proxy_pathlen() returns the proxy certificate path length for
135       the given certificate x if it is a proxy certificate.
136

NOTES

138       The value of the flags correspond to extension values which are cached
139       in the X509 structure. If the flags returned do not provide sufficient
140       information an application should examine extension values directly for
141       example using X509_get_ext_d2i().
142
143       If the key usage or extended key usage extension is absent then
144       typically usage is unrestricted. For this reason X509_get_key_usage()
145       and X509_get_extended_key_usage() return UINT32_MAX when the
146       corresponding extension is absent. Applications can additionally check
147       the return value of X509_get_extension_flags() and take appropriate
148       action is an extension is absent.
149
150       If X509_get0_subject_key_id() returns NULL then the extension may be
151       absent or malformed. Applications can determine the precise reason
152       using X509_get_ext_d2i().
153

RETURN VALUES

155       X509_get_pathlen() returns the path length value, or -1 if the
156       extension is not present.
157
158       X509_get_extension_flags(), X509_get_key_usage() and
159       X509_get_extended_key_usage() return sets of flags corresponding to the
160       certificate extension values.
161
162       X509_get0_subject_key_id() returns the subject key identifier as a
163       pointer to an ASN1_OCTET_STRING structure or NULL if the extension is
164       absent or an error occurred during parsing.
165
166       X509_get_proxy_pathlen() returns the path length value if the given
167       certificate is a proxy one and has a path length set, and -1 otherwise.
168

SEE ALSO

170       X509_check_purpose(3)
171

HISTORY

173       X509_get_pathlen(), X509_set_proxy_flag(), X509_set_proxy_pathlen() and
174       X509_get_proxy_pathlen() were added in OpenSSL 1.1.0.
175
177       Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.
178
179       Licensed under the OpenSSL license (the "License").  You may not use
180       this file except in compliance with the License.  You can obtain a copy
181       in the file LICENSE in the source distribution or at
182       <https://www.openssl.org/source/license.html>.
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1861.1.1q                            2022-07-21       X509_GET_EXTENSION_FLAGS(3)
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