1=pod
2
3=head1 NAME
4
5X509_get0_extensions, X509_CRL_get0_extensions, X509_REVOKED_get0_extensions,
6X509V3_get_d2i, X509V3_add1_i2d, X509V3_EXT_d2i, X509V3_EXT_i2d,
7X509_get_ext_d2i, X509_add1_ext_i2d, X509_CRL_get_ext_d2i,
8X509_CRL_add1_ext_i2d, X509_REVOKED_get_ext_d2i,
9X509_REVOKED_add1_ext_i2d - X509 extension decode and encode functions
10
11=head1 SYNOPSIS
12
13 #include <openssl/x509v3.h>
14
15 void *X509V3_get_d2i(const STACK_OF(X509_EXTENSION) *x, int nid, int *crit,
16                      int *idx);
17 int X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid, void *value,
18                     int crit, unsigned long flags);
19
20 void *X509V3_EXT_d2i(X509_EXTENSION *ext);
21 X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit, void *ext);
22
23 void *X509_get_ext_d2i(const X509 *x, int nid, int *crit, int *idx);
24 int X509_add1_ext_i2d(X509 *x, int nid, void *value, int crit,
25                       unsigned long flags);
26
27 void *X509_CRL_get_ext_d2i(const X509_CRL *crl, int nid, int *crit, int *idx);
28 int X509_CRL_add1_ext_i2d(X509_CRL *crl, int nid, void *value, int crit,
29                           unsigned long flags);
30
31 void *X509_REVOKED_get_ext_d2i(const X509_REVOKED *r, int nid, int *crit, int *idx);
32 int X509_REVOKED_add1_ext_i2d(X509_REVOKED *r, int nid, void *value, int crit,
33                               unsigned long flags);
34
35 const STACK_OF(X509_EXTENSION) *X509_get0_extensions(const X509 *x);
36 const STACK_OF(X509_EXTENSION) *X509_CRL_get0_extensions(const X509_CRL *crl);
37 const STACK_OF(X509_EXTENSION) *X509_REVOKED_get0_extensions(const X509_REVOKED *r);
38
39=head1 DESCRIPTION
40
41X509V3_get_ext_d2i() looks for an extension with OID B<nid> in the extensions
42B<x> and, if found, decodes it. If B<idx> is B<NULL> then only one
43occurrence of an extension is permissible otherwise the first extension after
44index B<*idx> is returned and B<*idx> updated to the location of the extension.
45If B<crit> is not B<NULL> then B<*crit> is set to a status value: -2 if the
46extension occurs multiple times (this is only returned if B<idx> is B<NULL>),
47-1 if the extension could not be found, 0 if the extension is found and is
48not critical and 1 if critical. A pointer to an extension specific structure
49or B<NULL> is returned.
50
51X509V3_add1_i2d() adds extension B<value> to STACK B<*x> (allocating a new
52STACK if necessary) using OID B<nid> and criticality B<crit> according
53to B<flags>.
54
55X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension
56B<ext> and returns a pointer to an extension specific structure or B<NULL>
57if the extension could not be decoded (invalid syntax or not supported).
58
59X509V3_EXT_i2d() encodes the extension specific structure B<ext>
60with OID B<ext_nid> and criticality B<crit>.
61
62X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of
63certificate B<x>, they are otherwise identical to X509V3_get_d2i() and
64X509V3_add_i2d().
65
66X509_CRL_get_ext_d2i() and X509_CRL_add1_ext_i2d() operate on the extensions
67of CRL B<crl>, they are otherwise identical to X509V3_get_d2i() and
68X509V3_add_i2d().
69
70X509_REVOKED_get_ext_d2i() and X509_REVOKED_add1_ext_i2d() operate on the
71extensions of B<X509_REVOKED> structure B<r> (i.e for CRL entry extensions),
72they are otherwise identical to X509V3_get_d2i() and X509V3_add_i2d().
73
74X509_get0_extensions(), X509_CRL_get0_extensions() and
75X509_REVOKED_get0_extensions() return a stack of all the extensions
76of a certificate a CRL or a CRL entry respectively.
77
78=head1 NOTES
79
80In almost all cases an extension can occur at most once and multiple
81occurrences is an error. Therefore, the B<idx> parameter is usually B<NULL>.
82
83The B<flags> parameter may be one of the following values.
84
85B<X509V3_ADD_DEFAULT> appends a new extension only if the extension does
86not already exist. An error is returned if the extension does already
87exist.
88
89B<X509V3_ADD_APPEND> appends a new extension, ignoring whether the extension
90already exists.
91
92B<X509V3_ADD_REPLACE> replaces an extension if it exists otherwise appends
93a new extension.
94
95B<X509V3_ADD_REPLACE_EXISTING> replaces an existing extension if it exists
96otherwise returns an error.
97
98B<X509V3_ADD_KEEP_EXISTING> appends a new extension only if the extension does
99not already exist. An error B<is not> returned if the extension does already
100exist.
101
102B<X509V3_ADD_DELETE> extension B<nid> is deleted: no new extension is added.
103
104If B<X509V3_ADD_SILENT> is ored with B<flags>: any error returned will not
105be added to the error queue.
106
107The function X509V3_get_d2i() will return B<NULL> if the extension is not
108found, occurs multiple times or cannot be decoded. It is possible to
109determine the precise reason by checking the value of B<*crit>.
110
111=head1 SUPPORTED EXTENSIONS
112
113The following sections contain a list of all supported extensions
114including their name and NID.
115
116=head2 PKIX Certificate Extensions
117
118The following certificate extensions are defined in PKIX standards such as
119RFC5280.
120
121 Basic Constraints                  NID_basic_constraints
122 Key Usage                          NID_key_usage
123 Extended Key Usage                 NID_ext_key_usage
124
125 Subject Key Identifier             NID_subject_key_identifier
126 Authority Key Identifier           NID_authority_key_identifier
127
128 Private Key Usage Period           NID_private_key_usage_period
129
130 Subject Alternative Name           NID_subject_alt_name
131 Issuer Alternative Name            NID_issuer_alt_name
132
133 Authority Information Access       NID_info_access
134 Subject Information Access         NID_sinfo_access
135
136 Name Constraints                   NID_name_constraints
137
138 Certificate Policies               NID_certificate_policies
139 Policy Mappings                    NID_policy_mappings
140 Policy Constraints                 NID_policy_constraints
141 Inhibit Any Policy                 NID_inhibit_any_policy
142
143 TLS Feature                        NID_tlsfeature
144
145=head2 Netscape Certificate Extensions
146
147The following are (largely obsolete) Netscape certificate extensions.
148
149 Netscape Cert Type                 NID_netscape_cert_type
150 Netscape Base Url                  NID_netscape_base_url
151 Netscape Revocation Url            NID_netscape_revocation_url
152 Netscape CA Revocation Url         NID_netscape_ca_revocation_url
153 Netscape Renewal Url               NID_netscape_renewal_url
154 Netscape CA Policy Url             NID_netscape_ca_policy_url
155 Netscape SSL Server Name           NID_netscape_ssl_server_name
156 Netscape Comment                   NID_netscape_comment
157
158=head2 Miscellaneous Certificate Extensions
159
160 Strong Extranet ID                 NID_sxnet
161 Proxy Certificate Information      NID_proxyCertInfo
162
163=head2 PKIX CRL Extensions
164
165The following are CRL extensions from PKIX standards such as RFC5280.
166
167 CRL Number                         NID_crl_number
168 CRL Distribution Points            NID_crl_distribution_points
169 Delta CRL Indicator                NID_delta_crl
170 Freshest CRL                       NID_freshest_crl
171 Invalidity Date                    NID_invalidity_date
172 Issuing Distribution Point         NID_issuing_distribution_point
173
174The following are CRL entry extensions from PKIX standards such as RFC5280.
175
176 CRL Reason Code                    NID_crl_reason
177 Certificate Issuer                 NID_certificate_issuer
178
179=head2 OCSP Extensions
180
181 OCSP Nonce                         NID_id_pkix_OCSP_Nonce
182 OCSP CRL ID                        NID_id_pkix_OCSP_CrlID
183 Acceptable OCSP Responses          NID_id_pkix_OCSP_acceptableResponses
184 OCSP No Check                      NID_id_pkix_OCSP_noCheck
185 OCSP Archive Cutoff                NID_id_pkix_OCSP_archiveCutoff
186 OCSP Service Locator               NID_id_pkix_OCSP_serviceLocator
187 Hold Instruction Code              NID_hold_instruction_code
188
189=head2 Certificate Transparency Extensions
190
191The following extensions are used by certificate transparency, RFC6962
192
193 CT Precertificate SCTs             NID_ct_precert_scts
194 CT Certificate SCTs                NID_ct_cert_scts
195
196=head1 RETURN VALUES
197
198X509V3_EXT_d2i() and *X509V3_get_d2i() return a pointer to an extension
199specific structure or B<NULL> if an error occurs.
200
201X509V3_EXT_i2d() returns a pointer to an B<X509_EXTENSION> structure
202or B<NULL> if an error occurs.
203
204X509V3_add1_i2d() returns 1 if the operation is successful and 0 if it
205fails due to a non-fatal error (extension not found, already exists,
206cannot be encoded) or -1 due to a fatal error such as a memory allocation
207failure.
208
209X509_get0_extensions(), X509_CRL_get0_extensions() and
210X509_REVOKED_get0_extensions() return a stack of extensions. They return
211NULL if no extensions are present.
212
213=head1 SEE ALSO
214
215L<d2i_X509(3)>,
216L<ERR_get_error(3)>,
217L<X509_CRL_get0_by_serial(3)>,
218L<X509_get0_signature(3)>,
219L<X509_get_ext_d2i(3)>,
220L<X509_get_extension_flags(3)>,
221L<X509_get_pubkey(3)>,
222L<X509_get_subject_name(3)>,
223L<X509_get_version(3)>,
224L<X509_NAME_add_entry_by_txt(3)>,
225L<X509_NAME_ENTRY_get_object(3)>,
226L<X509_NAME_get_index_by_NID(3)>,
227L<X509_NAME_print_ex(3)>,
228L<X509_new(3)>,
229L<X509_sign(3)>,
230L<X509_verify_cert(3)>
231
232=head1 COPYRIGHT
233
234Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
235
236Licensed under the Apache License 2.0 (the "License").  You may not use
237this file except in compliance with the License.  You can obtain a copy
238in the file LICENSE in the source distribution or at
239L<https://www.openssl.org/source/license.html>.
240
241=cut
242