1=pod 2 3=head1 NAME 4 5X509V3_get_d2i, X509V3_add1_i2d, X509V3_EXT_d2i, X509V3_EXT_i2d, 6X509_get_ext_d2i, X509_add1_ext_i2d, 7X509_ACERT_get_ext_d2i, X509_ACERT_add1_ext_i2d, 8X509_CRL_get_ext_d2i, X509_CRL_add1_ext_i2d, 9X509_REVOKED_get_ext_d2i, X509_REVOKED_add1_ext_i2d, 10X509_get0_extensions, X509_ACERT_get0_extensions, X509_CRL_get0_extensions, 11X509_REVOKED_get0_extensions - X509 extension decode and encode functions 12 13=head1 SYNOPSIS 14 15 #include <openssl/x509v3.h> 16 17 void *X509V3_get_d2i(const STACK_OF(X509_EXTENSION) *x, int nid, int *crit, 18 int *idx); 19 int X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid, void *value, 20 int crit, unsigned long flags); 21 22 void *X509V3_EXT_d2i(X509_EXTENSION *ext); 23 X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit, void *ext_struc); 24 25 void *X509_get_ext_d2i(const X509 *x, int nid, int *crit, int *idx); 26 int X509_add1_ext_i2d(X509 *x, int nid, void *value, int crit, 27 unsigned long flags); 28 29 void *X509_ACERT_get_ext_d2i(const X509_ACERT *x, int nid, int *crit, int *idx); 30 int X509_ACERT_add1_ext_i2d(X509_ACERT *x, int nid, void *value, int crit, 31 unsigned long flags); 32 33 void *X509_CRL_get_ext_d2i(const X509_CRL *crl, int nid, int *crit, int *idx); 34 int X509_CRL_add1_ext_i2d(X509_CRL *crl, int nid, void *value, int crit, 35 unsigned long flags); 36 37 void *X509_REVOKED_get_ext_d2i(const X509_REVOKED *r, int nid, int *crit, int *idx); 38 int X509_REVOKED_add1_ext_i2d(X509_REVOKED *r, int nid, void *value, int crit, 39 unsigned long flags); 40 41 const STACK_OF(X509_EXTENSION) *X509_get0_extensions(const X509 *x); 42 const STACK_OF(X509_EXTENSION) *X509_ACERT_get0_extensions(const X509 *x); 43 const STACK_OF(X509_EXTENSION) *X509_CRL_get0_extensions(const X509_CRL *crl); 44 const STACK_OF(X509_EXTENSION) *X509_REVOKED_get0_extensions(const X509_REVOKED *r); 45 46=head1 DESCRIPTION 47 48X509V3_get_d2i() looks for an extension with OID I<nid> in the extensions 49I<x> and, if found, decodes it. If I<idx> is NULL then only one 50occurrence of an extension is permissible, otherwise the first extension after 51index I<*idx> is returned and I<*idx> updated to the location of the extension. 52If I<crit> is not NULL then I<*crit> is set to a status value: -2 if the 53extension occurs multiple times (this is only returned if I<idx> is NULL), 54-1 if the extension could not be found, 0 if the extension is found and is 55not critical and 1 if critical. A pointer to an extension specific structure 56or NULL is returned. 57 58X509V3_add1_i2d() adds extension I<value> to STACK I<*x> (allocating a new 59STACK if necessary) using OID I<nid> and criticality I<crit> according 60to I<flags>. 61 62X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension 63I<ext> and returns a pointer to an extension specific structure or NULL 64if the extension could not be decoded (invalid syntax or not supported). 65 66X509V3_EXT_i2d() encodes the extension specific structure I<ext_struc> 67with OID I<ext_nid> and criticality I<crit>. 68 69X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of 70certificate I<x>. They are otherwise identical to X509V3_get_d2i() and 71X509V3_add1_i2d(). 72 73X509_ACERT_get_ext_d2i() and X509_ACERT_add1_ext_i2d() operate on the extensions 74of B<X509_ACERT> structure I<x>. They are otherwise identical to X509V3_get_d2i() 75and X509V3_add1_i2d(). 76 77X509_CRL_get_ext_d2i() and X509_CRL_add1_ext_i2d() operate on the extensions 78of CRL I<crl>. They are otherwise identical to X509V3_get_d2i() and 79X509V3_add1_i2d(). 80 81X509_REVOKED_get_ext_d2i() and X509_REVOKED_add1_ext_i2d() operate on the 82extensions of B<X509_REVOKED> structure I<r> (i.e for CRL entry extensions). 83They are otherwise identical to X509V3_get_d2i() and X509V3_add1_i2d(). 84 85X509_get0_extensions(), X509_ACERT_get0_extensions(), 86X509_CRL_get0_extensions() and X509_REVOKED_get0_extensions() return a 87STACK of all the extensions of a certificate, an attribute certificate, 88a CRL or a CRL entry respectively. 89 90=head1 NOTES 91 92In almost all cases an extension can occur at most once and multiple 93occurrences is an error. Therefore, the I<idx> parameter is usually NULL. 94 95The I<flags> parameter may be one of the following values. 96 97B<X509V3_ADD_DEFAULT> appends a new extension only if the extension does 98not exist. An error is returned if the extension exists. 99 100B<X509V3_ADD_APPEND> appends a new extension, ignoring whether the extension 101exists. 102 103B<X509V3_ADD_REPLACE> replaces an existing extension. If the extension does 104not exist, appends a new extension. 105 106B<X509V3_ADD_REPLACE_EXISTING> replaces an existing extension. If the 107extension does not exist, returns an error. 108 109B<X509V3_ADD_KEEP_EXISTING> appends a new extension only if the extension does 110not exist. An error is B<not> returned if the extension exists. 111 112B<X509V3_ADD_DELETE> deletes and frees an existing extension. If the extension 113does not exist, returns an error. No new extension is added. 114 115If B<X509V3_ADD_SILENT> is bitwise ORed with I<flags>: any error returned 116will not be added to the error queue. 117 118The function X509V3_get_d2i() and its variants 119will return NULL if the extension is not 120found, occurs multiple times or cannot be decoded. It is possible to 121determine the precise reason by checking the value of I<*crit>. 122 123The function X509V3_add1_i2d() and its variants allocate B<X509_EXTENSION> 124objects on STACK I<*x> depending on I<flags>. The B<X509_EXTENSION> objects 125must be explicitly freed using X509_EXTENSION_free(). 126 127=head1 SUPPORTED EXTENSIONS 128 129The following sections contain a list of all supported extensions 130including their name and NID. 131 132=head2 PKIX Certificate Extensions 133 134The following certificate extensions are defined in PKIX standards such as 135RFC5280. 136 137 Basic Constraints NID_basic_constraints 138 Key Usage NID_key_usage 139 Extended Key Usage NID_ext_key_usage 140 141 Subject Key Identifier NID_subject_key_identifier 142 Authority Key Identifier NID_authority_key_identifier 143 144 Private Key Usage Period NID_private_key_usage_period 145 146 Subject Alternative Name NID_subject_alt_name 147 Issuer Alternative Name NID_issuer_alt_name 148 149 Authority Information Access NID_info_access 150 Subject Information Access NID_sinfo_access 151 152 Name Constraints NID_name_constraints 153 154 Certificate Policies NID_certificate_policies 155 Policy Mappings NID_policy_mappings 156 Policy Constraints NID_policy_constraints 157 Inhibit Any Policy NID_inhibit_any_policy 158 159 TLS Feature NID_tlsfeature 160 161=head2 Netscape Certificate Extensions 162 163The following are (largely obsolete) Netscape certificate extensions. 164 165 Netscape Cert Type NID_netscape_cert_type 166 Netscape Base Url NID_netscape_base_url 167 Netscape Revocation Url NID_netscape_revocation_url 168 Netscape CA Revocation Url NID_netscape_ca_revocation_url 169 Netscape Renewal Url NID_netscape_renewal_url 170 Netscape CA Policy Url NID_netscape_ca_policy_url 171 Netscape SSL Server Name NID_netscape_ssl_server_name 172 Netscape Comment NID_netscape_comment 173 174=head2 Miscellaneous Certificate Extensions 175 176 Strong Extranet ID NID_sxnet 177 Proxy Certificate Information NID_proxyCertInfo 178 179=head2 PKIX CRL Extensions 180 181The following are CRL extensions from PKIX standards such as RFC5280. 182 183 CRL Number NID_crl_number 184 CRL Distribution Points NID_crl_distribution_points 185 Delta CRL Indicator NID_delta_crl 186 Freshest CRL NID_freshest_crl 187 Invalidity Date NID_invalidity_date 188 Issuing Distribution Point NID_issuing_distribution_point 189 190The following are CRL entry extensions from PKIX standards such as RFC5280. 191 192 CRL Reason Code NID_crl_reason 193 Certificate Issuer NID_certificate_issuer 194 195=head2 OCSP Extensions 196 197 OCSP Nonce NID_id_pkix_OCSP_Nonce 198 OCSP CRL ID NID_id_pkix_OCSP_CrlID 199 Acceptable OCSP Responses NID_id_pkix_OCSP_acceptableResponses 200 OCSP No Check NID_id_pkix_OCSP_noCheck 201 OCSP Archive Cutoff NID_id_pkix_OCSP_archiveCutoff 202 OCSP Service Locator NID_id_pkix_OCSP_serviceLocator 203 Hold Instruction Code NID_hold_instruction_code 204 205=head2 Certificate Transparency Extensions 206 207The following extensions are used by certificate transparency, RFC6962 208 209 CT Precertificate SCTs NID_ct_precert_scts 210 CT Certificate SCTs NID_ct_cert_scts 211 212=head1 RETURN VALUES 213 214X509V3_get_d2i(), its variants, and X509V3_EXT_d2i() return 215a pointer to an extension specific structure or NULL if an error occurs. 216 217X509V3_add1_i2d() and its variants return 1 if the operation is successful 218and 0 if it fails due to a non-fatal error (extension not found, already exists, 219cannot be encoded) or -1 due to a fatal error such as a memory allocation 220failure. 221 222X509V3_EXT_i2d() returns a pointer to an B<X509_EXTENSION> structure 223or NULL if an error occurs. 224 225X509_get0_extensions(), X509_CRL_get0_extensions() and 226X509_REVOKED_get0_extensions() return a stack of extensions. They return 227NULL if no extensions are present. 228 229=head1 SEE ALSO 230 231L<d2i_X509(3)>, 232L<ERR_get_error(3)>, 233L<X509_CRL_get0_by_serial(3)>, 234L<X509_get0_signature(3)>, 235L<X509_get_ext_d2i(3)>, 236L<X509_get_extension_flags(3)>, 237L<X509_get_pubkey(3)>, 238L<X509_get_subject_name(3)>, 239L<X509_get_version(3)>, 240L<X509_NAME_add_entry_by_txt(3)>, 241L<X509_NAME_ENTRY_get_object(3)>, 242L<X509_NAME_get_index_by_NID(3)>, 243L<X509_NAME_print_ex(3)>, 244L<X509_new(3)>, 245L<X509_sign(3)>, 246L<X509_verify_cert(3)> 247 248=head1 COPYRIGHT 249 250Copyright 2015-2022 The OpenSSL Project Authors. All Rights Reserved. 251 252Licensed under the Apache License 2.0 (the "License"). You may not use 253this file except in compliance with the License. You can obtain a copy 254in the file LICENSE in the source distribution or at 255L<https://www.openssl.org/source/license.html>. 256 257=cut 258
