=pod =head1 NAME X509V3_get_d2i, X509V3_add1_i2d, X509V3_EXT_d2i, X509V3_EXT_i2d, X509_get_ext_d2i, X509_add1_ext_i2d, X509_CRL_get_ext_d2i, X509_CRL_add1_ext_i2d, X509_REVOKED_get_ext_d2i, X509_REVOKED_add1_ext_i2d, X509_get0_extensions, X509_CRL_get0_extensions, X509_REVOKED_get0_extensions - X509 extension decode and encode functions =head1 SYNOPSIS #include void *X509V3_get_d2i(const STACK_OF(X509_EXTENSION) *x, int nid, int *crit, int *idx); int X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid, void *value, int crit, unsigned long flags); void *X509V3_EXT_d2i(X509_EXTENSION *ext); X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit, void *ext_struc); void *X509_get_ext_d2i(const X509 *x, int nid, int *crit, int *idx); int X509_add1_ext_i2d(X509 *x, int nid, void *value, int crit, unsigned long flags); void *X509_CRL_get_ext_d2i(const X509_CRL *crl, int nid, int *crit, int *idx); int X509_CRL_add1_ext_i2d(X509_CRL *crl, int nid, void *value, int crit, unsigned long flags); void *X509_REVOKED_get_ext_d2i(const X509_REVOKED *r, int nid, int *crit, int *idx); int X509_REVOKED_add1_ext_i2d(X509_REVOKED *r, int nid, void *value, int crit, unsigned long flags); const STACK_OF(X509_EXTENSION) *X509_get0_extensions(const X509 *x); const STACK_OF(X509_EXTENSION) *X509_CRL_get0_extensions(const X509_CRL *crl); const STACK_OF(X509_EXTENSION) *X509_REVOKED_get0_extensions(const X509_REVOKED *r); =head1 DESCRIPTION X509V3_get_d2i() looks for an extension with OID I in the extensions I and, if found, decodes it. If I is NULL then only one occurrence of an extension is permissible, otherwise the first extension after index I<*idx> is returned and I<*idx> updated to the location of the extension. If I is not NULL then I<*crit> is set to a status value: -2 if the extension occurs multiple times (this is only returned if I is NULL), -1 if the extension could not be found, 0 if the extension is found and is not critical and 1 if critical. A pointer to an extension specific structure or NULL is returned. X509V3_add1_i2d() adds extension I to STACK I<*x> (allocating a new STACK if necessary) using OID I and criticality I according to I. X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension I and returns a pointer to an extension specific structure or NULL if the extension could not be decoded (invalid syntax or not supported). X509V3_EXT_i2d() encodes the extension specific structure I with OID I and criticality I. X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of certificate I. They are otherwise identical to X509V3_get_d2i() and X509V3_add1_i2d(). X509_CRL_get_ext_d2i() and X509_CRL_add1_ext_i2d() operate on the extensions of CRL I. They are otherwise identical to X509V3_get_d2i() and X509V3_add1_i2d(). X509_REVOKED_get_ext_d2i() and X509_REVOKED_add1_ext_i2d() operate on the extensions of B structure I (i.e for CRL entry extensions). They are otherwise identical to X509V3_get_d2i() and X509V3_add1_i2d(). X509_get0_extensions(), X509_CRL_get0_extensions() and X509_REVOKED_get0_extensions() return a STACK of all the extensions of a certificate, a CRL or a CRL entry respectively. =head1 NOTES In almost all cases an extension can occur at most once and multiple occurrences is an error. Therefore, the I parameter is usually NULL. The I parameter may be one of the following values. B appends a new extension only if the extension does not exist. An error is returned if the extension exists. B appends a new extension, ignoring whether the extension exists. B replaces an existing extension. If the extension does not exist, appends a new extension. B replaces an existing extension. If the extension does not exist, returns an error. B appends a new extension only if the extension does not exist. An error is B returned if the extension exists. B deletes and frees an existing extension. If the extension does not exist, returns an error. No new extension is added. If B is bitwise ORed with I: any error returned will not be added to the error queue. The function X509V3_get_d2i() and its variants will return NULL if the extension is not found, occurs multiple times or cannot be decoded. It is possible to determine the precise reason by checking the value of I<*crit>. The returned pointer must be explicitly freed. The function X509V3_add1_i2d() and its variants allocate B objects on STACK I<*x> depending on I. The B objects must be explicitly freed using X509_EXTENSION_free(). =head1 SUPPORTED EXTENSIONS The following sections contain a list of all supported extensions including their name and NID. =head2 PKIX Certificate Extensions The following certificate extensions are defined in PKIX standards such as RFC5280. Basic Constraints NID_basic_constraints Key Usage NID_key_usage Extended Key Usage NID_ext_key_usage Subject Key Identifier NID_subject_key_identifier Authority Key Identifier NID_authority_key_identifier Private Key Usage Period NID_private_key_usage_period Subject Alternative Name NID_subject_alt_name Issuer Alternative Name NID_issuer_alt_name Authority Information Access NID_info_access Subject Information Access NID_sinfo_access Name Constraints NID_name_constraints Certificate Policies NID_certificate_policies Policy Mappings NID_policy_mappings Policy Constraints NID_policy_constraints Inhibit Any Policy NID_inhibit_any_policy TLS Feature NID_tlsfeature =head2 Netscape Certificate Extensions The following are (largely obsolete) Netscape certificate extensions. Netscape Cert Type NID_netscape_cert_type Netscape Base Url NID_netscape_base_url Netscape Revocation Url NID_netscape_revocation_url Netscape CA Revocation Url NID_netscape_ca_revocation_url Netscape Renewal Url NID_netscape_renewal_url Netscape CA Policy Url NID_netscape_ca_policy_url Netscape SSL Server Name NID_netscape_ssl_server_name Netscape Comment NID_netscape_comment =head2 Miscellaneous Certificate Extensions Strong Extranet ID NID_sxnet Proxy Certificate Information NID_proxyCertInfo =head2 PKIX CRL Extensions The following are CRL extensions from PKIX standards such as RFC5280. CRL Number NID_crl_number CRL Distribution Points NID_crl_distribution_points Delta CRL Indicator NID_delta_crl Freshest CRL NID_freshest_crl Invalidity Date NID_invalidity_date Issuing Distribution Point NID_issuing_distribution_point The following are CRL entry extensions from PKIX standards such as RFC5280. CRL Reason Code NID_crl_reason Certificate Issuer NID_certificate_issuer =head2 OCSP Extensions OCSP Nonce NID_id_pkix_OCSP_Nonce OCSP CRL ID NID_id_pkix_OCSP_CrlID Acceptable OCSP Responses NID_id_pkix_OCSP_acceptableResponses OCSP No Check NID_id_pkix_OCSP_noCheck OCSP Archive Cutoff NID_id_pkix_OCSP_archiveCutoff OCSP Service Locator NID_id_pkix_OCSP_serviceLocator Hold Instruction Code NID_hold_instruction_code =head2 Certificate Transparency Extensions The following extensions are used by certificate transparency, RFC6962 CT Precertificate SCTs NID_ct_precert_scts CT Certificate SCTs NID_ct_cert_scts =head1 RETURN VALUES X509V3_get_d2i(), its variants, and X509V3_EXT_d2i() return a pointer to an extension specific structure or NULL if an error occurs. X509V3_add1_i2d() and its variants return 1 if the operation is successful and 0 if it fails due to a non-fatal error (extension not found, already exists, cannot be encoded) or -1 due to a fatal error such as a memory allocation failure. X509V3_EXT_i2d() returns a pointer to an B structure or NULL if an error occurs. X509_get0_extensions(), X509_CRL_get0_extensions() and X509_REVOKED_get0_extensions() return a stack of extensions. They return NULL if no extensions are present. =head1 SEE ALSO L, L, L, L, L, L, L, L, L, L, L, L, L, L, L, L =head1 COPYRIGHT Copyright 2015-2024 The OpenSSL Project Authors. All Rights Reserved. Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L. =cut