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 #include <openssl/x509v3.h> 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); X509V3_get_d2i() looks for an extension with OID nid in the extensions x and, if found, decodes it. If idx is NULL then only one occurrence of an extension is permissible, otherwise the first extension after index *idx is returned and *idx updated to the location of the extension. If crit is not NULL then *crit is set to a status value: -2 if the extension occurs multiple times (this is only returned if idx 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 value to STACK *x (allocating a new STACK if necessary) using OID nid and criticality crit according to flags. X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension ext 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 ext_struc with OID ext_nid and criticality crit. X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of certificate x. 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 crl. 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 X509_REVOKED structure r (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. In almost all cases an extension can occur at most once and multiple occurrences is an error. Therefore, the idx parameter is usually NULL. The flags parameter may be one of the following values. X509V3_ADD_DEFAULT appends a new extension only if the extension does not exist. An error is returned if the extension exists. X509V3_ADD_APPEND appends a new extension, ignoring whether the extension exists. X509V3_ADD_REPLACE replaces an existing extension. If the extension does not exist, appends a new extension. X509V3_ADD_REPLACE_EXISTING replaces an existing extension. If the extension does not exist, returns an error. X509V3_ADD_KEEP_EXISTING appends a new extension only if the extension does not exist. An error is not returned if the extension exists. X509V3_ADD_DELETE deletes and frees an existing extension. If the extension does not exist, returns an error. No new extension is added. If X509V3_ADD_SILENT is bitwise ORed with flags: 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 *crit. The function X509V3_add1_i2d() and its variants allocate X509_EXTENSION objects on STACK *x depending on flags. The X509_EXTENSION objects must be explicitly freed using X509_EXTENSION_free(). The following sections contain a list of all supported extensions including their name and NID.

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

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

Miscellaneous Certificate Extensions
Strong Extranet ID NID_sxnet Proxy Certificate Information NID_proxyCertInfo

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

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

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 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 X509_EXTENSION 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. d2i_X509(3), ERR_get_error(3), X509_CRL_get0_by_serial(3), X509_get0_signature(3), X509_get_ext_d2i(3), X509_get_extension_flags(3), X509_get_pubkey(3), X509_get_subject_name(3), X509_get_version(3), X509_NAME_add_entry_by_txt(3), X509_NAME_ENTRY_get_object(3), X509_NAME_get_index_by_NID(3), X509_NAME_print_ex(3), X509_new(3), X509_sign(3), X509_verify_cert(3) Copyright 2015-2022 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 <https://www.openssl.org/source/license.html>.