X509V3_GET_D2I(3)

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

SYNOPSIS
#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);
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);

DESCRIPTION
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 is 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 it is 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 with OID ext_nid and criticality crit.

X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of certificate x, and 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, and 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 the X509_REVOKED structure r (i.e. for CRL entry extensions), and 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 already exist. An error is returned if the extension does already exist.

X509V3_ADD_APPEND appends a new extension, ignoring whether the extension already exists.

X509V3_ADD_REPLACE replaces an extension if it exists otherwise appends a new extension.

X509V3_ADD_REPLACE_EXISTING replaces an existing extension if it exists otherwise returns an error.

X509V3_ADD_KEEP_EXISTING appends a new extension only if the extension does not already exist. An error is not returned if the extension does already exist.

X509V3_ADD_DELETE deletes extension nid. No new extension is added.

If X509V3_ADD_SILENT is OR'd with flags, any error returned will not be added to the error queue.

The function X509V3_get_d2i() 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.

SUPPORTED EXTENSIONS
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 RFC 5280.
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

  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 RFC 5280.
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 RFC 5280.
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 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

RETURN VALUES
X509V3_get_d2i(), X509V3_EXT_d2i(), X509_get_ext_d2i(), X509_CRL_get_ext_d2i(), and X509_REVOKED_get_ext_d2i() return a pointer to an extension specific structure or NULL if an error occurs.

X509V3_add1_i2d(), X509_add1_ext_i2d(), X509_CRL_add1_ext_i2d(), and X509_REVOKED_add1_ext_i2d() return 1 if the operation is successful, 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. In some cases of failure, the reason can be determined with ERR_get_error(3).

The X509V3_EXT_i2d() function returns a pointer to an X509_EXTENSION structure if successful; otherwise NULL is returned and an error code can be retrieved with ERR_get_error(3).

X509_get0_extensions(), X509_CRL_get0_extensions(), and X509_REVOKED_get0_extensions() return a stack of extensions, or NULL if no extensions are present.

SEE ALSO
d2i_X509(3), d2i_X509_EXTENSION(3), X509_check_purpose(3), X509_CRL_get0_by_serial(3), X509_CRL_new(3), X509_EXTENSION_new(3), X509_get_pubkey(3), X509_get_subject_name(3), X509_get_version(3), X509_new(3), X509_REVOKED_new(3), X509V3_EXT_print(3), X509V3_extensions_print(3)

HISTORY
X509V3_EXT_d2i() first appeared in OpenSSL 0.9.2b. X509V3_EXT_i2d() first appeared in OpenSSL 0.9.3. Both functions have been available since OpenBSD 2.6.

X509V3_get_d2i(), X509_get_ext_d2i(), X509_CRL_get_ext_d2i(), and X509_REVOKED_get_ext_d2i() first appeared in OpenSSL 0.9.5 and have been available since OpenBSD 2.7.

X509V3_add1_i2d(), X509_add1_ext_i2d(), X509_CRL_add1_ext_i2d(), and X509_REVOKED_add1_ext_i2d() first appeared in OpenSSL 0.9.7 and have been available since OpenBSD 3.2.

X509_get0_extensions(), X509_CRL_get0_extensions(), and X509_REVOKED_get0_extensions() first appeared in OpenSSL 1.1.0 and have been available since OpenBSD 6.3.