openssl/doc/man3/X509V3_get_d2i.pod
Damian Hobson-Garcia 1eeec94f1f x509_acert: Add and retrieve certificate extensions
Add API to manage attribute certificate extensions

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15857)
2024-04-24 14:05:35 +01:00

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=pod
=head1 NAME
X509V3_get_d2i, X509V3_add1_i2d, X509V3_EXT_d2i, X509V3_EXT_i2d,
X509_get_ext_d2i, X509_add1_ext_i2d,
X509_ACERT_get_ext_d2i, X509_ACERT_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_ACERT_get0_extensions, X509_CRL_get0_extensions,
X509_REVOKED_get0_extensions - X509 extension decode and encode functions
=head1 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_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_ACERT_get_ext_d2i(const X509_ACERT *x, int nid, int *crit, int *idx);
int X509_ACERT_add1_ext_i2d(X509_ACERT *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_ACERT_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<nid> in the extensions
I<x> and, if found, decodes it. If I<idx> 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<crit> 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<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 I<value> to STACK I<*x> (allocating a new
STACK if necessary) using OID I<nid> and criticality I<crit> according
to I<flags>.
X509V3_EXT_d2i() attempts to decode the ASN.1 data contained in extension
I<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 I<ext_struc>
with OID I<ext_nid> and criticality I<crit>.
X509_get_ext_d2i() and X509_add1_ext_i2d() operate on the extensions of
certificate I<x>. They are otherwise identical to X509V3_get_d2i() and
X509V3_add1_i2d().
X509_ACERT_get_ext_d2i() and X509_ACERT_add1_ext_i2d() operate on the extensions
of B<X509_ACERT> structure I<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 I<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 B<X509_REVOKED> structure I<r> (i.e for CRL entry extensions).
They are otherwise identical to X509V3_get_d2i() and X509V3_add1_i2d().
X509_get0_extensions(), X509_ACERT_get0_extensions(),
X509_CRL_get0_extensions() and X509_REVOKED_get0_extensions() return a
STACK of all the extensions of a certificate, an attribute 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<idx> parameter is usually NULL.
The I<flags> parameter may be one of the following values.
B<X509V3_ADD_DEFAULT> appends a new extension only if the extension does
not exist. An error is returned if the extension exists.
B<X509V3_ADD_APPEND> appends a new extension, ignoring whether the extension
exists.
B<X509V3_ADD_REPLACE> replaces an existing extension. If the extension does
not exist, appends a new extension.
B<X509V3_ADD_REPLACE_EXISTING> replaces an existing extension. If the
extension does not exist, returns an error.
B<X509V3_ADD_KEEP_EXISTING> appends a new extension only if the extension does
not exist. An error is B<not> returned if the extension exists.
B<X509V3_ADD_DELETE> deletes and frees an existing extension. If the extension
does not exist, returns an error. No new extension is added.
If B<X509V3_ADD_SILENT> is bitwise ORed with I<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 I<*crit>.
The function X509V3_add1_i2d() and its variants allocate B<X509_EXTENSION>
objects on STACK I<*x> depending on I<flags>. The B<X509_EXTENSION> 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<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.
=head1 SEE ALSO
L<d2i_X509(3)>,
L<ERR_get_error(3)>,
L<X509_CRL_get0_by_serial(3)>,
L<X509_get0_signature(3)>,
L<X509_get_ext_d2i(3)>,
L<X509_get_extension_flags(3)>,
L<X509_get_pubkey(3)>,
L<X509_get_subject_name(3)>,
L<X509_get_version(3)>,
L<X509_NAME_add_entry_by_txt(3)>,
L<X509_NAME_ENTRY_get_object(3)>,
L<X509_NAME_get_index_by_NID(3)>,
L<X509_NAME_print_ex(3)>,
L<X509_new(3)>,
L<X509_sign(3)>,
L<X509_verify_cert(3)>
=head1 COPYRIGHT
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
L<https://www.openssl.org/source/license.html>.
=cut