.\" $OpenBSD: X509_EXTENSION_set_object.3,v 1.18 2024/05/12 11:49:47 tb Exp $ .\" full merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2016, 2021 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: May 12 2024 $ .Dt X509_EXTENSION_SET_OBJECT 3 .Os .Sh NAME .Nm X509_EXTENSION_new , .Nm X509_EXTENSION_dup , .Nm X509_EXTENSION_free , .Nm X509_EXTENSION_create_by_NID , .Nm X509_EXTENSION_create_by_OBJ , .Nm X509_EXTENSION_set_object , .Nm X509_EXTENSION_set_critical , .Nm X509_EXTENSION_set_data , .Nm X509_EXTENSION_get_object , .Nm X509_EXTENSION_get_critical , .Nm X509_EXTENSION_get_data .\" In the next line, the capital "E" is not a typo. .\" The ASN.1 structure is called "Extension", not "extension". .Nd create, change, and inspect X.509 Extension objects .Sh SYNOPSIS .In openssl/x509.h .Ft X509_EXTENSION * .Fn X509_EXTENSION_new void .Ft X509_EXTENSION * .Fn X509_EXTENSION_dup "X509_EXTENSION *ex" .Ft void .Fn X509_EXTENSION_free "X509_EXTENSION *ex" .Ft X509_EXTENSION * .Fo X509_EXTENSION_create_by_NID .Fa "X509_EXTENSION **ex" .Fa "int nid" .Fa "int crit" .Fa "ASN1_OCTET_STRING *data" .Fc .Ft X509_EXTENSION * .Fo X509_EXTENSION_create_by_OBJ .Fa "X509_EXTENSION **ex" .Fa "const ASN1_OBJECT *obj" .Fa "int crit" .Fa "ASN1_OCTET_STRING *data" .Fc .Ft int .Fo X509_EXTENSION_set_object .Fa "X509_EXTENSION *ex" .Fa "const ASN1_OBJECT *obj" .Fc .Ft int .Fo X509_EXTENSION_set_critical .Fa "X509_EXTENSION *ex" .Fa "int crit" .Fc .Ft int .Fo X509_EXTENSION_set_data .Fa "X509_EXTENSION *ex" .Fa "ASN1_OCTET_STRING *data" .Fc .Ft ASN1_OBJECT * .Fo X509_EXTENSION_get_object .Fa "X509_EXTENSION *ex" .Fc .Ft int .Fo X509_EXTENSION_get_critical .Fa "const X509_EXTENSION *ex" .Fc .Ft ASN1_OCTET_STRING * .Fo X509_EXTENSION_get_data .Fa "X509_EXTENSION *ex" .Fc .Sh DESCRIPTION .Fn X509_EXTENSION_new allocates and initializes an empty .Vt X509_EXTENSION object, representing an ASN.1 .Vt Extension structure defined in RFC 5280 section 4.1. It is a wrapper object around specific extension objects of different types and stores an extension type identifier and a criticality flag in addition to the DER-encoded form of the wrapped object. .Vt X509_EXTENSION objects can be used for X.509 v3 certificates inside .Vt X509_CINF objects and for X.509 v2 certificate revocation lists inside .Vt X509_CRL_INFO and .Vt X509_REVOKED objects. .Pp .Fn X509_EXTENSION_dup creates a deep copy of .Fa ex using .Xr ASN1_item_dup 3 . .Pp .Fn X509_EXTENSION_free frees .Fa ex and all objects it is using. .Pp .Fn X509_EXTENSION_create_by_NID creates an extension of type .Fa nid and criticality .Fa crit using data .Fa data . The created extension is returned and written to .Pf * Fa ex reusing or allocating a new extension if necessary, so .Pf * Fa ex should either be .Dv NULL or a valid .Vt X509_EXTENSION structure. It must not be an uninitialised pointer. .Pp .Fn X509_EXTENSION_create_by_OBJ is identical to .Fn X509_EXTENSION_create_by_NID except that it creates an extension using .Fa obj instead of a NID. .Pp .Fn X509_EXTENSION_set_object sets the extension type of .Fa ex to .Fa obj . The .Fa obj pointer is duplicated internally so .Fa obj should be freed up after use. .Pp .Fn X509_EXTENSION_set_critical sets the criticality of .Fa ex to .Fa crit . If .Fa crit is zero, the extension in non-critical, otherwise it is critical. .Pp .Fn X509_EXTENSION_set_data sets the data in extension .Fa ex to .Fa data . The .Fa data pointer is duplicated internally. .Pp .Fn X509_EXTENSION_get_object returns the extension type of .Fa ex as an .Vt ASN1_OBJECT pointer. The returned pointer is an internal value which must not be freed up. .Pp .Fn X509_EXTENSION_get_critical returns the criticality of extension .Fa ex it returns 1 for critical and 0 for non-critical. .Pp .Fn X509_EXTENSION_get_data returns the data of extension .Fa ex . The returned pointer is an internal value which must not be freed up. .Pp These functions manipulate the contents of an extension directly. Most applications will want to parse or encode and add an extension: they should use the extension encode and decode functions instead such as .Xr X509_add1_ext_i2d 3 and .Xr X509_get_ext_d2i 3 . .Pp The .Fa data associated with an extension is the extension encoding in an .Vt ASN1_OCTET_STRING structure. .Sh RETURN VALUES .Fn X509_EXTENSION_new , .Fn X509_EXTENSION_dup , .Fn X509_EXTENSION_create_by_NID , and .Fn X509_EXTENSION_create_by_OBJ return an .Vt X509_EXTENSION pointer or .Dv NULL if an error occurs. .Pp .Fn X509_EXTENSION_set_object , .Fn X509_EXTENSION_set_critical , and .Fn X509_EXTENSION_set_data return 1 for success or 0 for failure. .Pp .Fn X509_EXTENSION_get_object returns an .Vt ASN1_OBJECT pointer. .Pp .Fn X509_EXTENSION_get_critical returns 0 for non-critical or 1 for critical. .Pp .Fn X509_EXTENSION_get_data returns an .Vt ASN1_OCTET_STRING pointer. .Sh SEE ALSO .Xr ACCESS_DESCRIPTION_new 3 , .Xr AUTHORITY_KEYID_new 3 , .Xr BASIC_CONSTRAINTS_new 3 , .Xr d2i_X509_EXTENSION 3 , .Xr DIST_POINT_new 3 , .Xr ESS_SIGNING_CERT_new 3 , .Xr EXTENDED_KEY_USAGE_new 3 , .Xr GENERAL_NAME_new 3 , .Xr NAME_CONSTRAINTS_new 3 , .Xr OCSP_CRLID_new 3 , .Xr OCSP_SERVICELOC_new 3 , .Xr PKEY_USAGE_PERIOD_new 3 , .Xr POLICYINFO_new 3 , .Xr TS_REQ_new 3 , .Xr X509_check_ca 3 , .Xr X509_check_host 3 , .Xr X509_check_issued 3 , .Xr X509_get_extension_flags 3 , .Xr X509_REQ_add_extensions 3 , .Xr X509V3_EXT_get_nid 3 , .Xr X509V3_EXT_print 3 , .Xr X509V3_extensions_print 3 , .Xr X509V3_get_d2i 3 , .Xr X509v3_get_ext_by_NID 3 .Sh STANDARDS RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile .Sh HISTORY .Fn X509_EXTENSION_new and .Fn X509_EXTENSION_free first appeared in SSLeay 0.6.2, .Fn X509_EXTENSION_dup in SSLeay 0.6.5, and .Fn X509_EXTENSION_create_by_NID , .Fn X509_EXTENSION_create_by_OBJ , .Fn X509_EXTENSION_set_object , .Fn X509_EXTENSION_set_critical , .Fn X509_EXTENSION_set_data , .Fn X509_EXTENSION_get_object , .Fn X509_EXTENSION_get_critical , and .Fn X509_EXTENSION_get_data in SSLeay 0.8.0. These functions have been available since .Ox 2.4 .