X509_EXTENSION_SET_OBJECT(3ossl)

🎀 X509_EXTENSION_SET_OBJECT 🎀

okay bestie, welcome to the 3ossl manual page for X509_EXTENSION_SET_OBJECT — extension utility functions and your new fave little squad. this is where we set an extension’s object, criticality, and data; create extensions by NID or OBJ; and get all that info back out. no cap, we’re in the extension internals now. 💅

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✨ NAME ✨

extension utility functions, bestie — say hi to the whole squad:

• X509_EXTENSION_set_object — sets the extension object.
• X509_EXTENSION_set_critical — sets the criticality.
• X509_EXTENSION_set_data — sets the extension data.
• X509_EXTENSION_create_by_NID — creates an extension by NID.
• X509_EXTENSION_create_by_OBJ — creates an extension by OBJ.
• X509_EXTENSION_get_object — gets the extension object.
• X509_EXTENSION_get_critical — gets the criticality.
• X509_EXTENSION_get_data — gets the extension data.

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🧚 SYNOPSIS 🧚

        int X509_EXTENSION_set_object(X509_EXTENSION *ex, const ASN1_OBJECT *obj);
        int X509_EXTENSION_set_critical(X509_EXTENSION *ex, int crit);
        int X509_EXTENSION_set_data(X509_EXTENSION *ex, ASN1_OCTET_STRING *data);

        X509_EXTENSION *X509_EXTENSION_create_by_NID(X509_EXTENSION **ex,
                                                     int nid, int crit,
                                                     ASN1_OCTET_STRING *data);
        X509_EXTENSION *X509_EXTENSION_create_by_OBJ(X509_EXTENSION **ex,
                                                     const ASN1_OBJECT *obj, int crit,
                                                     ASN1_OCTET_STRING *data);

        ASN1_OBJECT *X509_EXTENSION_get_object(X509_EXTENSION *ex);
        int X509_EXTENSION_get_critical(const X509_EXTENSION *ex);
        ASN1_OCTET_STRING *X509_EXTENSION_get_data(X509_EXTENSION *ne);

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💖 DESCRIPTION 💖

• X509_EXTENSION_set_object() — sets the extension type of ex to obj. the obj pointer is duplicated internally, so obj should be freed up after use. 🫶
• X509_EXTENSION_set_critical() — sets the criticality of ex to crit. if crit is zero, the extension is non-critical; otherwise it is critical. 🔥
• X509_EXTENSION_set_data() — sets the data in extension ex to data. the data pointer is duplicated internally. 🎀
• X509_EXTENSION_create_by_NID() — creates an extension of type nid, criticality crit, using data as the data. the created extension is returned and written to *ex, reusing or allocating a new extension if necessary, so *ex should either be NULL or a valid X509_EXTENSION structure — it must not be an uninitialised pointer. ⚠️
• X509_EXTENSION_create_by_OBJ() — identical to X509_EXTENSION_create_by_NID(), except it creates an extension using obj instead of a NID. 💅
• X509_EXTENSION_get_object() — returns the extension type of ex as an ASN1_OBJECT pointer. the returned pointer is an internal value which must not be freed up. 🦋
• X509_EXTENSION_get_critical() — returns the criticality of extension ex; it returns 1 for critical and 0 for non-critical. ✨
• X509_EXTENSION_get_data() — returns the data of extension ex. the returned pointer is an internal value which must not be freed up. 🌸

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🔥 NOTES 🔥

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 X509_add1_ext_i2d() and X509_get_ext_d2i(). 👑

direct manipulation is a thing you can do, bestie, but most apps should take the encode/decode route instead. iykyk. 💀

the data associated with an extension is the extension encoding in an ASN1_OCTET_STRING structure. 🧚

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🌈 RETURN VALUES 🌈

• X509_EXTENSION_set_object(), X509_EXTENSION_set_critical(), and X509_EXTENSION_set_data() return 1 for success and 0 for failure. 🫶
• X509_EXTENSION_create_by_NID() and X509_EXTENSION_create_by_OBJ() return an X509_EXTENSION pointer or NULL if an error occurs. 😭
• X509_EXTENSION_get_object() returns an ASN1_OBJECT pointer. ⭐
• X509_EXTENSION_get_critical() returns 0 for non-critical and 1 for critical. 💜
• X509_EXTENSION_get_data() returns an ASN1_OCTET_STRING pointer. 🎀

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🦋 SEE ALSO 🦋

• X509V3_get_d2i(3) — go read that one too, bestie. 💖

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👑 COPYRIGHT 👑

Copyright 2015-2016 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>. 💅

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that’s the whole page, bestie 🫶 this beauty is from OpenSSL source version 3.5.6, dated 2026-04-07 — footer handled, periodt. 🎀