X509_EXTENSION_SET_OBJECT(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 X509_EXTENSION_SET_OBJECT — extension utility functions

okay so this is page X509_EXTENSION_SET_OBJECT(3ossl) from the OpenSSL manual, and it's literally all about poking at X509 extensions by hand — setting the object, setting criticality, setting data, creating them by NID or OBJ, and reading all that stuff back out. bestie, let's get into it 💖

✨ NAME ✨

X509_EXTENSION_set_object, X509_EXTENSION_set_critical, X509_EXTENSION_set_data, X509_EXTENSION_create_by_NID, X509_EXTENSION_create_by_OBJ, X509_EXTENSION_get_object, X509_EXTENSION_get_critical, X509_EXTENSION_get_data — extension utility functions 🎀

🌸 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);

🦋 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. like, it made its own copy, you don't gotta babysit it 💅

X509_EXTENSION_set_critical() sets the criticality of ex to crit. If crit is zero the extension is non-critical, otherwise it is critical. that's the whole vibe check: 0 = chill, not-0 = critical, main character energy 👑

X509_EXTENSION_set_data() sets the data in extension ex to data. The data pointer is duplicated internally. again, copied, so you're not on the hook for it ✨

X509_EXTENSION_create_by_NID() creates an extension of type nid, criticality crit, using data 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 🙈 (that would be giving unhinged behaviour, and not the cute kind)

X509_EXTENSION_create_by_OBJ() is identical to X509_EXTENSION_create_by_NID() except it creates an extension using obj instead of a NID. same energy, different input 🫶

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 — hands off, it's not yours, no cap 💀

X509_EXTENSION_get_critical() returns the criticality of extension ex. It returns 1 for critical and 0 for non-critical. simple as 🍓

X509_EXTENSION_get_data() returns the data of extension ex. The returned pointer is an internal value which must not be freed up. same rule, don't touch 😭

🧚 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(). lowkey important — if you're out here hand-assembling extensions when the encode/decode functions exist, that's a choice ❤️‍🔥

The data associated with an extension is the extension encoding in an ASN1_OCTET_STRING structure. that's the whole point of the data field, iykyk 🌈

⭐ RETURN VALUES ⭐

  • X509_EXTENSION_set_object(), X509_EXTENSION_set_critical() and X509_EXTENSION_set_data() return 1 for success and 0 for failure. slay or flop, no in-between 💅
  • 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. 🌸

🔥 SEE ALSO 🔥

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>.

okay that's the whole page, bestie — you're officially an extension manipulator 💖✨

and a cute lil sign-off for the footer: this was OpenSSL version 3.5.0, dated 2026-09-25, and the page is X509_EXTENSION_SET_OBJECT(3ossl). periodt 🎀🫶

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