SSL_GET_EX_NEW_INDEX(3)

📦 version 4.4.0, in alpine 3.24, arch rolling

💅 SSL_GET_EX_NEW_INDEX(3) — the libssl/libcrypto glow-up

okay so bestie, this is one of those pages from the libssl / libcrypto manual set, and it's all about the little secret pocket dimension where OpenSSL structures keep your stuff 🎀 Like, the library has these big important structs, and sometimes you just wanna tuck a lil something of your own in there. That's what this is. Internal application-specific data functions, periodt.

✨ SYNOPSIS ✨

library “libssl” libcrypto #include <openssl/ssl.h>

int
SSL_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
    CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);

int
SSL_set_ex_data(SSL *ssl, int idx, void *arg);

void *
SSL_get_ex_data(const SSL *ssl, int idx);

typedef int new_func(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
               int idx, long argl, void *argp);
typedef void free_func(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
               int idx, long argl, void *argp);
typedef int dup_func(CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from, void *from_d,
               int idx, long argl, void *argp);

Like, vibe check those typedefs — new_func, free_func, dup_func — they're giving callback energy and honestly? iconic 🔥

🌸 DESCRIPTION 🌸

So. Several OpenSSL structures can have application specific data attached to them — like lil friendship bracelets only your app knows the meaning of 🫶 These functions here are used internally by OpenSSL to manipulate that application specific data attached to a specific structure.

  • SSL_get_ex_new_index() — registers a brand new index for application specific data. New index, new you, slay ✨
  • SSL_set_ex_data() — stores application data at arg for idx into the ssl object. It's giving "put it in the box, bestie" 💖
  • SSL_get_ex_data() — retrieves the information for idx from ssl. The box opens, your stuff is still there, we love to see it 👑

ngl, if you want the full tea on this stuff: a detailed description of the *_get_ex_new_index() functionality can be found in RSA_get_ex_new_index(3), and the *_get_ex_data() and *_set_ex_data() functionality is described in CRYPTO_set_ex_data(3). Go read those too, iykyk 💅

💀 EXAMPLES 💀

An example of how to use the functionality is included in the example verify_callback() in SSL_CTX_set_verify(3). Literally go look at it, it ate 🌈

🦋 SEE ALSO 🦋

👑 HISTORY 👑

Precursor functions SSL_set_app_data() and SSL_get_app_data() first appeared in SSLeay 0.6.1. Ancient. Historical. Respect the elders 🧚

Then SSL_get_ex_new_index(), SSL_set_ex_data(), and SSL_get_ex_data() first appeared in SSLeay 0.9.0 and have been available since OpenBSD 2.4. Not me being this well-traveled 😭💜

no cap, every flag, every signature, every path up there is copy-pasted from the real page on purpose — the vibe is mine, the facts are sacred 🍓

anyway that's the whole page, stan CRYPTO_EX_DATA, and remember: this beauty shipped from the Debian libssl/libcrypto manual set, dated June 8, 2025, page SSL_GET_EX_NEW_INDEX(3) — mwah 💋⭐

📦 where this page comes from