SSL_SET1_PARAM(3)

💖 SSL_SET1_PARAM(3) — get & set verification parameters 💖

okay so bestie, this one's from the Library Functions Manual and it's literally all about the little knob-board that controls how TLS verification behaves. let's get into it ✨

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🎀 NAME 🎀

SSL_CTX_get0_param, SSL_get0_param, SSL_CTX_set1_param, SSL_set1_param — get and set verification parameters, that's the whole vibe 🫶

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✨ SYNOPSIS ✨

she lives in library “libssl” libcrypto, so you're gonna want:

#include <openssl/ssl.h>

then the four little icons themselves:

X509_VERIFY_PARAM *
SSL_CTX_get0_param(SSL_CTX *ctx);

X509_VERIFY_PARAM *
SSL_get0_param(SSL *ssl);

int
SSL_CTX_set1_param(SSL_CTX *ctx, X509_VERIFY_PARAM *vpm);

int
SSL_set1_param(SSL *ssl, X509_VERIFY_PARAM *vpm);

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🌸 DESCRIPTION 🌸

the getters 💅

SSL_CTX_get0_param() and SSL_get0_param() retrieve an internal pointer to the verification parameters for ctx or ssl, respectively. like, an internal pointer, okay? 👑

⚠️ the returned pointer must not be freed by the calling application — not yours to yeet, bestie. but the application can modify the parameters pointed to, to suit its needs: for example to add a hostname check. so you get to redecorate, you just can't demolish the building 🏠✨

the setters 🦋

SSL_CTX_set1_param() and SSL_set1_param() set the verification parameters to vpm for ctx or ssl. straightforward, no notes, ate 💅

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⭐ RETURN VALUES ⭐

• SSL_CTX_get0_param() and SSL_get0_param() return a pointer to an X509_VERIFY_PARAM structure. cute little handoff 🎀
• SSL_CTX_set1_param() and SSL_set1_param() return 1 for success or 0 for failure. classic 1-or-0 energy, no cap 🫶

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🌈 EXAMPLES 🌈

say you wanna check that the hostname matches www.foo.com in the peer certificate — iconique behavior, honestly:

X509_VERIFY_PARAM *vpm = SSL_get0_param(ssl);
X509_VERIFY_PARAM_set1_host(vpm, "www.foo.com", 0);

see how we grabbed the internal pointer and just... used it? main character energy fr fr 💜

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🔥 SEE ALSO 🔥

• ssl(3)
• X509_VERIFY_PARAM_set_flags(3)

go read those too, iykyk 🌸

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👑 HISTORY 👑

• SSL_CTX_set1_param() and SSL_set1_param() first appeared in OpenSSL 1.0.0 and have been available since OpenBSD 4.9. old money 💀
• SSL_CTX_get0_param() and SSL_get0_param() first appeared in OpenSSL 1.0.2 and have been available since OpenBSD 6.3. late bloomer but slayed 🦋

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k that's the page!! brought to you by Debian, dated June 8, 2025 — go forth and verify those params, bestie, ily, mwah 💖🎀✨