X509_STORE_SET_VERIFY_CB_FUNC(3SSL)
🌸 X509_STORE_SET_VERIFY_CB_FUNC(3SSL) 🌸
okay bestie, welcome to the OpenSSL manual page for X509_STORE_SET_VERIFY_CB_FUNC — 3SSL section, the whole verification-callback squad. grab a boba, this one's a long one and it comes in two parts 💖
✨ NAME ✨
so this page is the group chat for a whole roster of setter/getter-type functions, and their shared mission is set verification callback. the complete lineup is: X509_STORE_set_lookup_crls_cb, X509_STORE_set_verify_func, X509_STORE_get_cleanup, X509_STORE_set_cleanup, X509_STORE_get_lookup_crls, X509_STORE_set_lookup_crls, X509_STORE_get_lookup_certs, X509_STORE_set_lookup_certs, X509_STORE_get_check_policy, X509_STORE_set_check_policy, X509_STORE_get_cert_crl, X509_STORE_set_cert_crl, X509_STORE_get_check_crl, X509_STORE_set_check_crl, X509_STORE_get_get_crl, X509_STORE_set_get_crl, X509_STORE_get_check_revocation, X509_STORE_set_check_revocation, X509_STORE_get_check_issued, X509_STORE_set_check_issued, X509_STORE_CTX_get1_issuer, X509_STORE_get_get_issuer, X509_STORE_set_get_issuer, X509_STORE_CTX_get_verify, X509_STORE_set_verify, X509_STORE_get_verify_cb, X509_STORE_set_verify_cb_func, X509_STORE_set_verify_cb, X509_STORE_CTX_cert_crl_fn, X509_STORE_CTX_check_crl_fn, X509_STORE_CTX_check_issued_fn, X509_STORE_CTX_check_policy_fn, X509_STORE_CTX_check_revocation_fn, X509_STORE_CTX_cleanup_fn, X509_STORE_CTX_get_crl_fn, X509_STORE_CTX_get_issuer_fn, X509_STORE_CTX_lookup_certs_fn and X509_STORE_CTX_lookup_crls_fn. 💅
✨ SYNOPSIS ✨
#include <openssl/x509_vfy.h>
typedef int (*X509_STORE_CTX_get_issuer_fn)(X509 **issuer,
X509_STORE_CTX *ctx, const X509 *x);
typedef int (*X509_STORE_CTX_check_issued_fn)(X509_STORE_CTX *ctx,
const X509 *x, const X509 *issuer);
typedef int (*X509_STORE_CTX_check_revocation_fn)(X509_STORE_CTX *ctx);
typedef int (*X509_STORE_CTX_get_crl_fn)(X509_STORE_CTX *ctx,
X509_CRL **crl, X509 *x);
typedef int (*X509_STORE_CTX_check_crl_fn)(X509_STORE_CTX *ctx, X509_CRL *crl);
typedef int (*X509_STORE_CTX_cert_crl_fn)(X509_STORE_CTX *ctx,
X509_CRL *crl, X509 *x);
typedef int (*X509_STORE_CTX_check_policy_fn)(X509_STORE_CTX *ctx);
typedef STACK_OF(X509) *(*X509_STORE_CTX_lookup_certs_fn)(X509_STORE_CTX *ctx,
const X509_NAME *nm);
typedef STACK_OF(X509_CRL) *(*X509_STORE_CTX_lookup_crls_fn)(const
X509_STORE_CTX *ctx,
const X509_NAME *nm);
typedef int (*X509_STORE_CTX_cleanup_fn)(X509_STORE_CTX *ctx);
void X509_STORE_set_verify_cb(X509_STORE *xs,
X509_STORE_CTX_verify_cb verify_cb);
X509_STORE_CTX_verify_cb X509_STORE_get_verify_cb(const X509_STORE_CTX *ctx);
void X509_STORE_set_verify(X509_STORE *xs, X509_STORE_CTX_verify_fn verify);
X509_STORE_CTX_verify_fn X509_STORE_CTX_get_verify(const X509_STORE_CTX *ctx);
int X509_STORE_CTX_get1_issuer(X509 **issuer, X509_STORE_CTX *ctx, const X509 *x);
X509_STORE_CTX_get_issuer_fn X509_STORE_get_get_issuer(const X509_STORE_CTX *ctx);
void X509_STORE_set_get_issuer(X509_STORE *xs,
X509_STORE_CTX_get_issuer_fn get_issuer);
void X509_STORE_set_check_issued(X509_STORE *xs,
X509_STORE_CTX_check_issued_fn check_issued);
X509_STORE_CTX_check_issued_fn
X509_STORE_get_check_issued(const X509_STORE_CTX *ctx);
void X509_STORE_set_check_revocation(X509_STORE *xs,
X509_STORE_CTX_check_revocation_fn check_revocation);
X509_STORE_CTX_check_revocation_fn
X509_STORE_get_check_revocation(const X509_STORE_CTX *ctx);
void X509_STORE_set_get_crl(X509_STORE *xs,
X509_STORE_CTX_get_crl_fn get_crl);
X509_STORE_CTX_get_crl_fn X509_STORE_get_get_crl(const X509_STORE_CTX *ctx);
void X509_STORE_set_check_crl(X509_STORE *xs,
X509_STORE_CTX_check_crl_fn check_crl);
X509_STORE_CTX_check_crl_fn
X509_STORE_get_check_crl(const X509_STORE_CTX *ctx);
void X509_STORE_set_cert_crl(X509_STORE *xs,
X509_STORE_CTX_cert_crl_fn cert_crl);
X509_STORE_CTX_cert_crl_fn X509_STORE_get_cert_crl(const X509_STORE_CTX *ctx);
void X509_STORE_set_check_policy(X509_STORE *xs,
X509_STORE_CTX_check_policy_fn check_policy);
X509_STORE_CTX_check_policy_fn
X509_STORE_get_check_policy(const X509_STORE_CTX *ctx);
void X509_STORE_set_lookup_certs(X509_STORE *xs,
X509_STORE_CTX_lookup_certs_fn lookup_certs);
X509_STORE_CTX_lookup_certs_fn
X509_STORE_get_lookup_certs(const X509_STORE_CTX *ctx);
void X509_STORE_set_lookup_crls(X509_STORE *xs,
X509_STORE_CTX_lookup_crls_fn lookup_crls);
X509_STORE_CTX_lookup_crls_fn
X509_STORE_get_lookup_crls(const X509_STORE_CTX *ctx);
void X509_STORE_set_cleanup(X509_STORE *xs,
X509_STORE_CTX_cleanup_fn cleanup);
X509_STORE_CTX_cleanup_fn X509_STORE_get_cleanup(const X509_STORE_CTX *ctx);
/* Aliases */
void X509_STORE_set_verify_cb_func(X509_STORE *st,
X509_STORE_CTX_verify_cb verify_cb);
void X509_STORE_set_verify_func(X509_STORE *xs,
X509_STORE_CTX_verify_fn verify);
void X509_STORE_set_lookup_crls_cb(X509_STORE *xs,
X509_STORE_CTX_lookup_crls_fn lookup_crls);✨ DESCRIPTION ✨
X509_STORE_set_verify_cb() sets the verification callback of xs to verify_cb, and yeah it straight-up overwrites whatever callback was there before, no hesitation. the callback you assign with this function becomes a default for the one that can be assigned directly to the corresponding X509_STORE_CTX — so if you wanna know more about that whole situation, go peek at X509_STORE_CTX_set_verify_cb(3). 👑
X509_STORE_set_verify() sets the final chain verification function for xs to verify. its whole purpose? go through the chain of certificates and check that all the signatures are valid and that the current time is within the limits of each certificate's first and last validity time. ⏰ the final chain verification functions must return 0 on failure and 1 on success. if you don't provide a chain verification function, the internal default function will be used instead.
X509_STORE_CTX_get1_issuer() tries to find a certificate from the store component of ctx that has a subject name matching the issuer name of x and is accepted by the check_issued function in ctx. on success it assigns to *issuer the first match that has a suitable validity period, or otherwise the one with the latest expiration date of all matching certificates. if the function returns 1, the caller is responsible for freeing *issuer. and note bestie: this search does not support backtracking. 🚫🔙
X509_STORE_set_get_issuer() sets the function get_issuer that's used to get the "best" candidate issuer certificate of the given certificate x. when such a certificate is found, get_issuer must up-ref and assign it to *issuer and then return 1. otherwise get_issuer must return 0 if not found, and -1 (or 0) on failure. if X509_STORE_set_get_issuer() is not used or get_issuer is NULL, then X509_STORE_CTX_get1_issuer() is used as the default implementation. 🦋
X509_STORE_set_check_issued() sets the function to check that a given certificate x is issued by the issuer certificate issuer. this function must return 0 on failure (among others, if x hasn't been issued with issuer) and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_check_revocation() sets the revocation checking function. its purpose is to look through the final chain and check the revocation status for each certificate. it must return 0 on failure and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_get_crl() sets the function to get the crl for a given certificate x. when found, the crl must be assigned to *crl. this function must return 0 on failure and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_check_crl() sets the function to check the validity of the given crl. this function must return 0 on failure and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_cert_crl() sets the function to check the revocation status of the given certificate x against the given crl. this function must return 0 on failure and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_check_policy() sets the function to check the policies of all the certificates in the final chain.. (yes the double dot is canon, don't @ me 💀). this function must return 0 on failure and 1 on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_lookup_certs() and X509_STORE_set_lookup_crls() set the functions to look up all the certs or all the CRLs that match the given name nm. these functions return NULL on failure and a pointer to a stack of certificates (X509) or to a stack of CRLs (X509_CRL) on success. if no function to get the issuer is provided, the internal default function will be used instead.
X509_STORE_set_cleanup() sets the final cleanup function, which is called when the context (X509_STORE_CTX) is being torn down. this function doesn't return any value. if no function to get the issuer is provided, the internal default function will be used instead. 🧹
so about the getter squad: X509_STORE_get_verify_cb(), X509_STORE_CTX_get_verify(), X509_STORE_get_get_issuer(), X509_STORE_get_check_issued(), X509_STORE_get_check_revocation(), X509_STORE_get_get_crl(), X509_STORE_get_check_crl(), X509_STORE_set_verify(), X509_STORE_set_get_issuer(), X509_STORE_get_cert_crl(), X509_STORE_get_check_policy(), X509_STORE_get_lookup_certs(), X509_STORE_get_lookup_crls() and X509_STORE_get_cleanup() — all of them return the function pointer assigned with X509_STORE_set_check_issued(), X509_STORE_set_check_revocation(), X509_STORE_set_get_crl(), X509_STORE_set_check_crl(), X509_STORE_set_cert_crl(), X509_STORE_set_check_policy(), X509_STORE_set_lookup_certs(), X509_STORE_set_lookup_crls() and X509_STORE_set_cleanup(), or NULL if no assignment has been made. that's a whole mouthful but you got it. 🫶
and finally, the aliases: X509_STORE_set_verify_cb_func(), X509_STORE_set_verify_func() and X509_STORE_set_lookup_crls_cb() are aliases for X509_STORE_set_verify_cb(), X509_STORE_set_verify() and X509_STORE_set_lookup_crls, available as macros for backward compatibility. iconic legacy behavior, honestly. ✨
✨ NOTES ✨
okay so here's the tea: all the callbacks from an X509_STORE are inherited by the corresponding X509_STORE_CTX structure when it is initialized. so they don't just disappear into the void, they get passed down like family recipes. 🫶 see X509_STORE_CTX_set_verify_cb(3) for further details, bestie.
part 1 of 2 — more coming your way, don't go anywhere 💅
💀 BUGS 💀
Ok so minor lore drop: back in the day — like, before OpenSSL 1.0.0 — the macro version of this function was literally the only one that existed. No function version, no choice, just the macro. That's the whole bug/limitation bestie. Ancient history, but there it is. 🫠
🎀 RETURN VALUES 🎀
Here's the tea on what you actually get back:
- The
X509_STORE_set_*()functions do not return a value — nope, nothing, not even a little guy. Don't go assigning them to anything, it's giving void. 💀 - The
X509_STORE_get_*()functions hand you back a pointer of the appropriate function type. So like, you get a function pointer, and it's the right kind of function pointer. Slay. ✨ X509_STORE_CTX_get1_issuer()is the one with actual numbers to report:- Returns
1if a suitable certificate is found 🎉 - Returns
0if it's not found 🙈 - Returns
-1on other error 😭
- Returns
ngl the1/0/-1situation is very much "read the docs before youif (ret)this one," iykyk.-1is truthy in C, bestie. Be careful. 💅
🦋 SEE ALSO 🦋
Go read these next, they're all part of the same little friend group:
X509_STORE_CTX_set_verify_cb(3)X509_STORE_CTX_get0_chain(3)X509_STORE_CTX_verify_cb(3)X509_STORE_CTX_verify_fn(3)CMS_verify(3)
🌸 HISTORY 🌸
Storytime, because this function has main character energy going all the way back:
X509_STORE_set_verify_cb()was added in OpenSSL 1.0.0. Baby's first appearance. 👑
And then in OpenSSL 1.1.0, a whole squad got added at once — a full glow-up moment. Here's every single one, no skipping any besties:
X509_STORE_set_verify_cb()X509_STORE_get_verify_cb()X509_STORE_set_verify()X509_STORE_CTX_get_verify()X509_STORE_set_get_issuer()X509_STORE_get_get_issuer()X509_STORE_set_check_issued()X509_STORE_get_check_issued()X509_STORE_set_check_revocation()X509_STORE_get_check_revocation()X509_STORE_set_get_crl()X509_STORE_get_get_crl()X509_STORE_set_check_crl()X509_STORE_get_check_crl()X509_STORE_set_cert_crl()X509_STORE_get_cert_crl()X509_STORE_set_check_policy()X509_STORE_get_check_policy()X509_STORE_set_lookup_certs()X509_STORE_get_lookup_certs()X509_STORE_set_lookup_crls()X509_STORE_get_lookup_crls()X509_STORE_set_cleanup()X509_STORE_get_cleanup()
twenty-four functions. one release. iconic behaviour, honestly. 🌈✨
📜 COPYRIGHT 📜
Gotta give credit where credit is due, bestie:
Copyright 2009-2026 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>.
fr fr, read the license before you ship it. that's not me being dramatic, that's just the rules. 💅
and that's a wrap on this page!! it's from the OpenSSL 4.0.3 docs, dated 2026-09-2X — so like, extremely fresh, very demure, very mindful. go forth and set your verify callbacks, bestie, you've got this 🫶🌸💖
📦 where this page comes from
- ubuntu stonking: libssl-doc 4.0.3-1ubuntu1 · Apache-2.0
- 💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on : a language model's rewrite of the original, under its terms