X509_STORE_S...ERIFY_CB_FUNC(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

🌸 NAME 🌸

okay bestie, welcome to the X509_STORE_S...ERIFY_CB_FUNC(3ossl) page from OpenSSL — part 1. The vibe is “set verification callback,” and the squad list is genuinely huge. Here’s the whole crew, no cap:

  • 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
  • X509_STORE_CTX_lookup_crls_fn

All of these are here to set a verification callback, and yes, it’s giving very “one page, many function names” energy. 💅

✨ SYNOPSIS ✨

#include <openssl/x509_vfy.h>

typedef int (*X509_STORE_CTX_get_issuer_fn)(X509 **issuer,
                                            X509_STORE_CTX *ctx, X509 *x);
typedef int (*X509_STORE_CTX_check_issued_fn)(X509_STORE_CTX *ctx,
                                              X509 *x, 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, 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 💖

So here’s the tea, function by function. Every setter has a job, every callback has rules, and the defaults are very much part of the story. 🫶

  • X509_STORE_set_verify_cb() — sets the verification callback of xs to verify_cb, overwriting the previous callback. The callback assigned with this function becomes a default for the one that can be assigned directly to the corresponding X509_STORE_CTX, please see X509_STORE_CTX_set_verify_cb(3) for further information.
  • X509_STORE_set_verify() — sets the final chain verification function for xs to verify. Its purpose is to go through the chain of certificates and check that all 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 no chain verification function is provided, 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 has the latest expiration date of all matching certificates. If the function returns 1 the caller is responsible for freeing *issuer. Note that this search does not support backtracking. 🦋
  • X509_STORE_set_get_issuer() — sets the function get_issuer that is 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.. 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. (And yes, the original really has two dots there — I’m not touching it. 🙈)
  • 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.

Then there’s the getter crew. The original list is a little chaotic — it mixes a couple of setters in there — but I’m keeping it exactly as written. 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 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.

And the alias moment: 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. ✨

🎀 NOTES 🎀

All the callbacks from a X509_STORE are inherited by the corresponding X509_STORE_CTX structure when it is initialized. See X509_STORE_CTX_set_verify_cb(3) for further details. 💖

💀 BUGS 💀

Okay so lowkey a fun fact: the macro version of this function was literally the only one that existed before OpenSSL 1.0.0. Like, that's all you got, bestie. No cap. 🫶

✨ RETURN VALUES ✨

So what comes back? Depends which flavour you're using, girlie:

  • The X509_STORE_set_*() functions do not return a value. Nope, nothing, void, they just do their lil thing and dip. 💅
  • The X509_STORE_get_*() functions return a pointer of the appropriate function type. Iconic behaviour, honestly.
  • X509_STORE_CTX_get1_issuer() is the ✨special✨ one with actual numbers:
    • 1 — a suitable certificate is found 🎉
    • 0 — not found 😭
    • -1 — some other error, don't ask 💀
Fr fr memorize those three values, because -1 and 0 are not the same vibe and mixing them up is a whole mess. 🙈

🦋 SEE ALSO 🦋

Go read these next, bestie — they're all in the group chat together:

🌸 HISTORY 🌸

Storytime. 📖 The X509_STORE_set_verify_cb() function was added in OpenSSL 1.0.0. So it's been around a minute, iykyk.

Then in OpenSSL 1.1.0, a whole ✨era✨ of functions dropped. Like, the entire friend group showed up at once:

  • X509_STORE_set_verify_cb() and X509_STORE_get_verify_cb()
  • X509_STORE_set_verify() and X509_STORE_CTX_get_verify() (yes babes, that one is CTX, not STORE — keep the exact spelling, don't come for me 💅)
  • X509_STORE_set_get_issuer() and X509_STORE_get_get_issuer()
  • X509_STORE_set_check_issued() and X509_STORE_get_check_issued()
  • X509_STORE_set_check_revocation() and X509_STORE_get_check_revocation()
  • X509_STORE_set_get_crl() and X509_STORE_get_get_crl()
  • X509_STORE_set_check_crl() and X509_STORE_get_check_crl()
  • X509_STORE_set_cert_crl() and X509_STORE_get_cert_crl()
  • X509_STORE_set_check_policy() and X509_STORE_get_check_policy()
  • X509_STORE_set_lookup_certs() and X509_STORE_get_lookup_certs()
  • X509_STORE_set_lookup_crls() and X509_STORE_get_lookup_crls()
  • X509_STORE_set_cleanup() and X509_STORE_get_cleanup()

All twelve pairs, all 1.1.0 babies. Slay. 🌈

Copyright 2009-2021 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>.

Like, actually read the license, bestie — "except in compliance with the License" is doing a lot of heavy lifting in that sentence. 🎀

And that's the whole page! 💖 This lil masterpiece is from the 3.5.0 release, dated 2026-09-2X, and the page itself is X509_STORE_S...ERIFY_CB_FUNC(3ossl). Bye babes, go verify something. 🦋✨

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