Cryptography and SSL/TLS Toolkit



X509_STORE_CTX_new_ex, X509_STORE_CTX_new, X509_STORE_CTX_cleanup, X509_STORE_CTX_free, X509_STORE_CTX_init, X509_STORE_CTX_set0_trusted_stack, X509_STORE_CTX_set_cert, X509_STORE_CTX_set0_crls, X509_STORE_CTX_get0_chain, X509_STORE_CTX_set0_verified_chain, X509_STORE_CTX_get0_param, X509_STORE_CTX_set0_param, X509_STORE_CTX_get0_untrusted, X509_STORE_CTX_set0_untrusted, X509_STORE_CTX_get_num_untrusted, X509_STORE_CTX_set_default, X509_STORE_CTX_set_verify, X509_STORE_CTX_verify_fn - X509_STORE_CTX initialisation


 #include <openssl/x509_vfy.h>

 X509_STORE_CTX *X509_STORE_CTX_new_ex(OSSL_LIB_CTX *libctx, const char *propq);
 X509_STORE_CTX *X509_STORE_CTX_new(void);
 void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx);
 void X509_STORE_CTX_free(X509_STORE_CTX *ctx);

 int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *trust_store,
                         X509 *target, STACK_OF(X509) *chain);

 void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk);

 void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *x);
 STACK_OF(X509) *X509_STORE_CTX_get0_chain(const X509_STORE_CTX *ctx);
 void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *chain);
 void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk);

 X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(const X509_STORE_CTX *ctx);
 void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param);
 int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name);

 STACK_OF(X509)* X509_STORE_CTX_get0_untrusted(const X509_STORE_CTX *ctx);
 void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk);

 int X509_STORE_CTX_get_num_untrusted(const X509_STORE_CTX *ctx);

 typedef int (*X509_STORE_CTX_verify_fn)(X509_STORE_CTX *);
 void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx, X509_STORE_CTX_verify_fn verify);


These functions initialise an X509_STORE_CTX structure for subsequent use by X509_verify_cert(3) or X509_STORE_CTX_verify(3).

X509_STORE_CTX_new_ex() returns a newly initialised X509_STORE_CTX structure associated with the specified library context libctx and property query string propq. Any cryptographic algorithms fetched while performing processing with the X509_STORE_CTX will use that library context and property query string.

X509_STORE_CTX_new() is the same as X509_STORE_CTX_new_ex() except that the default library context and a NULL property query string are used.

X509_STORE_CTX_cleanup() internally cleans up an X509_STORE_CTX structure. It is used by X509_STORE_CTX_init() and X509_STORE_CTX_free().

X509_STORE_CTX_free() completely frees up ctx. After this call ctx is no longer valid. If ctx is NULL nothing is done.

X509_STORE_CTX_init() sets up ctx for a subsequent verification operation. It must be called before each call to X509_verify_cert(3) or X509_STORE_CTX_verify(3), i.e., a context is only good for one verification. If you want to verify a further certificate or chain with the same ctx then you must call X509_STORE_CTX_init() again. The trusted certificate store is set to trust_store of type X509_STORE. This may be NULL because there are no trusted certificates or because they are provided simply as a list using X509_STORE_CTX_set0_trusted_stack(). The certificate to be verified is set to target, and a list of additional certificates may be provided in chain, which will be untrusted but may be used to build the chain. Each of the trust_store, target and chain parameters can be NULL. Yet note that X509_verify_cert(3) and X509_STORE_CTX_verify(3) will need a verification target. This can also be set using X509_STORE_CTX_set_cert(). For X509_STORE_CTX_verify(3), which takes by default the first element of the list of untrusted certificates as its verification target, this can be also set indirectly using X509_STORE_CTX_set0_untrusted().

X509_STORE_CTX_set0_trusted_stack() sets the set of trusted certificates of ctx to sk. This is an alternative way of specifying trusted certificates instead of using an X509_STORE.

X509_STORE_CTX_set_cert() sets the target certificate to be verified in ctx to x.

X509_STORE_CTX_set0_verified_chain() sets the validated chain used by ctx to be chain. Ownership of the chain is transferred to ctx and should not be free'd by the caller. X509_STORE_CTX_get0_chain() returns the internal pointer used by the ctx that contains the validated chain.

X509_STORE_CTX_set0_crls() sets a set of CRLs to use to aid certificate verification to sk. These CRLs will only be used if CRL verification is enabled in the associated X509_VERIFY_PARAM structure. This might be used where additional "useful" CRLs are supplied as part of a protocol, for example in a PKCS#7 structure.

X509_STORE_CTX_get0_param() retrieves an internal pointer to the verification parameters associated with ctx.

X509_STORE_CTX_get0_untrusted() retrieves an internal pointer to the stack of untrusted certificates associated with ctx.

X509_STORE_CTX_set0_untrusted() sets the internal pointer to the stack of untrusted certificates associated with ctx to sk. X509_STORE_CTX_verify() will take the first element, if any, as its default target if the target certificate is not set explicitly.

X509_STORE_CTX_set0_param() sets the internal verification parameter pointer to param. After this call param should not be used.

X509_STORE_CTX_set_default() looks up and sets the default verification method to name. This uses the function X509_VERIFY_PARAM_lookup() to find an appropriate set of parameters from name.

X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates that were used in building the chain following a call to X509_verify_cert(3). With X509_STORE_CTX_verify(3), this does not count the first chain element.

X509_STORE_CTX_set_verify() provides the capability for overriding the default verify function. This function is responsible for verifying chain signatures and expiration times.

A verify function is defined as an X509_STORE_CTX_verify type which has the following signature:

 int (*verify)(X509_STORE_CTX *);

This function should receive the current X509_STORE_CTX as a parameter and return 1 on success or 0 on failure.


The certificates and CRLs in a store are used internally and should not be freed up until after the associated X509_STORE_CTX is freed.


The certificates and CRLs in a context are used internally and should not be freed up until after the associated X509_STORE_CTX is freed. Copies should be made or reference counts increased instead.


X509_STORE_CTX_new() returns a newly allocated context or NULL if an error occurred.

X509_STORE_CTX_init() returns 1 for success or 0 if an error occurred.

X509_STORE_CTX_get0_param() returns a pointer to an X509_VERIFY_PARAM structure or NULL if an error occurred.

X509_STORE_CTX_cleanup(), X509_STORE_CTX_free(), X509_STORE_CTX_set0_trusted_stack(), X509_STORE_CTX_set_cert(), X509_STORE_CTX_set0_crls() and X509_STORE_CTX_set0_param() do not return values.

X509_STORE_CTX_set_default() returns 1 for success or 0 if an error occurred.

X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates used.


X509_verify_cert(3), X509_STORE_CTX_verify(3), X509_VERIFY_PARAM_set_flags(3)


The X509_STORE_CTX_set0_crls() function was added in OpenSSL 1.0.0. The X509_STORE_CTX_get_num_untrusted() function was added in OpenSSL 1.1.0. The X509_STORE_CTX_new_ex() function was added in OpenSSL 3.0.

There is no need to call X509_STORE_CTX_cleanup() explicitly since OpenSSL 3.0.

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