NAME

       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

SYNOPSIS

        #include <openssl/x509_vfy.h>

        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 *store,
                                X509 *x509, 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(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(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(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(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);

DESCRIPTION

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

       X509_STORE_CTX_new() returns a newly initialised X509_STORE_CTX structure.

       X509_STORE_CTX_cleanup() internally cleans up an X509_STORE_CTX structure.  The context
       can then be reused with an new call to X509_STORE_CTX_init().

       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 After this call ctx is no longer valid.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(), i.e. a ctx is only good for one call to
       X509_verify_cert(); if you want to verify a second certificate with the same ctx then you
       must call X509_STORE_CTX_cleanup() and then X509_STORE_CTX_init() again before the second
       call to X509_verify_cert(). The trusted certificate store is set to store, the end entity
       certificate to be verified is set to x509 and a set of additional certificates (which will
       be untrusted but may be used to build the chain) in chain. Any or all of the store, x509
       and chain parameters can be NULL.

       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 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 a 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 point to the stack of untrusted
       certificates associated with ctx to sk.

       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().

       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.

NOTES

       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.

BUGS

       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.

RETURN VALUES

       X509_STORE_CTX_new() returns an newly allocates context or NULL is 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.

SEE ALSO

       X509_verify_cert(3) X509_VERIFY_PARAM_set_flags(3)

HISTORY

       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.

COPYRIGHT

       Copyright 2009-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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>.