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(X609_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 After this call ctx is no longer valid.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

       X509_STORE_CTX_set0_crls() was first added to OpenSSL 1.0.0 X509_STORE_CTX_get_num_untrusted() was first
       added to 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>.