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=head1 NAME

SSL_CTX_get0_param, SSL_get0_param, SSL_CTX_set1_param, SSL_set1_param,
SSL_CTX_set_purpose, SSL_CTX_set_trust, SSL_set_purpose, SSL_set_trust -
get and set verification parameters

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 X509_VERIFY_PARAM *SSL_CTX_get0_param(SSL_CTX *ctx);
 X509_VERIFY_PARAM *SSL_get0_param(SSL *ssl);
 int SSL_CTX_set1_param(SSL_CTX *ctx, X509_VERIFY_PARAM *vpm);
 int SSL_set1_param(SSL *ssl, X509_VERIFY_PARAM *vpm);

 int SSL_CTX_set_purpose(SSL_CTX *ctx, int purpose);
 int SSL_set_purpose(SSL *ssl, int purpose);

 int SSL_CTX_set_trust(SSL_CTX *ctx, int trust);
 int SSL_set_trust(SSL *ssl, int trust);

=head1 DESCRIPTION

SSL_CTX_get0_param() and SSL_get0_param() retrieve an internal pointer to
the verification parameters for B<ctx> or B<ssl> respectively. The returned
pointer must not be freed by the calling application.

SSL_CTX_set1_param() and SSL_set1_param() set the verification parameters
to B<vpm> for B<ctx> or B<ssl>.

The functions SSL_CTX_set_purpose() and SSL_set_purpose() are shorthands which
set the purpose parameter on the verification parameters object. These functions
are equivalent to calling X509_VERIFY_PARAM_set_purpose() directly.

The functions SSL_CTX_set_trust() and SSL_set_trust() are similarly shorthands
which set the trust parameter on the verification parameters object. These
functions are equivalent to calling X509_VERIFY_PARAM_set_trust() directly.

=head1 NOTES

Typically parameters are retrieved from an B<SSL_CTX> or B<SSL> structure
using SSL_CTX_get0_param() or SSL_get0_param() and an application modifies
them to suit its needs: for example to add a hostname check.

=head1 RETURN VALUES

SSL_CTX_get0_param() and SSL_get0_param() return a pointer to an
B<X509_VERIFY_PARAM> structure.

SSL_CTX_set1_param(), SSL_set1_param(), SSL_CTX_set_purpose(),
SSL_set_purpose(), SSL_CTX_set_trust() and SSL_set_trust() return 1 for success
and 0 for failure.

=head1 EXAMPLES

Check hostname matches "www.foo.com" in peer certificate:

 X509_VERIFY_PARAM *vpm = SSL_get0_param(ssl);
 X509_VERIFY_PARAM_set1_host(vpm, "www.foo.com", 0);

=head1 SEE ALSO

L<ssl(7)>,
L<X509_VERIFY_PARAM_set_flags(3)>

=head1 HISTORY

These functions were added in OpenSSL 1.0.2.

=head1 COPYRIGHT

Copyright 2015-2022 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
L<https://www.openssl.org/source/license.html>.

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