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=head1 NAME

SSL_set0_CA_list, SSL_CTX_set0_CA_list, SSL_get0_CA_list,
SSL_CTX_get0_CA_list, SSL_add1_to_CA_list, SSL_CTX_add1_to_CA_list,
SSL_get0_peer_CA_list - get or set CA list

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 void SSL_CTX_set0_CA_list(SSL_CTX *ctx, STACK_OF(X509_NAME) *name_list);
 void SSL_set0_CA_list(SSL *s, STACK_OF(X509_NAME) *name_list);
 const STACK_OF(X509_NAME) *SSL_CTX_get0_CA_list(const SSL_CTX *ctx);
 const STACK_OF(X509_NAME) *SSL_get0_CA_list(const SSL *s);
 int SSL_CTX_add1_to_CA_list(SSL_CTX *ctx, const X509 *x);
 int SSL_add1_to_CA_list(SSL *ssl, const X509 *x);

 const STACK_OF(X509_NAME) *SSL_get0_peer_CA_list(const SSL *s);

=head1 DESCRIPTION

SSL_CTX_set0_CA_list() sets the list of CAs to be sent to the peer to
B<name_list>. Ownership of B<name_list> is transferred to B<ctx> and
it should not be freed by the caller.

SSL_set0_CA_list() sets the list of CAs to be sent to the peer to B<name_list>
overriding any list set in the parent B<SSL_CTX> of B<s>. Ownership of
B<name_list> is transferred to B<s> and it should not be freed by the caller.

SSL_CTX_get0_CA_list() retrieves any previously set list of CAs set for
B<ctx>.

SSL_CTX_get0_CA_list() retrieves any previously set list of CAs set for
B<s> or if none are set the list from the parent B<SSL_CTX> is retrieved.

SSL_CTX_add1_to_CA_list() appends the CA subject name extracted from B<x> to the
list of CAs sent to peer for B<ctx>.

SSL_add1_to_CA_list() appends the CA subject name extracted from B<x> to the
list of CAs sent to the peer for B<s>, overriding the setting in the parent
B<SSL_CTX>.

SSL_get0_peer_CA_list() retrieves the list of CA names (if any) the peer
has sent.

=head1 NOTES

These functions are generalised versions of the client authentication
CA list functions such as L<SSL_CTX_set_client_CA_list(3)>.

For TLS versions before 1.3 the list of CA names is only sent from the server
to client when requesting a client certificate. So any list of CA names set
is never sent from client to server and the list of CA names retrieved by
SSL_get0_peer_CA_list() is always B<NULL>.

For TLS 1.3 the list of CA names is sent using the B<certificate_authorities>
extension and will be sent by a client (in the ClientHello message) or by
a server (when requesting a certificate).

=head1 RETURN VALUES

SSL_CTX_set0_CA_list() and SSL_set0_CA_list() do not return a value.

SSL_CTX_get0_CA_list() and SSL_get0_CA_list() return a stack of CA names
or B<NULL> is no CA names are set.

SSL_CTX_add1_to_CA_list() and SSL_add1_to_CA_list() return 1 for success and 0
for failure.

SSL_get0_peer_CA_list() returns a stack of CA names sent by the peer or
B<NULL> or an empty stack if no list was sent.

=head1 SEE ALSO

L<ssl(7)>,
L<SSL_CTX_set_client_CA_list(3)>,
L<SSL_get_client_CA_list(3)>,
L<SSL_load_client_CA_file(3)>,
L<SSL_CTX_load_verify_locations(3)>

=head1 COPYRIGHT

Copyright 2017-2018 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
L<https://www.openssl.org/source/license.html>.

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