SSL_CTX_SET0_CA_LIST(3) OpenSSL SSL_CTX_SET0_CA_LIST(3)
NAME
SSL_CTX_set_client_CA_list, SSL_set_client_CA_list,
SSL_get_client_CA_list, SSL_CTX_get_client_CA_list,
SSL_CTX_add_client_CA, SSL_add_client_CA, 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
SYNOPSIS
#include <openssl/ssl.h>
void SSL_CTX_set_client_CA_list(SSL_CTX *ctx, STACK_OF(X509_NAME) *list);
void SSL_set_client_CA_list(SSL *s, STACK_OF(X509_NAME) *list);
STACK_OF(X509_NAME) *SSL_get_client_CA_list(const SSL *s);
STACK_OF(X509_NAME) *SSL_CTX_get_client_CA_list(const SSL_CTX *ctx);
int SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *cacert);
int SSL_add_client_CA(SSL *ssl, X509 *cacert);
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);
DESCRIPTION
The functions described here set and manage the list of CA names that
are sent between two communicating peers.
For TLS versions 1.2 and earlier the list of CA names is only sent from
the server to the 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 NULL.
For TLS 1.3 the list of CA names is sent using the
certificate_authorities extension and may be sent by a client (in the
ClientHello message) or by a server (when requesting a certificate).
In most cases it is not necessary to set CA names on the client side.
The list of CA names that are acceptable to the client will be sent in
plaintext to the server. This has privacy implications and may also
have performance implications if the list is large. This optional
capability was introduced as part of TLSv1.3 and therefore setting CA
names on the client side will have no impact if that protocol version
has been disabled. Most servers do not need this and so this should be
avoided unless required.
The "client CA list" functions below only have an effect when called on
the server side.
SSL_CTX_set_client_CA_list() sets the list of CAs sent to the client
when requesting a client certificate for ctx. Ownership of list is
transferred to ctx and it should not be freed by the caller.
SSL_set_client_CA_list() sets the list of CAs sent to the client when
requesting a client certificate for the chosen ssl, overriding the
setting valid for ssl's SSL_CTX object. Ownership of list is
transferred to s and it should not be freed by the caller.
SSL_CTX_get_client_CA_list() returns the list of client CAs explicitly
set for ctx using SSL_CTX_set_client_CA_list(). The returned list
should not be freed by the caller.
SSL_get_client_CA_list() returns the list of client CAs explicitly set
for ssl using SSL_set_client_CA_list() or ssl's SSL_CTX object with
SSL_CTX_set_client_CA_list(), when in server mode. In client mode,
SSL_get_client_CA_list returns the list of client CAs sent from the
server, if any. The returned list should not be freed by the caller.
SSL_CTX_add_client_CA() adds the CA name extracted from cacert to the
list of CAs sent to the client when requesting a client certificate for
ctx.
SSL_add_client_CA() adds the CA name extracted from cacert to the list
of CAs sent to the client when requesting a client certificate for the
chosen ssl, overriding the setting valid for ssl's SSL_CTX object.
SSL_get0_peer_CA_list() retrieves the list of CA names (if any) the
peer has sent. This can be called on either the server or the client
side. The returned list should not be freed by the caller.
The "generic CA list" functions below are very similar to the "client
CA list" functions except that they have an effect on both the server
and client sides. The lists of CA names managed are separate - so you
cannot (for example) set CA names using the "client CA list" functions
and then get them using the "generic CA list" functions. Where a mix of
the two types of functions has been used on the server side then the
"client CA list" functions take precedence. Typically, on the server
side, the "client CA list " functions should be used in preference. As
noted above in most cases it is not necessary to set CA names on the
client side.
SSL_CTX_set0_CA_list() sets the list of CAs to be sent to the peer to
name_list. Ownership of name_list is transferred to 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
name_list overriding any list set in the parent SSL_CTX of s. Ownership
of name_list is transferred to s and it should not be freed by the
caller.
SSL_CTX_get0_CA_list() retrieves any previously set list of CAs set for
ctx. The returned list should not be freed by the caller.
SSL_get0_CA_list() retrieves any previously set list of CAs set for s
or if none are set the list from the parent SSL_CTX is retrieved. The
returned list should not be freed by the caller.
SSL_CTX_add1_to_CA_list() appends the CA subject name extracted from x
to the list of CAs sent to peer for ctx.
SSL_add1_to_CA_list() appends the CA subject name extracted from x to
the list of CAs sent to the peer for s, overriding the setting in the
parent SSL_CTX.
NOTES
When a TLS/SSL server requests a client certificate (see
SSL_CTX_set_verify(3)), it sends a list of CAs, for which it will
accept certificates, to the client.
This list must explicitly be set using SSL_CTX_set_client_CA_list() or
SSL_CTX_set0_CA_list() for ctx and SSL_set_client_CA_list() or
SSL_set0_CA_list() for the specific ssl. The list specified overrides
the previous setting. The CAs listed do not become trusted (list only
contains the names, not the complete certificates); use
SSL_CTX_load_verify_locations(3) to additionally load them for
verification.
If the list of acceptable CAs is compiled in a file, the
SSL_load_client_CA_file(3) function can be used to help to import the
necessary data.
SSL_CTX_add_client_CA(), SSL_CTX_add1_to_CA_list(), SSL_add_client_CA()
and SSL_add1_to_CA_list() can be used to add additional items the list
of CAs. If no list was specified before using
SSL_CTX_set_client_CA_list(), SSL_CTX_set0_CA_list(),
SSL_set_client_CA_list() or SSL_set0_CA_list(), a new CA list for ctx
or ssl (as appropriate) is opened.
RETURN VALUES
SSL_CTX_set_client_CA_list(), SSL_set_client_CA_list(),
SSL_CTX_set_client_CA_list(), SSL_set_client_CA_list(),
SSL_CTX_set0_CA_list() and SSL_set0_CA_list() do not return a value.
SSL_CTX_get_client_CA_list(), SSL_get_client_CA_list(),
SSL_CTX_get0_CA_list() and SSL_get0_CA_list() return a stack of CA
names or NULL is no CA names are set.
SSL_CTX_add_client_CA(),SSL_add_client_CA(), 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
NULL or an empty stack if no list was sent.
EXAMPLES
Scan all certificates in CAfile and list them as acceptable CAs:
SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(CAfile));
SEE ALSO
ssl(7), SSL_load_client_CA_file(3), SSL_CTX_load_verify_locations(3)
COPYRIGHT
Copyright 2000-2019 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>;.
1.1.1k 2021-03-25 SSL_CTX_SET0_CA_LIST(3)
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