The B<CAfile> is processed on execution of the SSL_CTX_load_verify_locations()
function.
-If on an TLS/SSL server no special setting is performed using *client_CA_list()
-functions, the certificates contained in B<CAfile> are listed to the client
-as available CAs during the TLS/SSL handshake.
-
If B<CApath> is not NULL, it points to a directory containing CA certificates
in PEM format. The files each contain one CA certificate. The files are
looked up by the CA subject name hash value, which must hence be available.
building the certificate chain or when actually performing the verification
of a peer certificate.
-On a server, the certificates in B<CApath> are not listed as available
-CA certificates to a client during a TLS/SSL handshake.
-
When looking up CA certificates, the OpenSSL library will first search the
certificates in B<CAfile>, then those in B<CApath>. Certificate matching
is done based on the subject name, the key identifier (if present), and the
no other certificates for the same parameters will be searched in case of
failure.
+In server mode, when requesting a client certificate, the server must send
+the list of CAs of which it will accept client certificates. This list
+is not influenced by the contents of B<CAfile> or B<CApath> and must
+explicitely be set using the
+L<SSL_CTX_set_client_CA_list(3)|SSL_CTX_set_client_CA_list(3)>
+family of functions.
+
When building its own certificate chain, an OpenSSL client/server will
try to fill in missing certificates from B<CAfile>/B<CApath>, if the
certificate chain was not explicitly specified (see
When a TLS/SSL server requests a client certificate (see
B<SSL_CTX_set_verify_options()>), it sends a list of CAs, for which
-it will accept certificates, to the client. If no special list is provided,
-the CAs available using the B<CAfile> option in
-L<SSL_CTX_load_verify_locations(3)|SSL_CTX_load_verify_locations(3)>
-are sent.
+it will accept certificates, to the client.
-This list can be explicitly set using the SSL_CTX_set_client_CA_list() for
+This list must explicitly be set using SSL_CTX_set_client_CA_list() for
B<ctx> and SSL_set_client_CA_list() for the specific B<ssl>. The list
specified overrides the previous setting. The CAs listed do not become
trusted (B<list> only contains the names, not the complete certificates); use
L<SSL_CTX_load_verify_locations(3)|SSL_CTX_load_verify_locations(3)>
to additionally load them for verification.
+If the list of acceptable CAs is compiled in a file, the
+L<SSL_load_client_CA_file(3)|SSL_load_client_CA_file(3)>
+function can be used to help importing the necessary data.
+
SSL_CTX_add_client_CA() and SSL_add_client_CA() can be used to add additional
items the list of client CAs. If no list was specified before using
SSL_CTX_set_client_CA_list() or SSL_set_client_CA_list(), a new client
-CA list for B<ctx> or B<ssl> (as appropriate) is opened. The CAs implicitly
-specified using
-L<SSL_CTX_load_verify_locations(3)|SSL_CTX_load_verify_locations(3)>
-are no longer used automatically.
+CA list for B<ctx> or B<ssl> (as appropriate) is opened.
These functions are only useful for TLS/SSL servers.
=back
+=head1 EXAMPLES
+
+Scan all certificates in B<CAfile> and list them as acceptable CAs:
+
+ SSL_CTX_set_client_CA_list(ctx,SSL_load_client_CA_file(CAfile));
+
=head1 SEE ALSO
L<ssl(3)|ssl(3)>,
L<SSL_get_client_CA_list(3)|SSL_get_client_CA_list(3)>,
-L<SSL_load_client_CA_file(3)|SSL_load_client_CA_file(3)>
+L<SSL_load_client_CA_file(3)|SSL_load_client_CA_file(3)>,
L<SSL_CTX_load_verify_locations(3)|SSL_CTX_load_verify_locations(3)>
=cut