=head1 NAME
-SSL_CTX_new - create a new SSL_CTX object as framework for TLS/SSL enabled functions
+SSL_CTX_new, SSLv3_method, SSLv3_server_method, SSLv3_client_method,
+TLSv1_method, TLSv1_server_method, TLSv1_client_method, TLSv1_1_method,
+TLSv1_1_server_method, TLSv1_1_client_method, TLS_method,
+TLS_server_method, TLS_client_method, SSLv23_method, SSLv23_server_method,
+SSLv23_client_method, DTLS_method, DTLS_server_method, DTLS_client_method,
+DTLSv1_method, DTLSv1_server_method, DTLSv1_client_method,
+DTLSv1_2_method, DTLSv1_2_server_method, DTLSv1_2_client_method -
+create a new SSL_CTX object as framework for TLS/SSL or DTLS enabled
+functions
=head1 SYNOPSIS
#include <openssl/ssl.h>
- SSL_CTX *SSL_CTX_new(SSL_METHOD *method);
+ SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
+
+ const SSL_METHOD *TLS_method(void);
+ const SSL_METHOD *TLS_server_method(void);
+ const SSL_METHOD *TLS_client_method(void);
+
+ #define SSLv23_method TLS_method
+ #define SSLv23_server_method TLS_server_method
+ #define SSLv23_client_method TLS_client_method
+
+ #ifndef OPENSSL_NO_SSL3_METHOD
+ const SSL_METHOD *SSLv3_method(void);
+ const SSL_METHOD *SSLv3_server_method(void);
+ const SSL_METHOD *SSLv3_client_method(void);
+ #endif
+
+ const SSL_METHOD *TLSv1_method(void);
+ const SSL_METHOD *TLSv1_server_method(void);
+ const SSL_METHOD *TLSv1_client_method(void);
+
+ const SSL_METHOD *TLSv1_1_method(void);
+ const SSL_METHOD *TLSv1_1_server_method(void);
+ const SSL_METHOD *TLSv1_1_client_method(void);
+
+ const SSL_METHOD *TLSv1_2_method(void);
+ const SSL_METHOD *TLSv1_2_server_method(void);
+ const SSL_METHOD *TLSv1_2_client_method(void);
+
+ const SSL_METHOD *DTLS_method(void);
+ const SSL_METHOD *DTLS_server_method(void);
+ const SSL_METHOD *DTLS_client_method(void);
+
+ const SSL_METHOD *DTLSv1_method(void);
+ const SSL_METHOD *DTLSv1_server_method(void);
+ const SSL_METHOD *DTLSv1_client_method(void);
+
+ const SSL_METHOD *DTLSv1_2_method(void);
+ const SSL_METHOD *DTLSv1_2_server_method(void);
+ const SSL_METHOD *DTLSv1_2_client_method(void);
=head1 DESCRIPTION
-SSL_CTX_new() creates a new B<SSL_CTX> object as framework to establish
-TLS/SSL enabled connections.
+SSL_CTX_new() creates a new B<SSL_CTX> object as framework to
+establish TLS/SSL or DTLS enabled connections.
=head1 NOTES
-The SSL_CTX object uses B<method> as connection method. The methods exist
-in a generic type (for client and server use), a server only type, and a
-client only type. B<method> can be of the following types:
+The SSL_CTX object uses B<method> as connection method.
+The methods exist in a generic type (for client and server use), a server only
+type, and a client only type.
+B<method> can be of the following types:
=over 4
-=item SSLv2_method(void), SSLv2_server_method(void), SSLv2_client_method(void)
+=item SSLv3_method(), SSLv3_server_method(), SSLv3_client_method()
-A TLS/SSL connection established with these methods will only understand
-the SSLv2 protocol. A client will send out SSLv2 client hello messages
-and will also indicate that it only understand SSLv2. A server will only
-understand SSLv2 client hello messages.
+An SSL connection established with these methods will only understand
+the SSLv3 protocol.
+A client will send out a SSLv3 client hello messages and will
+indicate that it supports SSLv3.
+A server will only understand SSLv3 client hello message and only
+support the SSLv3 protocol.
-=item SSLv3_method(void), SSLv3_server_method(void), SSLv3_client_method(void)
+=item TLSv1_method(), TLSv1_server_method(), TLSv1_client_method()
-A TLS/SSL connection established with these methods will only understand the
-SSLv3 protocol. A client will send out SSLv3 client hello messages
-and will indicate that it only understands SSLv3. A server will only understand
-SSLv3 client hello messages. This especially means, that it will
-not understand SSLv2 client hello messages which are widely used for
-compatibility reasons, see SSLv23_*_method().
+A TLS connection established with these methods will only understand
+the TLS 1.0 protocol.
-=item TLSv1_method(void), TLSv1_server_method(void), TLSv1_client_method(void)
+=item TLSv1_1_method(), TLSv1_1_server_method(), TLSv1_1_client_method()
-A TLS/SSL connection established with these methods will only understand the
-TLSv1 protocol. A client will send out TLSv1 client hello messages
-and will indicate that it only understands TLSv1. A server will only understand
-TLSv1 client hello messages. This especially means, that it will
-not understand SSLv2 client hello messages which are widely used for
-compatibility reasons, see SSLv23_*_method(). It will also not understand
-SSLv3 client hello messages.
+A TLS connection established with these methods will only understand
+the TLS 1.1 protocol.
-=item SSLv23_method(void), SSLv23_server_method(void), SSLv23_client_method(void)
+=item TLSv1_2_method(), TLSv1_2_server_method(), TLSv1_2_client_method()
-A TLS/SSL connection established with these methods will understand the SSLv2,
-SSLv3, and TLSv1 protocol. A client will send out SSLv2 client hello messages
-and will indicate that it also understands SSLv3 and TLSv1. A server will
-understand SSLv2, SSLv3, and TLSv1 client hello messages. This is the best
-choice when compatibility is a concern.
+A TLS connection established with these methods will only understand
+the TLS 1.2 protocol.
-=back
+=item TLS_method(), TLS_server_method(), TLS_client_method()
+
+A TLS/SSL connection established with these methods may understand
+the SSLv3, TLSv1, TLSv1.1 and TLSv1.2 protocols.
+
+If extensions are required (for example server name)
+a client will send out TLSv1 client hello messages including extensions and
+will indicate that it also understands TLSv1.1, TLSv1.2 and permits a
+fallback to SSLv3. A server will support SSLv3, TLSv1, TLSv1.1 and TLSv1.2
+protocols. This is the best choice when compatibility is a concern.
-If a generic method is used, it is necessary to explicitly set client or
-server mode with L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>
-or SSL_set_accept_state().
+=item SSLv23_method(), SSLv23_server_method(), SSLv23_client_method()
-The list of protocols available can later be limited using the SSL_OP_NO_SSLv2,
-SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1 options of the B<SSL_CTX_set_options()> or
-B<SSL_set_options()> functions. Using these options it is possible to choose
-e.g. SSLv23_server_method() and be able to negotiate with all possible
-clients, but to only allow newer protocols like SSLv3 or TLSv1.
+Use of these functions is deprecated. They have been replaced with TLS_method(),
+TLS_server_method() and TLS_client_method() respectively. New code should use
+those functions instead.
-SSL_CTX_new() initializes the list of ciphers, the session cache setting,
-the callbacks, the keys and certificates, and the options to its default
-values.
+=item DTLS_method(), DTLS_server_method(), DTLS_client_method()
+
+A DTLS connection established with those methods understands all
+supported DTLS protocols.
+Currently supported protocols are DTLS 1.0 and DTLS 1.2.
+
+=item DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
+
+A DTLS connection established with these methods will only understand
+the DTLS 1.0 protocol.
+
+=item DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
+
+A DTLS connection established with these methods will only understand
+the DTLS 1.2 protocol.
+
+=back
+
+TLS_method(), TLS_server_method(), TLS_client_method(), DTLS_method(),
+DTLS_server_method() and DTLS_client_method() are the version
+flexible methods.
+All other methods only support one specific protocol version.
+Use these methods instead of the other version specific methods.
+
+If you want to limit the supported protocols for the version flexible
+methods you can use SSL_CTX_set_min_proto_version(),
+SSL_set_min_proto_version(), SSL_CTX_set_max_proto_version() and
+SSL_set_max_proto_version() functions.
+They can also be limited using by using an option like SSL_OP_NO_SSLv3
+of the SSL_CTX_set_options() or SSL_set_options() functions, but
+that's not recommended.
+Using these functions it is possible to choose e.g. TLS_server_method()
+and be able to negotiate with all possible clients, but to only
+allow newer protocols like TLS 1.0, TLS 1.1 or TLS 1.2.
+
+SSL_CTX_new() initializes the list of ciphers, the session cache
+setting, the callbacks, the keys and certificates and the options
+to its default values.
=head1 RETURN VALUES
=back
+=head1 HISTORY
+
+Support for SSLv2 and the corresponding SSLv2_method(),
+SSLv2_server_method() and SSLv2_client_method() functions where
+removed in OpenSSL 1.1.0.
+
+SSLv23_method(), SSLv23_server_method() and SSLv23_client_method()
+were deprecated and the preferred TLS_method(), TLS_server_method()
+and TLS_client_method() functions were introduced in OpenSSL 1.1.0.
+
=head1 SEE ALSO
-L<SSL_CTX_free(3)|SSL_CTX_free(3)>, L<SSL_accept(3)|SSL_accept(3)>,
-L<ssl(3)|ssl(3)>, L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>
+L<SSL_CTX_free(3)>, L<SSL_accept(3)>,
+L<SSL_CTX_set_min_proto_version(3)>,
+L<ssl(3)>, L<SSL_set_connect_state(3)>
=cut
projects / openssl.git / blobdiff