mirror of
https://github.com/openssl/openssl.git
synced 2024-12-21 06:09:35 +08:00
260 lines
9.9 KiB
Plaintext
260 lines
9.9 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
TLSv1_2_method, TLSv1_2_server_method, TLSv1_2_client_method,
|
|
SSL_CTX_new, SSL_CTX_new_ex, SSL_CTX_up_ref, 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_ex(OSSL_LIB_CTX *libctx, const char *propq,
|
|
const SSL_METHOD *method);
|
|
SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
|
|
int SSL_CTX_up_ref(SSL_CTX *ctx);
|
|
|
|
const SSL_METHOD *TLS_method(void);
|
|
const SSL_METHOD *TLS_server_method(void);
|
|
const SSL_METHOD *TLS_client_method(void);
|
|
|
|
const SSL_METHOD *SSLv23_method(void);
|
|
const SSL_METHOD *SSLv23_server_method(void);
|
|
const SSL_METHOD *SSLv23_client_method(void);
|
|
|
|
#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
|
|
|
|
#ifndef OPENSSL_NO_TLS1_METHOD
|
|
const SSL_METHOD *TLSv1_method(void);
|
|
const SSL_METHOD *TLSv1_server_method(void);
|
|
const SSL_METHOD *TLSv1_client_method(void);
|
|
#endif
|
|
|
|
#ifndef OPENSSL_NO_TLS1_1_METHOD
|
|
const SSL_METHOD *TLSv1_1_method(void);
|
|
const SSL_METHOD *TLSv1_1_server_method(void);
|
|
const SSL_METHOD *TLSv1_1_client_method(void);
|
|
#endif
|
|
|
|
#ifndef OPENSSL_NO_TLS1_2_METHOD
|
|
const SSL_METHOD *TLSv1_2_method(void);
|
|
const SSL_METHOD *TLSv1_2_server_method(void);
|
|
const SSL_METHOD *TLSv1_2_client_method(void);
|
|
#endif
|
|
|
|
const SSL_METHOD *DTLS_method(void);
|
|
const SSL_METHOD *DTLS_server_method(void);
|
|
const SSL_METHOD *DTLS_client_method(void);
|
|
|
|
#ifndef OPENSSL_NO_DTLS1_METHOD
|
|
const SSL_METHOD *DTLSv1_method(void);
|
|
const SSL_METHOD *DTLSv1_server_method(void);
|
|
const SSL_METHOD *DTLSv1_client_method(void);
|
|
#endif
|
|
|
|
#ifndef OPENSSL_NO_DTLS1_2_METHOD
|
|
const SSL_METHOD *DTLSv1_2_method(void);
|
|
const SSL_METHOD *DTLSv1_2_server_method(void);
|
|
const SSL_METHOD *DTLSv1_2_client_method(void);
|
|
#endif
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_CTX_new_ex() creates a new B<SSL_CTX> object, which holds various
|
|
configuration and data relevant to SSL/TLS or DTLS session establishment.
|
|
These are later inherited by the B<SSL> object representing an active session.
|
|
The I<method> parameter specifies whether the context will be used for the
|
|
client or server side or both - for details see the L</NOTES> below.
|
|
The library context I<libctx> (see L<OSSL_LIB_CTX(3)>) is used to provide the
|
|
cryptographic algorithms needed for the session. Any cryptographic algorithms
|
|
that are used by any B<SSL> objects created from this B<SSL_CTX> will be fetched
|
|
from the I<libctx> using the property query string I<propq> (see
|
|
L<crypto(7)/ALGORITHM FETCHING>. Either or both the I<libctx> or I<propq>
|
|
parameters may be NULL.
|
|
|
|
SSL_CTX_new() does the same as SSL_CTX_new_ex() except that the default
|
|
library context is used and no property query string is specified.
|
|
|
|
An B<SSL_CTX> object is reference counted. Creating an B<SSL_CTX> object for the
|
|
first time increments the reference count. Freeing the B<SSL_CTX> (using
|
|
SSL_CTX_free) decrements it. When the reference count drops to zero, any memory
|
|
or resources allocated to the B<SSL_CTX> object are freed. SSL_CTX_up_ref()
|
|
increments the reference count for an existing B<SSL_CTX> structure.
|
|
|
|
An B<SSL_CTX> object should not be changed after it is used to create any B<SSL>
|
|
objects or from multiple threads concurrently, since the implementation does not
|
|
provide serialization of access for these cases.
|
|
|
|
=head1 NOTES
|
|
|
|
On session establishment, by default, no peer credentials verification is done.
|
|
This must be explicitly requested, typically using L<SSL_CTX_set_verify(3)>.
|
|
For verifying peer certificates many options can be set using various functions
|
|
such as L<SSL_CTX_load_verify_locations(3)> and L<SSL_CTX_set1_param(3)>.
|
|
The L<X509_VERIFY_PARAM_set_purpose(3)> function can be used, also in conjunction
|
|
with L<SSL_CTX_get0_param(3)>, to set the intended purpose of the session.
|
|
The default is B<X509_PURPOSE_SSL_SERVER> on the client side
|
|
and B<X509_PURPOSE_SSL_CLIENT> on the server side.
|
|
|
|
The SSL_CTX object uses I<method> as the connection method.
|
|
Three method variants are available: a generic method (for either client or
|
|
server use), a server-only method, and a client-only method.
|
|
|
|
The I<method> parameter of SSL_CTX_new_ex() and SSL_CTX_new()
|
|
can be one of the following:
|
|
|
|
=over 4
|
|
|
|
=item TLS_method(), TLS_server_method(), TLS_client_method()
|
|
|
|
These are the general-purpose I<version-flexible> SSL/TLS methods.
|
|
The actual protocol version used will be negotiated to the highest version
|
|
mutually supported by the client and the server.
|
|
The supported protocols are SSLv3, TLSv1, TLSv1.1, TLSv1.2 and TLSv1.3.
|
|
Applications should use these methods, and avoid the version-specific
|
|
methods described below, which are deprecated.
|
|
|
|
=item SSLv23_method(), SSLv23_server_method(), SSLv23_client_method()
|
|
|
|
These functions do not exist anymore, they have been renamed to
|
|
TLS_method(), TLS_server_method() and TLS_client_method() respectively.
|
|
Currently, the old function calls are renamed to the corresponding new
|
|
ones by preprocessor macros, to ensure that existing code which uses the
|
|
old function names still compiles. However, using the old function names
|
|
is deprecated and new code should call the new functions instead.
|
|
|
|
=item TLSv1_2_method(), TLSv1_2_server_method(), TLSv1_2_client_method()
|
|
|
|
A TLS/SSL connection established with these methods will only understand the
|
|
TLSv1.2 protocol. These methods are deprecated.
|
|
|
|
=item TLSv1_1_method(), TLSv1_1_server_method(), TLSv1_1_client_method()
|
|
|
|
A TLS/SSL connection established with these methods will only understand the
|
|
TLSv1.1 protocol. These methods are deprecated.
|
|
|
|
=item TLSv1_method(), TLSv1_server_method(), TLSv1_client_method()
|
|
|
|
A TLS/SSL connection established with these methods will only understand the
|
|
TLSv1 protocol. These methods are deprecated.
|
|
|
|
=item SSLv3_method(), SSLv3_server_method(), SSLv3_client_method()
|
|
|
|
A TLS/SSL connection established with these methods will only understand the
|
|
SSLv3 protocol.
|
|
The SSLv3 protocol is deprecated and should not be used.
|
|
|
|
=item DTLS_method(), DTLS_server_method(), DTLS_client_method()
|
|
|
|
These are the version-flexible DTLS methods.
|
|
Currently supported protocols are DTLS 1.0 and DTLS 1.2.
|
|
|
|
=item DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
|
|
|
|
These are the version-specific methods for DTLSv1.2.
|
|
These methods are deprecated.
|
|
|
|
=item DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
|
|
|
|
These are the version-specific methods for DTLSv1.
|
|
These methods are deprecated.
|
|
|
|
=back
|
|
|
|
SSL_CTX_new() initializes the list of ciphers, the session cache setting, the
|
|
callbacks, the keys and certificates and the options to their default values.
|
|
|
|
TLS_method(), TLS_server_method(), TLS_client_method(), DTLS_method(),
|
|
DTLS_server_method() and DTLS_client_method() are the I<version-flexible>
|
|
methods.
|
|
All other methods only support one specific protocol version.
|
|
Use the I<version-flexible> methods instead of the version specific methods.
|
|
|
|
If you want to limit the supported protocols for the version flexible
|
|
methods you can use L<SSL_CTX_set_min_proto_version(3)>,
|
|
L<SSL_set_min_proto_version(3)>, L<SSL_CTX_set_max_proto_version(3)> and
|
|
L<SSL_set_max_proto_version(3)> functions.
|
|
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, TLS 1.2 or TLS 1.3.
|
|
|
|
The list of protocols available can also be limited using the
|
|
B<SSL_OP_NO_SSLv3>, B<SSL_OP_NO_TLSv1>, B<SSL_OP_NO_TLSv1_1>,
|
|
B<SSL_OP_NO_TLSv1_3>, B<SSL_OP_NO_TLSv1_2> and B<SSL_OP_NO_TLSv1_3>
|
|
options of the
|
|
L<SSL_CTX_set_options(3)> or L<SSL_set_options(3)> functions, but this approach
|
|
is not recommended. Clients should avoid creating "holes" in the set of
|
|
protocols they support. When disabling a protocol, make sure that you also
|
|
disable either all previous or all subsequent protocol versions.
|
|
In clients, when a protocol version is disabled without disabling I<all>
|
|
previous protocol versions, the effect is to also disable all subsequent
|
|
protocol versions.
|
|
|
|
The SSLv3 protocol is deprecated and should generally not be used.
|
|
Applications should typically use L<SSL_CTX_set_min_proto_version(3)> to set
|
|
the minimum protocol to at least B<TLS1_VERSION>.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The following return values can occur:
|
|
|
|
=over 4
|
|
|
|
=item NULL
|
|
|
|
The creation of a new SSL_CTX object failed. Check the error stack to find out
|
|
the reason.
|
|
|
|
=item Pointer to an SSL_CTX object
|
|
|
|
The return value points to an allocated SSL_CTX object.
|
|
|
|
SSL_CTX_up_ref() returns 1 for success and 0 for failure.
|
|
|
|
=back
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<SSL_CTX_set_options(3)>, L<SSL_CTX_free(3)>,
|
|
SSL_CTX_set_verify(3), L<SSL_CTX_set1_param(3)>, L<SSL_CTX_get0_param(3)>,
|
|
L<SSL_connect(3)>, L<SSL_accept(3)>,
|
|
L<SSL_CTX_set_min_proto_version(3)>, L<ssl(7)>, L<SSL_set_connect_state(3)>
|
|
|
|
=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 added in OpenSSL 1.1.0.
|
|
|
|
All version-specific methods were deprecated in OpenSSL 1.1.0.
|
|
|
|
SSL_CTX_new_ex() was added in OpenSSL 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2023 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>.
|
|
|
|
=cut
|