manpagez: man pages & more
man DTLSv1_2_client_method(3)
Home | html | info | man
SSL_CTX_NEW(3ossl)                  OpenSSL                 SSL_CTX_NEW(3ossl)



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


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


DESCRIPTION

       SSL_CTX_new_ex() creates a new SSL_CTX object, which holds various
       configuration and data relevant to SSL/TLS or DTLS session
       establishment.  These are later inherited by the SSL object
       representing an active session.  The method parameter specifies whether
       the context will be used for the client or server side or both - for
       details see the "NOTES" below.  The library context libctx (see
       OSSL_LIB_CTX(3)) is used to provide the cryptographic algorithms needed
       for the session. Any cryptographic algorithms that are used by any SSL
       objects created from this SSL_CTX will be fetched from the libctx using
       the property query string propq (see "ALGORITHM FETCHING" in crypto(7).
       Either or both the libctx or propq parameters may be NULL.

       SSL_CTX_new(3) does the same as SSL_CTX_new_ex() except that the default
       library context is used and no property query string is specified.

       An SSL_CTX object is reference counted. Creating an SSL_CTX object for
       the first time increments the reference count. Freeing the SSL_CTX
       (using SSL_CTX_free) decrements it. When the reference count drops to
       zero, any memory or resources allocated to the SSL_CTX object are
       freed. SSL_CTX_up_ref() increments the reference count for an existing
       SSL_CTX structure.

       An SSL_CTX object should not be changed after it is used to create any
       SSL objects or from multiple threads concurrently, since the
       implementation does not provide serialization of access for these
       cases.


NOTES

       On session establishment, by default, no peer credentials verification
       is done.  This must be explicitly requested, typically using
       SSL_CTX_set_verify(3).  For verifying peer certificates many options
       can be set using various functions such as
       SSL_CTX_load_verify_locations(3) and SSL_CTX_set1_param(3).  The
       X509_VERIFY_PARAM_set_purpose(3) function can be used, also in
       conjunction with SSL_CTX_get0_param(3), to set the intended purpose of
       the session.  The default is X509_PURPOSE_SSL_SERVER on the client side
       and X509_PURPOSE_SSL_CLIENT on the server side.

       The SSL_CTX object uses 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 method parameter of SSL_CTX_new(3) can be one
       of the following:

       TLS_method(), TLS_server_method(), TLS_client_method()
           These are the general-purpose 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.

       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.

       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.

       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.

       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.

       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.

       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.

       DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
           These are the version-specific methods for DTLSv1.2.  These methods
           are deprecated.

       DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
           These are the version-specific methods for DTLSv1.  These methods
           are deprecated.

       SSL_CTX_new(3) 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 version-flexible
       methods.  All other methods only support one specific protocol version.
       Use the 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 SSL_CTX_set_min_proto_version(3),
       SSL_set_min_proto_version(3), SSL_CTX_set_max_proto_version(3) and
       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
       SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1, SSL_OP_NO_TLSv1_1, SSL_OP_NO_TLSv1_3,
       SSL_OP_NO_TLSv1_2 and SSL_OP_NO_TLSv1_3 options of the
       SSL_CTX_set_options(3) or 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 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 SSL_CTX_set_min_proto_version(3) to
       set the minimum protocol to at least TLS1_VERSION.


RETURN VALUES

       The following return values can occur:

       NULL
           The creation of a new SSL_CTX object failed. Check the error stack
           to find out the reason.

       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.


SEE ALSO

       SSL_CTX_set_options(3), SSL_CTX_free(3), SSL_CTX_set_verify(3),
       SSL_CTX_set1_param(3), SSL_CTX_get0_param(3), SSL_connect(3),
       SSL_accept(3), SSL_CTX_set_min_proto_version(3), ssl(7),
       SSL_set_connect_state(3)


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.


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
       <https://www.openssl.org/source/license.html>.

3.1.2                             2023-08-01                SSL_CTX_NEW(3ossl)

openssl 3.1.2 - Generated Mon Aug 14 07:38:15 CDT 2023
© manpagez.com 2000-2024
Individual documents may contain additional copyright information.