SSL_SET_SESSION_SECRET_CB(3ssl)     OpenSSL    SSL_SET_SESSION_SECRET_CB(3ssl)


NAME
       SSL_set_session_secret_cb, tls_session_secret_cb_fn - set the session
       secret callback

SYNOPSIS
        #include <openssl/ssl.h>

        typedef int (*tls_session_secret_cb_fn)(SSL *s, void *secret, int *secret_len,
                                                STACK_OF(SSL_CIPHER) *peer_ciphers,
                                                const SSL_CIPHER **cipher, void *arg);

        int SSL_set_session_secret_cb(SSL *s,
                                      tls_session_secret_cb_fn session_secret_cb,
                                      void *arg);

DESCRIPTION
       SSL_set_session_secret_cb() sets the session secret callback to be used
       (session_secret_cb), and an optional argument (arg) to be passed to
       that callback when it is called. This is only useful for an
       implementation of EAP-FAST (RFC4851). The presence of the callback also
       modifies the internal OpenSSL TLS state machine to match the modified
       TLS behaviour as described in RFC4851. Therefore this callback should
       not be used except when implementing EAP-FAST.

       The callback is expected to set the master secret to be used by filling
       in the data pointed to by *secret. The size of the secret buffer is
       initially available in *secret_len and may be updated by the callback
       (but must not be larger than the initial value).

       On the server side the set of ciphersuites offered by the peer is
       provided in the peer_ciphers stack. Optionally the callback may select
       the preferred ciphersuite by setting it in *cipher.

       On the client side the peer_ciphers stack will always be NULL. The
       callback may specify the preferred cipher in *cipher and this will be
       associated with the SSL_SESSION - but it does not affect the
       ciphersuite selected by the server.

       The callback is also supplied with an additional argument in arg which
       is the argument that was provided to the original
       SSL_set_session_secret_cb() call.

RETURN VALUES
       SSL_set_session_secret_cb() returns 1 on success and 0 on failure.

       If the callback returns 1 then this indicates it has successfully set
       the secret. A return value of 0 indicates that the secret has not been
       set. On the client this will cause an immediate abort of the handshake.

SEE ALSO
       ssl(7), SSL_get_session(3)

COPYRIGHT
       Copyright 2024 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>.

3.4.0                             2024-10-23   SSL_SET_SESSION_SECRET_CB(3ssl)