SSL_CTX_set_session_id_contexOpenSSL_CTX_set_session_id_context(3)

NAME    [Toc]    [Back]

       SSL_CTX_set_session_id_context, SSL_set_session_id_context
       - set context within which session can be reused (server
       side only)

LIBRARY    [Toc]    [Back]

       libcrypto, -lcrypto

SYNOPSIS    [Toc]    [Back]

        #include <openssl/ssl.h>

        int SSL_CTX_set_session_id_context(SSL_CTX *ctx, const unsigned char *sid_ctx,
                                           unsigned int sid_ctx_len);
        int SSL_set_session_id_context(SSL *ssl, const unsigned char *sid_ctx,
                                       unsigned int sid_ctx_len);

DESCRIPTION    [Toc]    [Back]

       SSL_CTX_set_session_id_context() sets the context sid_ctx
       of length sid_ctx_len within which a session can be reused
       for the ctx object.

       SSL_set_session_id_context() sets the context sid_ctx of
       length sid_ctx_len within which a session can be reused
       for the ssl object.

NOTES    [Toc]    [Back]

       Sessions are generated within a certain context. When
       exporting/importing sessions with i2d_SSL_SES-
       SION/d2i_SSL_SESSION it would be possible, to re-import a
       session generated from another context (e.g. another
       application), which might lead to malfunctions. Therefore
       each application must set its own session id context
       sid_ctx which is used to distinguish the contexts and is
       stored in exported sessions. The sid_ctx can be any kind
       of binary data with a given length, it is therefore possible
 to use e.g. the name of the application and/or the
       hostname and/or service name ...

       The session id context becomes part of the session. The
       session id context is set by the SSL/TLS server. The
       SSL_CTX_set_session_id_context() and SSL_set_ses-
       sion_id_context() functions are therefore only useful on
       the server side.

       OpenSSL clients will check the session id context returned
       by the server when reusing a session.

       The maximum length of the sid_ctx is limited to
       SSL_MAX_SSL_SESSION_ID_LENGTH.

WARNINGS    [Toc]    [Back]

       If the session id context is not set on an SSL/TLS server,
       stored sessions will not be reused but a fatal error will
       be flagged and the handshake will fail.

       If a server returns a different session id context to an
       OpenSSL client when reusing a session, an error will be
       flagged and the handshake will fail. OpenSSL servers will
       always return the correct session id context, as an
       OpenSSL server checks the session id context itself before
       reusing a session as described above.

RETURN VALUES    [Toc]    [Back]

       SSL_CTX_set_session_id_context() and SSL_set_ses-
       sion_id_context() return the following values:

       0   The length sid_ctx_len of the session id context
           sid_ctx exceeded the maximum allowed length of
           SSL_MAX_SSL_SESSION_ID_LENGTH. The error is logged to
           the error stack.

       1   The operation succeeded.

SEE ALSO    [Toc]    [Back]

       ssl(3)



2001-04-12                    0.SSL_CTX_set_session_id_context(3)