SSL_CTX_set_session_id_context(3)

     SSL_CTX_set_session_id_0.9.6ht(2SSL_CTX_set_session_id_context(3)

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

     SYNOPSIS
           #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
          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
          Sessions are generated within a certain context. When
          exporting/importing sessions with
          i2d_SSL_SESSION/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_session_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
          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.

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     SSL_CTX_set_session_id_0.9.6ht(2SSL_CTX_set_session_id_context(3)

          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
          SSL_CTX_set_session_id_context() and
          SSL_set_session_id_context() return the following values:

          o   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
          ssl(3)

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