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

  The SSL_set_session_id_context() function 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 or
  importing sessions with i2d_SSL_SESSION or d2i_SSL_SESSION it is possible,
  to reimport 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. For example, it is possible to use
  the name of the application, the hostname and/or the 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.

RESTRICTIONS
  If the session id context is not set on an SSL/TLS server, stored sessions
  will not be reused. 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,
  because an OpenSSL server checks the session id context before reusing a
  session.

RETURN VALUES
  The SSL_CTX_set_session_id_context() and SSL_set_session_id_context()
  functions 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
  Functions: ssl(3)

Index for Section 3

Alphabetical listing for S

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