SSL_SESSION_free(3)

NAME

       SSL_SESSION_free - free an allocated SSL_SESSION structure

SYNOPSIS

        #include <openssl/ssl.h>

        void SSL_SESSION_free(SSL_SESSION *session);

DESCRIPTION

       SSL_SESSION_free() decrements the reference count of session and
       removes the SSL_SESSION structure pointed to by session and frees up
       the allocated memory, if the reference count has reached 0.

NOTES

       SSL_SESSION objects are allocated, when a TLS/SSL handshake operation
       is successfully completed. Depending on the settings, see
       SSL_CTX_set_session_cache_mode(3), the SSL_SESSION objects are inter-
       nally referenced by the SSL_CTX and linked into its session cache. SSL
       objects may be using the SSL_SESSION object; as a session may be
       reused, several SSL objects may be using one SSL_SESSION object at the
       same time. It is therefore crucial to keep the reference count (usage
       information) correct and not delete a SSL_SESSION object that is still
       used, as this may lead to program failures due to dangling pointers.
       These failures may also appear delayed, e.g.  when an SSL_SESSION
       object was completely freed as the reference count incorrectly became
       0, but it is still referenced in the internal session cache and the
       cache list is processed during a SSL_CTX_flush_sessions(3) operation.

       SSL_SESSION_free() must only be called for SSL_SESSION objects, for
       which the reference count was explicitly incremented (e.g.  by calling
       SSL_get1_session(), see SSL_get_session(3)) or when the SSL_SESSION
       object was generated outside a TLS handshake operation, e.g. by using
       d2i_SSL_SESSION(3).  It must not be called on other SSL_SESSION
       objects, as this would cause incorrect reference counts and therefore
       program failures.

RETURN VALUES

       SSL_SESSION_free() does not provide diagnostic information.

SEE ALSO

       ssl(3), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3),
       SSL_CTX_flush_sessions(3),
        d2i_SSL_SESSION(3)

1.0.2t                            2019-09-10               SSL_SESSION_free(3)