SSL_SESSION_free(3) - NetBSD Manual Pages

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SSL_SESSION_free(3)                 OpenSSL                SSL_SESSION_free(3)




NAME

       SSL_SESSION_new, SSL_SESSION_dup, SSL_SESSION_up_ref, SSL_SESSION_free
       - create, free and manage SSL_SESSION structures


SYNOPSIS

        #include <openssl/ssl.h>

        SSL_SESSION *SSL_SESSION_new(void);
        SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src);
        int SSL_SESSION_up_ref(SSL_SESSION *ses);
        void SSL_SESSION_free(SSL_SESSION *session);


DESCRIPTION

       SSL_SESSION_new() creates a new SSL_SESSION structure and returns a
       pointer to it.

       SSL_SESSION_dup() creates a new SSL_SESSION structure that is a copy of
       src.  The copy is not owned by any cache that src may have been in.

       SSL_SESSION_up_ref() increments the reference count on the given
       SSL_SESSION structure.

       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.  If session
       is NULL nothing is done.


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
       internally 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_new returns a pointer to the newly allocated SSL_SESSION
       structure or NULL on error.

       SSL_SESSION_dup returns a pointer to the new copy or NULL on error.

       SSL_SESSION_up_ref returns 1 on success or 0 on error.


SEE ALSO

       ssl(7), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3),
       SSL_CTX_flush_sessions(3), d2i_SSL_SESSION(3)


HISTORY

       The SSL_SESSION_dup() function was added in OpenSSL 1.1.1.


COPYRIGHT

       Copyright 2000-2023 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>.



3.0.15                            2024-09-03               SSL_SESSION_free(3)