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SSL_SESSION_free(3) OpenSSL SSL_SESSION_free(3)
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SSL_SESSION_new, SSL_SESSION_dup, SSL_SESSION_up_ref, SSL_SESSION_free
- create, free and manage SSL_SESSION structures
SSL_SESSION *SSL_SESSION_dup(SSL_SESSION *src);
int SSL_SESSION_up_ref(SSL_SESSION *ses);
void SSL_SESSION_free(SSL_SESSION *session);
SSL_SESSION_new() creates a new SSL_SESSION structure and returns a
pointer to it.
SSL_SESSION_dup() copies the contents of the SSL_SESSION structure in
src and returns a pointer to it.
SSL_SESSION_up_ref() increments the reference count on the given
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.
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
SSL_SESSION_new returns a pointer to the newly allocated SSL_SESSION
structure or NULL on error.
SSL_SESSION_up_ref returns 1 on success or 0 on error.
ssl(7), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3),
The SSL_SESSION_dup() function was added in OpenSSL 1.1.1.
Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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
1.1.1i 2019-03-12 SSL_SESSION_free(3)