SSL_SESSION_new, SSL_SESSION_dup, SSL_SESSION_up_ref, SSL_SESSION_free - create,
free and manage SSL_SESSION structures
#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);
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.
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.
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.
ssl(7),
SSL_get_session(3),
SSL_CTX_set_session_cache_mode(3),
SSL_CTX_flush_sessions(3),
d2i_SSL_SESSION(3)
The
SSL_SESSION_dup() function was added in OpenSSL 1.1.1.
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>.