SSL_SESSION_free
Section: OpenSSL (3)
Updated: 2017-05-25
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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 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_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)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- NOTES
-
- RETURN VALUES
-
- SEE ALSO
-