SSL_SESSION_free - free an allocated SSL_SESSION structure
void SSL_SESSION_free(SSL_SESSION *session);
SSL_SESSION_free() decrements the reference count of ses-
sion and removes the SSL_SESSION structure pointed to by
session and frees up the allocated memory, if the the reference
count has reached 0.
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_free() does not provide diagnostic information.
ssl(3), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_flush_sessions(3),
2002-06-10 0.9.6g SSL_SESSION_free(3)
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