Sortix nightly manual
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SSL_SESSION_FREE(3) | Library Functions Manual | SSL_SESSION_FREE(3) |
NAME
SSL_SESSION_up_ref
,
SSL_SESSION_free
—
SSL_SESSION reference counting
SYNOPSIS
#include
<openssl/ssl.h>
int
SSL_SESSION_up_ref
(SSL_SESSION
*session);
void
SSL_SESSION_free
(SSL_SESSION
*session);
DESCRIPTION
SSL_SESSION_up_ref
() increments the reference
count of the given session by 1.
SSL_SESSION_free
() decrements the reference
count of the given session by 1. If the
reference count reaches 0, it frees the memory used by the
session. If
session is a
NULL
pointer, no action occurs.
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 is completely freed as the
reference count incorrectly becomes 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(3);
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_up_ref
() returns 1 on success or
0 on error.
SEE ALSO
d2i_SSL_SESSION(3), ssl(3), SSL_CTX_flush_sessions(3), SSL_CTX_set_session_cache_mode(3), SSL_get_session(3), SSL_SESSION_new(3)HISTORY
SSL_SESSION_free
() first appeared in SSLeay
0.5.2 and has been available since OpenBSD 2.4.
SSL_SESSION_up_ref
() first appeared in
OpenSSL 1.1.0 and has been available since OpenBSD
6.3.June 12, 2019 | Debian |