SSL_SESSION_free.3ssl man page

SSL_SESSION_new, SSL_SESSION_dup, SSL_SESSION_up_ref, SSL_SESSION_free — create, free and manage SSL_SESSION structures

Synopsis

 #include <openssl/ssl.h>

 SSL_SESSION *SSL_SESSION_new(void);
 SSL_SESSION *SSL_SESSION_dup(SSL_SESSION *src);
 int SSL_SESSION_up_ref(SSL_SESSION *ses);
 void SSL_SESSION_free(SSL_SESSION *session);

Description

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 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.

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_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.

See Also

ssl(7), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_flush_sessions(3), d2i_SSL_SESSION(3)

History

SSL_SESSION_dup() was added in OpenSSL 1.1.1.

Referenced By

d2i_SSL_SESSION.3ssl(3), ssl.3ssl(3), ssl.7ssl(7), SSL_CTX_add_session.3ssl(3), SSL_CTX_sess_set_get_cb.3ssl(3), SSL_get_session.3ssl(3), SSL_SESSION_get0_cipher.3ssl(3), SSL_SESSION_get0_hostname.3ssl(3), SSL_SESSION_has_ticket.3ssl(3), SSL_set_session.3ssl(3).

2018-09-11 1.1.1 OpenSSL