1SSL_SESSION_free(3) OpenSSL SSL_SESSION_free(3)
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6 SSL_SESSION_free - free an allocated SSL_SESSION structure
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9 #include <openssl/ssl.h>
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11 void SSL_SESSION_free(SSL_SESSION *session);
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14 SSL_SESSION_free() decrements the reference count of session and
15 removes the SSL_SESSION structure pointed to by session and frees up
16 the allocated memory, if the reference count has reached 0.
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19 SSL_SESSION objects are allocated, when a TLS/SSL handshake operation
20 is successfully completed. Depending on the settings, see
21 SSL_CTX_set_session_cache_mode(3), the SSL_SESSION objects are
22 internally referenced by the SSL_CTX and linked into its session cache.
23 SSL objects may be using the SSL_SESSION object; as a session may be
24 reused, several SSL objects may be using one SSL_SESSION object at the
25 same time. It is therefore crucial to keep the reference count (usage
26 information) correct and not delete a SSL_SESSION object that is still
27 used, as this may lead to program failures due to dangling pointers.
28 These failures may also appear delayed, e.g. when an SSL_SESSION
29 object was completely freed as the reference count incorrectly became
30 0, but it is still referenced in the internal session cache and the
31 cache list is processed during a SSL_CTX_flush_sessions(3) operation.
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33 SSL_SESSION_free() must only be called for SSL_SESSION objects, for
34 which the reference count was explicitly incremented (e.g. by calling
35 SSL_get1_session(), see SSL_get_session(3)) or when the SSL_SESSION
36 object was generated outside a TLS handshake operation, e.g. by using
37 d2i_SSL_SESSION(3). It must not be called on other SSL_SESSION
38 objects, as this would cause incorrect reference counts and therefore
39 program failures.
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42 SSL_SESSION_free() does not provide diagnostic information.
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45 ssl(3), SSL_get_session(3), SSL_CTX_set_session_cache_mode(3),
46 SSL_CTX_flush_sessions(3),
47 d2i_SSL_SESSION(3)
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511.0.2o 2018-03-27 SSL_SESSION_free(3)