5 SSL_CTX_set_session_ticket_cb,
6 SSL_SESSION_get0_ticket_appdata,
7 SSL_SESSION_set1_ticket_appdata,
8 SSL_CTX_generate_session_ticket_fn,
9 SSL_CTX_decrypt_session_ticket_fn - manage session ticket application data
13 #include <openssl/ssl.h>
15 typedef int (*SSL_CTX_generate_session_ticket_fn)(SSL *s, void *arg);
16 typedef SSL_TICKET_RETURN (*SSL_CTX_decrypt_session_ticket_fn)(SSL *s, SSL_SESSION *ss,
17 const unsigned char *keyname,
19 SSL_TICKET_RETURN retv,
21 int SSL_CTX_set_session_ticket_cb(SSL_CTX *ctx,
22 SSL_CTX_generate_session_ticket_fn gen_cb,
23 SSL_CTX_decrypt_session_ticket_fn dec_cb,
25 int SSL_SESSION_set1_ticket_appdata(SSL_SESSION *ss, const void *data, size_t len);
26 int SSL_SESSION_get0_ticket_appdata(SSL_SESSION *ss, void **data, size_t *len);
30 SSL_CTX_set_set_session_ticket_cb() sets the application callbacks B<gen_cb>
31 and B<dec_cb> that are used by a server to set and get application data stored
32 with a session, and placed into a session ticket. Either callback function may
33 be set to NULL. The value of B<arg> is passed to the callbacks.
35 B<gen_cb> is the application defined callback invoked when a session ticket is
36 about to be created. The application can call SSL_SESSION_set1_ticket_appdata()
37 at this time to add application data to the session ticket. The value of B<arg>
38 is the same as that given to SSL_CTX_set_session_ticket_cb(). The B<gen_cb>
39 callback is defined as type B<SSL_CTX_generate_session_ticket_fn>.
41 B<dec_cb> is the application defined callback invoked after session ticket
42 decryption has been attempted and any session ticket application data is available.
43 The application can call SSL_SESSION_get_ticket_appdata() at this time to retrieve
44 the application data. The value of B<arg> is the same as that given to
45 SSL_CTX_set_session_ticket_cb(). The B<retv> argument is the result of the ticket
46 decryption. The B<keyname> and B<keyname_len> identify the key used to decrypt the
47 session ticket. The B<dec_cb> callback is defined as type
48 B<SSL_CTX_decrypt_session_ticket_fn>.
50 SSL_SESSION_set1_ticket_appdata() sets the application data specified by
51 B<data> and B<len> into B<ss> which is then placed into any generated session
52 tickets. It can be called at any time before a session ticket is created to
53 update the data placed into the session ticket. However, given that sessions
54 and tickets are created by the handshake, the B<gen_cb> is provided to notify
55 the application that a session ticket is about to be generated.
57 SSL_SESSION_get0_ticket_appdata() assigns B<data> to the session ticket
58 application data and assigns B<len> to the length of the session ticket
59 application data from B<ss>. The application data can be set via
60 SSL_SESSION_set1_ticket_appdata() or by a session ticket. NULL will be assigned
61 to B<data> and 0 will be assigned to B<len> if there is no session ticket
62 application data. SSL_SESSION_get0_ticket_appdata() can be called any time
63 after a session has been created. The B<dec_cb> is provided to notify the
64 application that a session ticket has just been decrypted.
68 When the B<dec_cb> callback is invoked, the SSL_SESSION B<ss> has not yet been
69 assigned to the SSL B<s>. The B<retv> indicates the result of the ticket
70 decryption which can be modified by the callback before being returned. The
71 callback must check the B<retv> value before performing any action, as it's
72 called even if ticket decryption fails.
74 The B<keyname> and B<keyname_len> arguments to B<dec_cb> may be used to identify
75 the key that was used to encrypt the session ticket.
77 When the B<gen_cb> callback is invoked, the SSL_get_session() function can be
78 used to retrieve the SSL_SESSION for SSL_SESSION_set1_ticket_appdata().
80 By default, in TLSv1.2 and below, a new session ticket is not issued on a
81 successful resumption and therefore B<gen_cb> will not be called. In TLSv1.3 the
82 default behaviour is to always issue a new ticket on resumption. In both cases
83 this behaviour can be changed if a ticket key callback is in use (see
84 L<SSL_CTX_set_tlsext_ticket_key_cb(3)>).
88 The SSL_CTX_set_session_ticket_cb(), SSL_SESSION_set1_ticket_appdata() and
89 SSL_SESSION_get0_ticket_appdata() functions return 1 on success and 0 on
92 The B<gen_cb> callback must return 1 to continue the connection. A return of 0
93 will terminate the connection with an INTERNAL_ERROR alert.
95 The B<dec_cb> callback must return one of the following B<SSL_TICKET_RETURN>
96 values. Under normal circumstances the B<retv> value is returned unmodified,
97 but the callback can change the behavior of the post-ticket decryption code
98 by returning something different. The B<dec_cb> callback must check the B<retv>
99 value before performing any action.
101 typedef int SSL_TICKET_RETURN;
105 =item SSL_TICKET_FATAL_ERR_MALLOC
107 Fatal error, malloc failure.
109 =item SSL_TICKET_FATAL_ERR_OTHER
111 Fatal error, either from parsing or decrypting the ticket.
113 =item SSL_TICKET_NONE
117 =item SSL_TICKET_EMPTY
119 Empty ticket present.
121 =item SSL_TICKET_NO_DECRYPT
123 The ticket couldn't be decrypted.
125 =item SSL_TICKET_SUCCESS
127 A ticket was successfully decrypted, any session ticket application data should
130 =item TICKET_SUCCESS_RENEW
132 Same as B<TICKET_SUCCESS>, but the ticket needs to be renewed.
139 L<SSL_get_session(3)>
143 SSL_CTX_set_session_ticket_cb(), SSSL_SESSION_set1_ticket_appdata() and
144 SSL_SESSION_get_ticket_appdata() were added to OpenSSL 1.1.1.
148 Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
150 Licensed under the OpenSSL license (the "License"). You may not use
151 this file except in compliance with the License. You can obtain a copy
152 in the file LICENSE in the source distribution or at
153 L<https://www.openssl.org/source/license.html>.