xref: /freebsd/crypto/openssl/ssl/ssl_sess.c (revision 357378bbdedf24ce2b90e9bd831af4a9db3ec70a)
1 /*
2  * Copyright 1995-2024 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright 2005 Nokia. All rights reserved.
4  *
5  * Licensed under the Apache License 2.0 (the "License").  You may not use
6  * this file except in compliance with the License.  You can obtain a copy
7  * in the file LICENSE in the source distribution or at
8  * https://www.openssl.org/source/license.html
9  */
10 
11 #if defined(__TANDEM) && defined(_SPT_MODEL_)
12 # include <spthread.h>
13 # include <spt_extensions.h> /* timeval */
14 #endif
15 #include <stdio.h>
16 #include <openssl/rand.h>
17 #include <openssl/engine.h>
18 #include "internal/refcount.h"
19 #include "internal/cryptlib.h"
20 #include "ssl_local.h"
21 #include "statem/statem_local.h"
22 
23 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s);
24 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s);
25 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck);
26 
27 DEFINE_STACK_OF(SSL_SESSION)
28 
29 __owur static int sess_timedout(time_t t, SSL_SESSION *ss)
30 {
31     /* if timeout overflowed, it can never timeout! */
32     if (ss->timeout_ovf)
33         return 0;
34     return t > ss->calc_timeout;
35 }
36 
37 /*
38  * Returns -1/0/+1 as other XXXcmp-type functions
39  * Takes overflow of calculated timeout into consideration
40  */
41 __owur static int timeoutcmp(SSL_SESSION *a, SSL_SESSION *b)
42 {
43     /* if only one overflowed, then it is greater */
44     if (a->timeout_ovf && !b->timeout_ovf)
45         return 1;
46     if (!a->timeout_ovf && b->timeout_ovf)
47         return -1;
48     /* No overflow, or both overflowed, so straight compare is safe */
49     if (a->calc_timeout < b->calc_timeout)
50         return -1;
51     if (a->calc_timeout > b->calc_timeout)
52         return 1;
53     return 0;
54 }
55 
56 /*
57  * Calculates effective timeout, saving overflow state
58  * Locking must be done by the caller of this function
59  */
60 void ssl_session_calculate_timeout(SSL_SESSION *ss)
61 {
62     /* Force positive timeout */
63     if (ss->timeout < 0)
64         ss->timeout = 0;
65     ss->calc_timeout = ss->time + ss->timeout;
66     /*
67      * |timeout| is always zero or positive, so the check for
68      * overflow only needs to consider if |time| is positive
69      */
70     ss->timeout_ovf = ss->time > 0 && ss->calc_timeout < ss->time;
71     /*
72      * N.B. Realistic overflow can only occur in our lifetimes on a
73      *      32-bit machine in January 2038.
74      *      However, There are no controls to limit the |timeout|
75      *      value, except to keep it positive.
76      */
77 }
78 
79 /*
80  * SSL_get_session() and SSL_get1_session() are problematic in TLS1.3 because,
81  * unlike in earlier protocol versions, the session ticket may not have been
82  * sent yet even though a handshake has finished. The session ticket data could
83  * come in sometime later...or even change if multiple session ticket messages
84  * are sent from the server. The preferred way for applications to obtain
85  * a resumable session is to use SSL_CTX_sess_set_new_cb().
86  */
87 
88 SSL_SESSION *SSL_get_session(const SSL *ssl)
89 /* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
90 {
91     return ssl->session;
92 }
93 
94 SSL_SESSION *SSL_get1_session(SSL *ssl)
95 /* variant of SSL_get_session: caller really gets something */
96 {
97     SSL_SESSION *sess;
98     /*
99      * Need to lock this all up rather than just use CRYPTO_add so that
100      * somebody doesn't free ssl->session between when we check it's non-null
101      * and when we up the reference count.
102      */
103     if (!CRYPTO_THREAD_read_lock(ssl->lock))
104         return NULL;
105     sess = ssl->session;
106     if (sess)
107         SSL_SESSION_up_ref(sess);
108     CRYPTO_THREAD_unlock(ssl->lock);
109     return sess;
110 }
111 
112 int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
113 {
114     return CRYPTO_set_ex_data(&s->ex_data, idx, arg);
115 }
116 
117 void *SSL_SESSION_get_ex_data(const SSL_SESSION *s, int idx)
118 {
119     return CRYPTO_get_ex_data(&s->ex_data, idx);
120 }
121 
122 SSL_SESSION *SSL_SESSION_new(void)
123 {
124     SSL_SESSION *ss;
125 
126     if (!OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS, NULL))
127         return NULL;
128 
129     ss = OPENSSL_zalloc(sizeof(*ss));
130     if (ss == NULL) {
131         ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
132         return NULL;
133     }
134 
135     ss->verify_result = 1;      /* avoid 0 (= X509_V_OK) just in case */
136     ss->references = 1;
137     ss->timeout = 60 * 5 + 4;   /* 5 minute timeout by default */
138     ss->time = time(NULL);
139     ssl_session_calculate_timeout(ss);
140     ss->lock = CRYPTO_THREAD_lock_new();
141     if (ss->lock == NULL) {
142         ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
143         OPENSSL_free(ss);
144         return NULL;
145     }
146 
147     if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data)) {
148         CRYPTO_THREAD_lock_free(ss->lock);
149         OPENSSL_free(ss);
150         return NULL;
151     }
152     return ss;
153 }
154 
155 /*
156  * Create a new SSL_SESSION and duplicate the contents of |src| into it. If
157  * ticket == 0 then no ticket information is duplicated, otherwise it is.
158  */
159 static SSL_SESSION *ssl_session_dup_intern(const SSL_SESSION *src, int ticket)
160 {
161     SSL_SESSION *dest;
162 
163     dest = OPENSSL_malloc(sizeof(*dest));
164     if (dest == NULL) {
165         goto err;
166     }
167     memcpy(dest, src, sizeof(*dest));
168 
169     /*
170      * Set the various pointers to NULL so that we can call SSL_SESSION_free in
171      * the case of an error whilst halfway through constructing dest
172      */
173 #ifndef OPENSSL_NO_PSK
174     dest->psk_identity_hint = NULL;
175     dest->psk_identity = NULL;
176 #endif
177     dest->ext.hostname = NULL;
178     dest->ext.tick = NULL;
179     dest->ext.alpn_selected = NULL;
180 #ifndef OPENSSL_NO_SRP
181     dest->srp_username = NULL;
182 #endif
183     dest->peer_chain = NULL;
184     dest->peer = NULL;
185     dest->ticket_appdata = NULL;
186     memset(&dest->ex_data, 0, sizeof(dest->ex_data));
187 
188     /* As the copy is not in the cache, we remove the associated pointers */
189     dest->prev = NULL;
190     dest->next = NULL;
191     dest->owner = NULL;
192 
193     dest->references = 1;
194 
195     dest->lock = CRYPTO_THREAD_lock_new();
196     if (dest->lock == NULL) {
197         OPENSSL_free(dest);
198         dest = NULL;
199         goto err;
200     }
201 
202     if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, dest, &dest->ex_data))
203         goto err;
204 
205     if (src->peer != NULL) {
206         if (!X509_up_ref(src->peer))
207             goto err;
208         dest->peer = src->peer;
209     }
210 
211     if (src->peer_chain != NULL) {
212         dest->peer_chain = X509_chain_up_ref(src->peer_chain);
213         if (dest->peer_chain == NULL)
214             goto err;
215     }
216 #ifndef OPENSSL_NO_PSK
217     if (src->psk_identity_hint) {
218         dest->psk_identity_hint = OPENSSL_strdup(src->psk_identity_hint);
219         if (dest->psk_identity_hint == NULL) {
220             goto err;
221         }
222     }
223     if (src->psk_identity) {
224         dest->psk_identity = OPENSSL_strdup(src->psk_identity);
225         if (dest->psk_identity == NULL) {
226             goto err;
227         }
228     }
229 #endif
230 
231     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_SSL_SESSION,
232                             &dest->ex_data, &src->ex_data)) {
233         goto err;
234     }
235 
236     if (src->ext.hostname) {
237         dest->ext.hostname = OPENSSL_strdup(src->ext.hostname);
238         if (dest->ext.hostname == NULL) {
239             goto err;
240         }
241     }
242 
243     if (ticket != 0 && src->ext.tick != NULL) {
244         dest->ext.tick =
245             OPENSSL_memdup(src->ext.tick, src->ext.ticklen);
246         if (dest->ext.tick == NULL)
247             goto err;
248     } else {
249         dest->ext.tick_lifetime_hint = 0;
250         dest->ext.ticklen = 0;
251     }
252 
253     if (src->ext.alpn_selected != NULL) {
254         dest->ext.alpn_selected = OPENSSL_memdup(src->ext.alpn_selected,
255                                                  src->ext.alpn_selected_len);
256         if (dest->ext.alpn_selected == NULL)
257             goto err;
258     }
259 
260 #ifndef OPENSSL_NO_SRP
261     if (src->srp_username) {
262         dest->srp_username = OPENSSL_strdup(src->srp_username);
263         if (dest->srp_username == NULL) {
264             goto err;
265         }
266     }
267 #endif
268 
269     if (src->ticket_appdata != NULL) {
270         dest->ticket_appdata =
271             OPENSSL_memdup(src->ticket_appdata, src->ticket_appdata_len);
272         if (dest->ticket_appdata == NULL)
273             goto err;
274     }
275 
276     return dest;
277  err:
278     ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
279     SSL_SESSION_free(dest);
280     return NULL;
281 }
282 
283 SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src)
284 {
285     return ssl_session_dup_intern(src, 1);
286 }
287 
288 /*
289  * Used internally when duplicating a session which might be already shared.
290  * We will have resumed the original session. Subsequently we might have marked
291  * it as non-resumable (e.g. in another thread) - but this copy should be ok to
292  * resume from.
293  */
294 SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
295 {
296     SSL_SESSION *sess = ssl_session_dup_intern(src, ticket);
297 
298     if (sess != NULL)
299         sess->not_resumable = 0;
300 
301     return sess;
302 }
303 
304 const unsigned char *SSL_SESSION_get_id(const SSL_SESSION *s, unsigned int *len)
305 {
306     if (len)
307         *len = (unsigned int)s->session_id_length;
308     return s->session_id;
309 }
310 const unsigned char *SSL_SESSION_get0_id_context(const SSL_SESSION *s,
311                                                 unsigned int *len)
312 {
313     if (len != NULL)
314         *len = (unsigned int)s->sid_ctx_length;
315     return s->sid_ctx;
316 }
317 
318 unsigned int SSL_SESSION_get_compress_id(const SSL_SESSION *s)
319 {
320     return s->compress_meth;
321 }
322 
323 /*
324  * SSLv3/TLSv1 has 32 bytes (256 bits) of session ID space. As such, filling
325  * the ID with random junk repeatedly until we have no conflict is going to
326  * complete in one iteration pretty much "most" of the time (btw:
327  * understatement). So, if it takes us 10 iterations and we still can't avoid
328  * a conflict - well that's a reasonable point to call it quits. Either the
329  * RAND code is broken or someone is trying to open roughly very close to
330  * 2^256 SSL sessions to our server. How you might store that many sessions
331  * is perhaps a more interesting question ...
332  */
333 
334 #define MAX_SESS_ID_ATTEMPTS 10
335 static int def_generate_session_id(SSL *ssl, unsigned char *id,
336                                    unsigned int *id_len)
337 {
338     unsigned int retry = 0;
339     do
340         if (RAND_bytes_ex(ssl->ctx->libctx, id, *id_len, 0) <= 0)
341             return 0;
342     while (SSL_has_matching_session_id(ssl, id, *id_len) &&
343            (++retry < MAX_SESS_ID_ATTEMPTS)) ;
344     if (retry < MAX_SESS_ID_ATTEMPTS)
345         return 1;
346     /* else - woops a session_id match */
347     /*
348      * XXX We should also check the external cache -- but the probability of
349      * a collision is negligible, and we could not prevent the concurrent
350      * creation of sessions with identical IDs since we currently don't have
351      * means to atomically check whether a session ID already exists and make
352      * a reservation for it if it does not (this problem applies to the
353      * internal cache as well).
354      */
355     return 0;
356 }
357 
358 int ssl_generate_session_id(SSL *s, SSL_SESSION *ss)
359 {
360     unsigned int tmp;
361     GEN_SESSION_CB cb = def_generate_session_id;
362 
363     switch (s->version) {
364     case SSL3_VERSION:
365     case TLS1_VERSION:
366     case TLS1_1_VERSION:
367     case TLS1_2_VERSION:
368     case TLS1_3_VERSION:
369     case DTLS1_BAD_VER:
370     case DTLS1_VERSION:
371     case DTLS1_2_VERSION:
372         ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
373         break;
374     default:
375         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_UNSUPPORTED_SSL_VERSION);
376         return 0;
377     }
378 
379     /*-
380      * If RFC5077 ticket, use empty session ID (as server).
381      * Note that:
382      * (a) ssl_get_prev_session() does lookahead into the
383      *     ClientHello extensions to find the session ticket.
384      *     When ssl_get_prev_session() fails, statem_srvr.c calls
385      *     ssl_get_new_session() in tls_process_client_hello().
386      *     At that point, it has not yet parsed the extensions,
387      *     however, because of the lookahead, it already knows
388      *     whether a ticket is expected or not.
389      *
390      * (b) statem_clnt.c calls ssl_get_new_session() before parsing
391      *     ServerHello extensions, and before recording the session
392      *     ID received from the server, so this block is a noop.
393      */
394     if (s->ext.ticket_expected) {
395         ss->session_id_length = 0;
396         return 1;
397     }
398 
399     /* Choose which callback will set the session ID */
400     if (!CRYPTO_THREAD_read_lock(s->lock))
401         return 0;
402     if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock)) {
403         CRYPTO_THREAD_unlock(s->lock);
404         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
405                  SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
406         return 0;
407     }
408     if (s->generate_session_id)
409         cb = s->generate_session_id;
410     else if (s->session_ctx->generate_session_id)
411         cb = s->session_ctx->generate_session_id;
412     CRYPTO_THREAD_unlock(s->session_ctx->lock);
413     CRYPTO_THREAD_unlock(s->lock);
414     /* Choose a session ID */
415     memset(ss->session_id, 0, ss->session_id_length);
416     tmp = (int)ss->session_id_length;
417     if (!cb(s, ss->session_id, &tmp)) {
418         /* The callback failed */
419         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
420                  SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
421         return 0;
422     }
423     /*
424      * Don't allow the callback to set the session length to zero. nor
425      * set it higher than it was.
426      */
427     if (tmp == 0 || tmp > ss->session_id_length) {
428         /* The callback set an illegal length */
429         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
430                  SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
431         return 0;
432     }
433     ss->session_id_length = tmp;
434     /* Finally, check for a conflict */
435     if (SSL_has_matching_session_id(s, ss->session_id,
436                                     (unsigned int)ss->session_id_length)) {
437         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_SSL_SESSION_ID_CONFLICT);
438         return 0;
439     }
440 
441     return 1;
442 }
443 
444 int ssl_get_new_session(SSL *s, int session)
445 {
446     /* This gets used by clients and servers. */
447 
448     SSL_SESSION *ss = NULL;
449 
450     if ((ss = SSL_SESSION_new()) == NULL) {
451         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
452         return 0;
453     }
454 
455     /* If the context has a default timeout, use it */
456     if (s->session_ctx->session_timeout == 0)
457         ss->timeout = SSL_get_default_timeout(s);
458     else
459         ss->timeout = s->session_ctx->session_timeout;
460     ssl_session_calculate_timeout(ss);
461 
462     SSL_SESSION_free(s->session);
463     s->session = NULL;
464 
465     if (session) {
466         if (SSL_IS_TLS13(s)) {
467             /*
468              * We generate the session id while constructing the
469              * NewSessionTicket in TLSv1.3.
470              */
471             ss->session_id_length = 0;
472         } else if (!ssl_generate_session_id(s, ss)) {
473             /* SSLfatal() already called */
474             SSL_SESSION_free(ss);
475             return 0;
476         }
477 
478     } else {
479         ss->session_id_length = 0;
480     }
481 
482     if (s->sid_ctx_length > sizeof(ss->sid_ctx)) {
483         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
484         SSL_SESSION_free(ss);
485         return 0;
486     }
487     memcpy(ss->sid_ctx, s->sid_ctx, s->sid_ctx_length);
488     ss->sid_ctx_length = s->sid_ctx_length;
489     s->session = ss;
490     ss->ssl_version = s->version;
491     ss->verify_result = X509_V_OK;
492 
493     /* If client supports extended master secret set it in session */
494     if (s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS)
495         ss->flags |= SSL_SESS_FLAG_EXTMS;
496 
497     return 1;
498 }
499 
500 SSL_SESSION *lookup_sess_in_cache(SSL *s, const unsigned char *sess_id,
501                                   size_t sess_id_len)
502 {
503     SSL_SESSION *ret = NULL;
504 
505     if ((s->session_ctx->session_cache_mode
506          & SSL_SESS_CACHE_NO_INTERNAL_LOOKUP) == 0) {
507         SSL_SESSION data;
508 
509         data.ssl_version = s->version;
510         if (!ossl_assert(sess_id_len <= SSL_MAX_SSL_SESSION_ID_LENGTH))
511             return NULL;
512 
513         memcpy(data.session_id, sess_id, sess_id_len);
514         data.session_id_length = sess_id_len;
515 
516         if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock))
517             return NULL;
518         ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
519         if (ret != NULL) {
520             /* don't allow other threads to steal it: */
521             SSL_SESSION_up_ref(ret);
522         }
523         CRYPTO_THREAD_unlock(s->session_ctx->lock);
524         if (ret == NULL)
525             ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_miss);
526     }
527 
528     if (ret == NULL && s->session_ctx->get_session_cb != NULL) {
529         int copy = 1;
530 
531         ret = s->session_ctx->get_session_cb(s, sess_id, sess_id_len, &copy);
532 
533         if (ret != NULL) {
534             if (ret->not_resumable) {
535                 /* If its not resumable then ignore this session */
536                 if (!copy)
537                     SSL_SESSION_free(ret);
538                 return NULL;
539             }
540             ssl_tsan_counter(s->session_ctx,
541                              &s->session_ctx->stats.sess_cb_hit);
542 
543             /*
544              * Increment reference count now if the session callback asks us
545              * to do so (note that if the session structures returned by the
546              * callback are shared between threads, it must handle the
547              * reference count itself [i.e. copy == 0], or things won't be
548              * thread-safe).
549              */
550             if (copy)
551                 SSL_SESSION_up_ref(ret);
552 
553             /*
554              * Add the externally cached session to the internal cache as
555              * well if and only if we are supposed to.
556              */
557             if ((s->session_ctx->session_cache_mode &
558                  SSL_SESS_CACHE_NO_INTERNAL_STORE) == 0) {
559                 /*
560                  * Either return value of SSL_CTX_add_session should not
561                  * interrupt the session resumption process. The return
562                  * value is intentionally ignored.
563                  */
564                 (void)SSL_CTX_add_session(s->session_ctx, ret);
565             }
566         }
567     }
568 
569     return ret;
570 }
571 
572 /*-
573  * ssl_get_prev attempts to find an SSL_SESSION to be used to resume this
574  * connection. It is only called by servers.
575  *
576  *   hello: The parsed ClientHello data
577  *
578  * Returns:
579  *   -1: fatal error
580  *    0: no session found
581  *    1: a session may have been found.
582  *
583  * Side effects:
584  *   - If a session is found then s->session is pointed at it (after freeing an
585  *     existing session if need be) and s->verify_result is set from the session.
586  *   - Both for new and resumed sessions, s->ext.ticket_expected is set to 1
587  *     if the server should issue a new session ticket (to 0 otherwise).
588  */
589 int ssl_get_prev_session(SSL *s, CLIENTHELLO_MSG *hello)
590 {
591     /* This is used only by servers. */
592 
593     SSL_SESSION *ret = NULL;
594     int fatal = 0;
595     int try_session_cache = 0;
596     SSL_TICKET_STATUS r;
597 
598     if (SSL_IS_TLS13(s)) {
599         /*
600          * By default we will send a new ticket. This can be overridden in the
601          * ticket processing.
602          */
603         s->ext.ticket_expected = 1;
604         if (!tls_parse_extension(s, TLSEXT_IDX_psk_kex_modes,
605                                  SSL_EXT_CLIENT_HELLO, hello->pre_proc_exts,
606                                  NULL, 0)
607                 || !tls_parse_extension(s, TLSEXT_IDX_psk, SSL_EXT_CLIENT_HELLO,
608                                         hello->pre_proc_exts, NULL, 0))
609             return -1;
610 
611         ret = s->session;
612     } else {
613         /* sets s->ext.ticket_expected */
614         r = tls_get_ticket_from_client(s, hello, &ret);
615         switch (r) {
616         case SSL_TICKET_FATAL_ERR_MALLOC:
617         case SSL_TICKET_FATAL_ERR_OTHER:
618             fatal = 1;
619             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
620             goto err;
621         case SSL_TICKET_NONE:
622         case SSL_TICKET_EMPTY:
623             if (hello->session_id_len > 0) {
624                 try_session_cache = 1;
625                 ret = lookup_sess_in_cache(s, hello->session_id,
626                                            hello->session_id_len);
627             }
628             break;
629         case SSL_TICKET_NO_DECRYPT:
630         case SSL_TICKET_SUCCESS:
631         case SSL_TICKET_SUCCESS_RENEW:
632             break;
633         }
634     }
635 
636     if (ret == NULL)
637         goto err;
638 
639     /* Now ret is non-NULL and we own one of its reference counts. */
640 
641     /* Check TLS version consistency */
642     if (ret->ssl_version != s->version)
643         goto err;
644 
645     if (ret->sid_ctx_length != s->sid_ctx_length
646         || memcmp(ret->sid_ctx, s->sid_ctx, ret->sid_ctx_length)) {
647         /*
648          * We have the session requested by the client, but we don't want to
649          * use it in this context.
650          */
651         goto err;               /* treat like cache miss */
652     }
653 
654     if ((s->verify_mode & SSL_VERIFY_PEER) && s->sid_ctx_length == 0) {
655         /*
656          * We can't be sure if this session is being used out of context,
657          * which is especially important for SSL_VERIFY_PEER. The application
658          * should have used SSL[_CTX]_set_session_id_context. For this error
659          * case, we generate an error instead of treating the event like a
660          * cache miss (otherwise it would be easy for applications to
661          * effectively disable the session cache by accident without anyone
662          * noticing).
663          */
664 
665         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
666                  SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
667         fatal = 1;
668         goto err;
669     }
670 
671     if (sess_timedout(time(NULL), ret)) {
672         ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_timeout);
673         if (try_session_cache) {
674             /* session was from the cache, so remove it */
675             SSL_CTX_remove_session(s->session_ctx, ret);
676         }
677         goto err;
678     }
679 
680     /* Check extended master secret extension consistency */
681     if (ret->flags & SSL_SESS_FLAG_EXTMS) {
682         /* If old session includes extms, but new does not: abort handshake */
683         if (!(s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS)) {
684             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_INCONSISTENT_EXTMS);
685             fatal = 1;
686             goto err;
687         }
688     } else if (s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS) {
689         /* If new session includes extms, but old does not: do not resume */
690         goto err;
691     }
692 
693     if (!SSL_IS_TLS13(s)) {
694         /* We already did this for TLS1.3 */
695         SSL_SESSION_free(s->session);
696         s->session = ret;
697     }
698 
699     ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_hit);
700     s->verify_result = s->session->verify_result;
701     return 1;
702 
703  err:
704     if (ret != NULL) {
705         SSL_SESSION_free(ret);
706         /* In TLSv1.3 s->session was already set to ret, so we NULL it out */
707         if (SSL_IS_TLS13(s))
708             s->session = NULL;
709 
710         if (!try_session_cache) {
711             /*
712              * The session was from a ticket, so we should issue a ticket for
713              * the new session
714              */
715             s->ext.ticket_expected = 1;
716         }
717     }
718     if (fatal)
719         return -1;
720 
721     return 0;
722 }
723 
724 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
725 {
726     int ret = 0;
727     SSL_SESSION *s;
728 
729     /*
730      * add just 1 reference count for the SSL_CTX's session cache even though
731      * it has two ways of access: each session is in a doubly linked list and
732      * an lhash
733      */
734     SSL_SESSION_up_ref(c);
735     /*
736      * if session c is in already in cache, we take back the increment later
737      */
738 
739     if (!CRYPTO_THREAD_write_lock(ctx->lock)) {
740         SSL_SESSION_free(c);
741         return 0;
742     }
743     s = lh_SSL_SESSION_insert(ctx->sessions, c);
744 
745     /*
746      * s != NULL iff we already had a session with the given PID. In this
747      * case, s == c should hold (then we did not really modify
748      * ctx->sessions), or we're in trouble.
749      */
750     if (s != NULL && s != c) {
751         /* We *are* in trouble ... */
752         SSL_SESSION_list_remove(ctx, s);
753         SSL_SESSION_free(s);
754         /*
755          * ... so pretend the other session did not exist in cache (we cannot
756          * handle two SSL_SESSION structures with identical session ID in the
757          * same cache, which could happen e.g. when two threads concurrently
758          * obtain the same session from an external cache)
759          */
760         s = NULL;
761     } else if (s == NULL &&
762                lh_SSL_SESSION_retrieve(ctx->sessions, c) == NULL) {
763         /* s == NULL can also mean OOM error in lh_SSL_SESSION_insert ... */
764 
765         /*
766          * ... so take back the extra reference and also don't add
767          * the session to the SSL_SESSION_list at this time
768          */
769         s = c;
770     }
771 
772     /* Adjust last used time, and add back into the cache at the appropriate spot */
773     if (ctx->session_cache_mode & SSL_SESS_CACHE_UPDATE_TIME) {
774         c->time = time(NULL);
775         ssl_session_calculate_timeout(c);
776     }
777 
778     if (s == NULL) {
779         /*
780          * new cache entry -- remove old ones if cache has become too large
781          * delete cache entry *before* add, so we don't remove the one we're adding!
782          */
783 
784         ret = 1;
785 
786         if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
787             while (SSL_CTX_sess_number(ctx) >= SSL_CTX_sess_get_cache_size(ctx)) {
788                 if (!remove_session_lock(ctx, ctx->session_cache_tail, 0))
789                     break;
790                 else
791                     ssl_tsan_counter(ctx, &ctx->stats.sess_cache_full);
792             }
793         }
794     }
795 
796     SSL_SESSION_list_add(ctx, c);
797 
798     if (s != NULL) {
799         /*
800          * existing cache entry -- decrement previously incremented reference
801          * count because it already takes into account the cache
802          */
803 
804         SSL_SESSION_free(s);    /* s == c */
805         ret = 0;
806     }
807     CRYPTO_THREAD_unlock(ctx->lock);
808     return ret;
809 }
810 
811 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
812 {
813     return remove_session_lock(ctx, c, 1);
814 }
815 
816 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
817 {
818     SSL_SESSION *r;
819     int ret = 0;
820 
821     if ((c != NULL) && (c->session_id_length != 0)) {
822         if (lck) {
823             if (!CRYPTO_THREAD_write_lock(ctx->lock))
824                 return 0;
825         }
826         if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) != NULL) {
827             ret = 1;
828             r = lh_SSL_SESSION_delete(ctx->sessions, r);
829             SSL_SESSION_list_remove(ctx, r);
830         }
831         c->not_resumable = 1;
832 
833         if (lck)
834             CRYPTO_THREAD_unlock(ctx->lock);
835 
836         if (ctx->remove_session_cb != NULL)
837             ctx->remove_session_cb(ctx, c);
838 
839         if (ret)
840             SSL_SESSION_free(r);
841     }
842     return ret;
843 }
844 
845 void SSL_SESSION_free(SSL_SESSION *ss)
846 {
847     int i;
848 
849     if (ss == NULL)
850         return;
851     CRYPTO_DOWN_REF(&ss->references, &i, ss->lock);
852     REF_PRINT_COUNT("SSL_SESSION", ss);
853     if (i > 0)
854         return;
855     REF_ASSERT_ISNT(i < 0);
856 
857     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
858 
859     OPENSSL_cleanse(ss->master_key, sizeof(ss->master_key));
860     OPENSSL_cleanse(ss->session_id, sizeof(ss->session_id));
861     X509_free(ss->peer);
862     sk_X509_pop_free(ss->peer_chain, X509_free);
863     OPENSSL_free(ss->ext.hostname);
864     OPENSSL_free(ss->ext.tick);
865 #ifndef OPENSSL_NO_PSK
866     OPENSSL_free(ss->psk_identity_hint);
867     OPENSSL_free(ss->psk_identity);
868 #endif
869 #ifndef OPENSSL_NO_SRP
870     OPENSSL_free(ss->srp_username);
871 #endif
872     OPENSSL_free(ss->ext.alpn_selected);
873     OPENSSL_free(ss->ticket_appdata);
874     CRYPTO_THREAD_lock_free(ss->lock);
875     OPENSSL_clear_free(ss, sizeof(*ss));
876 }
877 
878 int SSL_SESSION_up_ref(SSL_SESSION *ss)
879 {
880     int i;
881 
882     if (CRYPTO_UP_REF(&ss->references, &i, ss->lock) <= 0)
883         return 0;
884 
885     REF_PRINT_COUNT("SSL_SESSION", ss);
886     REF_ASSERT_ISNT(i < 2);
887     return ((i > 1) ? 1 : 0);
888 }
889 
890 int SSL_set_session(SSL *s, SSL_SESSION *session)
891 {
892     ssl_clear_bad_session(s);
893     if (s->ctx->method != s->method) {
894         if (!SSL_set_ssl_method(s, s->ctx->method))
895             return 0;
896     }
897 
898     if (session != NULL) {
899         SSL_SESSION_up_ref(session);
900         s->verify_result = session->verify_result;
901     }
902     SSL_SESSION_free(s->session);
903     s->session = session;
904 
905     return 1;
906 }
907 
908 int SSL_SESSION_set1_id(SSL_SESSION *s, const unsigned char *sid,
909                         unsigned int sid_len)
910 {
911     if (sid_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
912       ERR_raise(ERR_LIB_SSL, SSL_R_SSL_SESSION_ID_TOO_LONG);
913       return 0;
914     }
915     s->session_id_length = sid_len;
916     if (sid != s->session_id)
917         memcpy(s->session_id, sid, sid_len);
918     return 1;
919 }
920 
921 long SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
922 {
923     time_t new_timeout = (time_t)t;
924 
925     if (s == NULL || t < 0)
926         return 0;
927     if (s->owner != NULL) {
928         if (!CRYPTO_THREAD_write_lock(s->owner->lock))
929             return 0;
930         s->timeout = new_timeout;
931         ssl_session_calculate_timeout(s);
932         SSL_SESSION_list_add(s->owner, s);
933         CRYPTO_THREAD_unlock(s->owner->lock);
934     } else {
935         s->timeout = new_timeout;
936         ssl_session_calculate_timeout(s);
937     }
938     return 1;
939 }
940 
941 long SSL_SESSION_get_timeout(const SSL_SESSION *s)
942 {
943     if (s == NULL)
944         return 0;
945     return (long)s->timeout;
946 }
947 
948 long SSL_SESSION_get_time(const SSL_SESSION *s)
949 {
950     if (s == NULL)
951         return 0;
952     return (long)s->time;
953 }
954 
955 long SSL_SESSION_set_time(SSL_SESSION *s, long t)
956 {
957     time_t new_time = (time_t)t;
958 
959     if (s == NULL)
960         return 0;
961     if (s->owner != NULL) {
962         if (!CRYPTO_THREAD_write_lock(s->owner->lock))
963             return 0;
964         s->time = new_time;
965         ssl_session_calculate_timeout(s);
966         SSL_SESSION_list_add(s->owner, s);
967         CRYPTO_THREAD_unlock(s->owner->lock);
968     } else {
969         s->time = new_time;
970         ssl_session_calculate_timeout(s);
971     }
972     return t;
973 }
974 
975 int SSL_SESSION_get_protocol_version(const SSL_SESSION *s)
976 {
977     return s->ssl_version;
978 }
979 
980 int SSL_SESSION_set_protocol_version(SSL_SESSION *s, int version)
981 {
982     s->ssl_version = version;
983     return 1;
984 }
985 
986 const SSL_CIPHER *SSL_SESSION_get0_cipher(const SSL_SESSION *s)
987 {
988     return s->cipher;
989 }
990 
991 int SSL_SESSION_set_cipher(SSL_SESSION *s, const SSL_CIPHER *cipher)
992 {
993     s->cipher = cipher;
994     return 1;
995 }
996 
997 const char *SSL_SESSION_get0_hostname(const SSL_SESSION *s)
998 {
999     return s->ext.hostname;
1000 }
1001 
1002 int SSL_SESSION_set1_hostname(SSL_SESSION *s, const char *hostname)
1003 {
1004     OPENSSL_free(s->ext.hostname);
1005     if (hostname == NULL) {
1006         s->ext.hostname = NULL;
1007         return 1;
1008     }
1009     s->ext.hostname = OPENSSL_strdup(hostname);
1010 
1011     return s->ext.hostname != NULL;
1012 }
1013 
1014 int SSL_SESSION_has_ticket(const SSL_SESSION *s)
1015 {
1016     return (s->ext.ticklen > 0) ? 1 : 0;
1017 }
1018 
1019 unsigned long SSL_SESSION_get_ticket_lifetime_hint(const SSL_SESSION *s)
1020 {
1021     return s->ext.tick_lifetime_hint;
1022 }
1023 
1024 void SSL_SESSION_get0_ticket(const SSL_SESSION *s, const unsigned char **tick,
1025                              size_t *len)
1026 {
1027     *len = s->ext.ticklen;
1028     if (tick != NULL)
1029         *tick = s->ext.tick;
1030 }
1031 
1032 uint32_t SSL_SESSION_get_max_early_data(const SSL_SESSION *s)
1033 {
1034     return s->ext.max_early_data;
1035 }
1036 
1037 int SSL_SESSION_set_max_early_data(SSL_SESSION *s, uint32_t max_early_data)
1038 {
1039     s->ext.max_early_data = max_early_data;
1040 
1041     return 1;
1042 }
1043 
1044 void SSL_SESSION_get0_alpn_selected(const SSL_SESSION *s,
1045                                     const unsigned char **alpn,
1046                                     size_t *len)
1047 {
1048     *alpn = s->ext.alpn_selected;
1049     *len = s->ext.alpn_selected_len;
1050 }
1051 
1052 int SSL_SESSION_set1_alpn_selected(SSL_SESSION *s, const unsigned char *alpn,
1053                                    size_t len)
1054 {
1055     OPENSSL_free(s->ext.alpn_selected);
1056     if (alpn == NULL || len == 0) {
1057         s->ext.alpn_selected = NULL;
1058         s->ext.alpn_selected_len = 0;
1059         return 1;
1060     }
1061     s->ext.alpn_selected = OPENSSL_memdup(alpn, len);
1062     if (s->ext.alpn_selected == NULL) {
1063         s->ext.alpn_selected_len = 0;
1064         return 0;
1065     }
1066     s->ext.alpn_selected_len = len;
1067 
1068     return 1;
1069 }
1070 
1071 X509 *SSL_SESSION_get0_peer(SSL_SESSION *s)
1072 {
1073     return s->peer;
1074 }
1075 
1076 int SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
1077                                 unsigned int sid_ctx_len)
1078 {
1079     if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
1080         ERR_raise(ERR_LIB_SSL, SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
1081         return 0;
1082     }
1083     s->sid_ctx_length = sid_ctx_len;
1084     if (sid_ctx != s->sid_ctx)
1085         memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
1086 
1087     return 1;
1088 }
1089 
1090 int SSL_SESSION_is_resumable(const SSL_SESSION *s)
1091 {
1092     /*
1093      * In the case of EAP-FAST, we can have a pre-shared "ticket" without a
1094      * session ID.
1095      */
1096     return !s->not_resumable
1097            && (s->session_id_length > 0 || s->ext.ticklen > 0);
1098 }
1099 
1100 long SSL_CTX_set_timeout(SSL_CTX *s, long t)
1101 {
1102     long l;
1103     if (s == NULL)
1104         return 0;
1105     l = s->session_timeout;
1106     s->session_timeout = t;
1107     return l;
1108 }
1109 
1110 long SSL_CTX_get_timeout(const SSL_CTX *s)
1111 {
1112     if (s == NULL)
1113         return 0;
1114     return s->session_timeout;
1115 }
1116 
1117 int SSL_set_session_secret_cb(SSL *s,
1118                               tls_session_secret_cb_fn tls_session_secret_cb,
1119                               void *arg)
1120 {
1121     if (s == NULL)
1122         return 0;
1123     s->ext.session_secret_cb = tls_session_secret_cb;
1124     s->ext.session_secret_cb_arg = arg;
1125     return 1;
1126 }
1127 
1128 int SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
1129                                   void *arg)
1130 {
1131     if (s == NULL)
1132         return 0;
1133     s->ext.session_ticket_cb = cb;
1134     s->ext.session_ticket_cb_arg = arg;
1135     return 1;
1136 }
1137 
1138 int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
1139 {
1140     if (s->version >= TLS1_VERSION) {
1141         OPENSSL_free(s->ext.session_ticket);
1142         s->ext.session_ticket = NULL;
1143         s->ext.session_ticket =
1144             OPENSSL_malloc(sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
1145         if (s->ext.session_ticket == NULL) {
1146             ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
1147             return 0;
1148         }
1149 
1150         if (ext_data != NULL) {
1151             s->ext.session_ticket->length = ext_len;
1152             s->ext.session_ticket->data = s->ext.session_ticket + 1;
1153             memcpy(s->ext.session_ticket->data, ext_data, ext_len);
1154         } else {
1155             s->ext.session_ticket->length = 0;
1156             s->ext.session_ticket->data = NULL;
1157         }
1158 
1159         return 1;
1160     }
1161 
1162     return 0;
1163 }
1164 
1165 void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
1166 {
1167     STACK_OF(SSL_SESSION) *sk;
1168     SSL_SESSION *current;
1169     unsigned long i;
1170 
1171     if (!CRYPTO_THREAD_write_lock(s->lock))
1172         return;
1173 
1174     sk = sk_SSL_SESSION_new_null();
1175     i = lh_SSL_SESSION_get_down_load(s->sessions);
1176     lh_SSL_SESSION_set_down_load(s->sessions, 0);
1177 
1178     /*
1179      * Iterate over the list from the back (oldest), and stop
1180      * when a session can no longer be removed.
1181      * Add the session to a temporary list to be freed outside
1182      * the SSL_CTX lock.
1183      * But still do the remove_session_cb() within the lock.
1184      */
1185     while (s->session_cache_tail != NULL) {
1186         current = s->session_cache_tail;
1187         if (t == 0 || sess_timedout((time_t)t, current)) {
1188             lh_SSL_SESSION_delete(s->sessions, current);
1189             SSL_SESSION_list_remove(s, current);
1190             current->not_resumable = 1;
1191             if (s->remove_session_cb != NULL)
1192                 s->remove_session_cb(s, current);
1193             /*
1194              * Throw the session on a stack, it's entirely plausible
1195              * that while freeing outside the critical section, the
1196              * session could be re-added, so avoid using the next/prev
1197              * pointers. If the stack failed to create, or the session
1198              * couldn't be put on the stack, just free it here
1199              */
1200             if (sk == NULL || !sk_SSL_SESSION_push(sk, current))
1201                 SSL_SESSION_free(current);
1202         } else {
1203             break;
1204         }
1205     }
1206 
1207     lh_SSL_SESSION_set_down_load(s->sessions, i);
1208     CRYPTO_THREAD_unlock(s->lock);
1209 
1210     sk_SSL_SESSION_pop_free(sk, SSL_SESSION_free);
1211 }
1212 
1213 int ssl_clear_bad_session(SSL *s)
1214 {
1215     if ((s->session != NULL) &&
1216         !(s->shutdown & SSL_SENT_SHUTDOWN) &&
1217         !(SSL_in_init(s) || SSL_in_before(s))) {
1218         SSL_CTX_remove_session(s->session_ctx, s->session);
1219         return 1;
1220     } else
1221         return 0;
1222 }
1223 
1224 /* locked by SSL_CTX in the calling function */
1225 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
1226 {
1227     if ((s->next == NULL) || (s->prev == NULL))
1228         return;
1229 
1230     if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail)) {
1231         /* last element in list */
1232         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1233             /* only one element in list */
1234             ctx->session_cache_head = NULL;
1235             ctx->session_cache_tail = NULL;
1236         } else {
1237             ctx->session_cache_tail = s->prev;
1238             s->prev->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1239         }
1240     } else {
1241         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1242             /* first element in list */
1243             ctx->session_cache_head = s->next;
1244             s->next->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1245         } else {
1246             /* middle of list */
1247             s->next->prev = s->prev;
1248             s->prev->next = s->next;
1249         }
1250     }
1251     s->prev = s->next = NULL;
1252     s->owner = NULL;
1253 }
1254 
1255 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
1256 {
1257     SSL_SESSION *next;
1258 
1259     if ((s->next != NULL) && (s->prev != NULL))
1260         SSL_SESSION_list_remove(ctx, s);
1261 
1262     if (ctx->session_cache_head == NULL) {
1263         ctx->session_cache_head = s;
1264         ctx->session_cache_tail = s;
1265         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1266         s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1267     } else {
1268         if (timeoutcmp(s, ctx->session_cache_head) >= 0) {
1269             /*
1270              * if we timeout after (or the same time as) the first
1271              * session, put us first - usual case
1272              */
1273             s->next = ctx->session_cache_head;
1274             s->next->prev = s;
1275             s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1276             ctx->session_cache_head = s;
1277         } else if (timeoutcmp(s, ctx->session_cache_tail) < 0) {
1278             /* if we timeout before the last session, put us last */
1279             s->prev = ctx->session_cache_tail;
1280             s->prev->next = s;
1281             s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1282             ctx->session_cache_tail = s;
1283         } else {
1284             /*
1285              * we timeout somewhere in-between - if there is only
1286              * one session in the cache it will be caught above
1287              */
1288             next = ctx->session_cache_head->next;
1289             while (next != (SSL_SESSION*)&(ctx->session_cache_tail)) {
1290                 if (timeoutcmp(s, next) >= 0) {
1291                     s->next = next;
1292                     s->prev = next->prev;
1293                     next->prev->next = s;
1294                     next->prev = s;
1295                     break;
1296                 }
1297                 next = next->next;
1298             }
1299         }
1300     }
1301     s->owner = ctx;
1302 }
1303 
1304 void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
1305                              int (*cb) (struct ssl_st *ssl, SSL_SESSION *sess))
1306 {
1307     ctx->new_session_cb = cb;
1308 }
1309 
1310 int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx)) (SSL *ssl, SSL_SESSION *sess) {
1311     return ctx->new_session_cb;
1312 }
1313 
1314 void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
1315                                 void (*cb) (SSL_CTX *ctx, SSL_SESSION *sess))
1316 {
1317     ctx->remove_session_cb = cb;
1318 }
1319 
1320 void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx)) (SSL_CTX *ctx,
1321                                                   SSL_SESSION *sess) {
1322     return ctx->remove_session_cb;
1323 }
1324 
1325 void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
1326                              SSL_SESSION *(*cb) (struct ssl_st *ssl,
1327                                                  const unsigned char *data,
1328                                                  int len, int *copy))
1329 {
1330     ctx->get_session_cb = cb;
1331 }
1332 
1333 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx)) (SSL *ssl,
1334                                                        const unsigned char
1335                                                        *data, int len,
1336                                                        int *copy) {
1337     return ctx->get_session_cb;
1338 }
1339 
1340 void SSL_CTX_set_info_callback(SSL_CTX *ctx,
1341                                void (*cb) (const SSL *ssl, int type, int val))
1342 {
1343     ctx->info_callback = cb;
1344 }
1345 
1346 void (*SSL_CTX_get_info_callback(SSL_CTX *ctx)) (const SSL *ssl, int type,
1347                                                  int val) {
1348     return ctx->info_callback;
1349 }
1350 
1351 void SSL_CTX_set_client_cert_cb(SSL_CTX *ctx,
1352                                 int (*cb) (SSL *ssl, X509 **x509,
1353                                            EVP_PKEY **pkey))
1354 {
1355     ctx->client_cert_cb = cb;
1356 }
1357 
1358 int (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx)) (SSL *ssl, X509 **x509,
1359                                                  EVP_PKEY **pkey) {
1360     return ctx->client_cert_cb;
1361 }
1362 
1363 void SSL_CTX_set_cookie_generate_cb(SSL_CTX *ctx,
1364                                     int (*cb) (SSL *ssl,
1365                                                unsigned char *cookie,
1366                                                unsigned int *cookie_len))
1367 {
1368     ctx->app_gen_cookie_cb = cb;
1369 }
1370 
1371 void SSL_CTX_set_cookie_verify_cb(SSL_CTX *ctx,
1372                                   int (*cb) (SSL *ssl,
1373                                              const unsigned char *cookie,
1374                                              unsigned int cookie_len))
1375 {
1376     ctx->app_verify_cookie_cb = cb;
1377 }
1378 
1379 int SSL_SESSION_set1_ticket_appdata(SSL_SESSION *ss, const void *data, size_t len)
1380 {
1381     OPENSSL_free(ss->ticket_appdata);
1382     ss->ticket_appdata_len = 0;
1383     if (data == NULL || len == 0) {
1384         ss->ticket_appdata = NULL;
1385         return 1;
1386     }
1387     ss->ticket_appdata = OPENSSL_memdup(data, len);
1388     if (ss->ticket_appdata != NULL) {
1389         ss->ticket_appdata_len = len;
1390         return 1;
1391     }
1392     return 0;
1393 }
1394 
1395 int SSL_SESSION_get0_ticket_appdata(SSL_SESSION *ss, void **data, size_t *len)
1396 {
1397     *data = ss->ticket_appdata;
1398     *len = ss->ticket_appdata_len;
1399     return 1;
1400 }
1401 
1402 void SSL_CTX_set_stateless_cookie_generate_cb(
1403     SSL_CTX *ctx,
1404     int (*cb) (SSL *ssl,
1405                unsigned char *cookie,
1406                size_t *cookie_len))
1407 {
1408     ctx->gen_stateless_cookie_cb = cb;
1409 }
1410 
1411 void SSL_CTX_set_stateless_cookie_verify_cb(
1412     SSL_CTX *ctx,
1413     int (*cb) (SSL *ssl,
1414                const unsigned char *cookie,
1415                size_t cookie_len))
1416 {
1417     ctx->verify_stateless_cookie_cb = cb;
1418 }
1419 
1420 IMPLEMENT_PEM_rw(SSL_SESSION, SSL_SESSION, PEM_STRING_SSL_SESSION, SSL_SESSION)
1421