xref: /freebsd/crypto/openssl/ssl/ssl_sess.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*
2  * Copyright 1995-2023 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 SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src)
156 {
157     return ssl_session_dup(src, 1);
158 }
159 
160 /*
161  * Create a new SSL_SESSION and duplicate the contents of |src| into it. If
162  * ticket == 0 then no ticket information is duplicated, otherwise it is.
163  */
164 SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
165 {
166     SSL_SESSION *dest;
167 
168     dest = OPENSSL_malloc(sizeof(*dest));
169     if (dest == NULL) {
170         goto err;
171     }
172     memcpy(dest, src, sizeof(*dest));
173 
174     /*
175      * Set the various pointers to NULL so that we can call SSL_SESSION_free in
176      * the case of an error whilst halfway through constructing dest
177      */
178 #ifndef OPENSSL_NO_PSK
179     dest->psk_identity_hint = NULL;
180     dest->psk_identity = NULL;
181 #endif
182     dest->ext.hostname = NULL;
183     dest->ext.tick = NULL;
184     dest->ext.alpn_selected = NULL;
185 #ifndef OPENSSL_NO_SRP
186     dest->srp_username = NULL;
187 #endif
188     dest->peer_chain = NULL;
189     dest->peer = NULL;
190     dest->ticket_appdata = NULL;
191     memset(&dest->ex_data, 0, sizeof(dest->ex_data));
192 
193     /* As the copy is not in the cache, we remove the associated pointers */
194     dest->prev = NULL;
195     dest->next = NULL;
196     dest->owner = NULL;
197 
198     dest->references = 1;
199 
200     dest->lock = CRYPTO_THREAD_lock_new();
201     if (dest->lock == NULL)
202         goto err;
203 
204     if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, dest, &dest->ex_data))
205         goto err;
206 
207     if (src->peer != NULL) {
208         if (!X509_up_ref(src->peer))
209             goto err;
210         dest->peer = src->peer;
211     }
212 
213     if (src->peer_chain != NULL) {
214         dest->peer_chain = X509_chain_up_ref(src->peer_chain);
215         if (dest->peer_chain == NULL)
216             goto err;
217     }
218 #ifndef OPENSSL_NO_PSK
219     if (src->psk_identity_hint) {
220         dest->psk_identity_hint = OPENSSL_strdup(src->psk_identity_hint);
221         if (dest->psk_identity_hint == NULL) {
222             goto err;
223         }
224     }
225     if (src->psk_identity) {
226         dest->psk_identity = OPENSSL_strdup(src->psk_identity);
227         if (dest->psk_identity == NULL) {
228             goto err;
229         }
230     }
231 #endif
232 
233     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_SSL_SESSION,
234                             &dest->ex_data, &src->ex_data)) {
235         goto err;
236     }
237 
238     if (src->ext.hostname) {
239         dest->ext.hostname = OPENSSL_strdup(src->ext.hostname);
240         if (dest->ext.hostname == NULL) {
241             goto err;
242         }
243     }
244 
245     if (ticket != 0 && src->ext.tick != NULL) {
246         dest->ext.tick =
247             OPENSSL_memdup(src->ext.tick, src->ext.ticklen);
248         if (dest->ext.tick == NULL)
249             goto err;
250     } else {
251         dest->ext.tick_lifetime_hint = 0;
252         dest->ext.ticklen = 0;
253     }
254 
255     if (src->ext.alpn_selected != NULL) {
256         dest->ext.alpn_selected = OPENSSL_memdup(src->ext.alpn_selected,
257                                                  src->ext.alpn_selected_len);
258         if (dest->ext.alpn_selected == NULL)
259             goto err;
260     }
261 
262 #ifndef OPENSSL_NO_SRP
263     if (src->srp_username) {
264         dest->srp_username = OPENSSL_strdup(src->srp_username);
265         if (dest->srp_username == NULL) {
266             goto err;
267         }
268     }
269 #endif
270 
271     if (src->ticket_appdata != NULL) {
272         dest->ticket_appdata =
273             OPENSSL_memdup(src->ticket_appdata, src->ticket_appdata_len);
274         if (dest->ticket_appdata == NULL)
275             goto err;
276     }
277 
278     return dest;
279  err:
280     ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
281     SSL_SESSION_free(dest);
282     return NULL;
283 }
284 
285 const unsigned char *SSL_SESSION_get_id(const SSL_SESSION *s, unsigned int *len)
286 {
287     if (len)
288         *len = (unsigned int)s->session_id_length;
289     return s->session_id;
290 }
291 const unsigned char *SSL_SESSION_get0_id_context(const SSL_SESSION *s,
292                                                 unsigned int *len)
293 {
294     if (len != NULL)
295         *len = (unsigned int)s->sid_ctx_length;
296     return s->sid_ctx;
297 }
298 
299 unsigned int SSL_SESSION_get_compress_id(const SSL_SESSION *s)
300 {
301     return s->compress_meth;
302 }
303 
304 /*
305  * SSLv3/TLSv1 has 32 bytes (256 bits) of session ID space. As such, filling
306  * the ID with random junk repeatedly until we have no conflict is going to
307  * complete in one iteration pretty much "most" of the time (btw:
308  * understatement). So, if it takes us 10 iterations and we still can't avoid
309  * a conflict - well that's a reasonable point to call it quits. Either the
310  * RAND code is broken or someone is trying to open roughly very close to
311  * 2^256 SSL sessions to our server. How you might store that many sessions
312  * is perhaps a more interesting question ...
313  */
314 
315 #define MAX_SESS_ID_ATTEMPTS 10
316 static int def_generate_session_id(SSL *ssl, unsigned char *id,
317                                    unsigned int *id_len)
318 {
319     unsigned int retry = 0;
320     do
321         if (RAND_bytes_ex(ssl->ctx->libctx, id, *id_len, 0) <= 0)
322             return 0;
323     while (SSL_has_matching_session_id(ssl, id, *id_len) &&
324            (++retry < MAX_SESS_ID_ATTEMPTS)) ;
325     if (retry < MAX_SESS_ID_ATTEMPTS)
326         return 1;
327     /* else - woops a session_id match */
328     /*
329      * XXX We should also check the external cache -- but the probability of
330      * a collision is negligible, and we could not prevent the concurrent
331      * creation of sessions with identical IDs since we currently don't have
332      * means to atomically check whether a session ID already exists and make
333      * a reservation for it if it does not (this problem applies to the
334      * internal cache as well).
335      */
336     return 0;
337 }
338 
339 int ssl_generate_session_id(SSL *s, SSL_SESSION *ss)
340 {
341     unsigned int tmp;
342     GEN_SESSION_CB cb = def_generate_session_id;
343 
344     switch (s->version) {
345     case SSL3_VERSION:
346     case TLS1_VERSION:
347     case TLS1_1_VERSION:
348     case TLS1_2_VERSION:
349     case TLS1_3_VERSION:
350     case DTLS1_BAD_VER:
351     case DTLS1_VERSION:
352     case DTLS1_2_VERSION:
353         ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
354         break;
355     default:
356         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_UNSUPPORTED_SSL_VERSION);
357         return 0;
358     }
359 
360     /*-
361      * If RFC5077 ticket, use empty session ID (as server).
362      * Note that:
363      * (a) ssl_get_prev_session() does lookahead into the
364      *     ClientHello extensions to find the session ticket.
365      *     When ssl_get_prev_session() fails, statem_srvr.c calls
366      *     ssl_get_new_session() in tls_process_client_hello().
367      *     At that point, it has not yet parsed the extensions,
368      *     however, because of the lookahead, it already knows
369      *     whether a ticket is expected or not.
370      *
371      * (b) statem_clnt.c calls ssl_get_new_session() before parsing
372      *     ServerHello extensions, and before recording the session
373      *     ID received from the server, so this block is a noop.
374      */
375     if (s->ext.ticket_expected) {
376         ss->session_id_length = 0;
377         return 1;
378     }
379 
380     /* Choose which callback will set the session ID */
381     if (!CRYPTO_THREAD_read_lock(s->lock))
382         return 0;
383     if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock)) {
384         CRYPTO_THREAD_unlock(s->lock);
385         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
386                  SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
387         return 0;
388     }
389     if (s->generate_session_id)
390         cb = s->generate_session_id;
391     else if (s->session_ctx->generate_session_id)
392         cb = s->session_ctx->generate_session_id;
393     CRYPTO_THREAD_unlock(s->session_ctx->lock);
394     CRYPTO_THREAD_unlock(s->lock);
395     /* Choose a session ID */
396     memset(ss->session_id, 0, ss->session_id_length);
397     tmp = (int)ss->session_id_length;
398     if (!cb(s, ss->session_id, &tmp)) {
399         /* The callback failed */
400         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
401                  SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
402         return 0;
403     }
404     /*
405      * Don't allow the callback to set the session length to zero. nor
406      * set it higher than it was.
407      */
408     if (tmp == 0 || tmp > ss->session_id_length) {
409         /* The callback set an illegal length */
410         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
411                  SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
412         return 0;
413     }
414     ss->session_id_length = tmp;
415     /* Finally, check for a conflict */
416     if (SSL_has_matching_session_id(s, ss->session_id,
417                                     (unsigned int)ss->session_id_length)) {
418         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_SSL_SESSION_ID_CONFLICT);
419         return 0;
420     }
421 
422     return 1;
423 }
424 
425 int ssl_get_new_session(SSL *s, int session)
426 {
427     /* This gets used by clients and servers. */
428 
429     SSL_SESSION *ss = NULL;
430 
431     if ((ss = SSL_SESSION_new()) == NULL) {
432         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_MALLOC_FAILURE);
433         return 0;
434     }
435 
436     /* If the context has a default timeout, use it */
437     if (s->session_ctx->session_timeout == 0)
438         ss->timeout = SSL_get_default_timeout(s);
439     else
440         ss->timeout = s->session_ctx->session_timeout;
441     ssl_session_calculate_timeout(ss);
442 
443     SSL_SESSION_free(s->session);
444     s->session = NULL;
445 
446     if (session) {
447         if (SSL_IS_TLS13(s)) {
448             /*
449              * We generate the session id while constructing the
450              * NewSessionTicket in TLSv1.3.
451              */
452             ss->session_id_length = 0;
453         } else if (!ssl_generate_session_id(s, ss)) {
454             /* SSLfatal() already called */
455             SSL_SESSION_free(ss);
456             return 0;
457         }
458 
459     } else {
460         ss->session_id_length = 0;
461     }
462 
463     if (s->sid_ctx_length > sizeof(ss->sid_ctx)) {
464         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
465         SSL_SESSION_free(ss);
466         return 0;
467     }
468     memcpy(ss->sid_ctx, s->sid_ctx, s->sid_ctx_length);
469     ss->sid_ctx_length = s->sid_ctx_length;
470     s->session = ss;
471     ss->ssl_version = s->version;
472     ss->verify_result = X509_V_OK;
473 
474     /* If client supports extended master secret set it in session */
475     if (s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS)
476         ss->flags |= SSL_SESS_FLAG_EXTMS;
477 
478     return 1;
479 }
480 
481 SSL_SESSION *lookup_sess_in_cache(SSL *s, const unsigned char *sess_id,
482                                   size_t sess_id_len)
483 {
484     SSL_SESSION *ret = NULL;
485 
486     if ((s->session_ctx->session_cache_mode
487          & SSL_SESS_CACHE_NO_INTERNAL_LOOKUP) == 0) {
488         SSL_SESSION data;
489 
490         data.ssl_version = s->version;
491         if (!ossl_assert(sess_id_len <= SSL_MAX_SSL_SESSION_ID_LENGTH))
492             return NULL;
493 
494         memcpy(data.session_id, sess_id, sess_id_len);
495         data.session_id_length = sess_id_len;
496 
497         if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock))
498             return NULL;
499         ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
500         if (ret != NULL) {
501             /* don't allow other threads to steal it: */
502             SSL_SESSION_up_ref(ret);
503         }
504         CRYPTO_THREAD_unlock(s->session_ctx->lock);
505         if (ret == NULL)
506             ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_miss);
507     }
508 
509     if (ret == NULL && s->session_ctx->get_session_cb != NULL) {
510         int copy = 1;
511 
512         ret = s->session_ctx->get_session_cb(s, sess_id, sess_id_len, &copy);
513 
514         if (ret != NULL) {
515             ssl_tsan_counter(s->session_ctx,
516                              &s->session_ctx->stats.sess_cb_hit);
517 
518             /*
519              * Increment reference count now if the session callback asks us
520              * to do so (note that if the session structures returned by the
521              * callback are shared between threads, it must handle the
522              * reference count itself [i.e. copy == 0], or things won't be
523              * thread-safe).
524              */
525             if (copy)
526                 SSL_SESSION_up_ref(ret);
527 
528             /*
529              * Add the externally cached session to the internal cache as
530              * well if and only if we are supposed to.
531              */
532             if ((s->session_ctx->session_cache_mode &
533                  SSL_SESS_CACHE_NO_INTERNAL_STORE) == 0) {
534                 /*
535                  * Either return value of SSL_CTX_add_session should not
536                  * interrupt the session resumption process. The return
537                  * value is intentionally ignored.
538                  */
539                 (void)SSL_CTX_add_session(s->session_ctx, ret);
540             }
541         }
542     }
543 
544     return ret;
545 }
546 
547 /*-
548  * ssl_get_prev attempts to find an SSL_SESSION to be used to resume this
549  * connection. It is only called by servers.
550  *
551  *   hello: The parsed ClientHello data
552  *
553  * Returns:
554  *   -1: fatal error
555  *    0: no session found
556  *    1: a session may have been found.
557  *
558  * Side effects:
559  *   - If a session is found then s->session is pointed at it (after freeing an
560  *     existing session if need be) and s->verify_result is set from the session.
561  *   - Both for new and resumed sessions, s->ext.ticket_expected is set to 1
562  *     if the server should issue a new session ticket (to 0 otherwise).
563  */
564 int ssl_get_prev_session(SSL *s, CLIENTHELLO_MSG *hello)
565 {
566     /* This is used only by servers. */
567 
568     SSL_SESSION *ret = NULL;
569     int fatal = 0;
570     int try_session_cache = 0;
571     SSL_TICKET_STATUS r;
572 
573     if (SSL_IS_TLS13(s)) {
574         /*
575          * By default we will send a new ticket. This can be overridden in the
576          * ticket processing.
577          */
578         s->ext.ticket_expected = 1;
579         if (!tls_parse_extension(s, TLSEXT_IDX_psk_kex_modes,
580                                  SSL_EXT_CLIENT_HELLO, hello->pre_proc_exts,
581                                  NULL, 0)
582                 || !tls_parse_extension(s, TLSEXT_IDX_psk, SSL_EXT_CLIENT_HELLO,
583                                         hello->pre_proc_exts, NULL, 0))
584             return -1;
585 
586         ret = s->session;
587     } else {
588         /* sets s->ext.ticket_expected */
589         r = tls_get_ticket_from_client(s, hello, &ret);
590         switch (r) {
591         case SSL_TICKET_FATAL_ERR_MALLOC:
592         case SSL_TICKET_FATAL_ERR_OTHER:
593             fatal = 1;
594             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
595             goto err;
596         case SSL_TICKET_NONE:
597         case SSL_TICKET_EMPTY:
598             if (hello->session_id_len > 0) {
599                 try_session_cache = 1;
600                 ret = lookup_sess_in_cache(s, hello->session_id,
601                                            hello->session_id_len);
602             }
603             break;
604         case SSL_TICKET_NO_DECRYPT:
605         case SSL_TICKET_SUCCESS:
606         case SSL_TICKET_SUCCESS_RENEW:
607             break;
608         }
609     }
610 
611     if (ret == NULL)
612         goto err;
613 
614     /* Now ret is non-NULL and we own one of its reference counts. */
615 
616     /* Check TLS version consistency */
617     if (ret->ssl_version != s->version)
618         goto err;
619 
620     if (ret->sid_ctx_length != s->sid_ctx_length
621         || memcmp(ret->sid_ctx, s->sid_ctx, ret->sid_ctx_length)) {
622         /*
623          * We have the session requested by the client, but we don't want to
624          * use it in this context.
625          */
626         goto err;               /* treat like cache miss */
627     }
628 
629     if ((s->verify_mode & SSL_VERIFY_PEER) && s->sid_ctx_length == 0) {
630         /*
631          * We can't be sure if this session is being used out of context,
632          * which is especially important for SSL_VERIFY_PEER. The application
633          * should have used SSL[_CTX]_set_session_id_context. For this error
634          * case, we generate an error instead of treating the event like a
635          * cache miss (otherwise it would be easy for applications to
636          * effectively disable the session cache by accident without anyone
637          * noticing).
638          */
639 
640         SSLfatal(s, SSL_AD_INTERNAL_ERROR,
641                  SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
642         fatal = 1;
643         goto err;
644     }
645 
646     if (sess_timedout(time(NULL), ret)) {
647         ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_timeout);
648         if (try_session_cache) {
649             /* session was from the cache, so remove it */
650             SSL_CTX_remove_session(s->session_ctx, ret);
651         }
652         goto err;
653     }
654 
655     /* Check extended master secret extension consistency */
656     if (ret->flags & SSL_SESS_FLAG_EXTMS) {
657         /* If old session includes extms, but new does not: abort handshake */
658         if (!(s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS)) {
659             SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_INCONSISTENT_EXTMS);
660             fatal = 1;
661             goto err;
662         }
663     } else if (s->s3.flags & TLS1_FLAGS_RECEIVED_EXTMS) {
664         /* If new session includes extms, but old does not: do not resume */
665         goto err;
666     }
667 
668     if (!SSL_IS_TLS13(s)) {
669         /* We already did this for TLS1.3 */
670         SSL_SESSION_free(s->session);
671         s->session = ret;
672     }
673 
674     ssl_tsan_counter(s->session_ctx, &s->session_ctx->stats.sess_hit);
675     s->verify_result = s->session->verify_result;
676     return 1;
677 
678  err:
679     if (ret != NULL) {
680         SSL_SESSION_free(ret);
681         /* In TLSv1.3 s->session was already set to ret, so we NULL it out */
682         if (SSL_IS_TLS13(s))
683             s->session = NULL;
684 
685         if (!try_session_cache) {
686             /*
687              * The session was from a ticket, so we should issue a ticket for
688              * the new session
689              */
690             s->ext.ticket_expected = 1;
691         }
692     }
693     if (fatal)
694         return -1;
695 
696     return 0;
697 }
698 
699 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
700 {
701     int ret = 0;
702     SSL_SESSION *s;
703 
704     /*
705      * add just 1 reference count for the SSL_CTX's session cache even though
706      * it has two ways of access: each session is in a doubly linked list and
707      * an lhash
708      */
709     SSL_SESSION_up_ref(c);
710     /*
711      * if session c is in already in cache, we take back the increment later
712      */
713 
714     if (!CRYPTO_THREAD_write_lock(ctx->lock)) {
715         SSL_SESSION_free(c);
716         return 0;
717     }
718     s = lh_SSL_SESSION_insert(ctx->sessions, c);
719 
720     /*
721      * s != NULL iff we already had a session with the given PID. In this
722      * case, s == c should hold (then we did not really modify
723      * ctx->sessions), or we're in trouble.
724      */
725     if (s != NULL && s != c) {
726         /* We *are* in trouble ... */
727         SSL_SESSION_list_remove(ctx, s);
728         SSL_SESSION_free(s);
729         /*
730          * ... so pretend the other session did not exist in cache (we cannot
731          * handle two SSL_SESSION structures with identical session ID in the
732          * same cache, which could happen e.g. when two threads concurrently
733          * obtain the same session from an external cache)
734          */
735         s = NULL;
736     } else if (s == NULL &&
737                lh_SSL_SESSION_retrieve(ctx->sessions, c) == NULL) {
738         /* s == NULL can also mean OOM error in lh_SSL_SESSION_insert ... */
739 
740         /*
741          * ... so take back the extra reference and also don't add
742          * the session to the SSL_SESSION_list at this time
743          */
744         s = c;
745     }
746 
747     /* Adjust last used time, and add back into the cache at the appropriate spot */
748     if (ctx->session_cache_mode & SSL_SESS_CACHE_UPDATE_TIME) {
749         c->time = time(NULL);
750         ssl_session_calculate_timeout(c);
751     }
752 
753     if (s == NULL) {
754         /*
755          * new cache entry -- remove old ones if cache has become too large
756          * delete cache entry *before* add, so we don't remove the one we're adding!
757          */
758 
759         ret = 1;
760 
761         if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
762             while (SSL_CTX_sess_number(ctx) >= SSL_CTX_sess_get_cache_size(ctx)) {
763                 if (!remove_session_lock(ctx, ctx->session_cache_tail, 0))
764                     break;
765                 else
766                     ssl_tsan_counter(ctx, &ctx->stats.sess_cache_full);
767             }
768         }
769     }
770 
771     SSL_SESSION_list_add(ctx, c);
772 
773     if (s != NULL) {
774         /*
775          * existing cache entry -- decrement previously incremented reference
776          * count because it already takes into account the cache
777          */
778 
779         SSL_SESSION_free(s);    /* s == c */
780         ret = 0;
781     }
782     CRYPTO_THREAD_unlock(ctx->lock);
783     return ret;
784 }
785 
786 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
787 {
788     return remove_session_lock(ctx, c, 1);
789 }
790 
791 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
792 {
793     SSL_SESSION *r;
794     int ret = 0;
795 
796     if ((c != NULL) && (c->session_id_length != 0)) {
797         if (lck) {
798             if (!CRYPTO_THREAD_write_lock(ctx->lock))
799                 return 0;
800         }
801         if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) != NULL) {
802             ret = 1;
803             r = lh_SSL_SESSION_delete(ctx->sessions, r);
804             SSL_SESSION_list_remove(ctx, r);
805         }
806         c->not_resumable = 1;
807 
808         if (lck)
809             CRYPTO_THREAD_unlock(ctx->lock);
810 
811         if (ctx->remove_session_cb != NULL)
812             ctx->remove_session_cb(ctx, c);
813 
814         if (ret)
815             SSL_SESSION_free(r);
816     }
817     return ret;
818 }
819 
820 void SSL_SESSION_free(SSL_SESSION *ss)
821 {
822     int i;
823 
824     if (ss == NULL)
825         return;
826     CRYPTO_DOWN_REF(&ss->references, &i, ss->lock);
827     REF_PRINT_COUNT("SSL_SESSION", ss);
828     if (i > 0)
829         return;
830     REF_ASSERT_ISNT(i < 0);
831 
832     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
833 
834     OPENSSL_cleanse(ss->master_key, sizeof(ss->master_key));
835     OPENSSL_cleanse(ss->session_id, sizeof(ss->session_id));
836     X509_free(ss->peer);
837     sk_X509_pop_free(ss->peer_chain, X509_free);
838     OPENSSL_free(ss->ext.hostname);
839     OPENSSL_free(ss->ext.tick);
840 #ifndef OPENSSL_NO_PSK
841     OPENSSL_free(ss->psk_identity_hint);
842     OPENSSL_free(ss->psk_identity);
843 #endif
844 #ifndef OPENSSL_NO_SRP
845     OPENSSL_free(ss->srp_username);
846 #endif
847     OPENSSL_free(ss->ext.alpn_selected);
848     OPENSSL_free(ss->ticket_appdata);
849     CRYPTO_THREAD_lock_free(ss->lock);
850     OPENSSL_clear_free(ss, sizeof(*ss));
851 }
852 
853 int SSL_SESSION_up_ref(SSL_SESSION *ss)
854 {
855     int i;
856 
857     if (CRYPTO_UP_REF(&ss->references, &i, ss->lock) <= 0)
858         return 0;
859 
860     REF_PRINT_COUNT("SSL_SESSION", ss);
861     REF_ASSERT_ISNT(i < 2);
862     return ((i > 1) ? 1 : 0);
863 }
864 
865 int SSL_set_session(SSL *s, SSL_SESSION *session)
866 {
867     ssl_clear_bad_session(s);
868     if (s->ctx->method != s->method) {
869         if (!SSL_set_ssl_method(s, s->ctx->method))
870             return 0;
871     }
872 
873     if (session != NULL) {
874         SSL_SESSION_up_ref(session);
875         s->verify_result = session->verify_result;
876     }
877     SSL_SESSION_free(s->session);
878     s->session = session;
879 
880     return 1;
881 }
882 
883 int SSL_SESSION_set1_id(SSL_SESSION *s, const unsigned char *sid,
884                         unsigned int sid_len)
885 {
886     if (sid_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
887       ERR_raise(ERR_LIB_SSL, SSL_R_SSL_SESSION_ID_TOO_LONG);
888       return 0;
889     }
890     s->session_id_length = sid_len;
891     if (sid != s->session_id)
892         memcpy(s->session_id, sid, sid_len);
893     return 1;
894 }
895 
896 long SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
897 {
898     time_t new_timeout = (time_t)t;
899 
900     if (s == NULL || t < 0)
901         return 0;
902     if (s->owner != NULL) {
903         if (!CRYPTO_THREAD_write_lock(s->owner->lock))
904             return 0;
905         s->timeout = new_timeout;
906         ssl_session_calculate_timeout(s);
907         SSL_SESSION_list_add(s->owner, s);
908         CRYPTO_THREAD_unlock(s->owner->lock);
909     } else {
910         s->timeout = new_timeout;
911         ssl_session_calculate_timeout(s);
912     }
913     return 1;
914 }
915 
916 long SSL_SESSION_get_timeout(const SSL_SESSION *s)
917 {
918     if (s == NULL)
919         return 0;
920     return (long)s->timeout;
921 }
922 
923 long SSL_SESSION_get_time(const SSL_SESSION *s)
924 {
925     if (s == NULL)
926         return 0;
927     return (long)s->time;
928 }
929 
930 long SSL_SESSION_set_time(SSL_SESSION *s, long t)
931 {
932     time_t new_time = (time_t)t;
933 
934     if (s == NULL)
935         return 0;
936     if (s->owner != NULL) {
937         if (!CRYPTO_THREAD_write_lock(s->owner->lock))
938             return 0;
939         s->time = new_time;
940         ssl_session_calculate_timeout(s);
941         SSL_SESSION_list_add(s->owner, s);
942         CRYPTO_THREAD_unlock(s->owner->lock);
943     } else {
944         s->time = new_time;
945         ssl_session_calculate_timeout(s);
946     }
947     return t;
948 }
949 
950 int SSL_SESSION_get_protocol_version(const SSL_SESSION *s)
951 {
952     return s->ssl_version;
953 }
954 
955 int SSL_SESSION_set_protocol_version(SSL_SESSION *s, int version)
956 {
957     s->ssl_version = version;
958     return 1;
959 }
960 
961 const SSL_CIPHER *SSL_SESSION_get0_cipher(const SSL_SESSION *s)
962 {
963     return s->cipher;
964 }
965 
966 int SSL_SESSION_set_cipher(SSL_SESSION *s, const SSL_CIPHER *cipher)
967 {
968     s->cipher = cipher;
969     return 1;
970 }
971 
972 const char *SSL_SESSION_get0_hostname(const SSL_SESSION *s)
973 {
974     return s->ext.hostname;
975 }
976 
977 int SSL_SESSION_set1_hostname(SSL_SESSION *s, const char *hostname)
978 {
979     OPENSSL_free(s->ext.hostname);
980     if (hostname == NULL) {
981         s->ext.hostname = NULL;
982         return 1;
983     }
984     s->ext.hostname = OPENSSL_strdup(hostname);
985 
986     return s->ext.hostname != NULL;
987 }
988 
989 int SSL_SESSION_has_ticket(const SSL_SESSION *s)
990 {
991     return (s->ext.ticklen > 0) ? 1 : 0;
992 }
993 
994 unsigned long SSL_SESSION_get_ticket_lifetime_hint(const SSL_SESSION *s)
995 {
996     return s->ext.tick_lifetime_hint;
997 }
998 
999 void SSL_SESSION_get0_ticket(const SSL_SESSION *s, const unsigned char **tick,
1000                              size_t *len)
1001 {
1002     *len = s->ext.ticklen;
1003     if (tick != NULL)
1004         *tick = s->ext.tick;
1005 }
1006 
1007 uint32_t SSL_SESSION_get_max_early_data(const SSL_SESSION *s)
1008 {
1009     return s->ext.max_early_data;
1010 }
1011 
1012 int SSL_SESSION_set_max_early_data(SSL_SESSION *s, uint32_t max_early_data)
1013 {
1014     s->ext.max_early_data = max_early_data;
1015 
1016     return 1;
1017 }
1018 
1019 void SSL_SESSION_get0_alpn_selected(const SSL_SESSION *s,
1020                                     const unsigned char **alpn,
1021                                     size_t *len)
1022 {
1023     *alpn = s->ext.alpn_selected;
1024     *len = s->ext.alpn_selected_len;
1025 }
1026 
1027 int SSL_SESSION_set1_alpn_selected(SSL_SESSION *s, const unsigned char *alpn,
1028                                    size_t len)
1029 {
1030     OPENSSL_free(s->ext.alpn_selected);
1031     if (alpn == NULL || len == 0) {
1032         s->ext.alpn_selected = NULL;
1033         s->ext.alpn_selected_len = 0;
1034         return 1;
1035     }
1036     s->ext.alpn_selected = OPENSSL_memdup(alpn, len);
1037     if (s->ext.alpn_selected == NULL) {
1038         s->ext.alpn_selected_len = 0;
1039         return 0;
1040     }
1041     s->ext.alpn_selected_len = len;
1042 
1043     return 1;
1044 }
1045 
1046 X509 *SSL_SESSION_get0_peer(SSL_SESSION *s)
1047 {
1048     return s->peer;
1049 }
1050 
1051 int SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
1052                                 unsigned int sid_ctx_len)
1053 {
1054     if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
1055         ERR_raise(ERR_LIB_SSL, SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
1056         return 0;
1057     }
1058     s->sid_ctx_length = sid_ctx_len;
1059     if (sid_ctx != s->sid_ctx)
1060         memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
1061 
1062     return 1;
1063 }
1064 
1065 int SSL_SESSION_is_resumable(const SSL_SESSION *s)
1066 {
1067     /*
1068      * In the case of EAP-FAST, we can have a pre-shared "ticket" without a
1069      * session ID.
1070      */
1071     return !s->not_resumable
1072            && (s->session_id_length > 0 || s->ext.ticklen > 0);
1073 }
1074 
1075 long SSL_CTX_set_timeout(SSL_CTX *s, long t)
1076 {
1077     long l;
1078     if (s == NULL)
1079         return 0;
1080     l = s->session_timeout;
1081     s->session_timeout = t;
1082     return l;
1083 }
1084 
1085 long SSL_CTX_get_timeout(const SSL_CTX *s)
1086 {
1087     if (s == NULL)
1088         return 0;
1089     return s->session_timeout;
1090 }
1091 
1092 int SSL_set_session_secret_cb(SSL *s,
1093                               tls_session_secret_cb_fn tls_session_secret_cb,
1094                               void *arg)
1095 {
1096     if (s == NULL)
1097         return 0;
1098     s->ext.session_secret_cb = tls_session_secret_cb;
1099     s->ext.session_secret_cb_arg = arg;
1100     return 1;
1101 }
1102 
1103 int SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
1104                                   void *arg)
1105 {
1106     if (s == NULL)
1107         return 0;
1108     s->ext.session_ticket_cb = cb;
1109     s->ext.session_ticket_cb_arg = arg;
1110     return 1;
1111 }
1112 
1113 int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
1114 {
1115     if (s->version >= TLS1_VERSION) {
1116         OPENSSL_free(s->ext.session_ticket);
1117         s->ext.session_ticket = NULL;
1118         s->ext.session_ticket =
1119             OPENSSL_malloc(sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
1120         if (s->ext.session_ticket == NULL) {
1121             ERR_raise(ERR_LIB_SSL, ERR_R_MALLOC_FAILURE);
1122             return 0;
1123         }
1124 
1125         if (ext_data != NULL) {
1126             s->ext.session_ticket->length = ext_len;
1127             s->ext.session_ticket->data = s->ext.session_ticket + 1;
1128             memcpy(s->ext.session_ticket->data, ext_data, ext_len);
1129         } else {
1130             s->ext.session_ticket->length = 0;
1131             s->ext.session_ticket->data = NULL;
1132         }
1133 
1134         return 1;
1135     }
1136 
1137     return 0;
1138 }
1139 
1140 void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
1141 {
1142     STACK_OF(SSL_SESSION) *sk;
1143     SSL_SESSION *current;
1144     unsigned long i;
1145 
1146     if (!CRYPTO_THREAD_write_lock(s->lock))
1147         return;
1148 
1149     sk = sk_SSL_SESSION_new_null();
1150     i = lh_SSL_SESSION_get_down_load(s->sessions);
1151     lh_SSL_SESSION_set_down_load(s->sessions, 0);
1152 
1153     /*
1154      * Iterate over the list from the back (oldest), and stop
1155      * when a session can no longer be removed.
1156      * Add the session to a temporary list to be freed outside
1157      * the SSL_CTX lock.
1158      * But still do the remove_session_cb() within the lock.
1159      */
1160     while (s->session_cache_tail != NULL) {
1161         current = s->session_cache_tail;
1162         if (t == 0 || sess_timedout((time_t)t, current)) {
1163             lh_SSL_SESSION_delete(s->sessions, current);
1164             SSL_SESSION_list_remove(s, current);
1165             current->not_resumable = 1;
1166             if (s->remove_session_cb != NULL)
1167                 s->remove_session_cb(s, current);
1168             /*
1169              * Throw the session on a stack, it's entirely plausible
1170              * that while freeing outside the critical section, the
1171              * session could be re-added, so avoid using the next/prev
1172              * pointers. If the stack failed to create, or the session
1173              * couldn't be put on the stack, just free it here
1174              */
1175             if (sk == NULL || !sk_SSL_SESSION_push(sk, current))
1176                 SSL_SESSION_free(current);
1177         } else {
1178             break;
1179         }
1180     }
1181 
1182     lh_SSL_SESSION_set_down_load(s->sessions, i);
1183     CRYPTO_THREAD_unlock(s->lock);
1184 
1185     sk_SSL_SESSION_pop_free(sk, SSL_SESSION_free);
1186 }
1187 
1188 int ssl_clear_bad_session(SSL *s)
1189 {
1190     if ((s->session != NULL) &&
1191         !(s->shutdown & SSL_SENT_SHUTDOWN) &&
1192         !(SSL_in_init(s) || SSL_in_before(s))) {
1193         SSL_CTX_remove_session(s->session_ctx, s->session);
1194         return 1;
1195     } else
1196         return 0;
1197 }
1198 
1199 /* locked by SSL_CTX in the calling function */
1200 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
1201 {
1202     if ((s->next == NULL) || (s->prev == NULL))
1203         return;
1204 
1205     if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail)) {
1206         /* last element in list */
1207         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1208             /* only one element in list */
1209             ctx->session_cache_head = NULL;
1210             ctx->session_cache_tail = NULL;
1211         } else {
1212             ctx->session_cache_tail = s->prev;
1213             s->prev->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1214         }
1215     } else {
1216         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1217             /* first element in list */
1218             ctx->session_cache_head = s->next;
1219             s->next->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1220         } else {
1221             /* middle of list */
1222             s->next->prev = s->prev;
1223             s->prev->next = s->next;
1224         }
1225     }
1226     s->prev = s->next = NULL;
1227     s->owner = NULL;
1228 }
1229 
1230 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
1231 {
1232     SSL_SESSION *next;
1233 
1234     if ((s->next != NULL) && (s->prev != NULL))
1235         SSL_SESSION_list_remove(ctx, s);
1236 
1237     if (ctx->session_cache_head == NULL) {
1238         ctx->session_cache_head = s;
1239         ctx->session_cache_tail = s;
1240         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1241         s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1242     } else {
1243         if (timeoutcmp(s, ctx->session_cache_head) >= 0) {
1244             /*
1245              * if we timeout after (or the same time as) the first
1246              * session, put us first - usual case
1247              */
1248             s->next = ctx->session_cache_head;
1249             s->next->prev = s;
1250             s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1251             ctx->session_cache_head = s;
1252         } else if (timeoutcmp(s, ctx->session_cache_tail) < 0) {
1253             /* if we timeout before the last session, put us last */
1254             s->prev = ctx->session_cache_tail;
1255             s->prev->next = s;
1256             s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1257             ctx->session_cache_tail = s;
1258         } else {
1259             /*
1260              * we timeout somewhere in-between - if there is only
1261              * one session in the cache it will be caught above
1262              */
1263             next = ctx->session_cache_head->next;
1264             while (next != (SSL_SESSION*)&(ctx->session_cache_tail)) {
1265                 if (timeoutcmp(s, next) >= 0) {
1266                     s->next = next;
1267                     s->prev = next->prev;
1268                     next->prev->next = s;
1269                     next->prev = s;
1270                     break;
1271                 }
1272                 next = next->next;
1273             }
1274         }
1275     }
1276     s->owner = ctx;
1277 }
1278 
1279 void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
1280                              int (*cb) (struct ssl_st *ssl, SSL_SESSION *sess))
1281 {
1282     ctx->new_session_cb = cb;
1283 }
1284 
1285 int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx)) (SSL *ssl, SSL_SESSION *sess) {
1286     return ctx->new_session_cb;
1287 }
1288 
1289 void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
1290                                 void (*cb) (SSL_CTX *ctx, SSL_SESSION *sess))
1291 {
1292     ctx->remove_session_cb = cb;
1293 }
1294 
1295 void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx)) (SSL_CTX *ctx,
1296                                                   SSL_SESSION *sess) {
1297     return ctx->remove_session_cb;
1298 }
1299 
1300 void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
1301                              SSL_SESSION *(*cb) (struct ssl_st *ssl,
1302                                                  const unsigned char *data,
1303                                                  int len, int *copy))
1304 {
1305     ctx->get_session_cb = cb;
1306 }
1307 
1308 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx)) (SSL *ssl,
1309                                                        const unsigned char
1310                                                        *data, int len,
1311                                                        int *copy) {
1312     return ctx->get_session_cb;
1313 }
1314 
1315 void SSL_CTX_set_info_callback(SSL_CTX *ctx,
1316                                void (*cb) (const SSL *ssl, int type, int val))
1317 {
1318     ctx->info_callback = cb;
1319 }
1320 
1321 void (*SSL_CTX_get_info_callback(SSL_CTX *ctx)) (const SSL *ssl, int type,
1322                                                  int val) {
1323     return ctx->info_callback;
1324 }
1325 
1326 void SSL_CTX_set_client_cert_cb(SSL_CTX *ctx,
1327                                 int (*cb) (SSL *ssl, X509 **x509,
1328                                            EVP_PKEY **pkey))
1329 {
1330     ctx->client_cert_cb = cb;
1331 }
1332 
1333 int (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx)) (SSL *ssl, X509 **x509,
1334                                                  EVP_PKEY **pkey) {
1335     return ctx->client_cert_cb;
1336 }
1337 
1338 void SSL_CTX_set_cookie_generate_cb(SSL_CTX *ctx,
1339                                     int (*cb) (SSL *ssl,
1340                                                unsigned char *cookie,
1341                                                unsigned int *cookie_len))
1342 {
1343     ctx->app_gen_cookie_cb = cb;
1344 }
1345 
1346 void SSL_CTX_set_cookie_verify_cb(SSL_CTX *ctx,
1347                                   int (*cb) (SSL *ssl,
1348                                              const unsigned char *cookie,
1349                                              unsigned int cookie_len))
1350 {
1351     ctx->app_verify_cookie_cb = cb;
1352 }
1353 
1354 int SSL_SESSION_set1_ticket_appdata(SSL_SESSION *ss, const void *data, size_t len)
1355 {
1356     OPENSSL_free(ss->ticket_appdata);
1357     ss->ticket_appdata_len = 0;
1358     if (data == NULL || len == 0) {
1359         ss->ticket_appdata = NULL;
1360         return 1;
1361     }
1362     ss->ticket_appdata = OPENSSL_memdup(data, len);
1363     if (ss->ticket_appdata != NULL) {
1364         ss->ticket_appdata_len = len;
1365         return 1;
1366     }
1367     return 0;
1368 }
1369 
1370 int SSL_SESSION_get0_ticket_appdata(SSL_SESSION *ss, void **data, size_t *len)
1371 {
1372     *data = ss->ticket_appdata;
1373     *len = ss->ticket_appdata_len;
1374     return 1;
1375 }
1376 
1377 void SSL_CTX_set_stateless_cookie_generate_cb(
1378     SSL_CTX *ctx,
1379     int (*cb) (SSL *ssl,
1380                unsigned char *cookie,
1381                size_t *cookie_len))
1382 {
1383     ctx->gen_stateless_cookie_cb = cb;
1384 }
1385 
1386 void SSL_CTX_set_stateless_cookie_verify_cb(
1387     SSL_CTX *ctx,
1388     int (*cb) (SSL *ssl,
1389                const unsigned char *cookie,
1390                size_t cookie_len))
1391 {
1392     ctx->verify_stateless_cookie_cb = cb;
1393 }
1394 
1395 IMPLEMENT_PEM_rw(SSL_SESSION, SSL_SESSION, PEM_STRING_SSL_SESSION, SSL_SESSION)
1396