xref: /freebsd/crypto/openssl/ssl/ssl_sess.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /* ssl/ssl_sess.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 /* ====================================================================
59  * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
60  *
61  * Redistribution and use in source and binary forms, with or without
62  * modification, are permitted provided that the following conditions
63  * are met:
64  *
65  * 1. Redistributions of source code must retain the above copyright
66  *    notice, this list of conditions and the following disclaimer.
67  *
68  * 2. Redistributions in binary form must reproduce the above copyright
69  *    notice, this list of conditions and the following disclaimer in
70  *    the documentation and/or other materials provided with the
71  *    distribution.
72  *
73  * 3. All advertising materials mentioning features or use of this
74  *    software must display the following acknowledgment:
75  *    "This product includes software developed by the OpenSSL Project
76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77  *
78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79  *    endorse or promote products derived from this software without
80  *    prior written permission. For written permission, please contact
81  *    openssl-core@openssl.org.
82  *
83  * 5. Products derived from this software may not be called "OpenSSL"
84  *    nor may "OpenSSL" appear in their names without prior written
85  *    permission of the OpenSSL Project.
86  *
87  * 6. Redistributions of any form whatsoever must retain the following
88  *    acknowledgment:
89  *    "This product includes software developed by the OpenSSL Project
90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91  *
92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103  * OF THE POSSIBILITY OF SUCH DAMAGE.
104  * ====================================================================
105  *
106  * This product includes cryptographic software written by Eric Young
107  * (eay@cryptsoft.com).  This product includes software written by Tim
108  * Hudson (tjh@cryptsoft.com).
109  *
110  */
111 /* ====================================================================
112  * Copyright 2005 Nokia. All rights reserved.
113  *
114  * The portions of the attached software ("Contribution") is developed by
115  * Nokia Corporation and is licensed pursuant to the OpenSSL open source
116  * license.
117  *
118  * The Contribution, originally written by Mika Kousa and Pasi Eronen of
119  * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
120  * support (see RFC 4279) to OpenSSL.
121  *
122  * No patent licenses or other rights except those expressly stated in
123  * the OpenSSL open source license shall be deemed granted or received
124  * expressly, by implication, estoppel, or otherwise.
125  *
126  * No assurances are provided by Nokia that the Contribution does not
127  * infringe the patent or other intellectual property rights of any third
128  * party or that the license provides you with all the necessary rights
129  * to make use of the Contribution.
130  *
131  * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
132  * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
133  * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
134  * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
135  * OTHERWISE.
136  */
137 
138 #include <stdio.h>
139 #include <openssl/lhash.h>
140 #include <openssl/rand.h>
141 #ifndef OPENSSL_NO_ENGINE
142 # include <openssl/engine.h>
143 #endif
144 #include "ssl_locl.h"
145 
146 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s);
147 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s);
148 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck);
149 
150 SSL_SESSION *SSL_get_session(const SSL *ssl)
151 /* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
152 {
153     return (ssl->session);
154 }
155 
156 SSL_SESSION *SSL_get1_session(SSL *ssl)
157 /* variant of SSL_get_session: caller really gets something */
158 {
159     SSL_SESSION *sess;
160     /*
161      * Need to lock this all up rather than just use CRYPTO_add so that
162      * somebody doesn't free ssl->session between when we check it's non-null
163      * and when we up the reference count.
164      */
165     CRYPTO_w_lock(CRYPTO_LOCK_SSL_SESSION);
166     sess = ssl->session;
167     if (sess)
168         sess->references++;
169     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_SESSION);
170     return (sess);
171 }
172 
173 int SSL_SESSION_get_ex_new_index(long argl, void *argp,
174                                  CRYPTO_EX_new *new_func,
175                                  CRYPTO_EX_dup *dup_func,
176                                  CRYPTO_EX_free *free_func)
177 {
178     return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_SSL_SESSION, argl, argp,
179                                    new_func, dup_func, free_func);
180 }
181 
182 int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
183 {
184     return (CRYPTO_set_ex_data(&s->ex_data, idx, arg));
185 }
186 
187 void *SSL_SESSION_get_ex_data(const SSL_SESSION *s, int idx)
188 {
189     return (CRYPTO_get_ex_data(&s->ex_data, idx));
190 }
191 
192 SSL_SESSION *SSL_SESSION_new(void)
193 {
194     SSL_SESSION *ss;
195 
196     ss = (SSL_SESSION *)OPENSSL_malloc(sizeof(SSL_SESSION));
197     if (ss == NULL) {
198         SSLerr(SSL_F_SSL_SESSION_NEW, ERR_R_MALLOC_FAILURE);
199         return (0);
200     }
201     memset(ss, 0, sizeof(SSL_SESSION));
202 
203     ss->verify_result = 1;      /* avoid 0 (= X509_V_OK) just in case */
204     ss->references = 1;
205     ss->timeout = 60 * 5 + 4;   /* 5 minute timeout by default */
206     ss->time = (unsigned long)time(NULL);
207     ss->prev = NULL;
208     ss->next = NULL;
209     ss->compress_meth = 0;
210 #ifndef OPENSSL_NO_TLSEXT
211     ss->tlsext_hostname = NULL;
212 # ifndef OPENSSL_NO_EC
213     ss->tlsext_ecpointformatlist_length = 0;
214     ss->tlsext_ecpointformatlist = NULL;
215     ss->tlsext_ellipticcurvelist_length = 0;
216     ss->tlsext_ellipticcurvelist = NULL;
217 # endif
218 #endif
219     CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
220 #ifndef OPENSSL_NO_PSK
221     ss->psk_identity_hint = NULL;
222     ss->psk_identity = NULL;
223 #endif
224 #ifndef OPENSSL_NO_SRP
225     ss->srp_username = NULL;
226 #endif
227     return (ss);
228 }
229 
230 /*
231  * Create a new SSL_SESSION and duplicate the contents of |src| into it. If
232  * ticket == 0 then no ticket information is duplicated, otherwise it is.
233  */
234 SSL_SESSION *ssl_session_dup(SSL_SESSION *src, int ticket)
235 {
236     SSL_SESSION *dest;
237 
238     dest = OPENSSL_malloc(sizeof(*src));
239     if (dest == NULL) {
240         goto err;
241     }
242     memcpy(dest, src, sizeof(*dest));
243 
244     /*
245      * Set the various pointers to NULL so that we can call SSL_SESSION_free in
246      * the case of an error whilst halfway through constructing dest
247      */
248 #ifndef OPENSSL_NO_PSK
249     dest->psk_identity_hint = NULL;
250     dest->psk_identity = NULL;
251 #endif
252     dest->ciphers = NULL;
253 #ifndef OPENSSL_NO_TLSEXT
254     dest->tlsext_hostname = NULL;
255 # ifndef OPENSSL_NO_EC
256     dest->tlsext_ecpointformatlist = NULL;
257     dest->tlsext_ellipticcurvelist = NULL;
258 # endif
259     dest->tlsext_tick = NULL;
260 #endif
261 #ifndef OPENSSL_NO_SRP
262     dest->srp_username = NULL;
263 #endif
264     memset(&dest->ex_data, 0, sizeof(dest->ex_data));
265 
266     /* We deliberately don't copy the prev and next pointers */
267     dest->prev = NULL;
268     dest->next = NULL;
269 
270     dest->references = 1;
271 
272     if (src->sess_cert != NULL)
273         CRYPTO_add(&src->sess_cert->references, 1, CRYPTO_LOCK_SSL_SESS_CERT);
274 
275     if (src->peer != NULL)
276         CRYPTO_add(&src->peer->references, 1, CRYPTO_LOCK_X509);
277 
278 #ifndef OPENSSL_NO_PSK
279     if (src->psk_identity_hint) {
280         dest->psk_identity_hint = BUF_strdup(src->psk_identity_hint);
281         if (dest->psk_identity_hint == NULL) {
282             goto err;
283         }
284     }
285     if (src->psk_identity) {
286         dest->psk_identity = BUF_strdup(src->psk_identity);
287         if (dest->psk_identity == NULL) {
288             goto err;
289         }
290     }
291 #endif
292 
293     if(src->ciphers != NULL) {
294         dest->ciphers = sk_SSL_CIPHER_dup(src->ciphers);
295         if (dest->ciphers == NULL)
296             goto err;
297     }
298 
299     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_SSL_SESSION,
300                                             &dest->ex_data, &src->ex_data)) {
301         goto err;
302     }
303 
304 #ifndef OPENSSL_NO_TLSEXT
305     if (src->tlsext_hostname) {
306         dest->tlsext_hostname = BUF_strdup(src->tlsext_hostname);
307         if (dest->tlsext_hostname == NULL) {
308             goto err;
309         }
310     }
311 # ifndef OPENSSL_NO_EC
312     if (src->tlsext_ecpointformatlist) {
313         dest->tlsext_ecpointformatlist =
314             BUF_memdup(src->tlsext_ecpointformatlist,
315                        src->tlsext_ecpointformatlist_length);
316         if (dest->tlsext_ecpointformatlist == NULL)
317             goto err;
318     }
319     if (src->tlsext_ellipticcurvelist) {
320         dest->tlsext_ellipticcurvelist =
321             BUF_memdup(src->tlsext_ellipticcurvelist,
322                        src->tlsext_ellipticcurvelist_length);
323         if (dest->tlsext_ellipticcurvelist == NULL)
324             goto err;
325     }
326 # endif
327 
328     if (ticket != 0) {
329         dest->tlsext_tick = BUF_memdup(src->tlsext_tick, src->tlsext_ticklen);
330         if(dest->tlsext_tick == NULL)
331             goto err;
332     } else {
333         dest->tlsext_tick_lifetime_hint = 0;
334         dest->tlsext_ticklen = 0;
335     }
336 #endif
337 
338 #ifndef OPENSSL_NO_SRP
339     if (src->srp_username) {
340         dest->srp_username = BUF_strdup(src->srp_username);
341         if (dest->srp_username == NULL) {
342             goto err;
343         }
344     }
345 #endif
346 
347     return dest;
348 err:
349     SSLerr(SSL_F_SSL_SESSION_DUP, ERR_R_MALLOC_FAILURE);
350     SSL_SESSION_free(dest);
351     return NULL;
352 }
353 
354 const unsigned char *SSL_SESSION_get_id(const SSL_SESSION *s,
355                                         unsigned int *len)
356 {
357     if (len)
358         *len = s->session_id_length;
359     return s->session_id;
360 }
361 
362 unsigned int SSL_SESSION_get_compress_id(const SSL_SESSION *s)
363 {
364     return s->compress_meth;
365 }
366 
367 /*
368  * Even with SSLv2, we have 16 bytes (128 bits) of session ID space.
369  * SSLv3/TLSv1 has 32 bytes (256 bits). As such, filling the ID with random
370  * gunk repeatedly until we have no conflict is going to complete in one
371  * iteration pretty much "most" of the time (btw: understatement). So, if it
372  * takes us 10 iterations and we still can't avoid a conflict - well that's a
373  * reasonable point to call it quits. Either the RAND code is broken or
374  * someone is trying to open roughly very close to 2^128 (or 2^256) SSL
375  * sessions to our server. How you might store that many sessions is perhaps
376  * a more interesting question ...
377  */
378 
379 #define MAX_SESS_ID_ATTEMPTS 10
380 static int def_generate_session_id(const SSL *ssl, unsigned char *id,
381                                    unsigned int *id_len)
382 {
383     unsigned int retry = 0;
384     do
385         if (RAND_pseudo_bytes(id, *id_len) <= 0)
386             return 0;
387     while (SSL_has_matching_session_id(ssl, id, *id_len) &&
388            (++retry < MAX_SESS_ID_ATTEMPTS)) ;
389     if (retry < MAX_SESS_ID_ATTEMPTS)
390         return 1;
391     /* else - woops a session_id match */
392     /*
393      * XXX We should also check the external cache -- but the probability of
394      * a collision is negligible, and we could not prevent the concurrent
395      * creation of sessions with identical IDs since we currently don't have
396      * means to atomically check whether a session ID already exists and make
397      * a reservation for it if it does not (this problem applies to the
398      * internal cache as well).
399      */
400     return 0;
401 }
402 
403 int ssl_get_new_session(SSL *s, int session)
404 {
405     /* This gets used by clients and servers. */
406 
407     unsigned int tmp;
408     SSL_SESSION *ss = NULL;
409     GEN_SESSION_CB cb = def_generate_session_id;
410 
411     if ((ss = SSL_SESSION_new()) == NULL)
412         return (0);
413 
414     /* If the context has a default timeout, use it */
415     if (s->session_ctx->session_timeout == 0)
416         ss->timeout = SSL_get_default_timeout(s);
417     else
418         ss->timeout = s->session_ctx->session_timeout;
419 
420     if (s->session != NULL) {
421         SSL_SESSION_free(s->session);
422         s->session = NULL;
423     }
424 
425     if (session) {
426         if (s->version == SSL2_VERSION) {
427             ss->ssl_version = SSL2_VERSION;
428             ss->session_id_length = SSL2_SSL_SESSION_ID_LENGTH;
429         } else if (s->version == SSL3_VERSION) {
430             ss->ssl_version = SSL3_VERSION;
431             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
432         } else if (s->version == TLS1_VERSION) {
433             ss->ssl_version = TLS1_VERSION;
434             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
435         } else if (s->version == TLS1_1_VERSION) {
436             ss->ssl_version = TLS1_1_VERSION;
437             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
438         } else if (s->version == TLS1_2_VERSION) {
439             ss->ssl_version = TLS1_2_VERSION;
440             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
441         } else if (s->version == DTLS1_BAD_VER) {
442             ss->ssl_version = DTLS1_BAD_VER;
443             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
444         } else if (s->version == DTLS1_VERSION) {
445             ss->ssl_version = DTLS1_VERSION;
446             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
447         } else if (s->version == DTLS1_2_VERSION) {
448             ss->ssl_version = DTLS1_2_VERSION;
449             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
450         } else {
451             SSLerr(SSL_F_SSL_GET_NEW_SESSION, SSL_R_UNSUPPORTED_SSL_VERSION);
452             SSL_SESSION_free(ss);
453             return (0);
454         }
455 #ifndef OPENSSL_NO_TLSEXT
456         /*-
457          * If RFC5077 ticket, use empty session ID (as server).
458          * Note that:
459          * (a) ssl_get_prev_session() does lookahead into the
460          *     ClientHello extensions to find the session ticket.
461          *     When ssl_get_prev_session() fails, s3_srvr.c calls
462          *     ssl_get_new_session() in ssl3_get_client_hello().
463          *     At that point, it has not yet parsed the extensions,
464          *     however, because of the lookahead, it already knows
465          *     whether a ticket is expected or not.
466          *
467          * (b) s3_clnt.c calls ssl_get_new_session() before parsing
468          *     ServerHello extensions, and before recording the session
469          *     ID received from the server, so this block is a noop.
470          */
471         if (s->tlsext_ticket_expected) {
472             ss->session_id_length = 0;
473             goto sess_id_done;
474         }
475 #endif
476         /* Choose which callback will set the session ID */
477         CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
478         if (s->generate_session_id)
479             cb = s->generate_session_id;
480         else if (s->session_ctx->generate_session_id)
481             cb = s->session_ctx->generate_session_id;
482         CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
483         /* Choose a session ID */
484         tmp = ss->session_id_length;
485         if (!cb(s, ss->session_id, &tmp)) {
486             /* The callback failed */
487             SSLerr(SSL_F_SSL_GET_NEW_SESSION,
488                    SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
489             SSL_SESSION_free(ss);
490             return (0);
491         }
492         /*
493          * Don't allow the callback to set the session length to zero. nor
494          * set it higher than it was.
495          */
496         if (!tmp || (tmp > ss->session_id_length)) {
497             /* The callback set an illegal length */
498             SSLerr(SSL_F_SSL_GET_NEW_SESSION,
499                    SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
500             SSL_SESSION_free(ss);
501             return (0);
502         }
503         /* If the session length was shrunk and we're SSLv2, pad it */
504         if ((tmp < ss->session_id_length) && (s->version == SSL2_VERSION))
505             memset(ss->session_id + tmp, 0, ss->session_id_length - tmp);
506         else
507             ss->session_id_length = tmp;
508         /* Finally, check for a conflict */
509         if (SSL_has_matching_session_id(s, ss->session_id,
510                                         ss->session_id_length)) {
511             SSLerr(SSL_F_SSL_GET_NEW_SESSION, SSL_R_SSL_SESSION_ID_CONFLICT);
512             SSL_SESSION_free(ss);
513             return (0);
514         }
515 #ifndef OPENSSL_NO_TLSEXT
516  sess_id_done:
517         if (s->tlsext_hostname) {
518             ss->tlsext_hostname = BUF_strdup(s->tlsext_hostname);
519             if (ss->tlsext_hostname == NULL) {
520                 SSLerr(SSL_F_SSL_GET_NEW_SESSION, ERR_R_INTERNAL_ERROR);
521                 SSL_SESSION_free(ss);
522                 return 0;
523             }
524         }
525 #endif
526     } else {
527         ss->session_id_length = 0;
528     }
529 
530     if (s->sid_ctx_length > sizeof ss->sid_ctx) {
531         SSLerr(SSL_F_SSL_GET_NEW_SESSION, ERR_R_INTERNAL_ERROR);
532         SSL_SESSION_free(ss);
533         return 0;
534     }
535     memcpy(ss->sid_ctx, s->sid_ctx, s->sid_ctx_length);
536     ss->sid_ctx_length = s->sid_ctx_length;
537     s->session = ss;
538     ss->ssl_version = s->version;
539     ss->verify_result = X509_V_OK;
540 
541     return (1);
542 }
543 
544 /*-
545  * ssl_get_prev attempts to find an SSL_SESSION to be used to resume this
546  * connection. It is only called by servers.
547  *
548  *   session_id: points at the session ID in the ClientHello. This code will
549  *       read past the end of this in order to parse out the session ticket
550  *       extension, if any.
551  *   len: the length of the session ID.
552  *   limit: a pointer to the first byte after the ClientHello.
553  *
554  * Returns:
555  *   -1: error
556  *    0: 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->tlsext_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, unsigned char *session_id, int len,
565                          const unsigned char *limit)
566 {
567     /* This is used only by servers. */
568 
569     SSL_SESSION *ret = NULL;
570     int fatal = 0;
571     int try_session_cache = 1;
572 #ifndef OPENSSL_NO_TLSEXT
573     int r;
574 #endif
575 
576     if (session_id + len > limit) {
577         fatal = 1;
578         goto err;
579     }
580 
581     if (len == 0)
582         try_session_cache = 0;
583 
584 #ifndef OPENSSL_NO_TLSEXT
585     /* sets s->tlsext_ticket_expected */
586     r = tls1_process_ticket(s, session_id, len, limit, &ret);
587     switch (r) {
588     case -1:                   /* Error during processing */
589         fatal = 1;
590         goto err;
591     case 0:                    /* No ticket found */
592     case 1:                    /* Zero length ticket found */
593         break;                  /* Ok to carry on processing session id. */
594     case 2:                    /* Ticket found but not decrypted. */
595     case 3:                    /* Ticket decrypted, *ret has been set. */
596         try_session_cache = 0;
597         break;
598     default:
599         abort();
600     }
601 #endif
602 
603     if (try_session_cache &&
604         ret == NULL &&
605         !(s->session_ctx->session_cache_mode &
606           SSL_SESS_CACHE_NO_INTERNAL_LOOKUP)) {
607         SSL_SESSION data;
608         data.ssl_version = s->version;
609         data.session_id_length = len;
610         if (len == 0)
611             return 0;
612         memcpy(data.session_id, session_id, len);
613         CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
614         ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
615         if (ret != NULL) {
616             /* don't allow other threads to steal it: */
617             CRYPTO_add(&ret->references, 1, CRYPTO_LOCK_SSL_SESSION);
618         }
619         CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
620         if (ret == NULL)
621             s->session_ctx->stats.sess_miss++;
622     }
623 
624     if (try_session_cache &&
625         ret == NULL && s->session_ctx->get_session_cb != NULL) {
626         int copy = 1;
627 
628         if ((ret = s->session_ctx->get_session_cb(s, session_id, len, &copy))) {
629             s->session_ctx->stats.sess_cb_hit++;
630 
631             /*
632              * Increment reference count now if the session callback asks us
633              * to do so (note that if the session structures returned by the
634              * callback are shared between threads, it must handle the
635              * reference count itself [i.e. copy == 0], or things won't be
636              * thread-safe).
637              */
638             if (copy)
639                 CRYPTO_add(&ret->references, 1, CRYPTO_LOCK_SSL_SESSION);
640 
641             /*
642              * Add the externally cached session to the internal cache as
643              * well if and only if we are supposed to.
644              */
645             if (!
646                 (s->session_ctx->session_cache_mode &
647                  SSL_SESS_CACHE_NO_INTERNAL_STORE))
648                 /*
649                  * The following should not return 1, otherwise, things are
650                  * very strange
651                  */
652                 SSL_CTX_add_session(s->session_ctx, ret);
653         }
654     }
655 
656     if (ret == NULL)
657         goto err;
658 
659     /* Now ret is non-NULL and we own one of its reference counts. */
660 
661     if (ret->sid_ctx_length != s->sid_ctx_length
662         || memcmp(ret->sid_ctx, s->sid_ctx, ret->sid_ctx_length)) {
663         /*
664          * We have the session requested by the client, but we don't want to
665          * use it in this context.
666          */
667         goto err;               /* treat like cache miss */
668     }
669 
670     if ((s->verify_mode & SSL_VERIFY_PEER) && s->sid_ctx_length == 0) {
671         /*
672          * We can't be sure if this session is being used out of context,
673          * which is especially important for SSL_VERIFY_PEER. The application
674          * should have used SSL[_CTX]_set_session_id_context. For this error
675          * case, we generate an error instead of treating the event like a
676          * cache miss (otherwise it would be easy for applications to
677          * effectively disable the session cache by accident without anyone
678          * noticing).
679          */
680 
681         SSLerr(SSL_F_SSL_GET_PREV_SESSION,
682                SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
683         fatal = 1;
684         goto err;
685     }
686 
687     if (ret->cipher == NULL) {
688         unsigned char buf[5], *p;
689         unsigned long l;
690 
691         p = buf;
692         l = ret->cipher_id;
693         l2n(l, p);
694         if ((ret->ssl_version >> 8) >= SSL3_VERSION_MAJOR)
695             ret->cipher = ssl_get_cipher_by_char(s, &(buf[2]));
696         else
697             ret->cipher = ssl_get_cipher_by_char(s, &(buf[1]));
698         if (ret->cipher == NULL)
699             goto err;
700     }
701 
702     if (ret->timeout < (long)(time(NULL) - ret->time)) { /* timeout */
703         s->session_ctx->stats.sess_timeout++;
704         if (try_session_cache) {
705             /* session was from the cache, so remove it */
706             SSL_CTX_remove_session(s->session_ctx, ret);
707         }
708         goto err;
709     }
710 
711     s->session_ctx->stats.sess_hit++;
712 
713     if (s->session != NULL)
714         SSL_SESSION_free(s->session);
715     s->session = ret;
716     s->verify_result = s->session->verify_result;
717     return 1;
718 
719  err:
720     if (ret != NULL) {
721         SSL_SESSION_free(ret);
722 #ifndef OPENSSL_NO_TLSEXT
723         if (!try_session_cache) {
724             /*
725              * The session was from a ticket, so we should issue a ticket for
726              * the new session
727              */
728             s->tlsext_ticket_expected = 1;
729         }
730 #endif
731     }
732     if (fatal)
733         return -1;
734     else
735         return 0;
736 }
737 
738 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
739 {
740     int ret = 0;
741     SSL_SESSION *s;
742 
743     /*
744      * add just 1 reference count for the SSL_CTX's session cache even though
745      * it has two ways of access: each session is in a doubly linked list and
746      * an lhash
747      */
748     CRYPTO_add(&c->references, 1, CRYPTO_LOCK_SSL_SESSION);
749     /*
750      * if session c is in already in cache, we take back the increment later
751      */
752 
753     CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
754     s = lh_SSL_SESSION_insert(ctx->sessions, c);
755 
756     /*
757      * s != NULL iff we already had a session with the given PID. In this
758      * case, s == c should hold (then we did not really modify
759      * ctx->sessions), or we're in trouble.
760      */
761     if (s != NULL && s != c) {
762         /* We *are* in trouble ... */
763         SSL_SESSION_list_remove(ctx, s);
764         SSL_SESSION_free(s);
765         /*
766          * ... so pretend the other session did not exist in cache (we cannot
767          * handle two SSL_SESSION structures with identical session ID in the
768          * same cache, which could happen e.g. when two threads concurrently
769          * obtain the same session from an external cache)
770          */
771         s = NULL;
772     }
773 
774     /* Put at the head of the queue unless it is already in the cache */
775     if (s == NULL)
776         SSL_SESSION_list_add(ctx, c);
777 
778     if (s != NULL) {
779         /*
780          * existing cache entry -- decrement previously incremented reference
781          * count because it already takes into account the cache
782          */
783 
784         SSL_SESSION_free(s);    /* s == c */
785         ret = 0;
786     } else {
787         /*
788          * new cache entry -- remove old ones if cache has become too large
789          */
790 
791         ret = 1;
792 
793         if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
794             while (SSL_CTX_sess_number(ctx) >
795                    SSL_CTX_sess_get_cache_size(ctx)) {
796                 if (!remove_session_lock(ctx, ctx->session_cache_tail, 0))
797                     break;
798                 else
799                     ctx->stats.sess_cache_full++;
800             }
801         }
802     }
803     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
804     return (ret);
805 }
806 
807 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
808 {
809     return remove_session_lock(ctx, c, 1);
810 }
811 
812 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
813 {
814     SSL_SESSION *r;
815     int ret = 0;
816 
817     if ((c != NULL) && (c->session_id_length != 0)) {
818         if (lck)
819             CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
820         if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) == c) {
821             ret = 1;
822             r = lh_SSL_SESSION_delete(ctx->sessions, c);
823             SSL_SESSION_list_remove(ctx, c);
824         }
825 
826         if (lck)
827             CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
828 
829         if (ret) {
830             r->not_resumable = 1;
831             if (ctx->remove_session_cb != NULL)
832                 ctx->remove_session_cb(ctx, r);
833             SSL_SESSION_free(r);
834         }
835     } else
836         ret = 0;
837     return (ret);
838 }
839 
840 void SSL_SESSION_free(SSL_SESSION *ss)
841 {
842     int i;
843 
844     if (ss == NULL)
845         return;
846 
847     i = CRYPTO_add(&ss->references, -1, CRYPTO_LOCK_SSL_SESSION);
848 #ifdef REF_PRINT
849     REF_PRINT("SSL_SESSION", ss);
850 #endif
851     if (i > 0)
852         return;
853 #ifdef REF_CHECK
854     if (i < 0) {
855         fprintf(stderr, "SSL_SESSION_free, bad reference count\n");
856         abort();                /* ok */
857     }
858 #endif
859 
860     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
861 
862     OPENSSL_cleanse(ss->key_arg, sizeof ss->key_arg);
863     OPENSSL_cleanse(ss->master_key, sizeof ss->master_key);
864     OPENSSL_cleanse(ss->session_id, sizeof ss->session_id);
865     if (ss->sess_cert != NULL)
866         ssl_sess_cert_free(ss->sess_cert);
867     if (ss->peer != NULL)
868         X509_free(ss->peer);
869     if (ss->ciphers != NULL)
870         sk_SSL_CIPHER_free(ss->ciphers);
871 #ifndef OPENSSL_NO_TLSEXT
872     if (ss->tlsext_hostname != NULL)
873         OPENSSL_free(ss->tlsext_hostname);
874     if (ss->tlsext_tick != NULL)
875         OPENSSL_free(ss->tlsext_tick);
876 # ifndef OPENSSL_NO_EC
877     ss->tlsext_ecpointformatlist_length = 0;
878     if (ss->tlsext_ecpointformatlist != NULL)
879         OPENSSL_free(ss->tlsext_ecpointformatlist);
880     ss->tlsext_ellipticcurvelist_length = 0;
881     if (ss->tlsext_ellipticcurvelist != NULL)
882         OPENSSL_free(ss->tlsext_ellipticcurvelist);
883 # endif                         /* OPENSSL_NO_EC */
884 #endif
885 #ifndef OPENSSL_NO_PSK
886     if (ss->psk_identity_hint != NULL)
887         OPENSSL_free(ss->psk_identity_hint);
888     if (ss->psk_identity != NULL)
889         OPENSSL_free(ss->psk_identity);
890 #endif
891 #ifndef OPENSSL_NO_SRP
892     if (ss->srp_username != NULL)
893         OPENSSL_free(ss->srp_username);
894 #endif
895     OPENSSL_cleanse(ss, sizeof(*ss));
896     OPENSSL_free(ss);
897 }
898 
899 int SSL_set_session(SSL *s, SSL_SESSION *session)
900 {
901     int ret = 0;
902     const SSL_METHOD *meth;
903 
904     if (session != NULL) {
905         meth = s->ctx->method->get_ssl_method(session->ssl_version);
906         if (meth == NULL)
907             meth = s->method->get_ssl_method(session->ssl_version);
908         if (meth == NULL) {
909             SSLerr(SSL_F_SSL_SET_SESSION, SSL_R_UNABLE_TO_FIND_SSL_METHOD);
910             return (0);
911         }
912 
913         if (meth != s->method) {
914             if (!SSL_set_ssl_method(s, meth))
915                 return (0);
916         }
917 #ifndef OPENSSL_NO_KRB5
918         if (s->kssl_ctx && !s->kssl_ctx->client_princ &&
919             session->krb5_client_princ_len > 0) {
920             s->kssl_ctx->client_princ =
921                 (char *)OPENSSL_malloc(session->krb5_client_princ_len + 1);
922             memcpy(s->kssl_ctx->client_princ, session->krb5_client_princ,
923                    session->krb5_client_princ_len);
924             s->kssl_ctx->client_princ[session->krb5_client_princ_len] = '\0';
925         }
926 #endif                          /* OPENSSL_NO_KRB5 */
927 
928         /* CRYPTO_w_lock(CRYPTO_LOCK_SSL); */
929         CRYPTO_add(&session->references, 1, CRYPTO_LOCK_SSL_SESSION);
930         if (s->session != NULL)
931             SSL_SESSION_free(s->session);
932         s->session = session;
933         s->verify_result = s->session->verify_result;
934         /* CRYPTO_w_unlock(CRYPTO_LOCK_SSL); */
935         ret = 1;
936     } else {
937         if (s->session != NULL) {
938             SSL_SESSION_free(s->session);
939             s->session = NULL;
940         }
941 
942         meth = s->ctx->method;
943         if (meth != s->method) {
944             if (!SSL_set_ssl_method(s, meth))
945                 return (0);
946         }
947         ret = 1;
948     }
949     return (ret);
950 }
951 
952 long SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
953 {
954     if (s == NULL)
955         return (0);
956     s->timeout = t;
957     return (1);
958 }
959 
960 long SSL_SESSION_get_timeout(const SSL_SESSION *s)
961 {
962     if (s == NULL)
963         return (0);
964     return (s->timeout);
965 }
966 
967 long SSL_SESSION_get_time(const SSL_SESSION *s)
968 {
969     if (s == NULL)
970         return (0);
971     return (s->time);
972 }
973 
974 long SSL_SESSION_set_time(SSL_SESSION *s, long t)
975 {
976     if (s == NULL)
977         return (0);
978     s->time = t;
979     return (t);
980 }
981 
982 X509 *SSL_SESSION_get0_peer(SSL_SESSION *s)
983 {
984     return s->peer;
985 }
986 
987 int SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
988                                 unsigned int sid_ctx_len)
989 {
990     if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
991         SSLerr(SSL_F_SSL_SESSION_SET1_ID_CONTEXT,
992                SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
993         return 0;
994     }
995     s->sid_ctx_length = sid_ctx_len;
996     memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
997 
998     return 1;
999 }
1000 
1001 long SSL_CTX_set_timeout(SSL_CTX *s, long t)
1002 {
1003     long l;
1004     if (s == NULL)
1005         return (0);
1006     l = s->session_timeout;
1007     s->session_timeout = t;
1008     return (l);
1009 }
1010 
1011 long SSL_CTX_get_timeout(const SSL_CTX *s)
1012 {
1013     if (s == NULL)
1014         return (0);
1015     return (s->session_timeout);
1016 }
1017 
1018 #ifndef OPENSSL_NO_TLSEXT
1019 int SSL_set_session_secret_cb(SSL *s,
1020                               int (*tls_session_secret_cb) (SSL *s,
1021                                                             void *secret,
1022                                                             int *secret_len,
1023                                                             STACK_OF(SSL_CIPHER)
1024                                                             *peer_ciphers,
1025                                                             SSL_CIPHER
1026                                                             **cipher,
1027                                                             void *arg),
1028                               void *arg)
1029 {
1030     if (s == NULL)
1031         return (0);
1032     s->tls_session_secret_cb = tls_session_secret_cb;
1033     s->tls_session_secret_cb_arg = arg;
1034     return (1);
1035 }
1036 
1037 int SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
1038                                   void *arg)
1039 {
1040     if (s == NULL)
1041         return (0);
1042     s->tls_session_ticket_ext_cb = cb;
1043     s->tls_session_ticket_ext_cb_arg = arg;
1044     return (1);
1045 }
1046 
1047 int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
1048 {
1049     if (s->version >= TLS1_VERSION) {
1050         if (s->tlsext_session_ticket) {
1051             OPENSSL_free(s->tlsext_session_ticket);
1052             s->tlsext_session_ticket = NULL;
1053         }
1054 
1055         s->tlsext_session_ticket =
1056             OPENSSL_malloc(sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
1057         if (!s->tlsext_session_ticket) {
1058             SSLerr(SSL_F_SSL_SET_SESSION_TICKET_EXT, ERR_R_MALLOC_FAILURE);
1059             return 0;
1060         }
1061 
1062         if (ext_data) {
1063             s->tlsext_session_ticket->length = ext_len;
1064             s->tlsext_session_ticket->data = s->tlsext_session_ticket + 1;
1065             memcpy(s->tlsext_session_ticket->data, ext_data, ext_len);
1066         } else {
1067             s->tlsext_session_ticket->length = 0;
1068             s->tlsext_session_ticket->data = NULL;
1069         }
1070 
1071         return 1;
1072     }
1073 
1074     return 0;
1075 }
1076 #endif                          /* OPENSSL_NO_TLSEXT */
1077 
1078 typedef struct timeout_param_st {
1079     SSL_CTX *ctx;
1080     long time;
1081     LHASH_OF(SSL_SESSION) *cache;
1082 } TIMEOUT_PARAM;
1083 
1084 static void timeout_doall_arg(SSL_SESSION *s, TIMEOUT_PARAM *p)
1085 {
1086     if ((p->time == 0) || (p->time > (s->time + s->timeout))) { /* timeout */
1087         /*
1088          * The reason we don't call SSL_CTX_remove_session() is to save on
1089          * locking overhead
1090          */
1091         (void)lh_SSL_SESSION_delete(p->cache, s);
1092         SSL_SESSION_list_remove(p->ctx, s);
1093         s->not_resumable = 1;
1094         if (p->ctx->remove_session_cb != NULL)
1095             p->ctx->remove_session_cb(p->ctx, s);
1096         SSL_SESSION_free(s);
1097     }
1098 }
1099 
1100 static IMPLEMENT_LHASH_DOALL_ARG_FN(timeout, SSL_SESSION, TIMEOUT_PARAM)
1101 
1102 void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
1103 {
1104     unsigned long i;
1105     TIMEOUT_PARAM tp;
1106 
1107     tp.ctx = s;
1108     tp.cache = s->sessions;
1109     if (tp.cache == NULL)
1110         return;
1111     tp.time = t;
1112     CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
1113     i = CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load;
1114     CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = 0;
1115     lh_SSL_SESSION_doall_arg(tp.cache, LHASH_DOALL_ARG_FN(timeout),
1116                              TIMEOUT_PARAM, &tp);
1117     CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = i;
1118     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
1119 }
1120 
1121 int ssl_clear_bad_session(SSL *s)
1122 {
1123     if ((s->session != NULL) &&
1124         !(s->shutdown & SSL_SENT_SHUTDOWN) &&
1125         !(SSL_in_init(s) || SSL_in_before(s))) {
1126         SSL_CTX_remove_session(s->ctx, s->session);
1127         return (1);
1128     } else
1129         return (0);
1130 }
1131 
1132 /* locked by SSL_CTX in the calling function */
1133 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
1134 {
1135     if ((s->next == NULL) || (s->prev == NULL))
1136         return;
1137 
1138     if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail)) {
1139         /* last element in list */
1140         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1141             /* only one element in list */
1142             ctx->session_cache_head = NULL;
1143             ctx->session_cache_tail = NULL;
1144         } else {
1145             ctx->session_cache_tail = s->prev;
1146             s->prev->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1147         }
1148     } else {
1149         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1150             /* first element in list */
1151             ctx->session_cache_head = s->next;
1152             s->next->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1153         } else {
1154             /* middle of list */
1155             s->next->prev = s->prev;
1156             s->prev->next = s->next;
1157         }
1158     }
1159     s->prev = s->next = NULL;
1160 }
1161 
1162 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
1163 {
1164     if ((s->next != NULL) && (s->prev != NULL))
1165         SSL_SESSION_list_remove(ctx, s);
1166 
1167     if (ctx->session_cache_head == NULL) {
1168         ctx->session_cache_head = s;
1169         ctx->session_cache_tail = s;
1170         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1171         s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1172     } else {
1173         s->next = ctx->session_cache_head;
1174         s->next->prev = s;
1175         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1176         ctx->session_cache_head = s;
1177     }
1178 }
1179 
1180 void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
1181                              int (*cb) (struct ssl_st *ssl,
1182                                         SSL_SESSION *sess))
1183 {
1184     ctx->new_session_cb = cb;
1185 }
1186 
1187 int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx)) (SSL *ssl, SSL_SESSION *sess) {
1188     return ctx->new_session_cb;
1189 }
1190 
1191 void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
1192                                 void (*cb) (SSL_CTX *ctx, SSL_SESSION *sess))
1193 {
1194     ctx->remove_session_cb = cb;
1195 }
1196 
1197 void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx)) (SSL_CTX *ctx,
1198                                                   SSL_SESSION *sess) {
1199     return ctx->remove_session_cb;
1200 }
1201 
1202 void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
1203                              SSL_SESSION *(*cb) (struct ssl_st *ssl,
1204                                                  unsigned char *data, int len,
1205                                                  int *copy))
1206 {
1207     ctx->get_session_cb = cb;
1208 }
1209 
1210 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx)) (SSL *ssl,
1211                                                        unsigned char *data,
1212                                                        int len, int *copy) {
1213     return ctx->get_session_cb;
1214 }
1215 
1216 void SSL_CTX_set_info_callback(SSL_CTX *ctx,
1217                                void (*cb) (const SSL *ssl, int type, int val))
1218 {
1219     ctx->info_callback = cb;
1220 }
1221 
1222 void (*SSL_CTX_get_info_callback(SSL_CTX *ctx)) (const SSL *ssl, int type,
1223                                                  int val) {
1224     return ctx->info_callback;
1225 }
1226 
1227 void SSL_CTX_set_client_cert_cb(SSL_CTX *ctx,
1228                                 int (*cb) (SSL *ssl, X509 **x509,
1229                                            EVP_PKEY **pkey))
1230 {
1231     ctx->client_cert_cb = cb;
1232 }
1233 
1234 int (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx)) (SSL *ssl, X509 **x509,
1235                                                  EVP_PKEY **pkey) {
1236     return ctx->client_cert_cb;
1237 }
1238 
1239 #ifndef OPENSSL_NO_ENGINE
1240 int SSL_CTX_set_client_cert_engine(SSL_CTX *ctx, ENGINE *e)
1241 {
1242     if (!ENGINE_init(e)) {
1243         SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE, ERR_R_ENGINE_LIB);
1244         return 0;
1245     }
1246     if (!ENGINE_get_ssl_client_cert_function(e)) {
1247         SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE,
1248                SSL_R_NO_CLIENT_CERT_METHOD);
1249         ENGINE_finish(e);
1250         return 0;
1251     }
1252     ctx->client_cert_engine = e;
1253     return 1;
1254 }
1255 #endif
1256 
1257 void SSL_CTX_set_cookie_generate_cb(SSL_CTX *ctx,
1258                                     int (*cb) (SSL *ssl,
1259                                                unsigned char *cookie,
1260                                                unsigned int *cookie_len))
1261 {
1262     ctx->app_gen_cookie_cb = cb;
1263 }
1264 
1265 void SSL_CTX_set_cookie_verify_cb(SSL_CTX *ctx,
1266                                   int (*cb) (SSL *ssl, unsigned char *cookie,
1267                                              unsigned int cookie_len))
1268 {
1269     ctx->app_verify_cookie_cb = cb;
1270 }
1271 
1272 IMPLEMENT_PEM_rw(SSL_SESSION, SSL_SESSION, PEM_STRING_SSL_SESSION,
1273                  SSL_SESSION)
1274