xref: /openbsd-src/lib/libssl/ssl_sess.c (revision cb39b41371628601fbe4c618205356d538b9d08a)
1 /* $OpenBSD: ssl_sess.c,v 1.44 2014/12/14 15:30:50 jsing Exp $ */
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 <openssl/lhash.h>
139 
140 #ifndef OPENSSL_NO_ENGINE
141 #include <openssl/engine.h>
142 #endif
143 
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 /* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
151 SSL_SESSION *
152 SSL_get_session(const SSL *ssl)
153 {
154 	return (ssl->session);
155 }
156 
157 /* variant of SSL_get_session: caller really gets something */
158 SSL_SESSION *
159 SSL_get1_session(SSL *ssl)
160 {
161 	SSL_SESSION *sess;
162 
163 	/*
164 	 * Need to lock this all up rather than just use CRYPTO_add so that
165 	 * somebody doesn't free ssl->session between when we check it's
166 	 * non-null and when we up the reference count.
167 	 */
168 	CRYPTO_w_lock(CRYPTO_LOCK_SSL_SESSION);
169 	sess = ssl->session;
170 	if (sess)
171 		sess->references++;
172 	CRYPTO_w_unlock(CRYPTO_LOCK_SSL_SESSION);
173 
174 	return (sess);
175 }
176 
177 int
178 SSL_SESSION_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
179     CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
180 {
181 	return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_SSL_SESSION,
182 	    argl, argp, new_func, dup_func, free_func);
183 }
184 
185 int
186 SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
187 {
188 	return (CRYPTO_set_ex_data(&s->ex_data, idx, arg));
189 }
190 
191 void *
192 SSL_SESSION_get_ex_data(const SSL_SESSION *s, int idx)
193 {
194 	return (CRYPTO_get_ex_data(&s->ex_data, idx));
195 }
196 
197 SSL_SESSION *
198 SSL_SESSION_new(void)
199 {
200 	SSL_SESSION *ss;
201 
202 	ss = calloc(1, sizeof(SSL_SESSION));
203 	if (ss == NULL) {
204 		SSLerr(SSL_F_SSL_SESSION_NEW, ERR_R_MALLOC_FAILURE);
205 		return (0);
206 	}
207 
208 	ss->verify_result = 1; /* avoid 0 (= X509_V_OK) just in case */
209 	ss->references = 1;
210 	ss->timeout=60*5+4; /* 5 minute timeout by default */
211 	ss->time = time(NULL);
212 	ss->prev = NULL;
213 	ss->next = NULL;
214 	ss->tlsext_hostname = NULL;
215 
216 	ss->tlsext_ecpointformatlist_length = 0;
217 	ss->tlsext_ecpointformatlist = NULL;
218 	ss->tlsext_ellipticcurvelist_length = 0;
219 	ss->tlsext_ellipticcurvelist = NULL;
220 
221 	CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
222 
223 	return (ss);
224 }
225 
226 const unsigned char *
227 SSL_SESSION_get_id(const SSL_SESSION *s, unsigned int *len)
228 {
229 	if (len)
230 		*len = s->session_id_length;
231 	return s->session_id;
232 }
233 
234 unsigned int
235 SSL_SESSION_get_compress_id(const SSL_SESSION *s)
236 {
237 	return 0;
238 }
239 
240 /*
241  * SSLv3/TLSv1 has 32 bytes (256 bits) of session ID space. As such, filling
242  * the ID with random gunk repeatedly until we have no conflict is going to
243  * complete in one iteration pretty much "most" of the time (btw:
244  * understatement). So, if it takes us 10 iterations and we still can't avoid
245  * a conflict - well that's a reasonable point to call it quits. Either the
246  * arc4random code is broken or someone is trying to open roughly very close to
247  * 2^128 (or 2^256) SSL sessions to our server. How you might store that many
248  * sessions is perhaps a more interesting question...
249  */
250 
251 #define MAX_SESS_ID_ATTEMPTS 10
252 
253 static int
254 def_generate_session_id(const SSL *ssl, unsigned char *id, unsigned int *id_len)
255 {
256 	unsigned int retry = 0;
257 
258 	do {
259 		arc4random_buf(id, *id_len);
260 	} while (SSL_has_matching_session_id(ssl, id, *id_len) &&
261 	    (++retry < MAX_SESS_ID_ATTEMPTS));
262 
263 	if (retry < MAX_SESS_ID_ATTEMPTS)
264 		return 1;
265 
266 	/* else - woops a session_id match */
267 	/* XXX We should also check the external cache --
268 	 * but the probability of a collision is negligible, and
269 	 * we could not prevent the concurrent creation of sessions
270 	 * with identical IDs since we currently don't have means
271 	 * to atomically check whether a session ID already exists
272 	 * and make a reservation for it if it does not
273 	 * (this problem applies to the internal cache as well).
274 	 */
275 	return 0;
276 }
277 
278 int
279 ssl_get_new_session(SSL *s, int session)
280 {
281 	unsigned int tmp;
282 	SSL_SESSION *ss = NULL;
283 	GEN_SESSION_CB cb = def_generate_session_id;
284 
285 	/* This gets used by clients and servers. */
286 
287 	if ((ss = SSL_SESSION_new()) == NULL)
288 		return (0);
289 
290 	/* If the context has a default timeout, use it */
291 	if (s->session_ctx->session_timeout == 0)
292 		ss->timeout = SSL_get_default_timeout(s);
293 	else
294 		ss->timeout = s->session_ctx->session_timeout;
295 
296 	if (s->session != NULL) {
297 		SSL_SESSION_free(s->session);
298 		s->session = NULL;
299 	}
300 
301 	if (session) {
302 		switch (s->version) {
303 		case SSL3_VERSION:
304 		case TLS1_VERSION:
305 		case TLS1_1_VERSION:
306 		case TLS1_2_VERSION:
307 		case DTLS1_BAD_VER:
308 		case DTLS1_VERSION:
309 			ss->ssl_version = s->version;
310 			ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
311 			break;
312 		default:
313 			SSLerr(SSL_F_SSL_GET_NEW_SESSION,
314 			    SSL_R_UNSUPPORTED_SSL_VERSION);
315 			SSL_SESSION_free(ss);
316 			return (0);
317 		}
318 
319 		/* If RFC4507 ticket use empty session ID. */
320 		if (s->tlsext_ticket_expected) {
321 			ss->session_id_length = 0;
322 			goto sess_id_done;
323 		}
324 
325 		/* Choose which callback will set the session ID. */
326 		CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
327 		if (s->generate_session_id)
328 			cb = s->generate_session_id;
329 		else if (s->session_ctx->generate_session_id)
330 			cb = s->session_ctx->generate_session_id;
331 		CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
332 
333 		/* Choose a session ID. */
334 		tmp = ss->session_id_length;
335 		if (!cb(s, ss->session_id, &tmp)) {
336 			/* The callback failed */
337 			SSLerr(SSL_F_SSL_GET_NEW_SESSION,
338 			SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
339 			SSL_SESSION_free(ss);
340 			return (0);
341 		}
342 
343 		/*
344 		 * Don't allow the callback to set the session length to zero.
345 		 * nor set it higher than it was.
346 		 */
347 		if (!tmp || (tmp > ss->session_id_length)) {
348 			/* The callback set an illegal length */
349 			SSLerr(SSL_F_SSL_GET_NEW_SESSION,
350 			SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
351 			SSL_SESSION_free(ss);
352 			return (0);
353 		}
354 		ss->session_id_length = tmp;
355 
356 		/* Finally, check for a conflict. */
357 		if (SSL_has_matching_session_id(s, ss->session_id,
358 			ss->session_id_length)) {
359 			SSLerr(SSL_F_SSL_GET_NEW_SESSION,
360 			SSL_R_SSL_SESSION_ID_CONFLICT);
361 			SSL_SESSION_free(ss);
362 			return (0);
363 		}
364 
365 sess_id_done:
366 		if (s->tlsext_hostname) {
367 			ss->tlsext_hostname = strdup(s->tlsext_hostname);
368 			if (ss->tlsext_hostname == NULL) {
369 				SSLerr(SSL_F_SSL_GET_NEW_SESSION,
370 				    ERR_R_INTERNAL_ERROR);
371 				SSL_SESSION_free(ss);
372 				return 0;
373 			}
374 		}
375 	} else {
376 		ss->session_id_length = 0;
377 	}
378 
379 	if (s->sid_ctx_length > sizeof ss->sid_ctx) {
380 		SSLerr(SSL_F_SSL_GET_NEW_SESSION, ERR_R_INTERNAL_ERROR);
381 		SSL_SESSION_free(ss);
382 		return 0;
383 	}
384 
385 	memcpy(ss->sid_ctx, s->sid_ctx, s->sid_ctx_length);
386 	ss->sid_ctx_length = s->sid_ctx_length;
387 	s->session = ss;
388 	ss->ssl_version = s->version;
389 	ss->verify_result = X509_V_OK;
390 
391 	return (1);
392 }
393 
394 /*
395  * ssl_get_prev attempts to find an SSL_SESSION to be used to resume this
396  * connection. It is only called by servers.
397  *
398  *   session_id: points at the session ID in the ClientHello. This code will
399  *       read past the end of this in order to parse out the session ticket
400  *       extension, if any.
401  *   len: the length of the session ID.
402  *   limit: a pointer to the first byte after the ClientHello.
403  *
404  * Returns:
405  *   -1: error
406  *    0: a session may have been found.
407  *
408  * Side effects:
409  *   - If a session is found then s->session is pointed at it (after freeing
410  *     an existing session if need be) and s->verify_result is set from the
411  *     session.
412  *   - Both for new and resumed sessions, s->tlsext_ticket_expected is set
413  *     to 1 if the server should issue a new session ticket (to 0 otherwise).
414  */
415 int
416 ssl_get_prev_session(SSL *s, unsigned char *session_id, int len,
417     const unsigned char *limit)
418 {
419 	SSL_SESSION *ret = NULL;
420 	int fatal = 0;
421 	int try_session_cache = 1;
422 	int r;
423 
424 	/* This is used only by servers. */
425 
426 	if (len > SSL_MAX_SSL_SESSION_ID_LENGTH)
427 		goto err;
428 
429 	if (len == 0)
430 		try_session_cache = 0;
431 
432 	/* Sets s->tlsext_ticket_expected. */
433 	r = tls1_process_ticket(s, session_id, len, limit, &ret);
434 	switch (r) {
435 	case -1: /* Error during processing */
436 		fatal = 1;
437 		goto err;
438 	case 0: /* No ticket found */
439 	case 1: /* Zero length ticket found */
440 		break; /* Ok to carry on processing session id. */
441 	case 2: /* Ticket found but not decrypted. */
442 	case 3: /* Ticket decrypted, *ret has been set. */
443 		try_session_cache = 0;
444 		break;
445 	default:
446 		abort();
447 	}
448 
449 	if (try_session_cache && ret == NULL &&
450 	    !(s->session_ctx->session_cache_mode &
451 	     SSL_SESS_CACHE_NO_INTERNAL_LOOKUP)) {
452 		SSL_SESSION data;
453 		data.ssl_version = s->version;
454 		data.session_id_length = len;
455 		if (len == 0)
456 			return 0;
457 		memcpy(data.session_id, session_id, len);
458 
459 		CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
460 		ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
461 		if (ret != NULL) {
462 			/* Don't allow other threads to steal it. */
463 			CRYPTO_add(&ret->references, 1,
464 			    CRYPTO_LOCK_SSL_SESSION);
465 		}
466 		CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
467 
468 		if (ret == NULL)
469 			s->session_ctx->stats.sess_miss++;
470 	}
471 
472 	if (try_session_cache && ret == NULL &&
473 	    s->session_ctx->get_session_cb != NULL) {
474 		int copy = 1;
475 
476 		if ((ret = s->session_ctx->get_session_cb(s, session_id,
477 		    len, &copy))) {
478 			s->session_ctx->stats.sess_cb_hit++;
479 
480 			/*
481 			 * Increment reference count now if the session
482 			 * callback asks us to do so (note that if the session
483 			 * structures returned by the callback are shared
484 			 * between threads, it must handle the reference count
485 			 * itself [i.e. copy == 0], or things won't be
486 			 * thread-safe).
487 			 */
488 			if (copy)
489 				CRYPTO_add(&ret->references, 1,
490 				    CRYPTO_LOCK_SSL_SESSION);
491 
492 			/*
493 			 * Add the externally cached session to the internal
494 			 * cache as well if and only if we are supposed to.
495 			 */
496 			if (!(s->session_ctx->session_cache_mode &
497 			    SSL_SESS_CACHE_NO_INTERNAL_STORE))
498 				/*
499 				 * The following should not return 1,
500 				 * otherwise, things are very strange.
501 				 */
502 				SSL_CTX_add_session(s->session_ctx, ret);
503 		}
504 	}
505 
506 	if (ret == NULL)
507 		goto err;
508 
509 	/* Now ret is non-NULL and we own one of its reference counts. */
510 
511 	if (ret->sid_ctx_length != s->sid_ctx_length ||
512 	    timingsafe_memcmp(ret->sid_ctx,
513 		s->sid_ctx, ret->sid_ctx_length) != 0) {
514 		/* We have the session requested by the client, but we don't
515 		 * want to use it in this context. */
516 		goto err; /* treat like cache miss */
517 	}
518 
519 	if ((s->verify_mode & SSL_VERIFY_PEER) && s->sid_ctx_length == 0) {
520 		/*
521 		 * We can't be sure if this session is being used out of
522 		 * context, which is especially important for SSL_VERIFY_PEER.
523 		 * The application should have used
524 		 * SSL[_CTX]_set_session_id_context.
525 		 *
526 		 * For this error case, we generate an error instead of treating
527 		 * the event like a cache miss (otherwise it would be easy for
528 		 * applications to effectively disable the session cache by
529 		 * accident without anyone noticing).
530 		 */
531 		SSLerr(SSL_F_SSL_GET_PREV_SESSION,
532 		    SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
533 		fatal = 1;
534 		goto err;
535 	}
536 
537 	if (ret->cipher == NULL) {
538 		ret->cipher = ssl3_get_cipher_by_id(ret->cipher_id);
539 		if (ret->cipher == NULL)
540 			goto err;
541 	}
542 
543 	if (ret->timeout < (time(NULL) - ret->time)) {
544 		/* timeout */
545 		s->session_ctx->stats.sess_timeout++;
546 		if (try_session_cache) {
547 			/* session was from the cache, so remove it */
548 			SSL_CTX_remove_session(s->session_ctx, ret);
549 		}
550 		goto err;
551 	}
552 
553 	s->session_ctx->stats.sess_hit++;
554 
555 	if (s->session != NULL)
556 		SSL_SESSION_free(s->session);
557 	s->session = ret;
558 	s->verify_result = s->session->verify_result;
559 	return 1;
560 
561 err:
562 	if (ret != NULL) {
563 		SSL_SESSION_free(ret);
564 		if (!try_session_cache) {
565 			/*
566 			 * The session was from a ticket, so we should
567 			 * issue a ticket for the new session.
568 			 */
569 			s->tlsext_ticket_expected = 1;
570 		}
571 	}
572 	if (fatal)
573 		return -1;
574 	else
575 		return 0;
576 }
577 
578 int
579 SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
580 {
581 	int ret = 0;
582 	SSL_SESSION *s;
583 
584 	/*
585 	 * Add just 1 reference count for the SSL_CTX's session cache
586 	 * even though it has two ways of access: each session is in a
587 	 * doubly linked list and an lhash.
588 	 */
589 	CRYPTO_add(&c->references, 1, CRYPTO_LOCK_SSL_SESSION);
590 
591 	/*
592 	 * If session c is in already in cache, we take back the increment
593 	 * later.
594 	 */
595 	CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
596 	s = lh_SSL_SESSION_insert(ctx->sessions, c);
597 
598 	/*
599 	 * s != NULL iff we already had a session with the given PID.
600 	 * In this case, s == c should hold (then we did not really modify
601 	 * ctx->sessions), or we're in trouble.
602 	 */
603 	if (s != NULL && s != c) {
604 		/* We *are* in trouble ... */
605 		SSL_SESSION_list_remove(ctx, s);
606 		SSL_SESSION_free(s);
607 		/*
608 		 * ... so pretend the other session did not exist in cache
609 		 * (we cannot handle two SSL_SESSION structures with identical
610 		 * session ID in the same cache, which could happen e.g. when
611 		 * two threads concurrently obtain the same session from an
612 		 * external cache).
613 		 */
614 		s = NULL;
615 	}
616 
617 	/* Put at the head of the queue unless it is already in the cache */
618 	if (s == NULL)
619 		SSL_SESSION_list_add(ctx, c);
620 
621 	if (s != NULL) {
622 		/*
623 		 * existing cache entry -- decrement previously incremented
624 		 * reference count because it already takes into account the
625 		 * cache.
626 		 */
627 		SSL_SESSION_free(s); /* s == c */
628 		ret = 0;
629 	} else {
630 		/*
631 		 * New cache entry -- remove old ones if cache has become
632 		 * too large.
633 		 */
634 
635 		ret = 1;
636 
637 		if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
638 			while (SSL_CTX_sess_number(ctx) >
639 			    SSL_CTX_sess_get_cache_size(ctx)) {
640 				if (!remove_session_lock(ctx,
641 				    ctx->session_cache_tail, 0))
642 					break;
643 				else
644 					ctx->stats.sess_cache_full++;
645 			}
646 		}
647 	}
648 	CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
649 	return (ret);
650 }
651 
652 int
653 SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
654 {
655 	return remove_session_lock(ctx, c, 1);
656 }
657 
658 static int
659 remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
660 {
661 	SSL_SESSION *r;
662 	int ret = 0;
663 
664 	if ((c != NULL) && (c->session_id_length != 0)) {
665 		if (lck)
666 			CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
667 		if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) == c) {
668 			ret = 1;
669 			r = lh_SSL_SESSION_delete(ctx->sessions, c);
670 			SSL_SESSION_list_remove(ctx, c);
671 		}
672 		if (lck)
673 			CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
674 
675 		if (ret) {
676 			r->not_resumable = 1;
677 			if (ctx->remove_session_cb != NULL)
678 				ctx->remove_session_cb(ctx, r);
679 			SSL_SESSION_free(r);
680 		}
681 	} else
682 		ret = 0;
683 	return (ret);
684 }
685 
686 void
687 SSL_SESSION_free(SSL_SESSION *ss)
688 {
689 	int i;
690 
691 	if (ss == NULL)
692 		return;
693 
694 	i = CRYPTO_add(&ss->references, -1, CRYPTO_LOCK_SSL_SESSION);
695 	if (i > 0)
696 		return;
697 
698 	CRYPTO_free_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
699 
700 	OPENSSL_cleanse(ss->master_key, sizeof ss->master_key);
701 	OPENSSL_cleanse(ss->session_id, sizeof ss->session_id);
702 	if (ss->sess_cert != NULL)
703 		ssl_sess_cert_free(ss->sess_cert);
704 	if (ss->peer != NULL)
705 		X509_free(ss->peer);
706 	if (ss->ciphers != NULL)
707 		sk_SSL_CIPHER_free(ss->ciphers);
708 	free(ss->tlsext_hostname);
709 	free(ss->tlsext_tick);
710 	ss->tlsext_ecpointformatlist_length = 0;
711 	free(ss->tlsext_ecpointformatlist);
712 	ss->tlsext_ellipticcurvelist_length = 0;
713 	free(ss->tlsext_ellipticcurvelist);
714 	OPENSSL_cleanse(ss, sizeof(*ss));
715 	free(ss);
716 }
717 
718 int
719 SSL_set_session(SSL *s, SSL_SESSION *session)
720 {
721 	int ret = 0;
722 	const SSL_METHOD *meth;
723 
724 	if (session != NULL) {
725 		meth = s->ctx->method->get_ssl_method(session->ssl_version);
726 		if (meth == NULL)
727 			meth = s->method->get_ssl_method(session->ssl_version);
728 		if (meth == NULL) {
729 			SSLerr(SSL_F_SSL_SET_SESSION,
730 			    SSL_R_UNABLE_TO_FIND_SSL_METHOD);
731 			return (0);
732 		}
733 
734 		if (meth != s->method) {
735 			if (!SSL_set_ssl_method(s, meth))
736 				return (0);
737 		}
738 
739 
740 		/* CRYPTO_w_lock(CRYPTO_LOCK_SSL);*/
741 		CRYPTO_add(&session->references, 1, CRYPTO_LOCK_SSL_SESSION);
742 		if (s->session != NULL)
743 			SSL_SESSION_free(s->session);
744 		s->session = session;
745 		s->verify_result = s->session->verify_result;
746 		/* CRYPTO_w_unlock(CRYPTO_LOCK_SSL);*/
747 		ret = 1;
748 	} else {
749 		if (s->session != NULL) {
750 			SSL_SESSION_free(s->session);
751 			s->session = NULL;
752 		}
753 
754 		meth = s->ctx->method;
755 		if (meth != s->method) {
756 			if (!SSL_set_ssl_method(s, meth))
757 				return (0);
758 		}
759 		ret = 1;
760 	}
761 	return (ret);
762 }
763 
764 long
765 SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
766 {
767 	if (s == NULL)
768 		return (0);
769 	s->timeout = t;
770 	return (1);
771 }
772 
773 long
774 SSL_SESSION_get_timeout(const SSL_SESSION *s)
775 {
776 	if (s == NULL)
777 		return (0);
778 	return (s->timeout);
779 }
780 
781 /* XXX 2038 */
782 long
783 SSL_SESSION_get_time(const SSL_SESSION *s)
784 {
785 	if (s == NULL)
786 		return (0);
787 	return (s->time);
788 }
789 
790 /* XXX 2038 */
791 long
792 SSL_SESSION_set_time(SSL_SESSION *s, long t)
793 {
794 	if (s == NULL)
795 		return (0);
796 	s->time = t;
797 	return (t);
798 }
799 
800 X509 *
801 SSL_SESSION_get0_peer(SSL_SESSION *s)
802 {
803 	return s->peer;
804 }
805 
806 int
807 SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
808     unsigned int sid_ctx_len)
809 {
810 	if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
811 		SSLerr(SSL_F_SSL_SESSION_SET1_ID_CONTEXT,
812 		    SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
813 		return 0;
814 	}
815 	s->sid_ctx_length = sid_ctx_len;
816 	memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
817 
818 	return 1;
819 }
820 
821 long
822 SSL_CTX_set_timeout(SSL_CTX *s, long t)
823 {
824 	long l;
825 
826 	if (s == NULL)
827 		return (0);
828 	l = s->session_timeout;
829 	s->session_timeout = t;
830 
831 	return (l);
832 }
833 
834 long
835 SSL_CTX_get_timeout(const SSL_CTX *s)
836 {
837 	if (s == NULL)
838 		return (0);
839 	return (s->session_timeout);
840 }
841 
842 int
843 SSL_set_session_secret_cb(SSL *s, int (*tls_session_secret_cb)(SSL *s,
844     void *secret, int *secret_len, STACK_OF(SSL_CIPHER) *peer_ciphers,
845     SSL_CIPHER **cipher, void *arg), void *arg)
846 {
847 	if (s == NULL)
848 		return (0);
849 	s->tls_session_secret_cb = tls_session_secret_cb;
850 	s->tls_session_secret_cb_arg = arg;
851 	return (1);
852 }
853 
854 int
855 SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
856     void *arg)
857 {
858 	if (s == NULL)
859 		return (0);
860 	s->tls_session_ticket_ext_cb = cb;
861 	s->tls_session_ticket_ext_cb_arg = arg;
862 	return (1);
863 }
864 
865 int
866 SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
867 {
868 	if (s->version >= TLS1_VERSION) {
869 		free(s->tlsext_session_ticket);
870 		s->tlsext_session_ticket =
871 		    malloc(sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
872 		if (!s->tlsext_session_ticket) {
873 			SSLerr(SSL_F_SSL_SET_SESSION_TICKET_EXT,
874 			    ERR_R_MALLOC_FAILURE);
875 			return 0;
876 		}
877 
878 		if (ext_data) {
879 			s->tlsext_session_ticket->length = ext_len;
880 			s->tlsext_session_ticket->data =
881 			    s->tlsext_session_ticket + 1;
882 			memcpy(s->tlsext_session_ticket->data,
883 			    ext_data, ext_len);
884 		} else {
885 			s->tlsext_session_ticket->length = 0;
886 			s->tlsext_session_ticket->data = NULL;
887 		}
888 
889 		return 1;
890 	}
891 
892 	return 0;
893 }
894 
895 typedef struct timeout_param_st {
896 	SSL_CTX *ctx;
897 	long time;
898 	LHASH_OF(SSL_SESSION) *cache;
899 } TIMEOUT_PARAM;
900 
901 static void
902 timeout_doall_arg(SSL_SESSION *s, TIMEOUT_PARAM *p)
903 {
904 	if ((p->time == 0) || (p->time > (s->time + s->timeout))) {
905 		/* timeout */
906 		/* The reason we don't call SSL_CTX_remove_session() is to
907 		 * save on locking overhead */
908 		(void)lh_SSL_SESSION_delete(p->cache, s);
909 		SSL_SESSION_list_remove(p->ctx, s);
910 		s->not_resumable = 1;
911 		if (p->ctx->remove_session_cb != NULL)
912 			p->ctx->remove_session_cb(p->ctx, s);
913 		SSL_SESSION_free(s);
914 	}
915 }
916 
917 static
918 IMPLEMENT_LHASH_DOALL_ARG_FN(timeout, SSL_SESSION, TIMEOUT_PARAM)
919 
920 /* XXX 2038 */
921 void
922 SSL_CTX_flush_sessions(SSL_CTX *s, long t)
923 {
924 	unsigned long i;
925 	TIMEOUT_PARAM tp;
926 
927 	tp.ctx = s;
928 	tp.cache = s->sessions;
929 	if (tp.cache == NULL)
930 		return;
931 	tp.time = t;
932 	CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
933 	i = CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load;
934 	CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = 0;
935 	lh_SSL_SESSION_doall_arg(tp.cache, LHASH_DOALL_ARG_FN(timeout),
936 	TIMEOUT_PARAM, &tp);
937 	CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = i;
938 	CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
939 }
940 
941 int
942 ssl_clear_bad_session(SSL *s)
943 {
944 	if ((s->session != NULL) && !(s->shutdown & SSL_SENT_SHUTDOWN) &&
945 	    !(SSL_in_init(s) || SSL_in_before(s))) {
946 		SSL_CTX_remove_session(s->ctx, s->session);
947 		return (1);
948 	} else
949 		return (0);
950 }
951 
952 /* locked by SSL_CTX in the calling function */
953 static void
954 SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
955 {
956 	if ((s->next == NULL) || (s->prev == NULL))
957 		return;
958 
959 	if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail)) {
960 		/* last element in list */
961 		if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
962 			/* only one element in list */
963 			ctx->session_cache_head = NULL;
964 			ctx->session_cache_tail = NULL;
965 		} else {
966 			ctx->session_cache_tail = s->prev;
967 			s->prev->next =
968 			    (SSL_SESSION *)&(ctx->session_cache_tail);
969 		}
970 	} else {
971 		if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
972 			/* first element in list */
973 			ctx->session_cache_head = s->next;
974 			s->next->prev =
975 			    (SSL_SESSION *)&(ctx->session_cache_head);
976 		} else {
977 			/* middle of list */
978 			s->next->prev = s->prev;
979 			s->prev->next = s->next;
980 		}
981 	}
982 	s->prev = s->next = NULL;
983 }
984 
985 static void
986 SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
987 {
988 	if ((s->next != NULL) && (s->prev != NULL))
989 		SSL_SESSION_list_remove(ctx, s);
990 
991 	if (ctx->session_cache_head == NULL) {
992 		ctx->session_cache_head = s;
993 		ctx->session_cache_tail = s;
994 		s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
995 		s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
996 	} else {
997 		s->next = ctx->session_cache_head;
998 		s->next->prev = s;
999 		s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1000 		ctx->session_cache_head = s;
1001 	}
1002 }
1003 
1004 void
1005 SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
1006     int (*cb)(struct ssl_st *ssl, SSL_SESSION *sess)) {
1007 	ctx->new_session_cb = cb;
1008 }
1009 
1010 int
1011 (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx))(SSL *ssl, SSL_SESSION *sess)
1012 {
1013 	return ctx->new_session_cb;
1014 }
1015 
1016 void
1017 SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
1018     void (*cb)(SSL_CTX *ctx, SSL_SESSION *sess))
1019 {
1020 	ctx->remove_session_cb = cb;
1021 }
1022 
1023 void
1024 (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx))(SSL_CTX * ctx, SSL_SESSION *sess)
1025 {
1026 	return ctx->remove_session_cb;
1027 }
1028 
1029 void
1030 SSL_CTX_sess_set_get_cb(SSL_CTX *ctx, SSL_SESSION *(*cb)(struct ssl_st *ssl,
1031     unsigned char *data, int len, int *copy))
1032 {
1033 	ctx->get_session_cb = cb;
1034 }
1035 
1036 SSL_SESSION *
1037 (*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(SSL *ssl, unsigned char *data,
1038     int len, int *copy)
1039 {
1040 	return ctx->get_session_cb;
1041 }
1042 
1043 void
1044 SSL_CTX_set_info_callback(SSL_CTX *ctx,
1045     void (*cb)(const SSL *ssl, int type, int val))
1046 {
1047 	ctx->info_callback = cb;
1048 }
1049 
1050 void
1051 (*SSL_CTX_get_info_callback(SSL_CTX *ctx))(const SSL *ssl, int type, int val)
1052 {
1053 	return ctx->info_callback;
1054 }
1055 
1056 void
1057 SSL_CTX_set_client_cert_cb(SSL_CTX *ctx,
1058     int (*cb)(SSL *ssl, X509 **x509, EVP_PKEY **pkey))
1059 {
1060 	ctx->client_cert_cb = cb;
1061 }
1062 
1063 int
1064 (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx))(SSL * ssl, X509 ** x509,
1065     EVP_PKEY **pkey)
1066 {
1067 	return ctx->client_cert_cb;
1068 }
1069 
1070 #ifndef OPENSSL_NO_ENGINE
1071 int
1072 SSL_CTX_set_client_cert_engine(SSL_CTX *ctx, ENGINE *e)
1073 {
1074 	if (!ENGINE_init(e)) {
1075 		SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE,
1076 		    ERR_R_ENGINE_LIB);
1077 		return 0;
1078 	}
1079 	if (!ENGINE_get_ssl_client_cert_function(e)) {
1080 		SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE,
1081 		    SSL_R_NO_CLIENT_CERT_METHOD);
1082 		ENGINE_finish(e);
1083 		return 0;
1084 	}
1085 	ctx->client_cert_engine = e;
1086 	return 1;
1087 }
1088 #endif
1089 
1090 void
1091 SSL_CTX_set_cookie_generate_cb(SSL_CTX *ctx,
1092     int (*cb)(SSL *ssl, unsigned char *cookie, unsigned int *cookie_len))
1093 {
1094 	ctx->app_gen_cookie_cb = cb;
1095 }
1096 
1097 void
1098 SSL_CTX_set_cookie_verify_cb(SSL_CTX *ctx,
1099     int (*cb)(SSL *ssl, unsigned char *cookie, unsigned int cookie_len))
1100 {
1101 	ctx->app_verify_cookie_cb = cb;
1102 }
1103 
1104 IMPLEMENT_PEM_rw(SSL_SESSION, SSL_SESSION, PEM_STRING_SSL_SESSION, SSL_SESSION)
1105