2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
60 #include <openssl/lhash.h>
61 #include <openssl/rand.h>
64 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s);
65 static void SSL_SESSION_list_add(SSL_CTX *ctx,SSL_SESSION *s);
66 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck);
67 static int ssl_session_num=0;
68 static STACK_OF(CRYPTO_EX_DATA_FUNCS) *ssl_session_meth=NULL;
70 SSL_SESSION *SSL_get_session(SSL *ssl)
71 /* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
76 SSL_SESSION *SSL_get1_session(SSL *ssl)
77 /* variant of SSL_get_session: caller really gets something */
80 /* Need to lock this all up rather than just use CRYPTO_add so that
81 * somebody doesn't free ssl->session between when we check it's
82 * non-null and when we up the reference count. */
83 CRYPTO_r_lock(CRYPTO_LOCK_SSL_SESSION);
87 CRYPTO_r_unlock(CRYPTO_LOCK_SSL_SESSION);
91 int SSL_SESSION_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
92 CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
95 return(CRYPTO_get_ex_new_index(ssl_session_num-1,
97 argl,argp,new_func,dup_func,free_func));
100 int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
102 return(CRYPTO_set_ex_data(&s->ex_data,idx,arg));
105 void *SSL_SESSION_get_ex_data(SSL_SESSION *s, int idx)
107 return(CRYPTO_get_ex_data(&s->ex_data,idx));
110 SSL_SESSION *SSL_SESSION_new(void)
114 ss=(SSL_SESSION *)OPENSSL_malloc(sizeof(SSL_SESSION));
117 SSLerr(SSL_F_SSL_SESSION_NEW,ERR_R_MALLOC_FAILURE);
120 memset(ss,0,sizeof(SSL_SESSION));
122 ss->verify_result = 1; /* avoid 0 (= X509_V_OK) just in case */
124 ss->timeout=60*5+4; /* 5 minute timeout by default */
129 CRYPTO_new_ex_data(ssl_session_meth,ss,&ss->ex_data);
133 /* Even with SSLv2, we have 16 bytes (128 bits) of session ID space. SSLv3/TLSv1
134 * has 32 bytes (256 bits). As such, filling the ID with random gunk repeatedly
135 * until we have no conflict is going to complete in one iteration pretty much
136 * "most" of the time (btw: understatement). So, if it takes us 10 iterations
137 * and we still can't avoid a conflict - well that's a reasonable point to call
138 * it quits. Either the RAND code is broken or someone is trying to open roughly
139 * very close to 2^128 (or 2^256) SSL sessions to our server. How you might
140 * store that many sessions is perhaps a more interesting question ... */
142 #define MAX_SESS_ID_ATTEMPTS 10
143 static int def_generate_session_id(const SSL *ssl, unsigned char *id,
144 unsigned int *id_len)
146 unsigned int retry = 0;
148 RAND_pseudo_bytes(id, *id_len);
149 while(SSL_has_matching_session_id(ssl, id, *id_len) &&
150 (++retry < MAX_SESS_ID_ATTEMPTS));
151 if(retry < MAX_SESS_ID_ATTEMPTS)
153 /* else - woops a session_id match */
154 /* XXX We should also check the external cache --
155 * but the probability of a collision is negligible, and
156 * we could not prevent the concurrent creation of sessions
157 * with identical IDs since we currently don't have means
158 * to atomically check whether a session ID already exists
159 * and make a reservation for it if it does not
160 * (this problem applies to the internal cache as well).
165 int ssl_get_new_session(SSL *s, int session)
167 /* This gets used by clients and servers. */
170 SSL_SESSION *ss=NULL;
171 GEN_SESSION_CB cb = def_generate_session_id;
173 if ((ss=SSL_SESSION_new()) == NULL) return(0);
175 /* If the context has a default timeout, use it */
176 if (s->ctx->session_timeout == 0)
177 ss->timeout=SSL_get_default_timeout(s);
179 ss->timeout=s->ctx->session_timeout;
181 if (s->session != NULL)
183 SSL_SESSION_free(s->session);
189 if (s->version == SSL2_VERSION)
191 ss->ssl_version=SSL2_VERSION;
192 ss->session_id_length=SSL2_SSL_SESSION_ID_LENGTH;
194 else if (s->version == SSL3_VERSION)
196 ss->ssl_version=SSL3_VERSION;
197 ss->session_id_length=SSL3_SSL_SESSION_ID_LENGTH;
199 else if (s->version == TLS1_VERSION)
201 ss->ssl_version=TLS1_VERSION;
202 ss->session_id_length=SSL3_SSL_SESSION_ID_LENGTH;
206 SSLerr(SSL_F_SSL_GET_NEW_SESSION,SSL_R_UNSUPPORTED_SSL_VERSION);
207 SSL_SESSION_free(ss);
210 /* Choose which callback will set the session ID */
211 CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
212 if(s->generate_session_id)
213 cb = s->generate_session_id;
214 else if(s->ctx->generate_session_id)
215 cb = s->ctx->generate_session_id;
216 CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
217 /* Choose a session ID */
218 tmp = ss->session_id_length;
219 if(!cb(s, ss->session_id, &tmp))
221 /* The callback failed */
222 SSLerr(SSL_F_SSL_GET_NEW_SESSION,
223 SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
224 SSL_SESSION_free(ss);
227 /* Don't allow the callback to set the session length to zero.
228 * nor set it higher than it was. */
229 if(!tmp || (tmp > ss->session_id_length))
231 /* The callback set an illegal length */
232 SSLerr(SSL_F_SSL_GET_NEW_SESSION,
233 SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
234 SSL_SESSION_free(ss);
237 /* If the session length was shrunk and we're SSLv2, pad it */
238 if((tmp < ss->session_id_length) && (s->version == SSL2_VERSION))
239 memset(ss->session_id + tmp, 0, ss->session_id_length - tmp);
241 ss->session_id_length = tmp;
242 /* Finally, check for a conflict */
243 if(SSL_has_matching_session_id(s, ss->session_id,
244 ss->session_id_length))
246 SSLerr(SSL_F_SSL_GET_NEW_SESSION,
247 SSL_R_SSL_SESSION_ID_CONFLICT);
248 SSL_SESSION_free(ss);
254 ss->session_id_length=0;
257 memcpy(ss->sid_ctx,s->sid_ctx,s->sid_ctx_length);
258 ss->sid_ctx_length=s->sid_ctx_length;
260 ss->ssl_version=s->version;
261 ss->verify_result = X509_V_OK;
266 int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len)
268 /* This is used only by servers. */
270 SSL_SESSION *ret=NULL,data;
273 data.ssl_version=s->version;
274 data.session_id_length=len;
275 if (len > SSL_MAX_SSL_SESSION_ID_LENGTH)
277 memcpy(data.session_id,session_id,len);
279 if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_NO_INTERNAL_LOOKUP))
281 CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
282 ret=(SSL_SESSION *)lh_retrieve(s->ctx->sessions,&data);
284 /* don't allow other threads to steal it: */
285 CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
286 CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
293 s->ctx->stats.sess_miss++;
295 if (s->ctx->get_session_cb != NULL
296 && (ret=s->ctx->get_session_cb(s,session_id,len,©))
299 s->ctx->stats.sess_cb_hit++;
301 /* Increment reference count now if the session callback
302 * asks us to do so (note that if the session structures
303 * returned by the callback are shared between threads,
304 * it must handle the reference count itself [i.e. copy == 0],
305 * or things won't be thread-safe). */
307 CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
309 /* The following should not return 1, otherwise,
310 * things are very strange */
311 SSL_CTX_add_session(s->ctx,ret);
317 /* Now ret is non-NULL, and we own one of its reference counts. */
319 if((s->verify_mode&SSL_VERIFY_PEER)
320 && (!s->sid_ctx_length || ret->sid_ctx_length != s->sid_ctx_length
321 || memcmp(ret->sid_ctx,s->sid_ctx,ret->sid_ctx_length)))
323 /* We've found the session named by the client, but we don't
324 * want to use it in this context. */
326 if (s->sid_ctx_length == 0)
328 /* application should have used SSL[_CTX]_set_session_id_context
329 * -- we could tolerate this and just pretend we never heard
330 * of this session, but then applications could effectively
331 * disable the session cache by accident without anyone noticing */
333 SSLerr(SSL_F_SSL_GET_PREV_SESSION,SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
339 #if 0 /* The client cannot always know when a session is not appropriate,
340 * so we shouldn't generate an error message. */
342 SSLerr(SSL_F_SSL_GET_PREV_SESSION,SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
344 goto err; /* treat like cache miss */
348 if (ret->cipher == NULL)
350 unsigned char buf[5],*p;
356 if ((ret->ssl_version>>8) == SSL3_VERSION_MAJOR)
357 ret->cipher=ssl_get_cipher_by_char(s,&(buf[2]));
359 ret->cipher=ssl_get_cipher_by_char(s,&(buf[1]));
360 if (ret->cipher == NULL)
365 #if 0 /* This is way too late. */
367 /* If a thread got the session, then 'swaped', and another got
368 * it and then due to a time-out decided to 'OPENSSL_free' it we could
369 * be in trouble. So I'll increment it now, then double decrement
370 * later - am I speaking rubbish?. */
371 CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
374 if ((long)(ret->time+ret->timeout) < (long)time(NULL)) /* timeout */
376 s->ctx->stats.sess_timeout++;
377 /* remove it from the cache */
378 SSL_CTX_remove_session(s->ctx,ret);
382 s->ctx->stats.sess_hit++;
384 /* ret->time=time(NULL); */ /* rezero timeout? */
385 /* again, just leave the session
386 * if it is the same session, we have just incremented and
387 * then decremented the reference count :-) */
388 if (s->session != NULL)
389 SSL_SESSION_free(s->session);
391 s->verify_result = s->session->verify_result;
396 SSL_SESSION_free(ret);
403 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
408 /* add just 1 reference count for the SSL_CTX's session cache
409 * even though it has two ways of access: each session is in a
410 * doubly linked list and an lhash */
411 CRYPTO_add(&c->references,1,CRYPTO_LOCK_SSL_SESSION);
412 /* if session c is in already in cache, we take back the increment later */
414 CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
415 s=(SSL_SESSION *)lh_insert(ctx->sessions,c);
417 /* s != NULL iff we already had a session with the given PID.
418 * In this case, s == c should hold (then we did not really modify
419 * ctx->sessions), or we're in trouble. */
420 if (s != NULL && s != c)
422 /* We *are* in trouble ... */
423 SSL_SESSION_list_remove(ctx,s);
425 /* ... so pretend the other session did not exist in cache
426 * (we cannot handle two SSL_SESSION structures with identical
427 * session ID in the same cache, which could happen e.g. when
428 * two threads concurrently obtain the same session from an external
433 /* Put at the head of the queue unless it is already in the cache */
435 SSL_SESSION_list_add(ctx,c);
439 /* existing cache entry -- decrement previously incremented reference
440 * count because it already takes into account the cache */
442 SSL_SESSION_free(s); /* s == c */
447 /* new cache entry -- remove old ones if cache has become too large */
451 if (SSL_CTX_sess_get_cache_size(ctx) > 0)
453 while (SSL_CTX_sess_number(ctx) >
454 SSL_CTX_sess_get_cache_size(ctx))
456 if (!remove_session_lock(ctx,
457 ctx->session_cache_tail, 0))
460 ctx->stats.sess_cache_full++;
464 CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
468 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
470 return remove_session_lock(ctx, c, 1);
473 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
478 if ((c != NULL) && (c->session_id_length != 0))
480 if(lck) CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
481 r=(SSL_SESSION *)lh_delete(ctx->sessions,c);
485 SSL_SESSION_list_remove(ctx,c);
488 if(lck) CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
493 if (ctx->remove_session_cb != NULL)
494 ctx->remove_session_cb(ctx,r);
503 void SSL_SESSION_free(SSL_SESSION *ss)
510 i=CRYPTO_add(&ss->references,-1,CRYPTO_LOCK_SSL_SESSION);
512 REF_PRINT("SSL_SESSION",ss);
518 fprintf(stderr,"SSL_SESSION_free, bad reference count\n");
523 CRYPTO_free_ex_data(ssl_session_meth,ss,&ss->ex_data);
525 memset(ss->key_arg,0,SSL_MAX_KEY_ARG_LENGTH);
526 memset(ss->master_key,0,SSL_MAX_MASTER_KEY_LENGTH);
527 memset(ss->session_id,0,SSL_MAX_SSL_SESSION_ID_LENGTH);
528 if (ss->sess_cert != NULL) ssl_sess_cert_free(ss->sess_cert);
529 if (ss->peer != NULL) X509_free(ss->peer);
530 if (ss->ciphers != NULL) sk_SSL_CIPHER_free(ss->ciphers);
531 memset(ss,0,sizeof(*ss));
535 int SSL_set_session(SSL *s, SSL_SESSION *session)
542 meth=s->ctx->method->get_ssl_method(session->ssl_version);
544 meth=s->method->get_ssl_method(session->ssl_version);
547 SSLerr(SSL_F_SSL_SET_SESSION,SSL_R_UNABLE_TO_FIND_SSL_METHOD);
551 if (meth != s->method)
553 if (!SSL_set_ssl_method(s,meth))
555 if (s->ctx->session_timeout == 0)
556 session->timeout=SSL_get_default_timeout(s);
558 session->timeout=s->ctx->session_timeout;
561 /* CRYPTO_w_lock(CRYPTO_LOCK_SSL);*/
562 CRYPTO_add(&session->references,1,CRYPTO_LOCK_SSL_SESSION);
563 if (s->session != NULL)
564 SSL_SESSION_free(s->session);
566 s->verify_result = s->session->verify_result;
567 /* CRYPTO_w_unlock(CRYPTO_LOCK_SSL);*/
572 if (s->session != NULL)
574 SSL_SESSION_free(s->session);
579 if (meth != s->method)
581 if (!SSL_set_ssl_method(s,meth))
589 long SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
591 if (s == NULL) return(0);
596 long SSL_SESSION_get_timeout(SSL_SESSION *s)
598 if (s == NULL) return(0);
602 long SSL_SESSION_get_time(SSL_SESSION *s)
604 if (s == NULL) return(0);
608 long SSL_SESSION_set_time(SSL_SESSION *s, long t)
610 if (s == NULL) return(0);
615 long SSL_CTX_set_timeout(SSL_CTX *s, long t)
618 if (s == NULL) return(0);
619 l=s->session_timeout;
620 s->session_timeout=t;
624 long SSL_CTX_get_timeout(SSL_CTX *s)
626 if (s == NULL) return(0);
627 return(s->session_timeout);
630 typedef struct timeout_param_st
637 static void timeout(SSL_SESSION *s, TIMEOUT_PARAM *p)
639 if ((p->time == 0) || (p->time > (s->time+s->timeout))) /* timeout */
641 /* The reason we don't call SSL_CTX_remove_session() is to
642 * save on locking overhead */
643 lh_delete(p->cache,s);
644 SSL_SESSION_list_remove(p->ctx,s);
646 if (p->ctx->remove_session_cb != NULL)
647 p->ctx->remove_session_cb(p->ctx,s);
652 static IMPLEMENT_LHASH_DOALL_ARG_FN(timeout, SSL_SESSION *, TIMEOUT_PARAM *)
654 void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
660 tp.cache=s->sessions;
661 if (tp.cache == NULL) return;
663 CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
664 i=tp.cache->down_load;
665 tp.cache->down_load=0;
666 lh_doall_arg(tp.cache, LHASH_DOALL_ARG_FN(timeout), &tp);
667 tp.cache->down_load=i;
668 CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
671 int ssl_clear_bad_session(SSL *s)
673 if ( (s->session != NULL) &&
674 !(s->shutdown & SSL_SENT_SHUTDOWN) &&
675 !(SSL_in_init(s) || SSL_in_before(s)))
677 SSL_CTX_remove_session(s->ctx,s->session);
684 /* locked by SSL_CTX in the calling function */
685 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
687 if ((s->next == NULL) || (s->prev == NULL)) return;
689 if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail))
690 { /* last element in list */
691 if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head))
692 { /* only one element in list */
693 ctx->session_cache_head=NULL;
694 ctx->session_cache_tail=NULL;
698 ctx->session_cache_tail=s->prev;
699 s->prev->next=(SSL_SESSION *)&(ctx->session_cache_tail);
704 if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head))
705 { /* first element in list */
706 ctx->session_cache_head=s->next;
707 s->next->prev=(SSL_SESSION *)&(ctx->session_cache_head);
710 { /* middle of list */
711 s->next->prev=s->prev;
712 s->prev->next=s->next;
715 s->prev=s->next=NULL;
718 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
720 if ((s->next != NULL) && (s->prev != NULL))
721 SSL_SESSION_list_remove(ctx,s);
723 if (ctx->session_cache_head == NULL)
725 ctx->session_cache_head=s;
726 ctx->session_cache_tail=s;
727 s->prev=(SSL_SESSION *)&(ctx->session_cache_head);
728 s->next=(SSL_SESSION *)&(ctx->session_cache_tail);
732 s->next=ctx->session_cache_head;
734 s->prev=(SSL_SESSION *)&(ctx->session_cache_head);
735 ctx->session_cache_head=s;