1 /* ssl/s23_clnt.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 #include <stdio.h>
113 #include "ssl_locl.h"
114 #include <openssl/buffer.h>
115 #include <openssl/rand.h>
116 #include <openssl/objects.h>
117 #include <openssl/evp.h>
118 
119 static const SSL_METHOD *ssl23_get_client_method(int ver);
120 static int ssl23_client_hello(SSL *s);
121 static int ssl23_get_server_hello(SSL *s);
122 static const SSL_METHOD *ssl23_get_client_method(int ver)
123 {
124 #ifndef OPENSSL_NO_SSL2
125     if (ver == SSL2_VERSION)
126         return (SSLv2_client_method());
127 #endif
128 #ifndef OPENSSL_NO_SSL3
129     if (ver == SSL3_VERSION)
130         return (SSLv3_client_method());
131 #endif
132     if (ver == TLS1_VERSION)
133         return (TLSv1_client_method());
134     else if (ver == TLS1_1_VERSION)
135         return (TLSv1_1_client_method());
136     else if (ver == TLS1_2_VERSION)
137         return (TLSv1_2_client_method());
138     else
139         return (NULL);
140 }
141 
142 IMPLEMENT_ssl23_meth_func(SSLv23_client_method,
143                           ssl_undefined_function,
144                           ssl23_connect, ssl23_get_client_method)
145 
146 int ssl23_connect(SSL *s)
147 {
148     BUF_MEM *buf = NULL;
149     unsigned long Time = (unsigned long)time(NULL);
150     void (*cb) (const SSL *ssl, int type, int val) = NULL;
151     int ret = -1;
152     int new_state, state;
153 
154     RAND_add(&Time, sizeof(Time), 0);
155     ERR_clear_error();
156     clear_sys_error();
157 
158     if (s->info_callback != NULL)
159         cb = s->info_callback;
160     else if (s->ctx->info_callback != NULL)
161         cb = s->ctx->info_callback;
162 
163     s->in_handshake++;
164     if (!SSL_in_init(s) || SSL_in_before(s))
165         SSL_clear(s);
166 
167     for (;;) {
168         state = s->state;
169 
170         switch (s->state) {
171         case SSL_ST_BEFORE:
172         case SSL_ST_CONNECT:
173         case SSL_ST_BEFORE | SSL_ST_CONNECT:
174         case SSL_ST_OK | SSL_ST_CONNECT:
175 
176             if (s->session != NULL) {
177                 SSLerr(SSL_F_SSL23_CONNECT,
178                        SSL_R_SSL23_DOING_SESSION_ID_REUSE);
179                 ret = -1;
180                 goto end;
181             }
182             s->server = 0;
183             if (cb != NULL)
184                 cb(s, SSL_CB_HANDSHAKE_START, 1);
185 
186             /* s->version=TLS1_VERSION; */
187             s->type = SSL_ST_CONNECT;
188 
189             if (s->init_buf == NULL) {
190                 if ((buf = BUF_MEM_new()) == NULL) {
191                     ret = -1;
192                     goto end;
193                 }
194                 if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
195                     ret = -1;
196                     goto end;
197                 }
198                 s->init_buf = buf;
199                 buf = NULL;
200             }
201 
202             if (!ssl3_setup_buffers(s)) {
203                 ret = -1;
204                 goto end;
205             }
206 
207             ssl3_init_finished_mac(s);
208 
209             s->state = SSL23_ST_CW_CLNT_HELLO_A;
210             s->ctx->stats.sess_connect++;
211             s->init_num = 0;
212             break;
213 
214         case SSL23_ST_CW_CLNT_HELLO_A:
215         case SSL23_ST_CW_CLNT_HELLO_B:
216 
217             s->shutdown = 0;
218             ret = ssl23_client_hello(s);
219             if (ret <= 0)
220                 goto end;
221             s->state = SSL23_ST_CR_SRVR_HELLO_A;
222             s->init_num = 0;
223 
224             break;
225 
226         case SSL23_ST_CR_SRVR_HELLO_A:
227         case SSL23_ST_CR_SRVR_HELLO_B:
228             ret = ssl23_get_server_hello(s);
229             if (ret >= 0)
230                 cb = NULL;
231             goto end;
232             /* break; */
233 
234         default:
235             SSLerr(SSL_F_SSL23_CONNECT, SSL_R_UNKNOWN_STATE);
236             ret = -1;
237             goto end;
238             /* break; */
239         }
240 
241         if (s->debug) {
242             (void)BIO_flush(s->wbio);
243         }
244 
245         if ((cb != NULL) && (s->state != state)) {
246             new_state = s->state;
247             s->state = state;
248             cb(s, SSL_CB_CONNECT_LOOP, 1);
249             s->state = new_state;
250         }
251     }
252  end:
253     s->in_handshake--;
254     if (buf != NULL)
255         BUF_MEM_free(buf);
256     if (cb != NULL)
257         cb(s, SSL_CB_CONNECT_EXIT, ret);
258     return (ret);
259 }
260 
261 static int ssl23_no_ssl2_ciphers(SSL *s)
262 {
263     SSL_CIPHER *cipher;
264     STACK_OF(SSL_CIPHER) *ciphers;
265     int i;
266     ciphers = SSL_get_ciphers(s);
267     for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
268         cipher = sk_SSL_CIPHER_value(ciphers, i);
269         if (cipher->algorithm_ssl == SSL_SSLV2)
270             return 0;
271     }
272     return 1;
273 }
274 
275 /*
276  * Fill a ClientRandom or ServerRandom field of length len. Returns <= 0 on
277  * failure, 1 on success.
278  */
279 int ssl_fill_hello_random(SSL *s, int server, unsigned char *result, int len)
280 {
281     int send_time = 0;
282 
283     if (len < 4)
284         return 0;
285     if (server)
286         send_time = (s->mode & SSL_MODE_SEND_SERVERHELLO_TIME) != 0;
287     else
288         send_time = (s->mode & SSL_MODE_SEND_CLIENTHELLO_TIME) != 0;
289     if (send_time) {
290         unsigned long Time = (unsigned long)time(NULL);
291         unsigned char *p = result;
292         l2n(Time, p);
293         return RAND_pseudo_bytes(p, len - 4);
294     } else
295         return RAND_pseudo_bytes(result, len);
296 }
297 
298 static int ssl23_client_hello(SSL *s)
299 {
300     unsigned char *buf;
301     unsigned char *p, *d;
302     int i, ch_len;
303     unsigned long l;
304     int ssl2_compat;
305     int version = 0, version_major, version_minor;
306 #ifndef OPENSSL_NO_COMP
307     int j;
308     SSL_COMP *comp;
309 #endif
310     int ret;
311     unsigned long mask, options = s->options;
312 
313     ssl2_compat = (options & SSL_OP_NO_SSLv2) ? 0 : 1;
314 
315     if (ssl2_compat && ssl23_no_ssl2_ciphers(s))
316         ssl2_compat = 0;
317 
318     /*
319      * SSL_OP_NO_X disables all protocols above X *if* there are
320      * some protocols below X enabled. This is required in order
321      * to maintain "version capability" vector contiguous. So
322      * that if application wants to disable TLS1.0 in favour of
323      * TLS1>=1, it would be insufficient to pass SSL_NO_TLSv1, the
324      * answer is SSL_OP_NO_TLSv1|SSL_OP_NO_SSLv3|SSL_OP_NO_SSLv2.
325      */
326     mask = SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1
327 #if !defined(OPENSSL_NO_SSL3)
328         | SSL_OP_NO_SSLv3
329 #endif
330 #if !defined(OPENSSL_NO_SSL2)
331         | (ssl2_compat ? SSL_OP_NO_SSLv2 : 0)
332 #endif
333         ;
334 #if !defined(OPENSSL_NO_TLS1_2_CLIENT)
335     version = TLS1_2_VERSION;
336 
337     if ((options & SSL_OP_NO_TLSv1_2) && (options & mask) != mask)
338         version = TLS1_1_VERSION;
339 #else
340     version = TLS1_1_VERSION;
341 #endif
342     mask &= ~SSL_OP_NO_TLSv1_1;
343     if ((options & SSL_OP_NO_TLSv1_1) && (options & mask) != mask)
344         version = TLS1_VERSION;
345     mask &= ~SSL_OP_NO_TLSv1;
346 #if !defined(OPENSSL_NO_SSL3)
347     if ((options & SSL_OP_NO_TLSv1) && (options & mask) != mask)
348         version = SSL3_VERSION;
349     mask &= ~SSL_OP_NO_SSLv3;
350 #endif
351 #if !defined(OPENSSL_NO_SSL2)
352     if ((options & SSL_OP_NO_SSLv3) && (options & mask) != mask)
353         version = SSL2_VERSION;
354 #endif
355 
356 #ifndef OPENSSL_NO_TLSEXT
357     if (version != SSL2_VERSION) {
358         /*
359          * have to disable SSL 2.0 compatibility if we need TLS extensions
360          */
361 
362         if (s->tlsext_hostname != NULL)
363             ssl2_compat = 0;
364         if (s->tlsext_status_type != -1)
365             ssl2_compat = 0;
366 # ifdef TLSEXT_TYPE_opaque_prf_input
367         if (s->ctx->tlsext_opaque_prf_input_callback != 0
368             || s->tlsext_opaque_prf_input != NULL)
369             ssl2_compat = 0;
370 # endif
371     }
372 #endif
373 
374     buf = (unsigned char *)s->init_buf->data;
375     if (s->state == SSL23_ST_CW_CLNT_HELLO_A) {
376 #if 0
377         /* don't reuse session-id's */
378         if (!ssl_get_new_session(s, 0)) {
379             return (-1);
380         }
381 #endif
382 
383         p = s->s3->client_random;
384         if (ssl_fill_hello_random(s, 0, p, SSL3_RANDOM_SIZE) <= 0)
385             return -1;
386 
387         if (version == TLS1_2_VERSION) {
388             version_major = TLS1_2_VERSION_MAJOR;
389             version_minor = TLS1_2_VERSION_MINOR;
390         } else if (version == TLS1_1_VERSION) {
391             version_major = TLS1_1_VERSION_MAJOR;
392             version_minor = TLS1_1_VERSION_MINOR;
393         } else if (version == TLS1_VERSION) {
394             version_major = TLS1_VERSION_MAJOR;
395             version_minor = TLS1_VERSION_MINOR;
396         }
397 #ifdef OPENSSL_FIPS
398         else if (FIPS_mode()) {
399             SSLerr(SSL_F_SSL23_CLIENT_HELLO,
400                    SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
401             return -1;
402         }
403 #endif
404         else if (version == SSL3_VERSION) {
405             version_major = SSL3_VERSION_MAJOR;
406             version_minor = SSL3_VERSION_MINOR;
407         } else if (version == SSL2_VERSION) {
408             version_major = SSL2_VERSION_MAJOR;
409             version_minor = SSL2_VERSION_MINOR;
410         } else {
411             SSLerr(SSL_F_SSL23_CLIENT_HELLO, SSL_R_NO_PROTOCOLS_AVAILABLE);
412             return (-1);
413         }
414 
415         s->client_version = version;
416 
417         if (ssl2_compat) {
418             /* create SSL 2.0 compatible Client Hello */
419 
420             /* two byte record header will be written last */
421             d = &(buf[2]);
422             p = d + 9;          /* leave space for message type, version,
423                                  * individual length fields */
424 
425             *(d++) = SSL2_MT_CLIENT_HELLO;
426             *(d++) = version_major;
427             *(d++) = version_minor;
428 
429             /* Ciphers supported */
430             i = ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), p, 0);
431             if (i == 0) {
432                 /* no ciphers */
433                 SSLerr(SSL_F_SSL23_CLIENT_HELLO, SSL_R_NO_CIPHERS_AVAILABLE);
434                 return -1;
435             }
436             s2n(i, d);
437             p += i;
438 
439             /*
440              * put in the session-id length (zero since there is no reuse)
441              */
442 #if 0
443             s->session->session_id_length = 0;
444 #endif
445             s2n(0, d);
446 
447             if (s->options & SSL_OP_NETSCAPE_CHALLENGE_BUG)
448                 ch_len = SSL2_CHALLENGE_LENGTH;
449             else
450                 ch_len = SSL2_MAX_CHALLENGE_LENGTH;
451 
452             /* write out sslv2 challenge */
453             /*
454              * Note that ch_len must be <= SSL3_RANDOM_SIZE (32), because it
455              * is one of SSL2_MAX_CHALLENGE_LENGTH (32) or
456              * SSL2_MAX_CHALLENGE_LENGTH (16), but leave the check in for
457              * futurproofing
458              */
459             if (SSL3_RANDOM_SIZE < ch_len)
460                 i = SSL3_RANDOM_SIZE;
461             else
462                 i = ch_len;
463             s2n(i, d);
464             memset(&(s->s3->client_random[0]), 0, SSL3_RANDOM_SIZE);
465             if (RAND_pseudo_bytes
466                 (&(s->s3->client_random[SSL3_RANDOM_SIZE - i]), i) <= 0)
467                 return -1;
468 
469             memcpy(p, &(s->s3->client_random[SSL3_RANDOM_SIZE - i]), i);
470             p += i;
471 
472             i = p - &(buf[2]);
473             buf[0] = ((i >> 8) & 0xff) | 0x80;
474             buf[1] = (i & 0xff);
475 
476             /* number of bytes to write */
477             s->init_num = i + 2;
478             s->init_off = 0;
479 
480             ssl3_finish_mac(s, &(buf[2]), i);
481         } else {
482             /* create Client Hello in SSL 3.0/TLS 1.0 format */
483 
484             /*
485              * do the record header (5 bytes) and handshake message header (4
486              * bytes) last
487              */
488             d = p = &(buf[9]);
489 
490             *(p++) = version_major;
491             *(p++) = version_minor;
492 
493             /* Random stuff */
494             memcpy(p, s->s3->client_random, SSL3_RANDOM_SIZE);
495             p += SSL3_RANDOM_SIZE;
496 
497             /* Session ID (zero since there is no reuse) */
498             *(p++) = 0;
499 
500             /* Ciphers supported (using SSL 3.0/TLS 1.0 format) */
501             i = ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &(p[2]),
502                                          ssl3_put_cipher_by_char);
503             if (i == 0) {
504                 SSLerr(SSL_F_SSL23_CLIENT_HELLO, SSL_R_NO_CIPHERS_AVAILABLE);
505                 return -1;
506             }
507 #ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
508             /*
509              * Some servers hang if client hello > 256 bytes as hack
510              * workaround chop number of supported ciphers to keep it well
511              * below this if we use TLS v1.2
512              */
513             if (TLS1_get_version(s) >= TLS1_2_VERSION
514                 && i > OPENSSL_MAX_TLS1_2_CIPHER_LENGTH)
515                 i = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
516 #endif
517             s2n(i, p);
518             p += i;
519 
520             /* COMPRESSION */
521 #ifdef OPENSSL_NO_COMP
522             *(p++) = 1;
523 #else
524             if ((s->options & SSL_OP_NO_COMPRESSION)
525                 || !s->ctx->comp_methods)
526                 j = 0;
527             else
528                 j = sk_SSL_COMP_num(s->ctx->comp_methods);
529             *(p++) = 1 + j;
530             for (i = 0; i < j; i++) {
531                 comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);
532                 *(p++) = comp->id;
533             }
534 #endif
535             *(p++) = 0;         /* Add the NULL method */
536 
537 #ifndef OPENSSL_NO_TLSEXT
538             /* TLS extensions */
539             if (ssl_prepare_clienthello_tlsext(s) <= 0) {
540                 SSLerr(SSL_F_SSL23_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
541                 return -1;
542             }
543             if ((p =
544                  ssl_add_clienthello_tlsext(s, p,
545                                             buf +
546                                             SSL3_RT_MAX_PLAIN_LENGTH)) ==
547                 NULL) {
548                 SSLerr(SSL_F_SSL23_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
549                 return -1;
550             }
551 #endif
552 
553             l = p - d;
554 
555             /* fill in 4-byte handshake header */
556             d = &(buf[5]);
557             *(d++) = SSL3_MT_CLIENT_HELLO;
558             l2n3(l, d);
559 
560             l += 4;
561 
562             if (l > SSL3_RT_MAX_PLAIN_LENGTH) {
563                 SSLerr(SSL_F_SSL23_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
564                 return -1;
565             }
566 
567             /* fill in 5-byte record header */
568             d = buf;
569             *(d++) = SSL3_RT_HANDSHAKE;
570             *(d++) = version_major;
571             /*
572              * Some servers hang if we use long client hellos and a record
573              * number > TLS 1.0.
574              */
575             if (TLS1_get_client_version(s) > TLS1_VERSION)
576                 *(d++) = 1;
577             else
578                 *(d++) = version_minor;
579             s2n((int)l, d);
580 
581             /* number of bytes to write */
582             s->init_num = p - buf;
583             s->init_off = 0;
584 
585             ssl3_finish_mac(s, &(buf[5]), s->init_num - 5);
586         }
587 
588         s->state = SSL23_ST_CW_CLNT_HELLO_B;
589         s->init_off = 0;
590     }
591 
592     /* SSL3_ST_CW_CLNT_HELLO_B */
593     ret = ssl23_write_bytes(s);
594 
595     if ((ret >= 2) && s->msg_callback) {
596         /* Client Hello has been sent; tell msg_callback */
597 
598         if (ssl2_compat)
599             s->msg_callback(1, SSL2_VERSION, 0, s->init_buf->data + 2,
600                             ret - 2, s, s->msg_callback_arg);
601         else
602             s->msg_callback(1, version, SSL3_RT_HANDSHAKE,
603                             s->init_buf->data + 5, ret - 5, s,
604                             s->msg_callback_arg);
605     }
606 
607     return ret;
608 }
609 
610 static int ssl23_get_server_hello(SSL *s)
611 {
612     char buf[8];
613     unsigned char *p;
614     int i;
615     int n;
616 
617     n = ssl23_read_bytes(s, 7);
618 
619     if (n != 7)
620         return (n);
621     p = s->packet;
622 
623     memcpy(buf, p, n);
624 
625     if ((p[0] & 0x80) && (p[2] == SSL2_MT_SERVER_HELLO) &&
626         (p[5] == 0x00) && (p[6] == 0x02)) {
627 #ifdef OPENSSL_NO_SSL2
628         SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, SSL_R_UNSUPPORTED_PROTOCOL);
629         goto err;
630 #else
631         /* we are talking sslv2 */
632         /*
633          * we need to clean up the SSLv3 setup and put in the sslv2 stuff.
634          */
635         int ch_len;
636 
637         if (s->options & SSL_OP_NO_SSLv2) {
638             SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, SSL_R_UNSUPPORTED_PROTOCOL);
639             goto err;
640         }
641         if (s->s2 == NULL) {
642             if (!ssl2_new(s))
643                 goto err;
644         } else
645             ssl2_clear(s);
646 
647         if (s->options & SSL_OP_NETSCAPE_CHALLENGE_BUG)
648             ch_len = SSL2_CHALLENGE_LENGTH;
649         else
650             ch_len = SSL2_MAX_CHALLENGE_LENGTH;
651 
652         /* write out sslv2 challenge */
653         /*
654          * Note that ch_len must be <= SSL3_RANDOM_SIZE (32), because it is
655          * one of SSL2_MAX_CHALLENGE_LENGTH (32) or SSL2_MAX_CHALLENGE_LENGTH
656          * (16), but leave the check in for futurproofing
657          */
658         i = (SSL3_RANDOM_SIZE < ch_len)
659             ? SSL3_RANDOM_SIZE : ch_len;
660         s->s2->challenge_length = i;
661         memcpy(s->s2->challenge,
662                &(s->s3->client_random[SSL3_RANDOM_SIZE - i]), i);
663 
664         if (s->s3 != NULL)
665             ssl3_free(s);
666 
667         if (!BUF_MEM_grow_clean(s->init_buf,
668                                 SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)) {
669             SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, ERR_R_BUF_LIB);
670             goto err;
671         }
672 
673         s->state = SSL2_ST_GET_SERVER_HELLO_A;
674         if (!(s->client_version == SSL2_VERSION))
675             /*
676              * use special padding (SSL 3.0 draft/RFC 2246, App. E.2)
677              */
678             s->s2->ssl2_rollback = 1;
679 
680         /*
681          * setup the 7 bytes we have read so we get them from the sslv2
682          * buffer
683          */
684         s->rstate = SSL_ST_READ_HEADER;
685         s->packet_length = n;
686         s->packet = &(s->s2->rbuf[0]);
687         memcpy(s->packet, buf, n);
688         s->s2->rbuf_left = n;
689         s->s2->rbuf_offs = 0;
690 
691         /* we have already written one */
692         s->s2->write_sequence = 1;
693 
694         s->method = SSLv2_client_method();
695         s->handshake_func = s->method->ssl_connect;
696 #endif
697     } else if (p[1] == SSL3_VERSION_MAJOR &&
698                p[2] <= TLS1_2_VERSION_MINOR &&
699                ((p[0] == SSL3_RT_HANDSHAKE && p[5] == SSL3_MT_SERVER_HELLO) ||
700                 (p[0] == SSL3_RT_ALERT && p[3] == 0 && p[4] == 2))) {
701         /* we have sslv3 or tls1 (server hello or alert) */
702 
703 #ifndef OPENSSL_NO_SSL3
704         if ((p[2] == SSL3_VERSION_MINOR) && !(s->options & SSL_OP_NO_SSLv3)) {
705 # ifdef OPENSSL_FIPS
706             if (FIPS_mode()) {
707                 SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,
708                        SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
709                 goto err;
710             }
711 # endif
712             s->version = SSL3_VERSION;
713             s->method = SSLv3_client_method();
714         } else
715 #endif
716         if ((p[2] == TLS1_VERSION_MINOR) && !(s->options & SSL_OP_NO_TLSv1)) {
717             s->version = TLS1_VERSION;
718             s->method = TLSv1_client_method();
719         } else if ((p[2] == TLS1_1_VERSION_MINOR) &&
720                    !(s->options & SSL_OP_NO_TLSv1_1)) {
721             s->version = TLS1_1_VERSION;
722             s->method = TLSv1_1_client_method();
723         } else if ((p[2] == TLS1_2_VERSION_MINOR) &&
724                    !(s->options & SSL_OP_NO_TLSv1_2)) {
725             s->version = TLS1_2_VERSION;
726             s->method = TLSv1_2_client_method();
727         } else {
728             SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, SSL_R_UNSUPPORTED_PROTOCOL);
729             goto err;
730         }
731 
732         /* ensure that TLS_MAX_VERSION is up-to-date */
733         OPENSSL_assert(s->version <= TLS_MAX_VERSION);
734 
735         if (p[0] == SSL3_RT_ALERT && p[5] != SSL3_AL_WARNING) {
736             /* fatal alert */
737 
738             void (*cb) (const SSL *ssl, int type, int val) = NULL;
739             int j;
740 
741             if (s->info_callback != NULL)
742                 cb = s->info_callback;
743             else if (s->ctx->info_callback != NULL)
744                 cb = s->ctx->info_callback;
745 
746             i = p[5];
747             if (cb != NULL) {
748                 j = (i << 8) | p[6];
749                 cb(s, SSL_CB_READ_ALERT, j);
750             }
751 
752             if (s->msg_callback)
753                 s->msg_callback(0, s->version, SSL3_RT_ALERT, p + 5, 2, s,
754                                 s->msg_callback_arg);
755 
756             s->rwstate = SSL_NOTHING;
757             SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, SSL_AD_REASON_OFFSET + p[6]);
758             goto err;
759         }
760 
761         if (!ssl_init_wbio_buffer(s, 1))
762             goto err;
763 
764         /* we are in this state */
765         s->state = SSL3_ST_CR_SRVR_HELLO_A;
766 
767         /*
768          * put the 7 bytes we have read into the input buffer for SSLv3
769          */
770         s->rstate = SSL_ST_READ_HEADER;
771         s->packet_length = n;
772         if (s->s3->rbuf.buf == NULL)
773             if (!ssl3_setup_read_buffer(s))
774                 goto err;
775         s->packet = &(s->s3->rbuf.buf[0]);
776         memcpy(s->packet, buf, n);
777         s->s3->rbuf.left = n;
778         s->s3->rbuf.offset = 0;
779 
780         s->handshake_func = s->method->ssl_connect;
781     } else {
782         SSLerr(SSL_F_SSL23_GET_SERVER_HELLO, SSL_R_UNKNOWN_PROTOCOL);
783         goto err;
784     }
785     s->init_num = 0;
786 
787     /*
788      * Since, if we are sending a ssl23 client hello, we are not reusing a
789      * session-id
790      */
791     if (!ssl_get_new_session(s, 0))
792         goto err;
793 
794     return (SSL_connect(s));
795  err:
796     return (-1);
797 }
798