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Paul Bakker5121ce52009-01-03 21:22:43 +00001/*
2 * SSLv3/TLSv1 server-side functions
3 *
Paul Bakkerfc8c4362010-03-21 17:37:16 +00004 * Copyright (C) 2006-2010, Paul Bakker <polarssl_maintainer at polarssl.org>
Paul Bakker77b385e2009-07-28 17:23:11 +00005 * All rights reserved.
Paul Bakkere0ccd0a2009-01-04 16:27:10 +00006 *
Paul Bakker5121ce52009-01-03 21:22:43 +00007 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 */
21
Paul Bakker40e46942009-01-03 21:51:57 +000022#include "polarssl/config.h"
Paul Bakker5121ce52009-01-03 21:22:43 +000023
Paul Bakker40e46942009-01-03 21:51:57 +000024#if defined(POLARSSL_SSL_SRV_C)
Paul Bakker5121ce52009-01-03 21:22:43 +000025
Paul Bakker40e46942009-01-03 21:51:57 +000026#include "polarssl/debug.h"
27#include "polarssl/ssl.h"
Paul Bakker5121ce52009-01-03 21:22:43 +000028
29#include <string.h>
30#include <stdlib.h>
31#include <stdio.h>
32#include <time.h>
33
34static int ssl_parse_client_hello( ssl_context *ssl )
35{
36 int ret, i, j, n;
37 int ciph_len, sess_len;
38 int chal_len, comp_len;
39 unsigned char *buf, *p;
40
41 SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
42
43 if( ( ret = ssl_fetch_input( ssl, 5 ) ) != 0 )
44 {
45 SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
46 return( ret );
47 }
48
49 buf = ssl->in_hdr;
50
51 if( ( buf[0] & 0x80 ) != 0 )
52 {
53 SSL_DEBUG_BUF( 4, "record header", buf, 5 );
54
55 SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
56 buf[2] ) );
57 SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
58 ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
59 SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
60 buf[3], buf[4] ) );
61
62 /*
63 * SSLv2 Client Hello
64 *
65 * Record layer:
66 * 0 . 1 message length
67 *
68 * SSL layer:
69 * 2 . 2 message type
70 * 3 . 4 protocol version
71 */
72 if( buf[2] != SSL_HS_CLIENT_HELLO ||
73 buf[3] != SSL_MAJOR_VERSION_3 )
74 {
75 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +000076 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +000077 }
78
79 n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
80
81 if( n < 17 || n > 512 )
82 {
83 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +000084 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +000085 }
86
87 ssl->max_major_ver = buf[3];
88 ssl->max_minor_ver = buf[4];
89
90 ssl->major_ver = SSL_MAJOR_VERSION_3;
91 ssl->minor_ver = ( buf[4] <= SSL_MINOR_VERSION_1 )
92 ? buf[4] : SSL_MINOR_VERSION_1;
93
94 if( ( ret = ssl_fetch_input( ssl, 2 + n ) ) != 0 )
95 {
96 SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
97 return( ret );
98 }
99
100 md5_update( &ssl->fin_md5 , buf + 2, n );
101 sha1_update( &ssl->fin_sha1, buf + 2, n );
102
103 buf = ssl->in_msg;
104 n = ssl->in_left - 5;
105
106 /*
107 * 0 . 1 cipherlist length
108 * 2 . 3 session id length
109 * 4 . 5 challenge length
110 * 6 . .. cipherlist
111 * .. . .. session id
112 * .. . .. challenge
113 */
114 SSL_DEBUG_BUF( 4, "record contents", buf, n );
115
116 ciph_len = ( buf[0] << 8 ) | buf[1];
117 sess_len = ( buf[2] << 8 ) | buf[3];
118 chal_len = ( buf[4] << 8 ) | buf[5];
119
120 SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
121 ciph_len, sess_len, chal_len ) );
122
123 /*
124 * Make sure each parameter length is valid
125 */
126 if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
127 {
128 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000129 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000130 }
131
132 if( sess_len < 0 || sess_len > 32 )
133 {
134 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000135 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000136 }
137
138 if( chal_len < 8 || chal_len > 32 )
139 {
140 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000141 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000142 }
143
144 if( n != 6 + ciph_len + sess_len + chal_len )
145 {
146 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000147 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000148 }
149
150 SSL_DEBUG_BUF( 3, "client hello, cipherlist",
151 buf + 6, ciph_len );
152 SSL_DEBUG_BUF( 3, "client hello, session id",
153 buf + 6 + ciph_len, sess_len );
154 SSL_DEBUG_BUF( 3, "client hello, challenge",
155 buf + 6 + ciph_len + sess_len, chal_len );
156
157 p = buf + 6 + ciph_len;
158 ssl->session->length = sess_len;
159 memset( ssl->session->id, 0, sizeof( ssl->session->id ) );
160 memcpy( ssl->session->id, p, ssl->session->length );
161
162 p += sess_len;
163 memset( ssl->randbytes, 0, 64 );
164 memcpy( ssl->randbytes + 32 - chal_len, p, chal_len );
165
166 for( i = 0; ssl->ciphers[i] != 0; i++ )
167 {
168 for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
169 {
170 if( p[0] == 0 &&
171 p[1] == 0 &&
172 p[2] == ssl->ciphers[i] )
173 goto have_cipher;
174 }
175 }
176 }
177 else
178 {
179 SSL_DEBUG_BUF( 4, "record header", buf, 5 );
180
181 SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
182 buf[0] ) );
183 SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
184 ( buf[3] << 8 ) | buf[4] ) );
185 SSL_DEBUG_MSG( 3, ( "client hello v3, protocol ver: [%d:%d]",
186 buf[1], buf[2] ) );
187
188 /*
189 * SSLv3 Client Hello
190 *
191 * Record layer:
192 * 0 . 0 message type
193 * 1 . 2 protocol version
194 * 3 . 4 message length
195 */
196 if( buf[0] != SSL_MSG_HANDSHAKE ||
197 buf[1] != SSL_MAJOR_VERSION_3 )
198 {
199 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000200 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000201 }
202
203 n = ( buf[3] << 8 ) | buf[4];
204
205 if( n < 45 || n > 512 )
206 {
207 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000208 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000209 }
210
211 if( ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 )
212 {
213 SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
214 return( ret );
215 }
216
217 buf = ssl->in_msg;
218 n = ssl->in_left - 5;
219
220 md5_update( &ssl->fin_md5 , buf, n );
221 sha1_update( &ssl->fin_sha1, buf, n );
222
223 /*
224 * SSL layer:
225 * 0 . 0 handshake type
226 * 1 . 3 handshake length
227 * 4 . 5 protocol version
228 * 6 . 9 UNIX time()
229 * 10 . 37 random bytes
230 * 38 . 38 session id length
231 * 39 . 38+x session id
232 * 39+x . 40+x cipherlist length
233 * 41+x . .. cipherlist
234 * .. . .. compression alg.
235 * .. . .. extensions
236 */
237 SSL_DEBUG_BUF( 4, "record contents", buf, n );
238
239 SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d",
240 buf[0] ) );
241 SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
242 ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
243 SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]",
244 buf[4], buf[5] ) );
245
246 /*
247 * Check the handshake type and protocol version
248 */
249 if( buf[0] != SSL_HS_CLIENT_HELLO ||
250 buf[4] != SSL_MAJOR_VERSION_3 )
251 {
252 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000253 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000254 }
255
256 ssl->major_ver = SSL_MAJOR_VERSION_3;
257 ssl->minor_ver = ( buf[5] <= SSL_MINOR_VERSION_1 )
258 ? buf[5] : SSL_MINOR_VERSION_1;
259
260 ssl->max_major_ver = buf[4];
261 ssl->max_minor_ver = buf[5];
262
263 memcpy( ssl->randbytes, buf + 6, 32 );
264
265 /*
266 * Check the handshake message length
267 */
268 if( buf[1] != 0 || n != 4 + ( ( buf[2] << 8 ) | buf[3] ) )
269 {
270 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000271 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000272 }
273
274 /*
275 * Check the session length
276 */
277 sess_len = buf[38];
278
279 if( sess_len < 0 || sess_len > 32 )
280 {
281 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000282 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000283 }
284
285 ssl->session->length = sess_len;
286 memset( ssl->session->id, 0, sizeof( ssl->session->id ) );
287 memcpy( ssl->session->id, buf + 39 , ssl->session->length );
288
289 /*
290 * Check the cipherlist length
291 */
292 ciph_len = ( buf[39 + sess_len] << 8 )
293 | ( buf[40 + sess_len] );
294
295 if( ciph_len < 2 || ciph_len > 256 || ( ciph_len % 2 ) != 0 )
296 {
297 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000298 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000299 }
300
301 /*
302 * Check the compression algorithms length
303 */
304 comp_len = buf[41 + sess_len + ciph_len];
305
306 if( comp_len < 1 || comp_len > 16 )
307 {
308 SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000309 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
Paul Bakker5121ce52009-01-03 21:22:43 +0000310 }
311
312 SSL_DEBUG_BUF( 3, "client hello, random bytes",
313 buf + 6, 32 );
314 SSL_DEBUG_BUF( 3, "client hello, session id",
315 buf + 38, sess_len );
316 SSL_DEBUG_BUF( 3, "client hello, cipherlist",
317 buf + 41 + sess_len, ciph_len );
318 SSL_DEBUG_BUF( 3, "client hello, compression",
319 buf + 42 + sess_len + ciph_len, comp_len );
320
321 /*
322 * Search for a matching cipher
323 */
324 for( i = 0; ssl->ciphers[i] != 0; i++ )
325 {
326 for( j = 0, p = buf + 41 + sess_len; j < ciph_len;
327 j += 2, p += 2 )
328 {
329 if( p[0] == 0 && p[1] == ssl->ciphers[i] )
330 goto have_cipher;
331 }
332 }
333 }
334
335 SSL_DEBUG_MSG( 1, ( "got no ciphers in common" ) );
336
Paul Bakker40e46942009-01-03 21:51:57 +0000337 return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
Paul Bakker5121ce52009-01-03 21:22:43 +0000338
339have_cipher:
340
341 ssl->session->cipher = ssl->ciphers[i];
342 ssl->in_left = 0;
343 ssl->state++;
344
345 SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
346
347 return( 0 );
348}
349
350static int ssl_write_server_hello( ssl_context *ssl )
351{
352 time_t t;
353 int ret, i, n;
354 unsigned char *buf, *p;
355
356 SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
357
358 /*
359 * 0 . 0 handshake type
360 * 1 . 3 handshake length
361 * 4 . 5 protocol version
362 * 6 . 9 UNIX time()
363 * 10 . 37 random bytes
364 */
365 buf = ssl->out_msg;
366 p = buf + 4;
367
368 *p++ = (unsigned char) ssl->major_ver;
369 *p++ = (unsigned char) ssl->minor_ver;
370
371 SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
372 buf[4], buf[5] ) );
373
374 t = time( NULL );
375 *p++ = (unsigned char)( t >> 24 );
376 *p++ = (unsigned char)( t >> 16 );
377 *p++ = (unsigned char)( t >> 8 );
378 *p++ = (unsigned char)( t );
379
380 SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) );
381
382 for( i = 28; i > 0; i-- )
383 *p++ = (unsigned char) ssl->f_rng( ssl->p_rng );
384
385 memcpy( ssl->randbytes + 32, buf + 6, 32 );
386
387 SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
388
389 /*
390 * 38 . 38 session id length
391 * 39 . 38+n session id
392 * 39+n . 40+n chosen cipher
393 * 41+n . 41+n chosen compression alg.
394 */
395 ssl->session->length = n = 32;
396 *p++ = (unsigned char) ssl->session->length;
397
398 if( ssl->s_get == NULL ||
399 ssl->s_get( ssl ) != 0 )
400 {
401 /*
402 * Not found, create a new session id
403 */
404 ssl->resume = 0;
405 ssl->state++;
406
407 for( i = 0; i < n; i++ )
408 ssl->session->id[i] =
409 (unsigned char) ssl->f_rng( ssl->p_rng );
410 }
411 else
412 {
413 /*
414 * Found a matching session, resume it
415 */
416 ssl->resume = 1;
417 ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC;
Paul Bakkerff60ee62010-03-16 21:09:09 +0000418
419 if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
420 {
421 SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
422 return( ret );
423 }
Paul Bakker5121ce52009-01-03 21:22:43 +0000424 }
425
426 memcpy( p, ssl->session->id, ssl->session->length );
427 p += ssl->session->length;
428
429 SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
430 SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
431 SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
432 ssl->resume ? "a" : "no" ) );
433
434 *p++ = (unsigned char)( ssl->session->cipher >> 8 );
435 *p++ = (unsigned char)( ssl->session->cipher );
436 *p++ = SSL_COMPRESS_NULL;
437
438 SSL_DEBUG_MSG( 3, ( "server hello, chosen cipher: %d",
439 ssl->session->cipher ) );
440 SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", 0 ) );
441
442 ssl->out_msglen = p - buf;
443 ssl->out_msgtype = SSL_MSG_HANDSHAKE;
444 ssl->out_msg[0] = SSL_HS_SERVER_HELLO;
445
446 ret = ssl_write_record( ssl );
447
448 SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
449
450 return( ret );
451}
452
453static int ssl_write_certificate_request( ssl_context *ssl )
454{
455 int ret, n;
456 unsigned char *buf, *p;
Paul Bakkerff60ee62010-03-16 21:09:09 +0000457 const x509_cert *crt;
Paul Bakker5121ce52009-01-03 21:22:43 +0000458
459 SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
460
461 ssl->state++;
462
463 if( ssl->authmode == SSL_VERIFY_NONE )
464 {
465 SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
466 return( 0 );
467 }
468
469 /*
470 * 0 . 0 handshake type
471 * 1 . 3 handshake length
472 * 4 . 4 cert type count
473 * 5 .. n-1 cert types
474 * n .. n+1 length of all DNs
475 * n+2 .. n+3 length of DN 1
476 * n+4 .. ... Distinguished Name #1
477 * ... .. ... length of DN 2, etc.
478 */
479 buf = ssl->out_msg;
480 p = buf + 4;
481
482 /*
483 * At the moment, only RSA certificates are supported
484 */
485 *p++ = 1;
486 *p++ = 1;
487
488 p += 2;
489 crt = ssl->ca_chain;
490
Paul Bakker1f761152010-02-18 18:16:31 +0000491 while( crt != NULL && crt->version != 0 )
Paul Bakker5121ce52009-01-03 21:22:43 +0000492 {
493 if( p - buf > 4096 )
494 break;
495
496 n = crt->subject_raw.len;
497 *p++ = (unsigned char)( n >> 8 );
498 *p++ = (unsigned char)( n );
499 memcpy( p, crt->subject_raw.p, n );
500
501 SSL_DEBUG_BUF( 3, "requested DN", p, n );
502 p += n; crt = crt->next;
503 }
504
505 ssl->out_msglen = n = p - buf;
506 ssl->out_msgtype = SSL_MSG_HANDSHAKE;
507 ssl->out_msg[0] = SSL_HS_CERTIFICATE_REQUEST;
508 ssl->out_msg[6] = (unsigned char)( ( n - 8 ) >> 8 );
509 ssl->out_msg[7] = (unsigned char)( ( n - 8 ) );
510
511 ret = ssl_write_record( ssl );
512
513 SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
514
515 return( ret );
516}
517
518static int ssl_write_server_key_exchange( ssl_context *ssl )
519{
520 int ret, n;
521 unsigned char hash[36];
522 md5_context md5;
523 sha1_context sha1;
524
525 SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
526
527 if( ssl->session->cipher != SSL_EDH_RSA_DES_168_SHA &&
Paul Bakkerb5ef0ba2009-01-11 20:25:36 +0000528 ssl->session->cipher != SSL_EDH_RSA_AES_256_SHA &&
529 ssl->session->cipher != SSL_EDH_RSA_CAMELLIA_256_SHA)
Paul Bakker5121ce52009-01-03 21:22:43 +0000530 {
531 SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
532 ssl->state++;
533 return( 0 );
534 }
535
Paul Bakker40e46942009-01-03 21:51:57 +0000536#if !defined(POLARSSL_DHM_C)
Paul Bakker5121ce52009-01-03 21:22:43 +0000537 SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000538 return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000539#else
540 /*
541 * Ephemeral DH parameters:
542 *
543 * struct {
544 * opaque dh_p<1..2^16-1>;
545 * opaque dh_g<1..2^16-1>;
546 * opaque dh_Ys<1..2^16-1>;
547 * } ServerDHParams;
548 */
549 if( ( ret = dhm_make_params( &ssl->dhm_ctx, 256, ssl->out_msg + 4,
550 &n, ssl->f_rng, ssl->p_rng ) ) != 0 )
551 {
552 SSL_DEBUG_RET( 1, "dhm_make_params", ret );
553 return( ret );
554 }
555
556 SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->dhm_ctx.X );
557 SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->dhm_ctx.P );
558 SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->dhm_ctx.G );
559 SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->dhm_ctx.GX );
560
561 /*
562 * digitally-signed struct {
563 * opaque md5_hash[16];
564 * opaque sha_hash[20];
565 * };
566 *
567 * md5_hash
568 * MD5(ClientHello.random + ServerHello.random
569 * + ServerParams);
570 * sha_hash
571 * SHA(ClientHello.random + ServerHello.random
572 * + ServerParams);
573 */
574 md5_starts( &md5 );
575 md5_update( &md5, ssl->randbytes, 64 );
576 md5_update( &md5, ssl->out_msg + 4, n );
577 md5_finish( &md5, hash );
578
579 sha1_starts( &sha1 );
580 sha1_update( &sha1, ssl->randbytes, 64 );
581 sha1_update( &sha1, ssl->out_msg + 4, n );
582 sha1_finish( &sha1, hash + 16 );
583
584 SSL_DEBUG_BUF( 3, "parameters hash", hash, 36 );
585
586 ssl->out_msg[4 + n] = (unsigned char)( ssl->rsa_key->len >> 8 );
587 ssl->out_msg[5 + n] = (unsigned char)( ssl->rsa_key->len );
588
589 ret = rsa_pkcs1_sign( ssl->rsa_key, RSA_PRIVATE,
Paul Bakkerfc22c442009-07-19 20:36:27 +0000590 SIG_RSA_RAW, 36, hash, ssl->out_msg + 6 + n );
Paul Bakker5121ce52009-01-03 21:22:43 +0000591 if( ret != 0 )
592 {
593 SSL_DEBUG_RET( 1, "rsa_pkcs1_sign", ret );
594 return( ret );
595 }
596
597 SSL_DEBUG_BUF( 3, "my RSA sig", ssl->out_msg + 6 + n,
598 ssl->rsa_key->len );
599
600 ssl->out_msglen = 6 + n + ssl->rsa_key->len;
601 ssl->out_msgtype = SSL_MSG_HANDSHAKE;
602 ssl->out_msg[0] = SSL_HS_SERVER_KEY_EXCHANGE;
603
604 ssl->state++;
605
606 if( ( ret = ssl_write_record( ssl ) ) != 0 )
607 {
608 SSL_DEBUG_RET( 1, "ssl_write_record", ret );
609 return( ret );
610 }
611
612 SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
613
614 return( 0 );
615#endif
616}
617
618static int ssl_write_server_hello_done( ssl_context *ssl )
619{
620 int ret;
621
622 SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
623
624 ssl->out_msglen = 4;
625 ssl->out_msgtype = SSL_MSG_HANDSHAKE;
626 ssl->out_msg[0] = SSL_HS_SERVER_HELLO_DONE;
627
628 ssl->state++;
629
630 if( ( ret = ssl_write_record( ssl ) ) != 0 )
631 {
632 SSL_DEBUG_RET( 1, "ssl_write_record", ret );
633 return( ret );
634 }
635
636 SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
637
638 return( 0 );
639}
640
641static int ssl_parse_client_key_exchange( ssl_context *ssl )
642{
643 int ret, i, n;
644
645 SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
646
647 if( ( ret = ssl_read_record( ssl ) ) != 0 )
648 {
649 SSL_DEBUG_RET( 1, "ssl_read_record", ret );
650 return( ret );
651 }
652
653 if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
654 {
655 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000656 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000657 }
658
659 if( ssl->in_msg[0] != SSL_HS_CLIENT_KEY_EXCHANGE )
660 {
661 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000662 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000663 }
664
665 if( ssl->session->cipher == SSL_EDH_RSA_DES_168_SHA ||
Paul Bakkerb5ef0ba2009-01-11 20:25:36 +0000666 ssl->session->cipher == SSL_EDH_RSA_AES_256_SHA ||
667 ssl->session->cipher == SSL_EDH_RSA_CAMELLIA_256_SHA)
Paul Bakker5121ce52009-01-03 21:22:43 +0000668 {
Paul Bakker40e46942009-01-03 21:51:57 +0000669#if !defined(POLARSSL_DHM_C)
Paul Bakker5121ce52009-01-03 21:22:43 +0000670 SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000671 return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000672#else
673 /*
674 * Receive G^Y mod P, premaster = (G^Y)^X mod P
675 */
676 n = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
677
678 if( n < 1 || n > ssl->dhm_ctx.len ||
679 n + 6 != ssl->in_hslen )
680 {
681 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000682 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000683 }
684
685 if( ( ret = dhm_read_public( &ssl->dhm_ctx,
686 ssl->in_msg + 6, n ) ) != 0 )
687 {
688 SSL_DEBUG_RET( 1, "dhm_read_public", ret );
Paul Bakker40e46942009-01-03 21:51:57 +0000689 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE | ret );
Paul Bakker5121ce52009-01-03 21:22:43 +0000690 }
691
692 SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->dhm_ctx.GY );
693
694 ssl->pmslen = ssl->dhm_ctx.len;
695
696 if( ( ret = dhm_calc_secret( &ssl->dhm_ctx,
697 ssl->premaster, &ssl->pmslen ) ) != 0 )
698 {
699 SSL_DEBUG_RET( 1, "dhm_calc_secret", ret );
Paul Bakker40e46942009-01-03 21:51:57 +0000700 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE | ret );
Paul Bakker5121ce52009-01-03 21:22:43 +0000701 }
702
703 SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->dhm_ctx.K );
704#endif
705 }
706 else
707 {
708 /*
709 * Decrypt the premaster using own private RSA key
710 */
711 i = 4;
712 n = ssl->rsa_key->len;
713 ssl->pmslen = 48;
714
715 if( ssl->minor_ver != SSL_MINOR_VERSION_0 )
716 {
717 i += 2;
718 if( ssl->in_msg[4] != ( ( n >> 8 ) & 0xFF ) ||
719 ssl->in_msg[5] != ( ( n ) & 0xFF ) )
720 {
721 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000722 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000723 }
724 }
725
726 if( ssl->in_hslen != i + n )
727 {
728 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000729 return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
Paul Bakker5121ce52009-01-03 21:22:43 +0000730 }
731
732 ret = rsa_pkcs1_decrypt( ssl->rsa_key, RSA_PRIVATE, &ssl->pmslen,
Paul Bakker060c5682009-01-12 21:48:39 +0000733 ssl->in_msg + i, ssl->premaster,
734 sizeof(ssl->premaster) );
Paul Bakker5121ce52009-01-03 21:22:43 +0000735
736 if( ret != 0 || ssl->pmslen != 48 ||
737 ssl->premaster[0] != ssl->max_major_ver ||
738 ssl->premaster[1] != ssl->max_minor_ver )
739 {
740 SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
741
742 /*
743 * Protection against Bleichenbacher's attack:
744 * invalid PKCS#1 v1.5 padding must not cause
745 * the connection to end immediately; instead,
746 * send a bad_record_mac later in the handshake.
747 */
748 ssl->pmslen = 48;
749
750 for( i = 0; i < ssl->pmslen; i++ )
751 ssl->premaster[i] = (unsigned char) ssl->f_rng( ssl->p_rng );
752 }
753 }
754
Paul Bakkerff60ee62010-03-16 21:09:09 +0000755 if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
756 {
757 SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
758 return( ret );
759 }
Paul Bakker5121ce52009-01-03 21:22:43 +0000760
761 if( ssl->s_set != NULL )
762 ssl->s_set( ssl );
763
764 ssl->state++;
765
766 SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
767
768 return( 0 );
769}
770
771static int ssl_parse_certificate_verify( ssl_context *ssl )
772{
773 int n1, n2, ret;
774 unsigned char hash[36];
775
776 SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
777
778 if( ssl->peer_cert == NULL )
779 {
780 SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
781 ssl->state++;
782 return( 0 );
783 }
784
785 ssl_calc_verify( ssl, hash );
786
787 if( ( ret = ssl_read_record( ssl ) ) != 0 )
788 {
789 SSL_DEBUG_RET( 1, "ssl_read_record", ret );
790 return( ret );
791 }
792
793 ssl->state++;
794
795 if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
796 {
797 SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000798 return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
Paul Bakker5121ce52009-01-03 21:22:43 +0000799 }
800
801 if( ssl->in_msg[0] != SSL_HS_CERTIFICATE_VERIFY )
802 {
803 SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000804 return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
Paul Bakker5121ce52009-01-03 21:22:43 +0000805 }
806
807 n1 = ssl->peer_cert->rsa.len;
808 n2 = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
809
810 if( n1 + 6 != ssl->in_hslen || n1 != n2 )
811 {
812 SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000813 return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
Paul Bakker5121ce52009-01-03 21:22:43 +0000814 }
815
816 ret = rsa_pkcs1_verify( &ssl->peer_cert->rsa, RSA_PUBLIC,
Paul Bakkerfc22c442009-07-19 20:36:27 +0000817 SIG_RSA_RAW, 36, hash, ssl->in_msg + 6 );
Paul Bakker5121ce52009-01-03 21:22:43 +0000818 if( ret != 0 )
819 {
820 SSL_DEBUG_RET( 1, "rsa_pkcs1_verify", ret );
821 return( ret );
822 }
823
824 SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
825
826 return( 0 );
827}
828
829/*
830 * SSL handshake -- server side
831 */
832int ssl_handshake_server( ssl_context *ssl )
833{
834 int ret = 0;
835
836 SSL_DEBUG_MSG( 2, ( "=> handshake server" ) );
837
838 while( ssl->state != SSL_HANDSHAKE_OVER )
839 {
840 SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
841
842 if( ( ret = ssl_flush_output( ssl ) ) != 0 )
843 break;
844
845 switch( ssl->state )
846 {
847 case SSL_HELLO_REQUEST:
848 ssl->state = SSL_CLIENT_HELLO;
849 break;
850
851 /*
852 * <== ClientHello
853 */
854 case SSL_CLIENT_HELLO:
855 ret = ssl_parse_client_hello( ssl );
856 break;
857
858 /*
859 * ==> ServerHello
860 * Certificate
861 * ( ServerKeyExchange )
862 * ( CertificateRequest )
863 * ServerHelloDone
864 */
865 case SSL_SERVER_HELLO:
866 ret = ssl_write_server_hello( ssl );
867 break;
868
869 case SSL_SERVER_CERTIFICATE:
870 ret = ssl_write_certificate( ssl );
871 break;
872
873 case SSL_SERVER_KEY_EXCHANGE:
874 ret = ssl_write_server_key_exchange( ssl );
875 break;
876
877 case SSL_CERTIFICATE_REQUEST:
878 ret = ssl_write_certificate_request( ssl );
879 break;
880
881 case SSL_SERVER_HELLO_DONE:
882 ret = ssl_write_server_hello_done( ssl );
883 break;
884
885 /*
886 * <== ( Certificate/Alert )
887 * ClientKeyExchange
888 * ( CertificateVerify )
889 * ChangeCipherSpec
890 * Finished
891 */
892 case SSL_CLIENT_CERTIFICATE:
893 ret = ssl_parse_certificate( ssl );
894 break;
895
896 case SSL_CLIENT_KEY_EXCHANGE:
897 ret = ssl_parse_client_key_exchange( ssl );
898 break;
899
900 case SSL_CERTIFICATE_VERIFY:
901 ret = ssl_parse_certificate_verify( ssl );
902 break;
903
904 case SSL_CLIENT_CHANGE_CIPHER_SPEC:
905 ret = ssl_parse_change_cipher_spec( ssl );
906 break;
907
908 case SSL_CLIENT_FINISHED:
909 ret = ssl_parse_finished( ssl );
910 break;
911
912 /*
913 * ==> ChangeCipherSpec
914 * Finished
915 */
916 case SSL_SERVER_CHANGE_CIPHER_SPEC:
917 ret = ssl_write_change_cipher_spec( ssl );
918 break;
919
920 case SSL_SERVER_FINISHED:
921 ret = ssl_write_finished( ssl );
922 break;
923
924 case SSL_FLUSH_BUFFERS:
925 SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
926 ssl->state = SSL_HANDSHAKE_OVER;
927 break;
928
929 default:
930 SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
Paul Bakker40e46942009-01-03 21:51:57 +0000931 return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
Paul Bakker5121ce52009-01-03 21:22:43 +0000932 }
933
934 if( ret != 0 )
935 break;
936 }
937
938 SSL_DEBUG_MSG( 2, ( "<= handshake server" ) );
939
940 return( ret );
941}
942
943#endif