Fix SSL 2.0 rollback checking: The previous implementation of the
[openssl.git] / ssl / s23_srvr.c
1 /* ssl/s23_srvr.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 #include <stdio.h>
60 #include <openssl/buffer.h>
61 #include <openssl/rand.h>
62 #include <openssl/objects.h>
63 #include <openssl/evp.h>
64 #include "ssl_locl.h"
65
66 static SSL_METHOD *ssl23_get_server_method(int ver);
67 int ssl23_get_client_hello(SSL *s);
68 static SSL_METHOD *ssl23_get_server_method(int ver)
69         {
70 #ifndef NO_SSL2
71         if (ver == SSL2_VERSION)
72                 return(SSLv2_server_method());
73 #endif
74         if (ver == SSL3_VERSION)
75                 return(SSLv3_server_method());
76         else if (ver == TLS1_VERSION)
77                 return(TLSv1_server_method());
78         else
79                 return(NULL);
80         }
81
82 SSL_METHOD *SSLv23_server_method(void)
83         {
84         static int init=1;
85         static SSL_METHOD SSLv23_server_data;
86
87         if (init)
88                 {
89                 memcpy((char *)&SSLv23_server_data,
90                         (char *)sslv23_base_method(),sizeof(SSL_METHOD));
91                 SSLv23_server_data.ssl_accept=ssl23_accept;
92                 SSLv23_server_data.get_ssl_method=ssl23_get_server_method;
93                 init=0;
94                 }
95         return(&SSLv23_server_data);
96         }
97
98 int ssl23_accept(SSL *s)
99         {
100         BUF_MEM *buf;
101         unsigned long Time=time(NULL);
102         void (*cb)()=NULL;
103         int ret= -1;
104         int new_state,state;
105
106         RAND_add(&Time,sizeof(Time),0);
107         ERR_clear_error();
108         clear_sys_error();
109
110         if (s->info_callback != NULL)
111                 cb=s->info_callback;
112         else if (s->ctx->info_callback != NULL)
113                 cb=s->ctx->info_callback;
114         
115         if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s); 
116         s->in_handshake++;
117
118         for (;;)
119                 {
120                 state=s->state;
121
122                 switch(s->state)
123                         {
124                 case SSL_ST_BEFORE:
125                 case SSL_ST_ACCEPT:
126                 case SSL_ST_BEFORE|SSL_ST_ACCEPT:
127                 case SSL_ST_OK|SSL_ST_ACCEPT:
128
129                         s->server=1;
130                         if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);
131
132                         /* s->version=SSL3_VERSION; */
133                         s->type=SSL_ST_ACCEPT;
134
135                         if (s->init_buf == NULL)
136                                 {
137                                 if ((buf=BUF_MEM_new()) == NULL)
138                                         {
139                                         ret= -1;
140                                         goto end;
141                                         }
142                                 if (!BUF_MEM_grow(buf,SSL3_RT_MAX_PLAIN_LENGTH))
143                                         {
144                                         ret= -1;
145                                         goto end;
146                                         }
147                                 s->init_buf=buf;
148                                 }
149
150                         ssl3_init_finished_mac(s);
151
152                         s->state=SSL23_ST_SR_CLNT_HELLO_A;
153                         s->ctx->stats.sess_accept++;
154                         s->init_num=0;
155                         break;
156
157                 case SSL23_ST_SR_CLNT_HELLO_A:
158                 case SSL23_ST_SR_CLNT_HELLO_B:
159
160                         s->shutdown=0;
161                         ret=ssl23_get_client_hello(s);
162                         if (ret >= 0) cb=NULL;
163                         goto end;
164                         /* break; */
165
166                 default:
167                         SSLerr(SSL_F_SSL23_ACCEPT,SSL_R_UNKNOWN_STATE);
168                         ret= -1;
169                         goto end;
170                         /* break; */
171                         }
172
173                 if ((cb != NULL) && (s->state != state))
174                         {
175                         new_state=s->state;
176                         s->state=state;
177                         cb(s,SSL_CB_ACCEPT_LOOP,1);
178                         s->state=new_state;
179                         }
180                 }
181 end:
182         if (cb != NULL)
183                 cb(s,SSL_CB_ACCEPT_EXIT,ret);
184         s->in_handshake--;
185         return(ret);
186         }
187
188
189 int ssl23_get_client_hello(SSL *s)
190         {
191         char buf_space[11]; /* Request this many bytes in initial read.
192                              * We can detect SSL 3.0/TLS 1.0 Client Hellos
193                              * ('type == 3') correctly only when the following
194                              * is in a single record, which is not guaranteed by
195                              * the protocol specification:
196                              * Byte  Content
197                              *  0     type            \
198                              *  1/2   version          > record header
199                              *  3/4   length          /
200                              *  5     msg_type        \
201                              *  6-8   length           > Client Hello message
202                              *  9/10  client_version  /
203                              */
204         char *buf= &(buf_space[0]);
205         unsigned char *p,*d,*dd;
206         unsigned int i;
207         unsigned int csl,sil,cl;
208         int n=0,j;
209         int type=0;
210         int v[2];
211 #ifndef NO_RSA
212         int use_sslv2_strong=0;
213 #endif
214
215         if (s->state == SSL23_ST_SR_CLNT_HELLO_A)
216                 {
217                 /* read the initial header */
218                 v[0]=v[1]=0;
219
220                 if (!ssl3_setup_buffers(s)) goto err;
221
222                 n=ssl23_read_bytes(s, sizeof buf_space);
223                 if (n != sizeof buf_space) return(n); /* n == -1 || n == 0 */
224
225                 p=s->packet;
226
227                 memcpy(buf,p,n);
228
229                 if ((p[0] & 0x80) && (p[2] == SSL2_MT_CLIENT_HELLO))
230                         {
231                         /*
232                          * SSLv2 header
233                          */
234                         if ((p[3] == 0x00) && (p[4] == 0x02))
235                                 {
236                                 v[0]=p[3]; v[1]=p[4];
237                                 /* SSLv2 */
238                                 if (!(s->options & SSL_OP_NO_SSLv2))
239                                         type=1;
240                                 }
241                         else if (p[3] == SSL3_VERSION_MAJOR)
242                                 {
243                                 v[0]=p[3]; v[1]=p[4];
244                                 /* SSLv3/TLSv1 */
245                                 if (p[4] >= TLS1_VERSION_MINOR)
246                                         {
247                                         if (!(s->options & SSL_OP_NO_TLSv1))
248                                                 {
249                                                 s->version=TLS1_VERSION;
250                                                 /* type=2; */ /* done later to survive restarts */
251                                                 s->state=SSL23_ST_SR_CLNT_HELLO_B;
252                                                 }
253                                         else if (!(s->options & SSL_OP_NO_SSLv3))
254                                                 {
255                                                 s->version=SSL3_VERSION;
256                                                 /* type=2; */
257                                                 s->state=SSL23_ST_SR_CLNT_HELLO_B;
258                                                 }
259                                         else if (!(s->options & SSL_OP_NO_SSLv2))
260                                                 {
261                                                 type=1;
262                                                 }
263                                         }
264                                 else if (!(s->options & SSL_OP_NO_SSLv3))
265                                         {
266                                         s->version=SSL3_VERSION;
267                                         /* type=2; */
268                                         s->state=SSL23_ST_SR_CLNT_HELLO_B;
269                                         }
270                                 else if (!(s->options & SSL_OP_NO_SSLv2))
271                                         type=1;
272
273                                 if (s->options & SSL_OP_NON_EXPORT_FIRST)
274                                         /* Not only utterly confusing, but broken
275                                          * ('fractured programming'?) -- the details
276                                          * of this block nearly make it work
277                                          * as intended in this environment, but on one
278                                          * of the fine points (w.r.t. restarts) it fails.
279                                          * The obvious fix would be even more devastating
280                                          * to program structure; if you want the functionality,
281                                          * throw this away and implement it in a way
282                                          * that makes sense */
283                                         {
284 #if 0
285                                         STACK_OF(SSL_CIPHER) *sk;
286                                         SSL_CIPHER *c;
287                                         int ne2,ne3;
288
289                                         j=((p[0]&0x7f)<<8)|p[1];
290                                         if (j > (1024*4))
291                                                 {
292                                                 SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_LARGE);
293                                                 goto err;
294                                                 }
295
296                                         n=ssl23_read_bytes(s,j+2);
297                                         if (n <= 0) return(n);
298                                         p=s->packet;
299
300                                         if ((buf=OPENSSL_malloc(n)) == NULL)
301                                                 {
302                                                 SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,ERR_R_MALLOC_FAILURE);
303                                                 goto err;
304                                                 }
305                                         memcpy(buf,p,n);
306
307                                         p+=5;
308                                         n2s(p,csl);
309                                         p+=4;
310
311                                         sk=ssl_bytes_to_cipher_list(
312                                                 s,p,csl,NULL);
313                                         if (sk != NULL)
314                                                 {
315                                                 ne2=ne3=0;
316                                                 for (j=0; j<sk_SSL_CIPHER_num(sk); j++)
317                                                         {
318                                                         c=sk_SSL_CIPHER_value(sk,j);
319                                                         if (!SSL_C_IS_EXPORT(c))
320                                                                 {
321                                                                 if ((c->id>>24L) == 2L)
322                                                                         ne2=1;
323                                                                 else
324                                                                         ne3=1;
325                                                                 }
326                                                         }
327                                                 if (ne2 && !ne3)
328                                                         {
329                                                         type=1;
330                                                         use_sslv2_strong=1;
331                                                         goto next_bit;
332                                                         }
333                                                 }
334 #else
335                                         SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_UNSUPPORTED_OPTION);
336                                         goto err;
337 #endif
338                                         }
339                                 }
340                         }
341                 else if ((p[0] == SSL3_RT_HANDSHAKE) &&
342                          (p[1] == SSL3_VERSION_MAJOR) &&
343                          (p[5] == SSL3_MT_CLIENT_HELLO) &&
344                          ((p[3] == 0 && p[4] < 5 /* silly record length? */)
345                                 || (p[9] == p[1])))
346                         {
347                         /*
348                          * SSLv3 or tls1 header
349                          */
350                         
351                         v[0]=p[1]; /* major version */
352                         /* We must look at client_version inside the Client Hello message
353                          * to get the correct minor version: */
354                         v[1]=p[10];
355                         /* However if we have only a pathologically small fragment of the
356                          * Client Hello message, we simply use the version from the
357                          * record header -- this is incorrect but unlikely to fail in
358                          * practice */
359                         if (p[3] == 0 && p[4] < 6)
360                                 v[1]=p[2];
361                         if (v[1] >= TLS1_VERSION_MINOR)
362                                 {
363                                 if (!(s->options & SSL_OP_NO_TLSv1))
364                                         {
365                                         s->version=TLS1_VERSION;
366                                         type=3;
367                                         }
368                                 else if (!(s->options & SSL_OP_NO_SSLv3))
369                                         {
370                                         s->version=SSL3_VERSION;
371                                         type=3;
372                                         }
373                                 }
374                         else if (!(s->options & SSL_OP_NO_SSLv3))
375                                 {
376                                 s->version=SSL3_VERSION;
377                                 type=3;
378                                 }
379                         }
380                 else if ((strncmp("GET ", (char *)p,4) == 0) ||
381                          (strncmp("POST ",(char *)p,5) == 0) ||
382                          (strncmp("HEAD ",(char *)p,5) == 0) ||
383                          (strncmp("PUT ", (char *)p,4) == 0))
384                         {
385                         SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_HTTP_REQUEST);
386                         goto err;
387                         }
388                 else if (strncmp("CONNECT",(char *)p,7) == 0)
389                         {
390                         SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_HTTPS_PROXY_REQUEST);
391                         goto err;
392                         }
393                 }
394
395         if (s->state == SSL23_ST_SR_CLNT_HELLO_B)
396                 {
397                 /* we have SSLv3/TLSv1 in an SSLv2 header
398                  * (other cases skip this state) */
399
400                 type=2;
401                 p=s->packet;
402                 v[0] = p[3]; /* == SSL3_VERSION_MAJOR */
403                 v[1] = p[4];
404
405                 n=((p[0]&0x7f)<<8)|p[1];
406                 if (n > (1024*4))
407                         {
408                         SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_LARGE);
409                         goto err;
410                         }
411
412                 j=ssl23_read_bytes(s,n+2);
413                 if (j <= 0) return(j);
414
415                 ssl3_finish_mac(s,&(s->packet[2]),s->packet_length-2);
416
417                 p=s->packet;
418                 p+=5;
419                 n2s(p,csl);
420                 n2s(p,sil);
421                 n2s(p,cl);
422                 d=(unsigned char *)s->init_buf->data;
423                 if ((csl+sil+cl+11) != s->packet_length)
424                         {
425                         SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_LENGTH_MISMATCH);
426                         goto err;
427                         }
428
429                 *(d++) = SSL3_VERSION_MAJOR; /* == v[0] */
430                 *(d++) = v[1];
431
432                 /* lets populate the random area */
433                 /* get the challenge_length */
434                 i=(cl > SSL3_RANDOM_SIZE)?SSL3_RANDOM_SIZE:cl;
435                 memset(d,0,SSL3_RANDOM_SIZE);
436                 memcpy(&(d[SSL3_RANDOM_SIZE-i]),&(p[csl+sil]),i);
437                 d+=SSL3_RANDOM_SIZE;
438
439                 /* no session-id reuse */
440                 *(d++)=0;
441
442                 /* ciphers */
443                 j=0;
444                 dd=d;
445                 d+=2;
446                 for (i=0; i<csl; i+=3)
447                         {
448                         if (p[i] != 0) continue;
449                         *(d++)=p[i+1];
450                         *(d++)=p[i+2];
451                         j+=2;
452                         }
453                 s2n(j,dd);
454
455                 /* COMPRESSION */
456                 *(d++)=1;
457                 *(d++)=0;
458                 
459                 i=(d-(unsigned char *)s->init_buf->data);
460
461                 /* get the data reused from the init_buf */
462                 s->s3->tmp.reuse_message=1;
463                 s->s3->tmp.message_type=SSL3_MT_CLIENT_HELLO;
464                 s->s3->tmp.message_size=i;
465                 }
466
467         /* imaginary new state (for program structure): */
468         /* s->state = SSL23_SR_CLNT_HELLO_C */
469
470         if (type == 1)
471                 {
472 #ifdef NO_SSL2
473                 SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_UNSUPPORTED_PROTOCOL);
474                 goto err;
475 #else
476                 /* we are talking sslv2 */
477                 /* we need to clean up the SSLv3/TLSv1 setup and put in the
478                  * sslv2 stuff. */
479
480                 if (s->s2 == NULL)
481                         {
482                         if (!ssl2_new(s))
483                                 goto err;
484                         }
485                 else
486                         ssl2_clear(s);
487
488                 if (s->s3 != NULL) ssl3_free(s);
489
490                 if (!BUF_MEM_grow(s->init_buf,
491                         SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER))
492                         {
493                         goto err;
494                         }
495
496                 s->state=SSL2_ST_GET_CLIENT_HELLO_A;
497                 if ((s->options & SSL_OP_MSIE_SSLV2_RSA_PADDING) ||
498                         use_sslv2_strong ||
499                         (s->options & SSL_OP_NO_TLSv1 && s->options & SSL_OP_NO_SSLv3))
500                         s->s2->ssl2_rollback=0;
501                 else
502                         s->s2->ssl2_rollback=1;
503
504                 /* setup the n bytes we have read so we get them from
505                  * the sslv2 buffer */
506                 s->rstate=SSL_ST_READ_HEADER;
507                 s->packet_length=n;
508                 s->packet= &(s->s2->rbuf[0]);
509                 memcpy(s->packet,buf,n);
510                 s->s2->rbuf_left=n;
511                 s->s2->rbuf_offs=0;
512
513                 s->method=SSLv2_server_method();
514                 s->handshake_func=s->method->ssl_accept;
515 #endif
516                 }
517
518         if ((type == 2) || (type == 3))
519                 {
520                 /* we have SSLv3/TLSv1 (type 2: SSL2 style, type 3: SSL3/TLS style) */
521
522                 if (!ssl_init_wbio_buffer(s,1)) goto err;
523
524                 /* we are in this state */
525                 s->state=SSL3_ST_SR_CLNT_HELLO_A;
526
527                 if (type == 3)
528                         {
529                         /* put the 'n' bytes we have read into the input buffer
530                          * for SSLv3 */
531                         s->rstate=SSL_ST_READ_HEADER;
532                         s->packet_length=n;
533                         s->packet= &(s->s3->rbuf.buf[0]);
534                         memcpy(s->packet,buf,n);
535                         s->s3->rbuf.left=n;
536                         s->s3->rbuf.offset=0;
537                         }
538                 else
539                         {
540                         s->packet_length=0;
541                         s->s3->rbuf.left=0;
542                         s->s3->rbuf.offset=0;
543                         }
544
545                 if (s->version == TLS1_VERSION)
546                         s->method = TLSv1_server_method();
547                 else
548                         s->method = SSLv3_server_method();
549 #if 0 /* ssl3_get_client_hello does this */
550                 s->client_version=(v[0]<<8)|v[1];
551 #endif
552                 s->handshake_func=s->method->ssl_accept;
553                 }
554         
555         if ((type < 1) || (type > 3))
556                 {
557                 /* bad, very bad */
558                 SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_UNKNOWN_PROTOCOL);
559                 goto err;
560                 }
561         s->init_num=0;
562
563         if (buf != buf_space) OPENSSL_free(buf);
564         s->first_packet=1;
565         return(SSL_accept(s));
566 err:
567         if (buf != buf_space) OPENSSL_free(buf);
568         return(-1);
569         }