dvd_css.c 28.4 KB
Newer Older
1 2 3 4
/*****************************************************************************
 * dvd_css.c: Functions for DVD authentification and unscrambling
 *****************************************************************************
 * Copyright (C) 1999-2001 VideoLAN
5
 * $Id: dvd_css.c,v 1.23 2001/04/10 17:47:05 stef Exp $
6 7 8
 *
 * Author: Stphane Borel <stef@via.ecp.fr>
 *
9 10 11
 * based on:
 *  - css-auth by Derek Fawcus <derek@spider.com>
 *  - DVD CSS ioctls example program by Andrew T. Veliath <andrewtv@usa.net>
Sam Hocevar's avatar
 
Sam Hocevar committed
12
 *  - The Divide and conquer attack by Frank A. Stevenson <frank@funcom.com>
13 14 15 16
 *  - DeCSSPlus by Ethan Hawke
 *  - DecVOB
 *  see http://www.lemuria.org/DeCSS/ by Tom Vogt for more information.
 * 
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
35 36
#include "defs.h"

37
#include <stdio.h>
38
#include <stdlib.h>
39 40 41 42
#include <unistd.h>
#include <string.h>

#include "common.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
43

44
#include "intf_msg.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
45

46
#include "dvd_css.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
47 48 49
#ifdef HAVE_CSS
#include "dvd_csstables.h"
#endif /* HAVE_CSS */
Sam Hocevar's avatar
 
Sam Hocevar committed
50
#include "dvd_ioctl.h"
51
#include "dvd_ifo.h"
Sam Hocevar's avatar
 
Sam Hocevar committed
52

53
#include "input_dvd.h"
54 55

/*****************************************************************************
Sam Hocevar's avatar
 
Sam Hocevar committed
56
 * Local prototypes
57
 *****************************************************************************/
Sam Hocevar's avatar
 
Sam Hocevar committed
58
#ifdef HAVE_CSS
Sam Hocevar's avatar
 
Sam Hocevar committed
59
static int  CSSGetASF    ( css_t *p_css );
Sam Hocevar's avatar
 
Sam Hocevar committed
60 61 62 63 64 65
static void CSSCryptKey  ( int i_key_type, int i_varient,
                           u8 const * pi_challenge, u8* pi_key );
static int  CSSCracker   ( int i_start, unsigned char * p_crypted,
                           unsigned char * p_decrypted,
                           dvd_key_t * p_sector_key, dvd_key_t * p_key );
#endif /* HAVE_CSS */
66 67

/*****************************************************************************
Sam Hocevar's avatar
 
Sam Hocevar committed
68
 * CSSTest : check if the disc is encrypted or not
69
 *****************************************************************************/
Sam Hocevar's avatar
 
Sam Hocevar committed
70
int CSSTest( int i_fd )
71
{
Sam Hocevar's avatar
 
Sam Hocevar committed
72
    int i_ret, i_copyright;
73

Sam Hocevar's avatar
 
Sam Hocevar committed
74
    i_ret = ioctl_ReadCopyright( i_fd, 0 /* i_layer */, &i_copyright );
75

Sam Hocevar's avatar
 
Sam Hocevar committed
76
    if( i_ret < 0 )
77
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
78 79 80 81
        /* Since it's the first ioctl we try to issue, we add a notice */
        intf_ErrMsg( "css error: ioctl_ReadCopyright failed, "
                     "make sure DVD ioctls were compiled in" );

Sam Hocevar's avatar
 
Sam Hocevar committed
82
        return i_ret;
83
    }
84

Sam Hocevar's avatar
 
Sam Hocevar committed
85
    return i_copyright;
86 87 88
}

/*****************************************************************************
Sam Hocevar's avatar
 
Sam Hocevar committed
89 90 91 92 93
 * CSSInit : CSS Structure initialisation and DVD authentication.
 *****************************************************************************
 * It simulates the mutual authentication between logical unit and host.
 * Since we don't need the disc key to find the title key, we just run the
 * basic unavoidable commands to authenticate device and disc.
94
 *****************************************************************************/
Sam Hocevar's avatar
 
Sam Hocevar committed
95
int CSSInit( css_t * p_css )
96
{
Sam Hocevar's avatar
 
Sam Hocevar committed
97 98
#ifdef HAVE_CSS
    /* structures defined in cdrom.h or dvdio.h */
Sam Hocevar's avatar
 
Sam Hocevar committed
99 100 101
    char p_buffer[2048 + 4 + 1];
    int  i_ret = -1;
    int  i;
102

Sam Hocevar's avatar
 
Sam Hocevar committed
103
    p_css->i_agid = 0;
104

Sam Hocevar's avatar
 
Sam Hocevar committed
105 106
    /* Test authentication success */
    switch( CSSGetASF( p_css ) )
107
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
108 109
        case -1:
            return -1;
110

Sam Hocevar's avatar
 
Sam Hocevar committed
111
        case 1:
Sam Hocevar's avatar
 
Sam Hocevar committed
112
            intf_WarnMsg( 3, "css info: already authenticated" );
Sam Hocevar's avatar
 
Sam Hocevar committed
113
            return 0;
114

Sam Hocevar's avatar
 
Sam Hocevar committed
115
        case 0:
Sam Hocevar's avatar
 
Sam Hocevar committed
116
            intf_WarnMsg( 3, "css info: need to authenticate" );
117 118
    }

Sam Hocevar's avatar
 
Sam Hocevar committed
119 120
    /* Init sequence, request AGID */
    for( i = 1; i < 4 ; ++i )
121
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
122 123
        intf_WarnMsg( 3, "css info: requesting AGID %d", i );

Sam Hocevar's avatar
 
Sam Hocevar committed
124
        i_ret = ioctl_LUSendAgid( p_css );
Sam Hocevar's avatar
 
Sam Hocevar committed
125 126

        if( i_ret != -1 )
127
        {
Sam Hocevar's avatar
 
Sam Hocevar committed
128
            /* No error during ioctl: we know the device is authenticated */
Sam Hocevar's avatar
 
Sam Hocevar committed
129
            break;
130
        }
131

Sam Hocevar's avatar
 
Sam Hocevar committed
132
        intf_ErrMsg( "css error: ioctl_LUSendAgid failed, invalidating" );
Sam Hocevar's avatar
 
Sam Hocevar committed
133 134

        p_css->i_agid = 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
135
        ioctl_InvalidateAgid( p_css );
Sam Hocevar's avatar
 
Sam Hocevar committed
136
    }
137

Sam Hocevar's avatar
 
Sam Hocevar committed
138
    /* Unable to authenticate without AGID */
Sam Hocevar's avatar
 
Sam Hocevar committed
139
    if( i_ret == -1 )
140
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
141
        intf_ErrMsg( "css error: ioctl_LUSendAgid failed, fatal" );
Sam Hocevar's avatar
 
Sam Hocevar committed
142
        return -1;
143
    }
144

Sam Hocevar's avatar
 
Sam Hocevar committed
145
    for( i = 0 ; i < 10; ++i )
146
    {
147
        p_css->disc.pi_challenge[i] = i;
148
    }
149

Sam Hocevar's avatar
 
Sam Hocevar committed
150 151 152
    /* Get challenge from host */
    for( i = 0 ; i < 10 ; ++i )
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
153
        p_buffer[9-i] = p_css->disc.pi_challenge[i];
154
    }
155

Sam Hocevar's avatar
 
Sam Hocevar committed
156
    /* Send challenge to LU */
Sam Hocevar's avatar
 
Sam Hocevar committed
157
    if( ioctl_HostSendChallenge( p_css, p_buffer ) < 0 )
158
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
159
        intf_ErrMsg( "css error: ioctl_HostSendChallenge failed" );
Sam Hocevar's avatar
 
Sam Hocevar committed
160
        return -1;
161
    }
162

Sam Hocevar's avatar
 
Sam Hocevar committed
163
    /* Get key1 from LU */
Sam Hocevar's avatar
 
Sam Hocevar committed
164
    if( ioctl_LUSendKey1( p_css, p_buffer ) < 0)
165
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
166
        intf_ErrMsg( "css error: ioctl_LUSendKey1 failed" );
Sam Hocevar's avatar
 
Sam Hocevar committed
167
        return -1;
168
    }
169

Sam Hocevar's avatar
 
Sam Hocevar committed
170 171
    /* Send key1 to host */
    for( i = 0 ; i < KEY_SIZE ; i++ )
172
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
173
        p_css->disc.pi_key1[i] = p_buffer[4-i];
174 175 176 177
    }

    for( i = 0 ; i < 32 ; ++i )
    {
178 179
        CSSCryptKey( 0, i, p_css->disc.pi_challenge,
                           p_css->disc.pi_key_check );
180

181 182
        if( memcmp( p_css->disc.pi_key_check,
                    p_css->disc.pi_key1, KEY_SIZE ) == 0 )
183
        {
Sam Hocevar's avatar
 
Sam Hocevar committed
184
            intf_WarnMsg( 3, "css info: drive authentic, using variant %d", i);
185
            p_css->disc.i_varient = i;
186 187 188 189 190 191
            break;
        }
    }

    if( i == 32 )
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
192
        intf_ErrMsg( "css error: drive would not authenticate" );
Sam Hocevar's avatar
 
Sam Hocevar committed
193
        return -1;
194
    }
195 196

    /* Get challenge from LU */
Sam Hocevar's avatar
 
Sam Hocevar committed
197
    if( ioctl_LUSendChallenge( p_css, p_buffer ) < 0 )
198
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
199
        intf_ErrMsg( "css error: ioctl_LUSendKeyChallenge failed" );
Sam Hocevar's avatar
 
Sam Hocevar committed
200
        return -1;
201 202
    }

203
    /* Send challenge to host */
204
    for( i = 0 ; i < 10 ; ++i )
205
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
206
        p_css->disc.pi_challenge[i] = p_buffer[9-i];
207 208
    }

209
    CSSCryptKey( 1, p_css->disc.i_varient, p_css->disc.pi_challenge,
Sam Hocevar's avatar
 
Sam Hocevar committed
210
                                               p_css->disc.pi_key2 );
211

212
    /* Get key2 from host */
213
    for( i = 0 ; i < KEY_SIZE ; ++i )
214
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
215
        p_buffer[4-i] = p_css->disc.pi_key2[i];
216
    }
217

218
    /* Send key2 to LU */
Sam Hocevar's avatar
 
Sam Hocevar committed
219
    if( ioctl_HostSendKey2( p_css, p_buffer ) < 0 )
220
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
221
        intf_ErrMsg( "css error: ioctl_HostSendKey2 failed" );
Sam Hocevar's avatar
 
Sam Hocevar committed
222
        return -1;
223
    }
224

Sam Hocevar's avatar
 
Sam Hocevar committed
225
    intf_WarnMsg( 3, "css info: authentication established" );
226

227 228
    memcpy( p_css->disc.pi_challenge, p_css->disc.pi_key1, KEY_SIZE );
    memcpy( p_css->disc.pi_challenge+KEY_SIZE, p_css->disc.pi_key2, KEY_SIZE );
Sam Hocevar's avatar
 
Sam Hocevar committed
229 230
    CSSCryptKey( 2, p_css->disc.i_varient, p_css->disc.pi_challenge,
                                               p_css->disc.pi_key_check );
231

Sam Hocevar's avatar
 
Sam Hocevar committed
232
    intf_WarnMsg( 1, "css info: received Session Key" );
233

234
    if( p_css->i_agid < 0 )
235
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
236
        return -1;
237
    }
238

239
    /* Test authentication success */
Sam Hocevar's avatar
 
Sam Hocevar committed
240
    switch( CSSGetASF( p_css ) )
241
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
242 243 244 245
        case -1:
            return -1;

        case 1:
Sam Hocevar's avatar
 
Sam Hocevar committed
246
            intf_WarnMsg( 3, "css info: already authenticated" );
Sam Hocevar's avatar
 
Sam Hocevar committed
247 248 249
            return 0;

        case 0:
Sam Hocevar's avatar
 
Sam Hocevar committed
250
            intf_WarnMsg( 3, "css info: need to get disc key" );
251
    }
252

253
    /* Get encrypted disc key */
Sam Hocevar's avatar
 
Sam Hocevar committed
254
    if( ioctl_ReadKey( p_css, p_buffer ) < 0 )
255
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
256
        intf_ErrMsg( "css error: ioctl_ReadKey failed" );
Sam Hocevar's avatar
 
Sam Hocevar committed
257
        return -1;
258
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
259

260
    /* Unencrypt disc key using bus key */
Sam Hocevar's avatar
 
Sam Hocevar committed
261
    for( i = 0 ; i < 2048 ; i++ )
262
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
263
        p_buffer[ i ] ^= p_css->disc.pi_key_check[ 4 - (i % KEY_SIZE) ];
264
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
265 266
    memcpy( p_css->disc.pi_key_check, p_buffer, 2048 );

267
    /* Test authentication success */
Sam Hocevar's avatar
 
Sam Hocevar committed
268
    switch( CSSGetASF( p_css ) )
269
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
270 271 272 273
        case -1:
            return -1;

        case 1:
Sam Hocevar's avatar
 
Sam Hocevar committed
274
            intf_WarnMsg( 3, "css info: successfully authenticated" );
Sam Hocevar's avatar
 
Sam Hocevar committed
275
            return 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
276

Sam Hocevar's avatar
 
Sam Hocevar committed
277
        case 0:
278 279
            intf_ErrMsg( "css error: no way to authenticate" );
            return -1;
Sam Hocevar's avatar
 
Sam Hocevar committed
280
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
281

Sam Hocevar's avatar
 
Sam Hocevar committed
282 283 284
#else /* HAVE_CSS */
    intf_ErrMsg( "css error: CSS decryption is disabled in this module" );

Sam Hocevar's avatar
 
Sam Hocevar committed
285
#endif /* HAVE_CSS */
Sam Hocevar's avatar
 
Sam Hocevar committed
286 287
    return -1;

288 289
}

290
/*****************************************************************************
Stéphane Borel's avatar
 
Stéphane Borel committed
291
 * CSSGetKey : get title key.
Sam Hocevar's avatar
 
Sam Hocevar committed
292
 *****************************************************************************
293
 * The DVD should have been opened and authenticated before.
294
 *****************************************************************************/
Stéphane Borel's avatar
 
Stéphane Borel committed
295
int CSSGetKey( css_t * p_css )
296
{
Sam Hocevar's avatar
 
Sam Hocevar committed
297
#ifdef HAVE_CSS
298 299 300 301
    /*
     * Title key cracking method from Ethan Hawke,
     * with Frank A. Stevenson algorithm.
     * Does not use any player key table and ioctls.
302
     */
Stéphane Borel's avatar
 
Stéphane Borel committed
303 304 305
    u8          pi_buf[0x800];
    dvd_key_t   pi_key;
    title_key_t p_title_key[10];
306 307 308
    off_t       i_pos;
    boolean_t   b_encrypted;
    boolean_t   b_stop_scanning;
309
    int         i_title;
310 311 312
    int         i_bytes_read;
    int         i_best_plen;
    int         i_best_p;
313 314 315
    int         i_registered_keys;
    int         i_total_keys_found;
    int         i_highest;
316
    int         i,j,k;
317

Stéphane Borel's avatar
 
Stéphane Borel committed
318 319 320 321 322 323 324 325 326 327 328
    memset( p_title_key, 0, 10 );
    memset( &pi_key, 0, 10 );
    b_encrypted = 0;
    b_stop_scanning = 0;
    i_registered_keys = 0 ;
    i_total_keys_found = 0 ;
    i_highest = 0;

    /* Position of the title on the disc */
    i_title = p_css->i_title;
    i_pos = p_css->i_title_pos;
329

330 331
//fprintf( stderr, "CSS %d start pos: %lld\n", i_title, i_pos );

Stéphane Borel's avatar
 
Stéphane Borel committed
332 333 334
    do {
    i_pos = lseek( p_css->i_fd, i_pos, SEEK_SET );
    i_bytes_read = read( p_css->i_fd, pi_buf, 0x800 );
335

Stéphane Borel's avatar
 
Stéphane Borel committed
336 337 338 339 340 341
    /* PES_scrambling_control */
    if( pi_buf[0x14] & 0x30 )
    {
        b_encrypted = 1;
        i_best_plen = 0;
        i_best_p = 0;
342

Stéphane Borel's avatar
 
Stéphane Borel committed
343 344 345 346
        for( i = 2 ; i < 0x30 ; i++ )
        {
            for( j = i ; ( j < 0x80 ) &&
                   ( pi_buf[0x7F - (j%i)] == pi_buf[0x7F-j] ) ; j++ );
347
            {
Stéphane Borel's avatar
 
Stéphane Borel committed
348
                if( ( j > i_best_plen ) && ( j > i ) )
349
                {
Stéphane Borel's avatar
 
Stéphane Borel committed
350 351
                    i_best_plen = j;
                    i_best_p = i;
352
                }
353
            }
Stéphane Borel's avatar
 
Stéphane Borel committed
354
        }
355

Stéphane Borel's avatar
 
Stéphane Borel committed
356 357 358 359 360 361 362
        if( ( i_best_plen > 20 ) && ( i_best_plen / i_best_p >= 2) )
        {
            i = CSSCracker( 0,  &pi_buf[0x80],
                    &pi_buf[0x80 - ( i_best_plen / i_best_p) *i_best_p],
                    (dvd_key_t*)&pi_buf[0x54],
                    &pi_key );
            while( i>=0 )
363
            {
Stéphane Borel's avatar
 
Stéphane Borel committed
364 365
                k = 0;
                for( j=0 ; j<i_registered_keys ; j++ )
366
                {
Stéphane Borel's avatar
 
Stéphane Borel committed
367 368
                    if( memcmp( &(p_title_key[j].pi_key),
                                &pi_key, sizeof(dvd_key_t) ) == 0 )
369
                    {
Stéphane Borel's avatar
 
Stéphane Borel committed
370
                        p_title_key[j].i_occ++;
371
                        i_total_keys_found++;
Stéphane Borel's avatar
 
Stéphane Borel committed
372
                        k = 1;
373
                    }
374 375
                }

Sam Hocevar's avatar
 
Sam Hocevar committed
376 377 378 379 380 381 382 383 384 385 386 387
                if( k == 0 )
                {
                    memcpy( &(p_title_key[i_registered_keys].pi_key),
                                            &pi_key, sizeof(dvd_key_t) );
                    p_title_key[i_registered_keys++].i_occ = 1;
                    i_total_keys_found++;
                }
                i = CSSCracker( i, &pi_buf[0x80],
                    &pi_buf[0x80 - ( i_best_plen / i_best_p) *i_best_p],
                    (dvd_key_t*)&pi_buf[0x54], &pi_key);
            }

Sam Hocevar's avatar
 
Sam Hocevar committed
388
            /* Stop search if we find one occurence of the key 
Sam Hocevar's avatar
 
Sam Hocevar committed
389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
             * I have never found a DVD for which it is not enough
             * but we should take care of that */
            if( i_registered_keys == 1 && p_title_key[0].i_occ >= 1 )
            {
                b_stop_scanning = 1;
            }
        }
    }

    i_pos += i_bytes_read;
    } while( i_bytes_read == 0x800 && !b_stop_scanning);

    if( b_stop_scanning)
    {
        intf_WarnMsg( 1,
            "css info: found enough occurencies of the same key." );
    }

    if( !b_encrypted )
    {
        intf_WarnMsg( 3, "css warning: this file was _NOT_ encrypted!" );
410
        return 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
411 412 413 414 415
    }

    if( b_encrypted && i_registered_keys == 0 )
    {
        intf_ErrMsg( "css error: unable to determine keys from file" );
416
        return -1;
Sam Hocevar's avatar
 
Sam Hocevar committed
417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472
    }

    for( i = 0 ; i < i_registered_keys - 1 ; i++ )
    {
        for( j = i + 1 ; j < i_registered_keys ; j++ )
        {
            if( p_title_key[j].i_occ > p_title_key[i].i_occ )
            {
                memcpy( &pi_key, &(p_title_key[j].pi_key), sizeof(dvd_key_t) );
                k = p_title_key[j].i_occ;

                memcpy( &(p_title_key[j].pi_key),
                        &(p_title_key[i].pi_key), sizeof(dvd_key_t) );
                p_title_key[j].i_occ = p_title_key[i].i_occ;

                memcpy( &(p_title_key[i].pi_key),&pi_key, sizeof(dvd_key_t) );
                p_title_key[i].i_occ = k;
            }
        }
    }

#ifdef STATS
    intf_WarnMsg( 1, "css info: key(s) & key probability" );
    intf_WarnMsg( 1, "----------------------------------" );
#endif
    for( i=0 ; i<i_registered_keys ; i++ )
    {
#ifdef STATS
        intf_WarnMsg( 1, "%d) %02X %02X %02X %02X %02X - %3.2f%%", i,
                      p_title_key[i].pi_key[0], p_title_key[i].pi_key[1],
                      p_title_key[i].pi_key[2], p_title_key[i].pi_key[3],
                      p_title_key[i].pi_key[4],
                      p_title_key[i].i_occ * 100.0 / i_total_keys_found );
#endif
        if( p_title_key[i_highest].i_occ * 100.0 / i_total_keys_found
                           <= p_title_key[i].i_occ*100.0 / i_total_keys_found )
        {
            i_highest = i;
        }
    }


    /* The "find the key with the highest probability" code
     * is untested, as I haven't been able to find a VOB that
     * produces multiple keys (RT)
     */
    intf_WarnMsg( 3, "css info: title %d, key %02X %02X %02X %02X %02X",
                  i_title, p_title_key[i_highest].pi_key[0],
                           p_title_key[i_highest].pi_key[1],
                           p_title_key[i_highest].pi_key[2],
                           p_title_key[i_highest].pi_key[3],
                           p_title_key[i_highest].pi_key[4] );

    memcpy( p_css->pi_title_key,
            p_title_key[i_highest].pi_key, KEY_SIZE );

473
    intf_WarnMsg( 2, "css info: vts key initialized" );
Sam Hocevar's avatar
 
Sam Hocevar committed
474
    return 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
475

Sam Hocevar's avatar
 
Sam Hocevar committed
476
#else /* HAVE_CSS */
477 478
    intf_ErrMsg( "css error: css decryption unavailable" );
    return -1;
Sam Hocevar's avatar
 
Sam Hocevar committed
479

Sam Hocevar's avatar
 
Sam Hocevar committed
480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518
#endif /* HAVE_CSS */
}

/*****************************************************************************
 * CSSDescrambleSector
 *****************************************************************************
 * sec : sector to descramble
 * key : title key for this sector
 *****************************************************************************/
int CSSDescrambleSector( dvd_key_t pi_key, u8* pi_sec )
{
#ifdef HAVE_CSS
    unsigned int    i_t1, i_t2, i_t3, i_t4, i_t5, i_t6;
    u8*             pi_end = pi_sec + 0x800;

    /* PES_scrambling_control */
    if( pi_sec[0x14] & 0x30)
    {
        i_t1 = ((pi_key)[0] ^ pi_sec[0x54]) | 0x100;
        i_t2 = (pi_key)[1] ^ pi_sec[0x55];
        i_t3 = (((pi_key)[2]) | ((pi_key)[3] << 8) |
               ((pi_key)[4] << 16)) ^ ((pi_sec[0x56]) |
               (pi_sec[0x57] << 8) | (pi_sec[0x58] << 16));
        i_t4 = i_t3 & 7;
        i_t3 = i_t3 * 2 + 8 - i_t4;
        pi_sec += 0x80;
        i_t5 = 0;

        while( pi_sec != pi_end )
        {
            i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
            i_t2 = i_t1>>1;
            i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
            i_t4 = pi_css_tab5[i_t4];
            i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
                                         i_t3 ) >> 8 ) ^ i_t3 ) >> 5) & 0xff;
            i_t3 = (i_t3 << 8 ) | i_t6;
            i_t6 = pi_css_tab4[i_t6];
            i_t5 += i_t6 + i_t4;
Sam Hocevar's avatar
 
Sam Hocevar committed
519 520
            *pi_sec = pi_css_tab1[*pi_sec] ^( i_t5 & 0xff );
            pi_sec++;
Sam Hocevar's avatar
 
Sam Hocevar committed
521 522 523 524 525
            i_t5 >>= 8;
        }
    }

    return 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
526

Sam Hocevar's avatar
 
Sam Hocevar committed
527 528
#else /* HAVE_CSS */
    return 1;
Sam Hocevar's avatar
 
Sam Hocevar committed
529

Sam Hocevar's avatar
 
Sam Hocevar committed
530 531 532 533
#endif /* HAVE_CSS */
}

#ifdef HAVE_CSS
Sam Hocevar's avatar
 
Sam Hocevar committed
534 535

/* Following functions are local */
Sam Hocevar's avatar
 
Sam Hocevar committed
536 537 538 539 540 541 542 543 544

/*****************************************************************************
 * CSSGetASF : Get Authentification success flag
 *****************************************************************************
 * Returns :
 *  -1 on ioctl error,
 *  0 if the device needs to be authenticated,
 *  1 either.
 *****************************************************************************/
Sam Hocevar's avatar
 
Sam Hocevar committed
545
static int CSSGetASF( css_t *p_css )
Sam Hocevar's avatar
 
Sam Hocevar committed
546
{
Sam Hocevar's avatar
 
Sam Hocevar committed
547
    int i_oldagid = p_css->i_agid, i_asf = 0;
Sam Hocevar's avatar
 
Sam Hocevar committed
548

Sam Hocevar's avatar
 
Sam Hocevar committed
549
    for( p_css->i_agid = 0 ; p_css->i_agid < 4 ; p_css->i_agid++ )
Sam Hocevar's avatar
 
Sam Hocevar committed
550
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
551
        if( ioctl_LUSendASF( p_css, &i_asf ) == 0 )
Sam Hocevar's avatar
 
Sam Hocevar committed
552
        {
Sam Hocevar's avatar
 
Sam Hocevar committed
553 554 555 556
            intf_WarnMsg( 3, "css info: %sauthenticated", i_asf ? "":"not " );

            p_css->i_agid = i_oldagid;
            return i_asf;
Sam Hocevar's avatar
 
Sam Hocevar committed
557 558 559 560 561
        }
    }

    /* The ioctl process has failed */
    intf_ErrMsg( "css error: GetASF fatal error" );
Sam Hocevar's avatar
 
Sam Hocevar committed
562 563

    p_css->i_agid = i_oldagid;
Sam Hocevar's avatar
 
Sam Hocevar committed
564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
    return -1;
}

/*****************************************************************************
 * CSSCryptKey : shuffles bits and unencrypt keys.
 *****************************************************************************
 * Used during authentication and disc key negociation in CSSInit.
 * i_key_type : 0->key1, 1->key2, 2->buskey.
 * i_varient : between 0 and 31.
 *****************************************************************************/
static void CSSCryptKey( int i_key_type, int i_varient,
                         u8 const * pi_challenge, u8* pi_key )
{
    /* Permutation table for challenge */
    u8      ppi_perm_challenge[3][10] =
            { { 1, 3, 0, 7, 5, 2, 9, 6, 4, 8 },
              { 6, 1, 9, 3, 8, 5, 7, 4, 0, 2 },
              { 4, 0, 3, 5, 7, 2, 8, 6, 1, 9 } };

    /* Permutation table for varient table for key2 and buskey */
    u8      ppi_perm_varient[2][32] =
            { { 0x0a, 0x08, 0x0e, 0x0c, 0x0b, 0x09, 0x0f, 0x0d,
                0x1a, 0x18, 0x1e, 0x1c, 0x1b, 0x19, 0x1f, 0x1d,
                0x02, 0x00, 0x06, 0x04, 0x03, 0x01, 0x07, 0x05,
                0x12, 0x10, 0x16, 0x14, 0x13, 0x11, 0x17, 0x15 },
              { 0x12, 0x1a, 0x16, 0x1e, 0x02, 0x0a, 0x06, 0x0e,
                0x10, 0x18, 0x14, 0x1c, 0x00, 0x08, 0x04, 0x0c,
                0x13, 0x1b, 0x17, 0x1f, 0x03, 0x0b, 0x07, 0x0f,
                0x11, 0x19, 0x15, 0x1d, 0x01, 0x09, 0x05, 0x0d } };

    u8      pi_varients[32] =
            {   0xB7, 0x74, 0x85, 0xD0, 0xCC, 0xDB, 0xCA, 0x73,
                0x03, 0xFE, 0x31, 0x03, 0x52, 0xE0, 0xB7, 0x42,
                0x63, 0x16, 0xF2, 0x2A, 0x79, 0x52, 0xFF, 0x1B,
                0x7A, 0x11, 0xCA, 0x1A, 0x9B, 0x40, 0xAD, 0x01 };

    /* The "secret" key */
    u8      pi_secret[5] = { 0x55, 0xD6, 0xC4, 0xC5, 0x28 };

    u8      pi_bits[30];
    u8      pi_scratch[10];
    u8      pi_tmp1[5];
    u8      pi_tmp2[5];
    u8      i_lfsr0_o;  /* 1 bit used */
    u8      i_lfsr1_o;  /* 1 bit used */
    u32     i_lfsr0;
    u32     i_lfsr1;
    u8      i_css_varient;
    u8      i_cse;
    u8      i_index;
    u8      i_combined;
    u8      i_carry;
    u8      i_val = 0;
    int     i_term = 0;
    int     i_bit;
    int     i;

    for (i = 9; i >= 0; --i)
        pi_scratch[i] = pi_challenge[ppi_perm_challenge[i_key_type][i]];

    i_css_varient = ( i_key_type == 0 ) ? i_varient :
                    ppi_perm_varient[i_key_type-1][i_varient];

    /*
     * This encryption engine implements one of 32 variations
     * one the same theme depending upon the choice in the
     * varient parameter (0 - 31).
     *
     * The algorithm itself manipulates a 40 bit input into
     * a 40 bit output.
     * The parameter 'input' is 80 bits.  It consists of
     * the 40 bit input value that is to be encrypted followed
     * by a 40 bit seed value for the pseudo random number
     * generators.
     */

    /* Feed the secret into the input values such that
     * we alter the seed to the LFSR's used above,  then
     * generate the bits to play with.
     */
    for( i = 5 ; --i >= 0 ; )
    {
        pi_tmp1[i] = pi_scratch[5 + i] ^ pi_secret[i] ^ pi_crypt_tab2[i];
    }

    /*
     * We use two LFSR's (seeded from some of the input data bytes) to
     * generate two streams of pseudo-random bits.  These two bit streams
     * are then combined by simply adding with carry to generate a final
     * sequence of pseudo-random bits which is stored in the buffer that
     * 'output' points to the end of - len is the size of this buffer.
     *
     * The first LFSR is of degree 25,  and has a polynomial of:
     * x^13 + x^5 + x^4 + x^1 + 1
     *
     * The second LSFR is of degree 17,  and has a (primitive) polynomial of:
     * x^15 + x^1 + 1
     *
     * I don't know if these polynomials are primitive modulo 2,  and thus
     * represent maximal-period LFSR's.
     *
     *
     * Note that we take the output of each LFSR from the new shifted in
     * bit,  not the old shifted out bit.  Thus for ease of use the LFSR's
     * are implemented in bit reversed order.
     *
     */
    
    /* In order to ensure that the LFSR works we need to ensure that the
     * initial values are non-zero.  Thus when we initialise them from
     * the seed,  we ensure that a bit is set.
     */
    i_lfsr0 = ( pi_tmp1[0] << 17 ) | ( pi_tmp1[1] << 9 ) |
              (( pi_tmp1[2] & ~7 ) << 1 ) | 8 | ( pi_tmp1[2] & 7 );
    i_lfsr1 = ( pi_tmp1[3] << 9 ) | 0x100 | pi_tmp1[4];

    i_index = sizeof(pi_bits);
    i_carry = 0;

    do
    {
        for( i_bit = 0, i_val = 0 ; i_bit < 8 ; ++i_bit )
        {

            i_lfsr0_o = ( ( i_lfsr0 >> 24 ) ^ ( i_lfsr0 >> 21 ) ^
                        ( i_lfsr0 >> 20 ) ^ ( i_lfsr0 >> 12 ) ) & 1;
            i_lfsr0 = ( i_lfsr0 << 1 ) | i_lfsr0_o;
Stéphane Borel's avatar
 
Stéphane Borel committed
691

Sam Hocevar's avatar
 
Sam Hocevar committed
692 693 694 695 696 697 698
            i_lfsr1_o = ( ( i_lfsr1 >> 16 ) ^ ( i_lfsr1 >> 2 ) ) & 1;
            i_lfsr1 = ( i_lfsr1 << 1 ) | i_lfsr1_o;

            i_combined = !i_lfsr1_o + i_carry + !i_lfsr0_o;
            /* taking bit 1 */
            i_carry = ( i_combined >> 1 ) & 1;
            i_val |= ( i_combined & 1 ) << i_bit;
699
        }
Sam Hocevar's avatar
 
Sam Hocevar committed
700 701 702
    
        pi_bits[--i_index] = i_val;
    } while( i_index > 0 );
703

Sam Hocevar's avatar
 
Sam Hocevar committed
704 705 706 707 708
    /* This term is used throughout the following to
     * select one of 32 different variations on the
     * algorithm.
     */
    i_cse = pi_varients[i_css_varient] ^ pi_crypt_tab2[i_css_varient];
709

Sam Hocevar's avatar
 
Sam Hocevar committed
710 711 712 713 714 715
    /* Now the actual blocks doing the encryption.  Each
     * of these works on 40 bits at a time and are quite
     * similar.
     */
    i_index = 0;
    for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_scratch[i] )
Stéphane Borel's avatar
 
Stéphane Borel committed
716
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
717 718 719 720
        i_index = pi_bits[25 + i] ^ pi_scratch[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;

        pi_tmp1[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
Stéphane Borel's avatar
 
Stéphane Borel committed
721
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
722
    pi_tmp1[4] ^= pi_tmp1[0];
723

Sam Hocevar's avatar
 
Sam Hocevar committed
724
    for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
Stéphane Borel's avatar
 
Stéphane Borel committed
725
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
726 727 728 729
        i_index = pi_bits[20 + i] ^ pi_tmp1[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;

        pi_tmp2[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
Stéphane Borel's avatar
 
Stéphane Borel committed
730
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
731
    pi_tmp2[4] ^= pi_tmp2[0];
732

Sam Hocevar's avatar
 
Sam Hocevar committed
733
    for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp2[i] )
Stéphane Borel's avatar
 
Stéphane Borel committed
734
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
735 736 737 738 739
        i_index = pi_bits[15 + i] ^ pi_tmp2[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
        i_index = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;

        pi_tmp1[i] = pi_crypt_tab0[i_index] ^ pi_crypt_tab2[i_index];
Stéphane Borel's avatar
 
Stéphane Borel committed
740
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
741
    pi_tmp1[4] ^= pi_tmp1[0];
742

Sam Hocevar's avatar
 
Sam Hocevar committed
743
    for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
Stéphane Borel's avatar
 
Stéphane Borel committed
744
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
745 746
        i_index = pi_bits[10 + i] ^ pi_tmp1[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
747

Sam Hocevar's avatar
 
Sam Hocevar committed
748
        i_index = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
749

Sam Hocevar's avatar
 
Sam Hocevar committed
750
        pi_tmp2[i] = pi_crypt_tab0[i_index] ^ pi_crypt_tab2[i_index];
Stéphane Borel's avatar
 
Stéphane Borel committed
751
    }
Sam Hocevar's avatar
 
Sam Hocevar committed
752
    pi_tmp2[4] ^= pi_tmp2[0];
753

Sam Hocevar's avatar
 
Sam Hocevar committed
754
    for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp2[i] )
Stéphane Borel's avatar
 
Stéphane Borel committed
755
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
756 757
        i_index = pi_bits[5 + i] ^ pi_tmp2[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
758

Sam Hocevar's avatar
 
Sam Hocevar committed
759 760 761
        pi_tmp1[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
    }
    pi_tmp1[4] ^= pi_tmp1[0];
762

Sam Hocevar's avatar
 
Sam Hocevar committed
763 764 765 766
    for(i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
    {
        i_index = pi_bits[i] ^ pi_tmp1[i];
        i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
Stéphane Borel's avatar
 
Stéphane Borel committed
767

Sam Hocevar's avatar
 
Sam Hocevar committed
768 769
        pi_key[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
    }
770

Sam Hocevar's avatar
 
Sam Hocevar committed
771
    return;
772 773 774
}

/*****************************************************************************
Sam Hocevar's avatar
 
Sam Hocevar committed
775 776 777
 * CSSCracker : title key decryption by cracking
 *****************************************************************************
 * This function is called by CSSGetKeys to find a key
778
 *****************************************************************************/
Sam Hocevar's avatar
 
Sam Hocevar committed
779 780 781 782 783
static int CSSCracker( int i_start,
                       unsigned char * p_crypted,
                       unsigned char * p_decrypted,
                       dvd_key_t * p_sector_key,
                       dvd_key_t * p_key )
784
{
Sam Hocevar's avatar
 
Sam Hocevar committed
785 786 787 788 789 790
    unsigned char pi_buffer[10];
    unsigned int i_t1, i_t2, i_t3, i_t4, i_t5, i_t6;
    unsigned int i_try;
    unsigned int i_candidate;
    unsigned int i, j;
    int i_exit = -1;
791

Sam Hocevar's avatar
 
Sam Hocevar committed
792 793

    for( i = 0 ; i < 10 ; i++ )
794
    {
Sam Hocevar's avatar
 
Sam Hocevar committed
795 796 797 798 799 800 801 802
        pi_buffer[i] = pi_css_tab1[p_crypted[i]] ^ p_decrypted[i];
    }

    for( i_try = i_start ; i_try < 0x10000 ; i_try++ )
    {
        i_t1 = i_try >> 8 | 0x100;
        i_t2 = i_try & 0xff;
        i_t3 = 0;               /* not needed */
803 804
        i_t5 = 0;

Sam Hocevar's avatar
 
Sam Hocevar committed
805 806
        /* iterate cipher 4 times to reconstruct LFSR2 */
        for( i = 0 ; i < 4 ; i++ )
807
        {
Sam Hocevar's avatar
 
Sam Hocevar committed
808
            /* advance LFSR1 normaly */
809
            i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
Sam Hocevar's avatar
 
Sam Hocevar committed
810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837
            i_t2 = i_t1 >> 1;
            i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
            i_t4 = pi_css_tab5[i_t4];
            /* deduce i_t6 & i_t5 */
            i_t6 = pi_buffer[i];
            if( i_t5 )
            {
                i_t6 = ( i_t6 + 0xff ) & 0x0ff;
            }
            if( i_t6 < i_t4 )
            {
                i_t6 += 0x100;
            }
            i_t6 -= i_t4;
            i_t5 += i_t6 + i_t4;
            i_t6 = pi_css_tab4[ i_t6 ];
            /* feed / advance i_t3 / i_t5 */
            i_t3 = ( i_t3 << 8 ) | i_t6;
            i_t5 >>= 8;
        }

        i_candidate = i_t3;

        /* iterate 6 more times to validate candidate key */
        for( ; i < 10 ; i++ )
        {
            i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
            i_t2 = i_t1 >> 1;
838 839 840
            i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
            i_t4 = pi_css_tab5[i_t4];
            i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
Sam Hocevar's avatar
 
Sam Hocevar committed
841 842
                                         i_t3 ) >> 8 ) ^ i_t3 ) >> 5 ) & 0xff;
            i_t3 = ( i_t3 << 8 ) | i_t6;
843 844
            i_t6 = pi_css_tab4[i_t6];
            i_t5 += i_t6 + i_t4;
Sam Hocevar's avatar
 
Sam Hocevar committed
845 846 847 848 849
            if( ( i_t5 & 0xff ) != pi_buffer[i] )
            {
                break;
            }

850
            i_t5 >>= 8;
851
        }
Sam Hocevar's avatar
 
Sam Hocevar committed
852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898

        if( i == 10 )
        {
            /* Do 4 backwards steps of iterating t3 to deduce initial state */
            i_t3 = i_candidate;
            for( i = 0 ; i < 4 ; i++ )
            {
                i_t1 = i_t3 & 0xff;
                i_t3 = ( i_t3 >> 8 );
                /* easy to code, and fast enough bruteforce
                 * search for byte shifted in */
                for( j = 0 ; j < 256 ; j++ )
                {
                    i_t3 = ( i_t3 & 0x1ffff) | ( j << 17 );
                    i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
                                   i_t3 ) >> 8 ) ^ i_t3 ) >> 5 ) & 0xff;
                    if( i_t6 == i_t1 )
                    {
                        break;
                    }
                }
            }

            i_t4 = ( i_t3 >> 1 ) - 4;
            for( i_t5 = 0 ; i_t5 < 8; i_t5++ )
            {
                if( ( ( i_t4 + i_t5 ) * 2 + 8 - ( (i_t4 + i_t5 ) & 7 ) )
                                                                      == i_t3 )
                {
                    (*p_key)[0] = i_try>>8;
                    (*p_key)[1] = i_try & 0xFF;
                    (*p_key)[2] = ( ( i_t4 + i_t5 ) >> 0) & 0xFF;
                    (*p_key)[3] = ( ( i_t4 + i_t5 ) >> 8) & 0xFF;
                    (*p_key)[4] = ( ( i_t4 + i_t5 ) >> 16) & 0xFF;
                    i_exit = i_try + 1;
                }
            }
        }
    }

    if( i_exit >= 0 )
    {
        (*p_key)[0] ^= (*p_sector_key)[0];
        (*p_key)[1] ^= (*p_sector_key)[1];
        (*p_key)[2] ^= (*p_sector_key)[2];
        (*p_key)[3] ^= (*p_sector_key)[3];
        (*p_key)[4] ^= (*p_sector_key)[4];
899 900
    }

Sam Hocevar's avatar
 
Sam Hocevar committed
901
    return i_exit;
902
}
Sam Hocevar's avatar
 
Sam Hocevar committed
903

Sam Hocevar's avatar
 
Sam Hocevar committed
904
#endif /* HAVE_CSS */
Sam Hocevar's avatar
 
Sam Hocevar committed
905