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-rw-r--r--libdvdcss/css.c1731
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diff --git a/libdvdcss/css.c b/libdvdcss/css.c
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-/*****************************************************************************
- * css.c: Functions for DVD authentication and descrambling
- *****************************************************************************
- * Copyright (C) 1999-2008 VideoLAN
- * $Id$
- *
- * Authors: Stéphane Borel <stef@via.ecp.fr>
- * Håkan Hjort <d95hjort@dtek.chalmers.se>
- *
- * based on:
- * - css-auth by Derek Fawcus <derek@spider.com>
- * - DVD CSS ioctls example program by Andrew T. Veliath <andrewtv@usa.net>
- * - The Divide and conquer attack by Frank A. Stevenson <frank@funcom.com>
- * (see http://www-2.cs.cmu.edu/~dst/DeCSS/FrankStevenson/index.html)
- * - DeCSSPlus by Ethan Hawke
- * - DecVOB
- * see http://www.lemuria.org/DeCSS/ by Tom Vogt for more information.
- *
- * This library 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 library 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 library; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- *****************************************************************************/
-
-/*****************************************************************************
- * Preamble
- *****************************************************************************/
-#include "config.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#ifdef HAVE_SYS_PARAM_H
-# include <sys/param.h>
-#endif
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#include <fcntl.h>
-
-#ifdef HAVE_LIMITS_H
-# include <limits.h>
-#endif
-
-#include "dvdcss/dvdcss.h"
-
-#include "common.h"
-#include "css.h"
-#include "libdvdcss.h"
-#include "csstables.h"
-#include "ioctl.h"
-#include "device.h"
-
-/*****************************************************************************
- * Local prototypes
- *****************************************************************************/
-static void PrintKey ( dvdcss_t, char *, uint8_t const * );
-
-static int GetBusKey ( dvdcss_t );
-static int GetASF ( dvdcss_t );
-
-static void CryptKey ( int, int, uint8_t const *, uint8_t * );
-static void DecryptKey ( uint8_t,
- uint8_t const *, uint8_t const *, uint8_t * );
-
-static int DecryptDiscKey ( dvdcss_t, uint8_t const *, dvd_key_t );
-static int CrackDiscKey ( dvdcss_t, uint8_t * );
-
-static void DecryptTitleKey ( dvd_key_t, dvd_key_t );
-static int RecoverTitleKey ( int, uint8_t const *,
- uint8_t const *, uint8_t const *, uint8_t * );
-static int CrackTitleKey ( dvdcss_t, int, int, dvd_key_t );
-
-static int AttackPattern ( uint8_t const[], int, uint8_t * );
-#if 0
-static int AttackPadding ( uint8_t const[], int, uint8_t * );
-#endif
-
-/*****************************************************************************
- * _dvdcss_test: check if the disc is encrypted or not
- *****************************************************************************
- * Sets b_scrambled, b_ioctls
- *****************************************************************************/
-void _dvdcss_test( dvdcss_t dvdcss )
-{
- char const *psz_type, *psz_rpc;
- int i_ret, i_copyright, i_type, i_mask, i_rpc;
-
- i_ret = ioctl_ReadCopyright( dvdcss->i_fd, 0 /* i_layer */, &i_copyright );
-
- if( i_ret < 0 )
- {
- /* Maybe we didn't have enough privileges to read the copyright
- * (see ioctl_ReadCopyright comments).
- * Apparently, on unencrypted DVDs _dvdcss_disckey() always fails, so
- * we can check this as a workaround. */
-#ifdef WIN32
- i_ret = 0;
-#else
- /* Since it's the first ioctl we try to issue, we add a notice */
- print_error( dvdcss, "css error: could not get \"copyright\""
- " information, make sure there is a DVD in the drive,"
- " and that you have used the correct device node." );
- /* Try without ioctls */
- dvdcss->b_ioctls = 0;
-#endif
- i_copyright = 1;
- if( _dvdcss_disckey( dvdcss ) < 0 )
- {
- i_copyright = 0;
- }
- }
-
- print_debug( dvdcss, "disc reports copyright information 0x%x",
- i_copyright );
- dvdcss->b_scrambled = i_copyright;
-
- i_ret = ioctl_ReportRPC( dvdcss->i_fd, &i_type, &i_mask, &i_rpc);
-
- if( i_ret < 0 )
- {
- print_error( dvdcss, "css error: could not get RPC status, region-free drive?" );
- return;
- }
-
- switch( i_rpc )
- {
- case 0: psz_rpc = "RPC-I"; break;
- case 1: psz_rpc = "RPC-II"; break;
- default: psz_rpc = "unknown RPC scheme"; break;
- }
-
- switch( i_type )
- {
- case 0: psz_type = "no region code set"; break;
- case 1: psz_type = "region code set"; break;
- case 2: psz_type = "one region change remaining"; break;
- case 3: psz_type = "region code set permanently"; break;
- default: psz_type = "unknown status"; break;
- }
-
- print_debug( dvdcss, "drive region mask 0x%x, %s, %s",
- i_mask, psz_rpc, psz_type );
-
- if( i_copyright && i_rpc == 1 && i_type == 0 )
- {
- print_error( dvdcss, "css error: drive will prevent access to "
- "scrambled data" );
- }
-}
-
-/*****************************************************************************
- * _dvdcss_title: crack or decrypt the current title key if needed
- *****************************************************************************
- * This function should only be called by dvdcss->pf_seek and should eventually
- * not be external if possible.
- *****************************************************************************/
-int _dvdcss_title ( dvdcss_t dvdcss, int i_block )
-{
- dvd_title_t *p_title;
- dvd_title_t *p_newtitle;
- dvd_key_t p_title_key;
- int i_fd, i_ret = -1, b_cache = 0;
-
- if( ! dvdcss->b_scrambled )
- {
- return 0;
- }
-
- /* Check if we've already cracked this key */
- p_title = dvdcss->p_titles;
- while( p_title != NULL
- && p_title->p_next != NULL
- && p_title->p_next->i_startlb <= i_block )
- {
- p_title = p_title->p_next;
- }
-
- if( p_title != NULL
- && p_title->i_startlb == i_block )
- {
- /* We've already cracked this key, nothing to do */
- memcpy( dvdcss->css.p_title_key, p_title->p_key, sizeof(dvd_key_t) );
- return 0;
- }
-
- /* Check whether the key is in our disk cache */
- if( dvdcss->psz_cachefile[0] )
- {
- /* XXX: be careful, we use sprintf and not snprintf */
- sprintf( dvdcss->psz_block, "%.10x", i_block );
- i_fd = open( dvdcss->psz_cachefile, O_RDONLY );
- b_cache = 1;
-
- if( i_fd >= 0 )
- {
- char psz_key[KEY_SIZE * 3];
- unsigned int k0, k1, k2, k3, k4;
-
- psz_key[KEY_SIZE * 3 - 1] = '\0';
-
- if( read( i_fd, psz_key, KEY_SIZE * 3 - 1 ) == KEY_SIZE * 3 - 1
- && sscanf( psz_key, "%x:%x:%x:%x:%x",
- &k0, &k1, &k2, &k3, &k4 ) == 5 )
- {
- p_title_key[0] = k0;
- p_title_key[1] = k1;
- p_title_key[2] = k2;
- p_title_key[3] = k3;
- p_title_key[4] = k4;
- PrintKey( dvdcss, "title key found in cache ", p_title_key );
-
- /* Don't try to save it again */
- b_cache = 0;
- i_ret = 1;
- }
-
- close( i_fd );
- }
- }
-
- /* Crack or decrypt CSS title key for current VTS */
- if( i_ret < 0 )
- {
- i_ret = _dvdcss_titlekey( dvdcss, i_block, p_title_key );
-
- if( i_ret < 0 )
- {
- print_error( dvdcss, "fatal error in vts css key" );
- return i_ret;
- }
-
- if( i_ret == 0 )
- {
- print_debug( dvdcss, "unencrypted title" );
- /* We cache this anyway, so we don't need to check again. */
- }
- }
-
- /* Key is valid, we store it on disk. */
- if( dvdcss->psz_cachefile[0] && b_cache )
- {
- i_fd = open( dvdcss->psz_cachefile, O_RDWR|O_CREAT, 0644 );
- if( i_fd >= 0 )
- {
- char psz_key[KEY_SIZE * 3 + 2];
-
- sprintf( psz_key, "%02x:%02x:%02x:%02x:%02x\r\n",
- p_title_key[0], p_title_key[1], p_title_key[2],
- p_title_key[3], p_title_key[4] );
-
- write( i_fd, psz_key, KEY_SIZE * 3 + 1 );
- close( i_fd );
- }
- }
-
- /* Find our spot in the list */
- p_newtitle = NULL;
- p_title = dvdcss->p_titles;
- while( ( p_title != NULL ) && ( p_title->i_startlb < i_block ) )
- {
- p_newtitle = p_title;
- p_title = p_title->p_next;
- }
-
- /* Save the found title */
- p_title = p_newtitle;
-
- /* Write in the new title and its key */
- p_newtitle = malloc( sizeof( dvd_title_t ) );
- p_newtitle->i_startlb = i_block;
- memcpy( p_newtitle->p_key, p_title_key, KEY_SIZE );
-
- /* Link it at the head of the (possibly empty) list */
- if( p_title == NULL )
- {
- p_newtitle->p_next = dvdcss->p_titles;
- dvdcss->p_titles = p_newtitle;
- }
- /* Link the new title inside the list */
- else
- {
- p_newtitle->p_next = p_title->p_next;
- p_title->p_next = p_newtitle;
- }
-
- memcpy( dvdcss->css.p_title_key, p_title_key, KEY_SIZE );
- return 0;
-}
-
-/*****************************************************************************
- * _dvdcss_disckey: get disc key.
- *****************************************************************************
- * This function should only be called if DVD ioctls are present.
- * It will set dvdcss->i_method = DVDCSS_METHOD_TITLE if it fails to find
- * a valid disc key.
- * Two decryption methods are offered:
- * -disc key hash crack,
- * -decryption with player keys if they are available.
- *****************************************************************************/
-int _dvdcss_disckey( dvdcss_t dvdcss )
-{
- unsigned char p_buffer[ DVD_DISCKEY_SIZE ];
- dvd_key_t p_disc_key;
- int i;
-
- if( GetBusKey( dvdcss ) < 0 )
- {
- return -1;
- }
-
- /* Get encrypted disc key */
- if( ioctl_ReadDiscKey( dvdcss->i_fd, &dvdcss->css.i_agid, p_buffer ) < 0 )
- {
- print_error( dvdcss, "ioctl ReadDiscKey failed" );
- return -1;
- }
-
- /* This should have invaidated the AGID and got us ASF=1. */
- if( GetASF( dvdcss ) != 1 )
- {
- /* Region mismatch (or region not set) is the most likely source. */
- print_error( dvdcss,
- "ASF not 1 after reading disc key (region mismatch?)" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* Shuffle disc key using bus key */
- for( i = 0 ; i < DVD_DISCKEY_SIZE ; i++ )
- {
- p_buffer[ i ] ^= dvdcss->css.p_bus_key[ 4 - (i % KEY_SIZE) ];
- }
-
- /* Decrypt disc key */
- switch( dvdcss->i_method )
- {
- case DVDCSS_METHOD_KEY:
-
- /* Decrypt disc key with player key. */
- PrintKey( dvdcss, "decrypting disc key ", p_buffer );
- if( ! DecryptDiscKey( dvdcss, p_buffer, p_disc_key ) )
- {
- PrintKey( dvdcss, "decrypted disc key is ", p_disc_key );
- break;
- }
- print_debug( dvdcss, "failed to decrypt the disc key, "
- "faulty drive/kernel? "
- "cracking title keys instead" );
-
- /* Fallback, but not to DISC as the disc key might be faulty */
- memset( p_disc_key, 0, KEY_SIZE );
- dvdcss->i_method = DVDCSS_METHOD_TITLE;
- break;
-
- case DVDCSS_METHOD_DISC:
-
- /* Crack Disc key to be able to use it */
- memcpy( p_disc_key, p_buffer, KEY_SIZE );
- PrintKey( dvdcss, "cracking disc key ", p_disc_key );
- if( ! CrackDiscKey( dvdcss, p_disc_key ) )
- {
- PrintKey( dvdcss, "cracked disc key is ", p_disc_key );
- break;
- }
- print_debug( dvdcss, "failed to crack the disc key" );
- memset( p_disc_key, 0, KEY_SIZE );
- dvdcss->i_method = DVDCSS_METHOD_TITLE;
- break;
-
- default:
-
- print_debug( dvdcss, "disc key needs not be decrypted" );
- memset( p_disc_key, 0, KEY_SIZE );
- break;
- }
-
- memcpy( dvdcss->css.p_disc_key, p_disc_key, KEY_SIZE );
-
- return 0;
-}
-
-
-/*****************************************************************************
- * _dvdcss_titlekey: get title key.
- *****************************************************************************/
-int _dvdcss_titlekey( dvdcss_t dvdcss, int i_pos, dvd_key_t p_title_key )
-{
- static uint8_t p_garbage[ DVDCSS_BLOCK_SIZE ]; /* we never read it back */
- uint8_t p_key[ KEY_SIZE ];
- int i, i_ret = 0;
-
- if( dvdcss->b_ioctls && ( dvdcss->i_method == DVDCSS_METHOD_KEY ||
- dvdcss->i_method == DVDCSS_METHOD_DISC ) )
- {
- /* We have a decrypted Disc key and the ioctls are available,
- * read the title key and decrypt it.
- */
-
- print_debug( dvdcss, "getting title key at block %i the classic way",
- i_pos );
-
- /* We need to authenticate again every time to get a new session key */
- if( GetBusKey( dvdcss ) < 0 )
- {
- i_ret = -1;
- }
-
- /* Get encrypted title key */
- if( ioctl_ReadTitleKey( dvdcss->i_fd, &dvdcss->css.i_agid,
- i_pos, p_key ) < 0 )
- {
- print_debug( dvdcss,
- "ioctl ReadTitleKey failed (region mismatch?)" );
- i_ret = -1;
- }
-
- /* Test ASF, it will be reset to 0 if we got a Region error */
- switch( GetASF( dvdcss ) )
- {
- case -1:
- /* An error getting the ASF status, something must be wrong. */
- print_debug( dvdcss, "lost ASF requesting title key" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- i_ret = -1;
- break;
-
- case 0:
- /* This might either be a title that has no key,
- * or we encountered a region error. */
- print_debug( dvdcss, "lost ASF requesting title key" );
- break;
-
- case 1:
- /* Drive status is ok. */
- /* If the title key request failed, but we did not loose ASF,
- * we might stil have the AGID. Other code assume that we
- * will not after this so invalidate it(?). */
- if( i_ret < 0 )
- {
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- }
- break;
- }
-
- if( !( i_ret < 0 ) )
- {
- /* Decrypt title key using the bus key */
- for( i = 0 ; i < KEY_SIZE ; i++ )
- {
- p_key[ i ] ^= dvdcss->css.p_bus_key[ 4 - (i % KEY_SIZE) ];
- }
-
- /* If p_key is all zero then there really wasn't any key present
- * even though we got to read it without an error. */
- if( !( p_key[0] | p_key[1] | p_key[2] | p_key[3] | p_key[4] ) )
- {
- i_ret = 0;
- }
- else
- {
- PrintKey( dvdcss, "initial disc key ", dvdcss->css.p_disc_key );
- DecryptTitleKey( dvdcss->css.p_disc_key, p_key );
- PrintKey( dvdcss, "decrypted title key ", p_key );
- i_ret = 1;
- }
-
- /* All went well either there wasn't a key or we have it now. */
- memcpy( p_title_key, p_key, KEY_SIZE );
- PrintKey( dvdcss, "title key is ", p_title_key );
-
- return i_ret;
- }
-
- /* The title key request failed */
- print_debug( dvdcss, "resetting drive and cracking title key" );
-
- /* Read an unscrambled sector and reset the drive */
- dvdcss->pf_seek( dvdcss, 0 );
- dvdcss->pf_read( dvdcss, p_garbage, 1 );
- dvdcss->pf_seek( dvdcss, 0 );
- _dvdcss_disckey( dvdcss );
-
- /* Fallback */
- }
-
- /* METHOD is TITLE, we can't use the ioctls or requesting the title key
- * failed above. For these cases we try to crack the key instead. */
-
- /* For now, the read limit is 9Gb / 2048 = 4718592 sectors. */
- i_ret = CrackTitleKey( dvdcss, i_pos, 4718592, p_key );
-
- memcpy( p_title_key, p_key, KEY_SIZE );
- PrintKey( dvdcss, "title key is ", p_title_key );
-
- return i_ret;
-}
-
-/*****************************************************************************
- * _dvdcss_unscramble: does the actual descrambling of data
- *****************************************************************************
- * sec : sector to unscramble
- * key : title key for this sector
- *****************************************************************************/
-int _dvdcss_unscramble( dvd_key_t p_key, uint8_t *p_sec )
-{
- unsigned int i_t1, i_t2, i_t3, i_t4, i_t5, i_t6;
- uint8_t *p_end = p_sec + DVDCSS_BLOCK_SIZE;
-
- /* PES_scrambling_control */
- if( !(p_sec[0x14] & 0x30) )
- {
- return 0;
- }
-
- i_t1 = (p_key[0] ^ p_sec[0x54]) | 0x100;
- i_t2 = p_key[1] ^ p_sec[0x55];
- i_t3 = (p_key[2] | (p_key[3] << 8) |
- (p_key[4] << 16)) ^ (p_sec[0x56] |
- (p_sec[0x57] << 8) | (p_sec[0x58] << 16));
- i_t4 = i_t3 & 7;
- i_t3 = i_t3 * 2 + 8 - i_t4;
- p_sec += 0x80;
- i_t5 = 0;
-
- while( p_sec != p_end )
- {
- i_t4 = p_css_tab2[i_t2] ^ p_css_tab3[i_t1];
- i_t2 = i_t1>>1;
- i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
- i_t4 = p_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 = p_css_tab4[i_t6];
- i_t5 += i_t6 + i_t4;
- *p_sec = p_css_tab1[*p_sec] ^ ( i_t5 & 0xff );
- p_sec++;
- i_t5 >>= 8;
- }
-
- return 0;
-}
-
-/* Following functions are local */
-
-/*****************************************************************************
- * GetBusKey : Go through the CSS Authentication process
- *****************************************************************************
- * It simulates the mutual authentication between logical unit and host,
- * and stops when a session key (called bus key) has been established.
- * Always do the full auth sequence. Some drives seem to lie and always
- * respond with ASF=1. For instance the old DVD roms on Compaq Armada says
- * that ASF=1 from the start and then later fail with a 'read of scrambled
- * block without authentication' error.
- *****************************************************************************/
-static int GetBusKey( dvdcss_t dvdcss )
-{
- uint8_t p_buffer[10];
- uint8_t p_challenge[2*KEY_SIZE];
- dvd_key_t p_key1;
- dvd_key_t p_key2;
- dvd_key_t p_key_check;
- uint8_t i_variant = 0;
- int i_ret = -1;
- int i;
-
- print_debug( dvdcss, "requesting AGID" );
- i_ret = ioctl_ReportAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
-
- /* We might have to reset hung authentication processes in the drive
- * by invalidating the corresponding AGID'. As long as we haven't got
- * an AGID, invalidate one (in sequence) and try again. */
- for( i = 0; i_ret == -1 && i < 4 ; ++i )
- {
- print_debug( dvdcss, "ioctl ReportAgid failed, "
- "invalidating AGID %d", i );
-
- /* This is really _not good_, should be handled by the OS.
- * Invalidating an AGID could make another process fail somewhere
- * in its authentication process. */
- dvdcss->css.i_agid = i;
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
-
- print_debug( dvdcss, "requesting AGID" );
- i_ret = ioctl_ReportAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- }
-
- /* Unable to authenticate without AGID */
- if( i_ret == -1 )
- {
- print_error( dvdcss, "ioctl ReportAgid failed, fatal" );
- return -1;
- }
-
- /* Setup a challenge, any values should work */
- for( i = 0 ; i < 10; ++i )
- {
- p_challenge[i] = i;
- }
-
- /* Get challenge from host */
- for( i = 0 ; i < 10 ; ++i )
- {
- p_buffer[9-i] = p_challenge[i];
- }
-
- /* Send challenge to LU */
- if( ioctl_SendChallenge( dvdcss->i_fd,
- &dvdcss->css.i_agid, p_buffer ) < 0 )
- {
- print_error( dvdcss, "ioctl SendChallenge failed" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* Get key1 from LU */
- if( ioctl_ReportKey1( dvdcss->i_fd, &dvdcss->css.i_agid, p_buffer ) < 0)
- {
- print_error( dvdcss, "ioctl ReportKey1 failed" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* Send key1 to host */
- for( i = 0 ; i < KEY_SIZE ; i++ )
- {
- p_key1[i] = p_buffer[4-i];
- }
-
- for( i = 0 ; i < 32 ; ++i )
- {
- CryptKey( 0, i, p_challenge, p_key_check );
-
- if( memcmp( p_key_check, p_key1, KEY_SIZE ) == 0 )
- {
- print_debug( dvdcss, "drive authenticated, using variant %d", i );
- i_variant = i;
- break;
- }
- }
-
- if( i == 32 )
- {
- print_error( dvdcss, "drive would not authenticate" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* Get challenge from LU */
- if( ioctl_ReportChallenge( dvdcss->i_fd,
- &dvdcss->css.i_agid, p_buffer ) < 0 )
- {
- print_error( dvdcss, "ioctl ReportKeyChallenge failed" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* Send challenge to host */
- for( i = 0 ; i < 10 ; ++i )
- {
- p_challenge[i] = p_buffer[9-i];
- }
-
- CryptKey( 1, i_variant, p_challenge, p_key2 );
-
- /* Get key2 from host */
- for( i = 0 ; i < KEY_SIZE ; ++i )
- {
- p_buffer[4-i] = p_key2[i];
- }
-
- /* Send key2 to LU */
- if( ioctl_SendKey2( dvdcss->i_fd, &dvdcss->css.i_agid, p_buffer ) < 0 )
- {
- print_error( dvdcss, "ioctl SendKey2 failed" );
- ioctl_InvalidateAgid( dvdcss->i_fd, &dvdcss->css.i_agid );
- return -1;
- }
-
- /* The drive has accepted us as authentic. */
- print_debug( dvdcss, "authentication established" );
-
- memcpy( p_challenge, p_key1, KEY_SIZE );
- memcpy( p_challenge + KEY_SIZE, p_key2, KEY_SIZE );
-
- CryptKey( 2, i_variant, p_challenge, dvdcss->css.p_bus_key );
-
- return 0;
-}
-
-/*****************************************************************************
- * PrintKey : debug function that dumps a key value
- *****************************************************************************/
-static void PrintKey( dvdcss_t dvdcss, char *prefix, uint8_t const *data )
-{
- print_debug( dvdcss, "%s%02x:%02x:%02x:%02x:%02x", prefix,
- data[0], data[1], data[2], data[3], data[4] );
-}
-
-/*****************************************************************************
- * GetASF : Get Authentication success flag
- *****************************************************************************
- * Returns :
- * -1 on ioctl error,
- * 0 if the device needs to be authenticated,
- * 1 either.
- *****************************************************************************/
-static int GetASF( dvdcss_t dvdcss )
-{
- int i_asf = 0;
-
- if( ioctl_ReportASF( dvdcss->i_fd, NULL, &i_asf ) != 0 )
- {
- /* The ioctl process has failed */
- print_error( dvdcss, "GetASF fatal error" );
- return -1;
- }
-
- if( i_asf )
- {
- print_debug( dvdcss, "GetASF authenticated, ASF=1" );
- }
- else
- {
- print_debug( dvdcss, "GetASF not authenticated, ASF=0" );
- }
-
- return i_asf;
-}
-
-/*****************************************************************************
- * CryptKey : shuffles bits and unencrypt keys.
- *****************************************************************************
- * Used during authentication and disc key negociation in GetBusKey.
- * i_key_type : 0->key1, 1->key2, 2->buskey.
- * i_variant : between 0 and 31.
- *****************************************************************************/
-static void CryptKey( int i_key_type, int i_variant,
- uint8_t const *p_challenge, uint8_t *p_key )
-{
- /* Permutation table for challenge */
- uint8_t pp_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 variant table for key2 and buskey */
- uint8_t pp_perm_variant[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 } };
-
- uint8_t p_variants[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 */
- uint8_t p_secret[5] = { 0x55, 0xD6, 0xC4, 0xC5, 0x28 };
-
- uint8_t p_bits[30], p_scratch[10], p_tmp1[5], p_tmp2[5];
- uint8_t i_lfsr0_o; /* 1 bit used */
- uint8_t i_lfsr1_o; /* 1 bit used */
- uint8_t i_css_variant, i_cse, i_index, i_combined, i_carry;
- uint8_t i_val = 0;
- uint32_t i_lfsr0, i_lfsr1;
- int i_term = 0;
- int i_bit;
- int i;
-
- for (i = 9; i >= 0; --i)
- p_scratch[i] = p_challenge[pp_perm_challenge[i_key_type][i]];
-
- i_css_variant = ( i_key_type == 0 ) ? i_variant :
- pp_perm_variant[i_key_type-1][i_variant];
-
- /*
- * This encryption engine implements one of 32 variations
- * one the same theme depending upon the choice in the
- * variant 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 ; )
- {
- p_tmp1[i] = p_scratch[5 + i] ^ p_secret[i] ^ p_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 = ( p_tmp1[0] << 17 ) | ( p_tmp1[1] << 9 ) |
- (( p_tmp1[2] & ~7 ) << 1 ) | 8 | ( p_tmp1[2] & 7 );
- i_lfsr1 = ( p_tmp1[3] << 9 ) | 0x100 | p_tmp1[4];
-
- i_index = sizeof(p_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;
-
- 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;
- }
-
- p_bits[--i_index] = i_val;
- } while( i_index > 0 );
-
- /* This term is used throughout the following to
- * select one of 32 different variations on the
- * algorithm.
- */
- i_cse = p_variants[i_css_variant] ^ p_crypt_tab2[i_css_variant];
-
- /* 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 = p_scratch[i] )
- {
- i_index = p_bits[25 + i] ^ p_scratch[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
-
- p_tmp1[i] = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
- }
- p_tmp1[4] ^= p_tmp1[0];
-
- for( i = 5, i_term = 0 ; --i >= 0 ; i_term = p_tmp1[i] )
- {
- i_index = p_bits[20 + i] ^ p_tmp1[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
-
- p_tmp2[i] = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
- }
- p_tmp2[4] ^= p_tmp2[0];
-
- for( i = 5, i_term = 0 ; --i >= 0 ; i_term = p_tmp2[i] )
- {
- i_index = p_bits[15 + i] ^ p_tmp2[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
- i_index = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
-
- p_tmp1[i] = p_crypt_tab0[i_index] ^ p_crypt_tab2[i_index];
- }
- p_tmp1[4] ^= p_tmp1[0];
-
- for( i = 5, i_term = 0 ; --i >= 0 ; i_term = p_tmp1[i] )
- {
- i_index = p_bits[10 + i] ^ p_tmp1[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
-
- i_index = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
-
- p_tmp2[i] = p_crypt_tab0[i_index] ^ p_crypt_tab2[i_index];
- }
- p_tmp2[4] ^= p_tmp2[0];
-
- for( i = 5, i_term = 0 ; --i >= 0 ; i_term = p_tmp2[i] )
- {
- i_index = p_bits[5 + i] ^ p_tmp2[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
-
- p_tmp1[i] = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
- }
- p_tmp1[4] ^= p_tmp1[0];
-
- for(i = 5, i_term = 0 ; --i >= 0 ; i_term = p_tmp1[i] )
- {
- i_index = p_bits[i] ^ p_tmp1[i];
- i_index = p_crypt_tab1[i_index] ^ ~p_crypt_tab2[i_index] ^ i_cse;
-
- p_key[i] = p_crypt_tab2[i_index] ^ p_crypt_tab3[i_index] ^ i_term;
- }
-
- return;
-}
-
-/*****************************************************************************
- * DecryptKey: decrypt p_crypted with p_key.
- *****************************************************************************
- * Used to decrypt the disc key, with a player key, after requesting it
- * in _dvdcss_disckey and to decrypt title keys, with a disc key, requested
- * in _dvdcss_titlekey.
- * The player keys and the resulting disc key are only used as KEKs
- * (key encryption keys).
- * Decryption is slightly dependant on the type of key:
- * -for disc key, invert is 0x00,
- * -for title key, invert if 0xff.
- *****************************************************************************/
-static void DecryptKey( uint8_t invert, uint8_t const *p_key,
- uint8_t const *p_crypted, uint8_t *p_result )
-{
- unsigned int i_lfsr1_lo;
- unsigned int i_lfsr1_hi;
- unsigned int i_lfsr0;
- unsigned int i_combined;
- uint8_t o_lfsr0;
- uint8_t o_lfsr1;
- uint8_t k[5];
- int i;
-
- i_lfsr1_lo = p_key[0] | 0x100;
- i_lfsr1_hi = p_key[1];
-
- i_lfsr0 = ( ( p_key[4] << 17 )
- | ( p_key[3] << 9 )
- | ( p_key[2] << 1 ) )
- + 8 - ( p_key[2] & 7 );
- i_lfsr0 = ( p_css_tab4[i_lfsr0 & 0xff] << 24 ) |
- ( p_css_tab4[( i_lfsr0 >> 8 ) & 0xff] << 16 ) |
- ( p_css_tab4[( i_lfsr0 >> 16 ) & 0xff] << 8 ) |
- p_css_tab4[( i_lfsr0 >> 24 ) & 0xff];
-
- i_combined = 0;
- for( i = 0 ; i < KEY_SIZE ; ++i )
- {
- o_lfsr1 = p_css_tab2[i_lfsr1_hi] ^ p_css_tab3[i_lfsr1_lo];
- i_lfsr1_hi = i_lfsr1_lo >> 1;
- i_lfsr1_lo = ( ( i_lfsr1_lo & 1 ) << 8 ) ^ o_lfsr1;
- o_lfsr1 = p_css_tab4[o_lfsr1];
-
- o_lfsr0 = ((((((( i_lfsr0 >> 8 ) ^ i_lfsr0 ) >> 1 )
- ^ i_lfsr0 ) >> 3 ) ^ i_lfsr0 ) >> 7 );
- i_lfsr0 = ( i_lfsr0 >> 8 ) | ( o_lfsr0 << 24 );
-
- i_combined += ( o_lfsr0 ^ invert ) + o_lfsr1;
- k[i] = i_combined & 0xff;
- i_combined >>= 8;
- }
-
- p_result[4] = k[4] ^ p_css_tab1[p_crypted[4]] ^ p_crypted[3];
- p_result[3] = k[3] ^ p_css_tab1[p_crypted[3]] ^ p_crypted[2];
- p_result[2] = k[2] ^ p_css_tab1[p_crypted[2]] ^ p_crypted[1];
- p_result[1] = k[1] ^ p_css_tab1[p_crypted[1]] ^ p_crypted[0];
- p_result[0] = k[0] ^ p_css_tab1[p_crypted[0]] ^ p_result[4];
-
- p_result[4] = k[4] ^ p_css_tab1[p_result[4]] ^ p_result[3];
- p_result[3] = k[3] ^ p_css_tab1[p_result[3]] ^ p_result[2];
- p_result[2] = k[2] ^ p_css_tab1[p_result[2]] ^ p_result[1];
- p_result[1] = k[1] ^