drms.c

uclinux 下的vlc播放器源代码

            p_bordel[ 1 ] += 0x20E;
            p_bordel[ 5 ] += 0x223D;
            p_bordel[ 13 ] -= 0x576;
            p_bordel[ 15 ] += 0x576;
            return;
        case 91:
            p_bordel[ 2 ] -= 0x64;
            p_bordel[ 3 ] += 0x64;
            p_bordel[ 12 ] -= 1;
            p_bordel[ 13 ] += 1;
            break;
        case 99:
            p_bordel[ 0 ] += 1;
            p_bordel[ j ] += p_bordel[ 13 ];
            break;
    }

    TinyShuffle8( p_bordel );
}

/*****************************************************************************
 * TinyShuffle[12345678]: tiny shuffle subroutines
 *****************************************************************************
 * These standalone functions are little helpers for the shuffling process.
 *****************************************************************************/
static void TinyShuffle1( uint32_t * p_bordel )
{
    uint32_t i_cmd = (p_bordel[ 5 ] + 10) >> 2;

    if( p_bordel[ 5 ] > 0x7D0 )
    {
        i_cmd -= 0x305;
    }

    switch( i_cmd & 3 )
    {
        case 0:
            p_bordel[ 5 ] += 5;
            break;
        case 1:
            p_bordel[ 4 ] -= 1;
            break;
        case 2:
            if( p_bordel[ 4 ] & 5 )
            {
                p_bordel[ 1 ] ^= 0x4D;
            }
            /* no break */
        case 3:
            p_bordel[ 12 ] += 5;
            break;
    }
}

static void TinyShuffle2( uint32_t * p_bordel )
{
    uint32_t i, j;

    for( i = 0, j = 0; i < 16; i++ )
    {
        if( (p_bordel[ i ] & 0x777) > (p_bordel[ j ] & 0x777) )
        {
            j = i;
        }
    }

    if( j > 5 )
    {
        for( ; j < 15; j++ )
        {
            p_bordel[ j ] += p_bordel[ j + 1 ];
        }
    }
    else
    {
        p_bordel[ 2 ] &= 0xB62FC;
    }
}

static void TinyShuffle3( uint32_t * p_bordel )
{
    uint32_t i_cmd = p_bordel[ 6 ] + 0x194B;

    if( p_bordel[ 6 ] > 0x2710 )
    {
        i_cmd >>= 1;
    }

    switch( i_cmd & 3 )
    {
        case 1:
            p_bordel[ 3 ] += 0x19FE;
            break;
        case 2:
            p_bordel[ 7 ] -= p_bordel[ 3 ] >> 2;
            /* no break */
        case 0:
            p_bordel[ 5 ] ^= 0x248A;
            break;
    }
}

static void TinyShuffle4( uint32_t * p_bordel )
{
    uint32_t i, j;

    for( i = 0, j = 0; i < 16; i++ )
    {
        if( p_bordel[ i ] < p_bordel[ j ] )
        {
            j = i;
        }
    }

    if( (p_bordel[ j ] % (j + 1)) > 10 )
    {
        p_bordel[ 1 ] -= 1;
        p_bordel[ 2 ] += 0x13;
        p_bordel[ 12 ] += 1;
    }
}

static void TinyShuffle5( uint32_t * p_bordel )
{
    uint32_t i;

    p_bordel[ 2 ] &= 0x7F3F;

    for( i = 0; i < 5; i++ )
    {
        switch( ( p_bordel[ 2 ] + 10 + i ) % 5 )
        {
            case 0:
                p_bordel[ 12 ] &= p_bordel[ 2 ];
                /* no break */
            case 1:
                p_bordel[ 3 ] ^= p_bordel[ 15 ];
                break;
            case 2:
                p_bordel[ 15 ] += 0x576;
                /* no break */
            case 3:
                p_bordel[ 7 ] -= 0x2D;
                /* no break */
            case 4:
                p_bordel[ 1 ] <<= 1;
                break;
        }
    }
}

static void TinyShuffle6( uint32_t * p_bordel )
{
    uint32_t i, j;

    for( i = 0; i < 8; i++ )
    {
        j = p_bordel[ 3 ] & 0x7514 ? 5 : 7;
        SWAP( p_bordel[ i ], p_bordel[ i + j ] );
    }
}

static void TinyShuffle7( uint32_t * p_bordel )
{
    uint32_t i;

    i = (((p_bordel[ 9 ] + p_bordel[ 15 ] + 12) >> 2) - p_bordel[ 4 ]) & 7;

    while( i-- )
    {
        SWAP( p_bordel[ i ], p_bordel[ i + 3 ] );
    }

    SWAP( p_bordel[ 1 ], p_bordel[ 10 ] );
}

static void TinyShuffle8( uint32_t * p_bordel )
{
    uint32_t i;

    i = (p_bordel[ 0 ] & p_bordel[ 6 ]) & 0xF;

    switch( p_bordel[ i ] % 1000 )
    {
        case 7:
            if( (p_bordel[ i ] & 0x777) > (p_bordel[ 7 ] & 0x5555) )
            {
                p_bordel[ i ] ^= p_bordel[ 5 ] & p_bordel[ 3 ];
            }
            break;
        case 19:
            p_bordel[ 15 ] &= 0x5555;
            break;
        case 93:
            p_bordel[ i ] ^= p_bordel[ 15 ];
            break;
        case 100:
            SWAP( p_bordel[ 0 ], p_bordel[ 3 ] );
            SWAP( p_bordel[ 1 ], p_bordel[ 6 ] );
            SWAP( p_bordel[ 3 ], p_bordel[ 6 ] );
            SWAP( p_bordel[ 4 ], p_bordel[ 9 ] );
            SWAP( p_bordel[ 5 ], p_bordel[ 8 ] );
            SWAP( p_bordel[ 6 ], p_bordel[ 7 ] );
            SWAP( p_bordel[ 13 ], p_bordel[ 14 ] );
            break;
        case 329:
            p_bordel[ i ] += p_bordel[ 1 ] ^ 0x80080011;
            p_bordel[ i ] += p_bordel[ 2 ] ^ 0xBEEFDEAD;
            p_bordel[ i ] += p_bordel[ 3 ] ^ 0x8765F444;
            p_bordel[ i ] += p_bordel[ 4 ] ^ 0x78145326;
            break;
        case 567:
            p_bordel[ 12 ] -= p_bordel[ i ];
            p_bordel[ 13 ] += p_bordel[ i ];
            break;
        case 612:
            p_bordel[ i ] += p_bordel[ 1 ];
            p_bordel[ i ] -= p_bordel[ 7 ];
            p_bordel[ i ] -= p_bordel[ 8 ];
            p_bordel[ i ] += p_bordel[ 9 ];
            p_bordel[ i ] += p_bordel[ 13 ];
            break;
        case 754:
            i = __MIN( i, 12 );
            p_bordel[ i + 1 ] >>= 1;
            p_bordel[ i + 2 ] <<= 4;
            p_bordel[ i + 3 ] >>= 3;
            break;
        case 777:
            p_bordel[ 1 ] += 0x20E;
            p_bordel[ 5 ] += 0x223D;
            p_bordel[ 13 ] -= 0x576;
            p_bordel[ 15 ] += 0x576;
            break;
        case 981:
            if( (p_bordel[ i ] ^ 0x8765F441) < 0x2710 )
            {
                SWAP( p_bordel[ 0 ], p_bordel[ 1 ] );
            }
            else
            {
                SWAP( p_bordel[ 1 ], p_bordel[ 11 ] );
            }
            break;
    }
}

/*****************************************************************************
 * GetSystemKey: get the system key
 *****************************************************************************
 * Compute the system key from various system information, see HashSystemInfo.
 *****************************************************************************/
static int GetSystemKey( uint32_t *p_sys_key, vlc_bool_t b_ipod )
{
    static char const p_secret5[ 8 ] = "YuaFlafu";
    static char const p_secret6[ 8 ] = "zPif98ga";
    struct md5_s md5;
    int64_t i_ipod_id;
    uint32_t p_system_hash[ 4 ];

    /* Compute the MD5 hash of our system info */
    if( ( !b_ipod && HashSystemInfo( p_system_hash ) ) ||
        (  b_ipod && GetiPodID( &i_ipod_id ) ) )
    {
        return -1;
    }

    /* Combine our system info hash with additional secret data. The resulting
     * MD5 hash will be our system key. */
    InitMD5( &md5 );
    AddMD5( &md5, (const uint8_t*)p_secret5, 8 );

    if( !b_ipod )
    {
        AddMD5( &md5, (const uint8_t *)p_system_hash, 6 );
        AddMD5( &md5, (const uint8_t *)p_system_hash, 6 );
        AddMD5( &md5, (const uint8_t *)p_system_hash, 6 );
        AddMD5( &md5, (const uint8_t*)p_secret6, 8 );
    }
    else
    {
        i_ipod_id = U64_AT(&i_ipod_id);
        AddMD5( &md5, (const uint8_t *)&i_ipod_id, sizeof(i_ipod_id) );
        AddMD5( &md5, (const uint8_t *)&i_ipod_id, sizeof(i_ipod_id) );
        AddMD5( &md5, (const uint8_t *)&i_ipod_id, sizeof(i_ipod_id) );
    }

    EndMD5( &md5 );

    memcpy( p_sys_key, md5.p_digest, 16 );

    return 0;
}

#ifdef WIN32
#   define DRMS_DIRNAME "drms"
#else
#   define DRMS_DIRNAME ".drms"
#endif

/*****************************************************************************
 * WriteUserKey: write the user key to hard disk
 *****************************************************************************
 * Write the user key to the hard disk so that it can be reused later or used
 * on operating systems other than Win32.
 *****************************************************************************/
static int WriteUserKey( void *_p_drms, uint32_t *p_user_key )
{
    struct drms_s *p_drms = (struct drms_s *)_p_drms;
    FILE *file;
    int i_ret = -1;
    char psz_path[ PATH_MAX ];

    snprintf( psz_path, PATH_MAX - 1,
              "%s/" DRMS_DIRNAME, p_drms->psz_homedir );

#if defined( HAVE_ERRNO_H )
#   if defined( WIN32 )
    if( !mkdir( psz_path ) || errno == EEXIST )
#   else
    if( !mkdir( psz_path, 0755 ) || errno == EEXIST )
#   endif
#else
    if( !mkdir( psz_path ) )
#endif
    {
        snprintf( psz_path, PATH_MAX - 1, "%s/" DRMS_DIRNAME "/%08X.%03d",
                  p_drms->psz_homedir, p_drms->i_user, p_drms->i_key );

        file = utf8_fopen( psz_path, "wb" );
        if( file != NULL )
        {
            i_ret = fwrite( p_user_key, sizeof(uint32_t),
                            4, file ) == 4 ? 0 : -1;
            fclose( file );
        }
    }

    return i_ret;
}

/*****************************************************************************
 * ReadUserKey: read the user key from hard disk
 *****************************************************************************
 * Retrieve the user key from the hard disk if available.
 *****************************************************************************/
static int ReadUserKey( void *_p_drms, uint32_t *p_user_key )
{
    struct drms_s *p_drms = (struct drms_s *)_p_drms;
    FILE *file;
    int i_ret = -1;
    char psz_path[ PATH_MAX ];

    snprintf( psz_path, PATH_MAX - 1,
              "%s/" DRMS_DIRNAME "/%08X.%03d", p_drms->psz_homedir,
              p_drms->i_user, p_drms->i_key );

    file = utf8_fopen( psz_path, "rb" );
    if( file != NULL )
    {
        i_ret = fread( p_user_key, sizeof(uint32_t),
                       4, file ) == 4 ? 0 : -1;
        fclose( file );
    }

    return i_ret;
}

/*****************************************************************************
 * GetUserKey: get the user key
 *****************************************************************************
 * Retrieve the user key from the hard disk if available, otherwise generate
 * it from the system key. If the key could be successfully generated, write
 * it to the hard disk for future use.
 *****************************************************************************/
static int GetUserKey( void *_p_drms, uint32_t *p_user_key )
{
    static char const p_secret7[] = "mUfnpognadfgf873";
    struct drms_s *p_drms = (struct drms_s *)_p_drms;
    struct aes_s aes;
    struct shuffle_s shuffle;
    uint32_t i, y;
    uint32_t *p_sci_data = NULL;
    uint32_t i_user, i_key;
    uint32_t p_sys_key[ 4 ];
    uint32_t i_sci_size = 0, i_blocks, i_remaining;
    uint32_t *p_sci0, *p_sci1, *p_buffer;
    uint32_t p_sci_key[ 4 ];
    char *psz_ipod;
    int i_ret = -5;

    if( ReadUserKey( p_drms, p_user_key ) == 0 )
    {
        REVERSE( p_user_key, 4 );
        return 0;
    }

    psz_ipod = getenv( "IPOD" );

    if( GetSystemKey( p_sys_key, psz_ipod ? VLC_TRUE : VLC_FALSE ) )
    {
        return -3;
    }

    if( GetSCIData( psz_ipod, &p_sci_data, &i_sci_size ) )
    {
        return -4;
    }

    /* Phase 1: unscramble the SCI data using the system key and shuffle
     *          it using DoShuffle(). */

    /* Skip the first 4 bytes (some sort of header). Decrypt the rest. */
    i_blocks = (i_sci_size - 4) / 16;
    i_remaining = (i_sci_size - 4) - (i_blocks * 16);
    p_buffer = p_sci_data + 1;

    /* Decrypt and shuffle our data at the same time */