ref: 37da9bcec4e98d7bbc29407e534ac4c857d4ddb4
dir: /common/mp4ff/drms.c/
/*****************************************************************************
* drms.c: DRMS
*****************************************************************************
* Copyright (C) 2004 VideoLAN
* $Id: drms.c,v 1.6 2004/04/12 18:17:41 menno Exp $
*
* Authors: Jon Lech Johansen <[email protected]>
* Sam Hocevar <[email protected]>
*
* 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.
*****************************************************************************/
#include <stdlib.h> /* malloc(), free() */
#ifndef _WIN32
#include "config.h"
#endif
#include "mp4ffint.h"
#ifdef ITUNES_DRM
#ifdef _WIN32
# include <io.h>
# include <stdio.h>
# include <sys/stat.h>
# define PATH_MAX MAX_PATH
#else
# include <stdio.h>
#endif
#ifdef HAVE_ERRNO_H
# include <errno.h>
#endif
#ifdef _WIN32
# include <tchar.h>
# include <shlobj.h>
# include <windows.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
/* In Solaris (and perhaps others) PATH_MAX is in limits.h. */
#ifdef HAVE_LIMITS_H
# include <limits.h>
#endif
#ifdef HAVE_IOKIT_IOKITLIB_H
# include <mach/mach.h>
# include <IOKit/IOKitLib.h>
# include <CoreFoundation/CFNumber.h>
#endif
#ifdef HAVE_SYSFS_LIBSYSFS_H
# include <sysfs/libsysfs.h>
#endif
#include "drms.h"
#include "drmstables.h"
/*****************************************************************************
* aes_s: AES keys structure
*****************************************************************************
* This structure stores a set of keys usable for encryption and decryption
* with the AES/Rijndael algorithm.
*****************************************************************************/
struct aes_s
{
uint32_t pp_enc_keys[ AES_KEY_COUNT + 1 ][ 4 ];
uint32_t pp_dec_keys[ AES_KEY_COUNT + 1 ][ 4 ];
};
/*****************************************************************************
* md5_s: MD5 message structure
*****************************************************************************
* This structure stores the static information needed to compute an MD5
* hash. It has an extra data buffer to allow non-aligned writes.
*****************************************************************************/
struct md5_s
{
uint64_t i_bits; /* Total written bits */
uint32_t p_digest[4]; /* The MD5 digest */
uint32_t p_data[16]; /* Buffer to cache non-aligned writes */
};
/*****************************************************************************
* shuffle_s: shuffle structure
*****************************************************************************
* This structure stores the static information needed to shuffle data using
* a custom algorithm.
*****************************************************************************/
struct shuffle_s
{
uint32_t p_commands[ 20 ];
uint32_t p_bordel[ 16 ];
};
/*****************************************************************************
* drms_s: DRMS structure
*****************************************************************************
* This structure stores the static information needed to decrypt DRMS data.
*****************************************************************************/
struct drms_s
{
uint32_t i_user;
uint32_t i_key;
uint8_t p_iviv[ 16 ];
uint8_t *p_name;
uint32_t p_key[ 4 ];
struct aes_s aes;
char psz_homedir[ PATH_MAX ];
};
/*****************************************************************************
* Local prototypes
*****************************************************************************/
static void InitAES ( struct aes_s *, uint32_t * );
static void DecryptAES ( struct aes_s *, uint32_t *, const uint32_t * );
static void InitMD5 ( struct md5_s * );
static void AddMD5 ( struct md5_s *, const uint8_t *, uint32_t );
static void EndMD5 ( struct md5_s * );
static void Digest ( struct md5_s *, uint32_t * );
static void InitShuffle ( struct shuffle_s *, uint32_t * );
static void DoShuffle ( struct shuffle_s *, uint32_t *, uint32_t );
static int GetSystemKey ( uint32_t *, uint32_t );
static int WriteUserKey ( void *, uint32_t * );
static int ReadUserKey ( void *, uint32_t * );
static int GetUserKey ( void *, uint32_t * );
static int GetSCIData ( char *, uint32_t **, uint32_t * );
static int HashSystemInfo ( uint32_t * );
static int GetiPodID ( int64_t * );
#ifdef WORDS_BIGENDIAN
/*****************************************************************************
* Reverse: reverse byte order
*****************************************************************************/
static __inline void Reverse( uint32_t *p_buffer, int n )
{
int i;
for( i = 0; i < n; i++ )
{
p_buffer[ i ] = GetDWLE(&p_buffer[ i ]);
}
}
# define REVERSE( p, n ) Reverse( p, n )
#else
# define REVERSE( p, n )
#endif
/*****************************************************************************
* BlockXOR: XOR two 128 bit blocks
*****************************************************************************/
static __inline void BlockXOR( uint32_t *p_dest, uint32_t *p_s1, uint32_t *p_s2 )
{
int i;
for( i = 0; i < 4; i++ )
{
p_dest[ i ] = p_s1[ i ] ^ p_s2[ i ];
}
}
/*****************************************************************************
* drms_alloc: allocate a DRMS structure
*****************************************************************************/
void *drms_alloc( char *psz_homedir )
{
struct drms_s *p_drms;
p_drms = malloc( sizeof(struct drms_s) );
if( p_drms == NULL )
{
return NULL;
}
memset( p_drms, 0, sizeof(struct drms_s) );
strncpy( p_drms->psz_homedir, psz_homedir, PATH_MAX );
p_drms->psz_homedir[ PATH_MAX - 1 ] = '\0';
return (void *)p_drms;
}
/*****************************************************************************
* drms_free: free a previously allocated DRMS structure
*****************************************************************************/
void drms_free( void *_p_drms )
{
struct drms_s *p_drms = (struct drms_s *)_p_drms;
if( p_drms->p_name != NULL )
{
free( (void *)p_drms->p_name );
}
free( p_drms );
}
/*****************************************************************************
* drms_decrypt: unscramble a chunk of data
*****************************************************************************/
void drms_decrypt( void *_p_drms, uint32_t *p_buffer, uint32_t i_bytes )
{
struct drms_s *p_drms = (struct drms_s *)_p_drms;
uint32_t p_key[ 4 ];
unsigned int i_blocks;
/* AES is a block cypher, round down the byte count */
i_blocks = i_bytes / 16;
i_bytes = i_blocks * 16;
/* Initialise the key */
memcpy( p_key, p_drms->p_key, 16 );
/* Unscramble */
while( i_blocks-- )
{
uint32_t p_tmp[ 4 ];
REVERSE( p_buffer, 4 );
DecryptAES( &p_drms->aes, p_tmp, p_buffer );
BlockXOR( p_tmp, p_key, p_tmp );
/* Use the previous scrambled data as the key for next block */
memcpy( p_key, p_buffer, 16 );
/* Copy unscrambled data back to the buffer */
memcpy( p_buffer, p_tmp, 16 );
REVERSE( p_buffer, 4 );
p_buffer += 4;
}
}
/*****************************************************************************
* drms_init: initialise a DRMS structure
*****************************************************************************/
int drms_init( void *_p_drms, uint32_t i_type,
uint8_t *p_info, uint32_t i_len )
{
struct drms_s *p_drms = (struct drms_s *)_p_drms;
int i_ret = 0;
switch( i_type )
{
case FOURCC_user:
if( i_len < sizeof(p_drms->i_user) )
{
i_ret = -1;
break;
}
p_drms->i_user = U32_AT( p_info );
break;
case FOURCC_key:
if( i_len < sizeof(p_drms->i_key) )
{
i_ret = -1;
break;
}
p_drms->i_key = U32_AT( p_info );
break;
case FOURCC_iviv:
if( i_len < sizeof(p_drms->p_key) )
{
i_ret = -1;
break;
}
memcpy( p_drms->p_iviv, p_info, 16 );
break;
case FOURCC_name:
p_drms->p_name = strdup( p_info );
if( p_drms->p_name == NULL )
{
i_ret = -1;
}
break;
case FOURCC_priv:
{
uint32_t p_priv[ 64 ];
struct md5_s md5;
if( i_len < 64 )
{
i_ret = -1;
break;
}
InitMD5( &md5 );
AddMD5( &md5, p_drms->p_name, strlen( p_drms->p_name ) );
AddMD5( &md5, p_drms->p_iviv, 16 );
EndMD5( &md5 );
if( GetUserKey( p_drms, p_drms->p_key ) )
{
i_ret = -1;
break;
}
InitAES( &p_drms->aes, p_drms->p_key );
memcpy( p_priv, p_info, 64 );
memcpy( p_drms->p_key, md5.p_digest, 16 );
drms_decrypt( p_drms, p_priv, 64 );
REVERSE( p_priv, 64 );
if( p_priv[ 0 ] != 0x6e757469 ) /* itun */
{
i_ret = -1;
break;
}
InitAES( &p_drms->aes, p_priv + 6 );
memcpy( p_drms->p_key, p_priv + 12, 16 );
free( (void *)p_drms->p_name );
p_drms->p_name = NULL;
}
break;
}
return i_ret;
}
/* The following functions are local */
/*****************************************************************************
* InitAES: initialise AES/Rijndael encryption/decryption tables
*****************************************************************************
* The Advanced Encryption Standard (AES) is described in RFC 3268
*****************************************************************************/
static void InitAES( struct aes_s *p_aes, uint32_t *p_key )
{
unsigned int i, t;
uint32_t i_key, i_seed;
memset( p_aes->pp_enc_keys[1], 0, 16 );
memcpy( p_aes->pp_enc_keys[0], p_key, 16 );
/* Generate the key tables */
i_seed = p_aes->pp_enc_keys[ 0 ][ 3 ];
for( i_key = 0; i_key < AES_KEY_COUNT; i_key++ )
{
uint32_t j;
i_seed = AES_ROR( i_seed, 8 );
j = p_aes_table[ i_key ];
j ^= p_aes_encrypt[ (i_seed >> 24) & 0xff ]
^ AES_ROR( p_aes_encrypt[ (i_seed >> 16) & 0xff ], 8 )
^ AES_ROR( p_aes_encrypt[ (i_seed >> 8) & 0xff ], 16 )
^ AES_ROR( p_aes_encrypt[ i_seed & 0xff ], 24 );
j ^= p_aes->pp_enc_keys[ i_key ][ 0 ];
p_aes->pp_enc_keys[ i_key + 1 ][ 0 ] = j;
j ^= p_aes->pp_enc_keys[ i_key ][ 1 ];
p_aes->pp_enc_keys[ i_key + 1 ][ 1 ] = j;
j ^= p_aes->pp_enc_keys[ i_key ][ 2 ];
p_aes->pp_enc_keys[ i_key + 1 ][ 2 ] = j;
j ^= p_aes->pp_enc_keys[ i_key ][ 3 ];
p_aes->pp_enc_keys[ i_key + 1 ][ 3 ] = j;
i_seed = j;
}
memcpy( p_aes->pp_dec_keys[ 0 ],
p_aes->pp_enc_keys[ 0 ], 16 );
for( i = 1; i < AES_KEY_COUNT; i++ )
{
for( t = 0; t < 4; t++ )
{
uint32_t j, k, l, m, n;
j = p_aes->pp_enc_keys[ i ][ t ];
k = (((j >> 7) & 0x01010101) * 27) ^ ((j & 0xff7f7f7f) << 1);
l = (((k >> 7) & 0x01010101) * 27) ^ ((k & 0xff7f7f7f) << 1);
m = (((l >> 7) & 0x01010101) * 27) ^ ((l & 0xff7f7f7f) << 1);
j ^= m;
n = AES_ROR( l ^ j, 16 ) ^ AES_ROR( k ^ j, 8 ) ^ AES_ROR( j, 24 );
p_aes->pp_dec_keys[ i ][ t ] = k ^ l ^ m ^ n;
}
}
}
/*****************************************************************************
* DecryptAES: decrypt an AES/Rijndael 128 bit block
*****************************************************************************/
static void DecryptAES( struct aes_s *p_aes,
uint32_t *p_dest, const uint32_t *p_src )
{
uint32_t p_wtxt[ 4 ]; /* Working cyphertext */
uint32_t p_tmp[ 4 ];
unsigned int i_round, t;
for( t = 0; t < 4; t++ )
{
/* FIXME: are there any endianness issues here? */
p_wtxt[ t ] = p_src[ t ] ^ p_aes->pp_enc_keys[ AES_KEY_COUNT ][ t ];
}
/* Rounds 0 - 8 */
for( i_round = 0; i_round < (AES_KEY_COUNT - 1); i_round++ )
{
for( t = 0; t < 4; t++ )
{
p_tmp[ t ] = AES_XOR_ROR( p_aes_itable, p_wtxt );
}
for( t = 0; t < 4; t++ )
{
p_wtxt[ t ] = p_tmp[ t ]
^ p_aes->pp_dec_keys[ (AES_KEY_COUNT - 1) - i_round ][ t ];
}
}
/* Final round (9) */
for( t = 0; t < 4; t++ )
{
p_dest[ t ] = AES_XOR_ROR( p_aes_decrypt, p_wtxt );
p_dest[ t ] ^= p_aes->pp_dec_keys[ 0 ][ t ];
}
}
/*****************************************************************************
* InitMD5: initialise an MD5 message
*****************************************************************************
* The MD5 message-digest algorithm is described in RFC 1321
*****************************************************************************/
static void InitMD5( struct md5_s *p_md5 )
{
p_md5->p_digest[ 0 ] = 0x67452301;
p_md5->p_digest[ 1 ] = 0xefcdab89;
p_md5->p_digest[ 2 ] = 0x98badcfe;
p_md5->p_digest[ 3 ] = 0x10325476;
memset( p_md5->p_data, 0, 64 );
p_md5->i_bits = 0;
}
/*****************************************************************************
* AddMD5: add i_len bytes to an MD5 message
*****************************************************************************/
static void AddMD5( struct md5_s *p_md5, const uint8_t *p_src, uint32_t i_len )
{
unsigned int i_current; /* Current bytes in the spare buffer */
unsigned int i_offset = 0;
i_current = (p_md5->i_bits / 8) & 63;
p_md5->i_bits += 8 * i_len;
/* If we can complete our spare buffer to 64 bytes, do it and add the
* resulting buffer to the MD5 message */
if( i_len >= (64 - i_current) )
{
memcpy( ((uint8_t *)p_md5->p_data) + i_current, p_src,
(64 - i_current) );
Digest( p_md5, p_md5->p_data );
i_offset += (64 - i_current);
i_len -= (64 - i_current);
i_current = 0;
}
/* Add as many entire 64 bytes blocks as we can to the MD5 message */
while( i_len >= 64 )
{
uint32_t p_tmp[ 16 ];
memcpy( p_tmp, p_src + i_offset, 64 );
Digest( p_md5, p_tmp );
i_offset += 64;
i_len -= 64;
}
/* Copy our remaining data to the message's spare buffer */
memcpy( ((uint8_t *)p_md5->p_data) + i_current, p_src + i_offset, i_len );
}
/*****************************************************************************
* EndMD5: finish an MD5 message
*****************************************************************************
* This function adds adequate padding to the end of the message, and appends
* the bit count so that we end at a block boundary.
*****************************************************************************/
static void EndMD5( struct md5_s *p_md5 )
{
unsigned int i_current;
i_current = (p_md5->i_bits / 8) & 63;
/* Append 0x80 to our buffer. No boundary check because the temporary
* buffer cannot be full, otherwise AddMD5 would have emptied it. */
((uint8_t *)p_md5->p_data)[ i_current++ ] = 0x80;
/* If less than 8 bytes are available at the end of the block, complete
* this 64 bytes block with zeros and add it to the message. We'll add
* our length at the end of the next block. */
if( i_current > 56 )
{
memset( ((uint8_t *)p_md5->p_data) + i_current, 0, (64 - i_current) );
Digest( p_md5, p_md5->p_data );
i_current = 0;
}
/* Fill the unused space in our last block with zeroes and put the
* message length at the end. */
memset( ((uint8_t *)p_md5->p_data) + i_current, 0, (56 - i_current) );
p_md5->p_data[ 14 ] = p_md5->i_bits & 0xffffffff;
p_md5->p_data[ 15 ] = (p_md5->i_bits >> 32);
REVERSE( &p_md5->p_data[ 14 ], 2 );
Digest( p_md5, p_md5->p_data );
}
#define F1( x, y, z ) ((z) ^ ((x) & ((y) ^ (z))))
#define F2( x, y, z ) F1((z), (x), (y))
#define F3( x, y, z ) ((x) ^ (y) ^ (z))
#define F4( x, y, z ) ((y) ^ ((x) | ~(z)))
#define MD5_DO( f, w, x, y, z, data, s ) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
/*****************************************************************************
* Digest: update the MD5 digest with 64 bytes of data
*****************************************************************************/
static void Digest( struct md5_s *p_md5, uint32_t *p_input )
{
uint32_t a, b, c, d;
REVERSE( p_input, 16 );
a = p_md5->p_digest[ 0 ];
b = p_md5->p_digest[ 1 ];
c = p_md5->p_digest[ 2 ];
d = p_md5->p_digest[ 3 ];
MD5_DO( F1, a, b, c, d, p_input[ 0 ] + 0xd76aa478, 7 );
MD5_DO( F1, d, a, b, c, p_input[ 1 ] + 0xe8c7b756, 12 );
MD5_DO( F1, c, d, a, b, p_input[ 2 ] + 0x242070db, 17 );
MD5_DO( F1, b, c, d, a, p_input[ 3 ] + 0xc1bdceee, 22 );
MD5_DO( F1, a, b, c, d, p_input[ 4 ] + 0xf57c0faf, 7 );
MD5_DO( F1, d, a, b, c, p_input[ 5 ] + 0x4787c62a, 12 );
MD5_DO( F1, c, d, a, b, p_input[ 6 ] + 0xa8304613, 17 );
MD5_DO( F1, b, c, d, a, p_input[ 7 ] + 0xfd469501, 22 );
MD5_DO( F1, a, b, c, d, p_input[ 8 ] + 0x698098d8, 7 );
MD5_DO( F1, d, a, b, c, p_input[ 9 ] + 0x8b44f7af, 12 );
MD5_DO( F1, c, d, a, b, p_input[ 10 ] + 0xffff5bb1, 17 );
MD5_DO( F1, b, c, d, a, p_input[ 11 ] + 0x895cd7be, 22 );
MD5_DO( F1, a, b, c, d, p_input[ 12 ] + 0x6b901122, 7 );
MD5_DO( F1, d, a, b, c, p_input[ 13 ] + 0xfd987193, 12 );
MD5_DO( F1, c, d, a, b, p_input[ 14 ] + 0xa679438e, 17 );
MD5_DO( F1, b, c, d, a, p_input[ 15 ] + 0x49b40821, 22 );
MD5_DO( F2, a, b, c, d, p_input[ 1 ] + 0xf61e2562, 5 );
MD5_DO( F2, d, a, b, c, p_input[ 6 ] + 0xc040b340, 9 );
MD5_DO( F2, c, d, a, b, p_input[ 11 ] + 0x265e5a51, 14 );
MD5_DO( F2, b, c, d, a, p_input[ 0 ] + 0xe9b6c7aa, 20 );
MD5_DO( F2, a, b, c, d, p_input[ 5 ] + 0xd62f105d, 5 );
MD5_DO( F2, d, a, b, c, p_input[ 10 ] + 0x02441453, 9 );
MD5_DO( F2, c, d, a, b, p_input[ 15 ] + 0xd8a1e681, 14 );
MD5_DO( F2, b, c, d, a, p_input[ 4 ] + 0xe7d3fbc8, 20 );
MD5_DO( F2, a, b, c, d, p_input[ 9 ] + 0x21e1cde6, 5 );
MD5_DO( F2, d, a, b, c, p_input[ 14 ] + 0xc33707d6, 9 );
MD5_DO( F2, c, d, a, b, p_input[ 3 ] + 0xf4d50d87, 14 );
MD5_DO( F2, b, c, d, a, p_input[ 8 ] + 0x455a14ed, 20 );
MD5_DO( F2, a, b, c, d, p_input[ 13 ] + 0xa9e3e905, 5 );
MD5_DO( F2, d, a, b, c, p_input[ 2 ] + 0xfcefa3f8, 9 );
MD5_DO( F2, c, d, a, b, p_input[ 7 ] + 0x676f02d9, 14 );
MD5_DO( F2, b, c, d, a, p_input[ 12 ] + 0x8d2a4c8a, 20 );
MD5_DO( F3, a, b, c, d, p_input[ 5 ] + 0xfffa3942, 4 );
MD5_DO( F3, d, a, b, c, p_input[ 8 ] + 0x8771f681, 11 );
MD5_DO( F3, c, d, a, b, p_input[ 11 ] + 0x6d9d6122, 16 );
MD5_DO( F3, b, c, d, a, p_input[ 14 ] + 0xfde5380c, 23 );
MD5_DO( F3, a, b, c, d, p_input[ 1 ] + 0xa4beea44, 4 );
MD5_DO( F3, d, a, b, c, p_input[ 4 ] + 0x4bdecfa9, 11 );
MD5_DO( F3, c, d, a, b, p_input[ 7 ] + 0xf6bb4b60, 16 );
MD5_DO( F3, b, c, d, a, p_input[ 10 ] + 0xbebfbc70, 23 );
MD5_DO( F3, a, b, c, d, p_input[ 13 ] + 0x289b7ec6, 4 );
MD5_DO( F3, d, a, b, c, p_input[ 0 ] + 0xeaa127fa, 11 );
MD5_DO( F3, c, d, a, b, p_input[ 3 ] + 0xd4ef3085, 16 );
MD5_DO( F3, b, c, d, a, p_input[ 6 ] + 0x04881d05, 23 );
MD5_DO( F3, a, b, c, d, p_input[ 9 ] + 0xd9d4d039, 4 );
MD5_DO( F3, d, a, b, c, p_input[ 12 ] + 0xe6db99e5, 11 );
MD5_DO( F3, c, d, a, b, p_input[ 15 ] + 0x1fa27cf8, 16 );
MD5_DO( F3, b, c, d, a, p_input[ 2 ] + 0xc4ac5665, 23 );
MD5_DO( F4, a, b, c, d, p_input[ 0 ] + 0xf4292244, 6 );
MD5_DO( F4, d, a, b, c, p_input[ 7 ] + 0x432aff97, 10 );
MD5_DO( F4, c, d, a, b, p_input[ 14 ] + 0xab9423a7, 15 );
MD5_DO( F4, b, c, d, a, p_input[ 5 ] + 0xfc93a039, 21 );
MD5_DO( F4, a, b, c, d, p_input[ 12 ] + 0x655b59c3, 6 );
MD5_DO( F4, d, a, b, c, p_input[ 3 ] + 0x8f0ccc92, 10 );
MD5_DO( F4, c, d, a, b, p_input[ 10 ] + 0xffeff47d, 15 );
MD5_DO( F4, b, c, d, a, p_input[ 1 ] + 0x85845dd1, 21 );
MD5_DO( F4, a, b, c, d, p_input[ 8 ] + 0x6fa87e4f, 6 );
MD5_DO( F4, d, a, b, c, p_input[ 15 ] + 0xfe2ce6e0, 10 );
MD5_DO( F4, c, d, a, b, p_input[ 6 ] + 0xa3014314, 15 );
MD5_DO( F4, b, c, d, a, p_input[ 13 ] + 0x4e0811a1, 21 );
MD5_DO( F4, a, b, c, d, p_input[ 4 ] + 0xf7537e82, 6 );
MD5_DO( F4, d, a, b, c, p_input[ 11 ] + 0xbd3af235, 10 );
MD5_DO( F4, c, d, a, b, p_input[ 2 ] + 0x2ad7d2bb, 15 );
MD5_DO( F4, b, c, d, a, p_input[ 9 ] + 0xeb86d391, 21 );
p_md5->p_digest[ 0 ] += a;
p_md5->p_digest[ 1 ] += b;
p_md5->p_digest[ 2 ] += c;
p_md5->p_digest[ 3 ] += d;
}
/*****************************************************************************
* InitShuffle: initialise a shuffle structure
*****************************************************************************
* This function initialises tables in the p_shuffle structure that will be
* used later by DoShuffle. The only external parameter is p_sys_key.
*****************************************************************************/
static void InitShuffle( struct shuffle_s *p_shuffle, uint32_t *p_sys_key )
{
char p_secret1[] = "Tv!*";
static char const p_secret2[] = "v8rhvsaAvOKMFfUH%798=[;."
"f8677680a634ba87fnOIf)(*";
unsigned int i;
/* Fill p_commands using the key and a secret seed */
for( i = 0; i < 20; i++ )
{
struct md5_s md5;
int32_t i_hash;
InitMD5( &md5 );
AddMD5( &md5, (uint8_t *)p_sys_key, 16 );
AddMD5( &md5, (uint8_t *)p_secret1, 4 );
EndMD5( &md5 );
p_secret1[ 3 ]++;
REVERSE( md5.p_digest, 1 );
i_hash = ((int32_t)U32_AT(md5.p_digest)) % 1024;
p_shuffle->p_commands[ i ] = i_hash < 0 ? i_hash * -1 : i_hash;
}
/* Fill p_bordel with completely meaningless initial values. */
for( i = 0; i < 4; i++ )
{
p_shuffle->p_bordel[ 4 * i ] = U32_AT(p_sys_key + i);
memcpy( p_shuffle->p_bordel + 4 * i + 1, p_secret2 + 12 * i, 12 );
REVERSE( p_shuffle->p_bordel + 4 * i + 1, 3 );
}
}
/*****************************************************************************
* DoShuffle: shuffle buffer
*****************************************************************************
* This is so ugly and uses so many MD5 checksums that it is most certainly
* one-way, though why it needs to be so complicated is beyond me.
*****************************************************************************/
static void DoShuffle( struct shuffle_s *p_shuffle,
uint32_t *p_buffer, uint32_t i_size )
{
struct md5_s md5;
uint32_t p_big_bordel[ 16 ];
uint32_t *p_bordel = p_shuffle->p_bordel;
unsigned int i;
/* Using the MD5 hash of a memory block is probably not one-way enough
* for the iTunes people. This function randomises p_bordel depending on
* the values in p_commands to make things even more messy in p_bordel. */
for( i = 0; i < 20; i++ )
{
uint8_t i_command, i_index;
if( !p_shuffle->p_commands[ i ] )
{
continue;
}
i_command = (p_shuffle->p_commands[ i ] & 0x300) >> 8;
i_index = p_shuffle->p_commands[ i ] & 0xff;
switch( i_command )
{
case 0x3:
p_bordel[ i_index & 0xf ] = p_bordel[ i_index >> 4 ]
+ p_bordel[ ((i_index + 0x10) >> 4) & 0xf ];
break;
case 0x2:
p_bordel[ i_index >> 4 ] ^= p_shuffle_xor[ 0xff - i_index ];
break;
case 0x1:
p_bordel[ i_index >> 4 ] -= p_shuffle_sub[ 0xff - i_index ];
break;
default:
p_bordel[ i_index >> 4 ] += p_shuffle_add[ 0xff - i_index ];
break;
}
}
/* Convert our newly randomised p_bordel to big endianness and take
* its MD5 hash. */
InitMD5( &md5 );
for( i = 0; i < 16; i++ )
{
p_big_bordel[ i ] = U32_AT(p_bordel + i);
}
AddMD5( &md5, (uint8_t *)p_big_bordel, 64 );
EndMD5( &md5 );
/* XOR our buffer with the computed checksum */
for( i = 0; i < i_size; i++ )
{
p_buffer[ i ] ^= md5.p_digest[ i ];
}
}
/*****************************************************************************
* GetSystemKey: get the system key
*****************************************************************************
* Compute the system key from various system information, see HashSystemInfo.
*****************************************************************************/
static int GetSystemKey( uint32_t *p_sys_key, uint32_t b_ipod )
{
static char const p_secret1[ 8 ] = "YuaFlafu";
static char const p_secret2[ 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, p_secret1, 8 );
if( !b_ipod )
{
AddMD5( &md5, (uint8_t *)p_system_hash, 6 );
AddMD5( &md5, (uint8_t *)p_system_hash, 6 );
AddMD5( &md5, (uint8_t *)p_system_hash, 6 );
AddMD5( &md5, p_secret2, 8 );
}
else
{
i_ipod_id = U64_AT(&i_ipod_id);
AddMD5( &md5, (uint8_t *)&i_ipod_id, sizeof(i_ipod_id) );
AddMD5( &md5, (uint8_t *)&i_ipod_id, sizeof(i_ipod_id) );
AddMD5( &md5, (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 ];
sprintf( 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
{
sprintf( psz_path, /*PATH_MAX - 1,*/ "%s/" DRMS_DIRNAME "/%08X.%03d",
p_drms->psz_homedir, p_drms->i_user, p_drms->i_key );
file = fopen( psz_path, "w" );
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 ];
sprintf( psz_path, /*PATH_MAX - 1,*/
"%s/" DRMS_DIRNAME "/%08X.%03d", p_drms->psz_homedir,
p_drms->i_user, p_drms->i_key );
file = fopen( psz_path, "r" );
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_secret[] = "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;
uint32_t i_user, i_key;
uint32_t p_sys_key[ 4 ];
uint32_t i_sci_size, i_blocks, i_remaining;
uint32_t *p_sci0, *p_sci1, *p_buffer;
uint32_t p_sci_key[ 4 ];
char *psz_ipod;
int i_ret = -1;
if( !ReadUserKey( p_drms, p_user_key ) )
{
REVERSE( p_user_key, 4 );
return 0;
}
psz_ipod = getenv( "IPOD" );
if( GetSystemKey( p_sys_key, psz_ipod ? 1 : 0 ) )
{
return -1;
}
if( GetSCIData( psz_ipod, &p_sci_data, &i_sci_size ) )
{
return -1;
}
/* 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 */
InitAES( &aes, p_sys_key );
REVERSE( p_sys_key, 4 );
InitShuffle( &shuffle, p_sys_key );
memcpy( p_sci_key, p_secret, 16 );
REVERSE( p_sci_key, 4 );
while( i_blocks-- )
{
uint32_t p_tmp[ 4 ];
REVERSE( p_buffer, 4 );
DecryptAES( &aes, p_tmp, p_buffer );
BlockXOR( p_tmp, p_sci_key, p_tmp );
/* Use the previous scrambled data as the key for next block */
memcpy( p_sci_key, p_buffer, 16 );
/* Shuffle the decrypted data using a custom routine */
DoShuffle( &shuffle, p_tmp, 4 );
/* Copy this block back to p_buffer */
memcpy( p_buffer, p_tmp, 16 );
p_buffer += 4;
}
if( i_remaining >= 4 )
{
i_remaining /= 4;
REVERSE( p_buffer, i_remaining );
DoShuffle( &shuffle, p_buffer, i_remaining );
}
/* Phase 2: look for the user key in the generated data. I must admit I
* do not understand what is going on here, because it almost
* looks like we are browsing data that makes sense, even though
* the DoShuffle() part made it completely meaningless. */
y = 0;
REVERSE( p_sci_data + 5, 1 );
i = U32_AT( p_sci_data + 5 );
i_sci_size -= 22 * sizeof(uint32_t);
p_sci1 = p_sci_data + 22;
p_sci0 = NULL;
while( i_sci_size >= 20 && i > 0 )
{
if( p_sci0 == NULL )
{
i_sci_size -= 18 * sizeof(uint32_t);
if( i_sci_size < 20 )
{
break;
}
p_sci0 = p_sci1;
REVERSE( p_sci1 + 17, 1 );
y = U32_AT( p_sci1 + 17 );
p_sci1 += 18;
}
if( !y )
{
i--;
p_sci0 = NULL;
continue;
}
i_user = U32_AT( p_sci0 );
i_key = U32_AT( p_sci1 );
REVERSE( &i_user, 1 );
REVERSE( &i_key, 1 );
if( i_user == p_drms->i_user && ( ( i_key == p_drms->i_key ) ||
( !p_drms->i_key && ( p_sci1 == (p_sci0 + 18) ) ) ) )
{
memcpy( p_user_key, p_sci1 + 1, 16 );
REVERSE( p_sci1 + 1, 4 );
WriteUserKey( p_drms, p_sci1 + 1 );
i_ret = 0;
break;
}
y--;
p_sci1 += 5;
i_sci_size -= 5 * sizeof(uint32_t);
}
free( p_sci_data );
return i_ret;
}
/*****************************************************************************
* GetSCIData: get SCI data from "SC Info.sidb"
*****************************************************************************
* Read SCI data from "\Apple Computer\iTunes\SC Info\SC Info.sidb"
*****************************************************************************/
static int GetSCIData( char *psz_ipod, uint32_t **pp_sci,
uint32_t *pi_sci_size )
{
FILE *file;
char *psz_path = NULL;
char p_tmp[ PATH_MAX ];
int i_ret = -1;
if( psz_ipod == NULL )
{
#ifdef _WIN32
char *p_filename = "\\Apple Computer\\iTunes\\SC Info\\SC Info.sidb";
typedef HRESULT (WINAPI *SHGETFOLDERPATH)( HWND, int, HANDLE, DWORD,
LPSTR );
HINSTANCE shfolder_dll = NULL;
SHGETFOLDERPATH dSHGetFolderPath = NULL;
if( ( shfolder_dll = LoadLibrary( _T("SHFolder.dll") ) ) != NULL )
{
dSHGetFolderPath =
(SHGETFOLDERPATH)GetProcAddress( shfolder_dll,
_T("SHGetFolderPathA") );
}
if( dSHGetFolderPath != NULL &&
SUCCEEDED( dSHGetFolderPath( NULL, /*CSIDL_COMMON_APPDATA*/ 0x0023,
NULL, 0, p_tmp ) ) )
{
strncat( p_tmp, p_filename, min( strlen( p_filename ),
(sizeof(p_tmp)/sizeof(p_tmp[0]) - 1) -
strlen( p_tmp ) ) );
psz_path = p_tmp;
}
if( shfolder_dll != NULL )
{
FreeLibrary( shfolder_dll );
}
#endif
}
else
{
#define ISCINFO "iSCInfo"
if( strstr( psz_ipod, ISCINFO ) == NULL )
{
sprintf( p_tmp, /*sizeof(p_tmp)/sizeof(p_tmp[0]) - 1,*/
"%s/iPod_Control/iTunes/" ISCINFO, psz_ipod );
psz_path = p_tmp;
}
else
{
psz_path = psz_ipod;
}
}
if( psz_path == NULL )
{
return -1;
}
file = fopen( psz_path, "r" );
if( file != NULL )
{
struct stat st;
if( !fstat( fileno( file ), &st ) )
{
*pp_sci = malloc( st.st_size );
if( *pp_sci != NULL )
{
if( fread( *pp_sci, 1, st.st_size,
file ) == (size_t)st.st_size )
{
*pi_sci_size = st.st_size;
i_ret = 0;
}
else
{
free( (void *)*pp_sci );
*pp_sci = NULL;
}
}
}
fclose( file );
}
return i_ret;
}
/*****************************************************************************
* HashSystemInfo: hash system information
*****************************************************************************
* This function computes the MD5 hash of the C: hard drive serial number,
* BIOS version, CPU type and Windows version.
*****************************************************************************/
static int HashSystemInfo( uint32_t *p_system_hash )
{
struct md5_s md5;
int i_ret = 0;
#ifdef _WIN32
HKEY i_key;
unsigned int i;
DWORD i_size;
DWORD i_serial;
LPBYTE p_reg_buf;
static LPCTSTR p_reg_keys[ 3 ][ 2 ] =
{
{
_T("HARDWARE\\DESCRIPTION\\System"),
_T("SystemBiosVersion")
},
{
_T("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0"),
_T("ProcessorNameString")
},
{
_T("SOFTWARE\\Microsoft\\Windows\\CurrentVersion"),
_T("ProductId")
}
};
InitMD5( &md5 );
AddMD5( &md5, "cache-control", 13 );
AddMD5( &md5, "Ethernet", 8 );
GetVolumeInformation( _T("C:\\"), NULL, 0, &i_serial,
NULL, NULL, NULL, 0 );
AddMD5( &md5, (uint8_t *)&i_serial, 4 );
for( i = 0; i < sizeof(p_reg_keys) / sizeof(p_reg_keys[ 0 ]); i++ )
{
if( RegOpenKeyEx( HKEY_LOCAL_MACHINE, p_reg_keys[ i ][ 0 ],
0, KEY_READ, &i_key ) != ERROR_SUCCESS )
{
continue;
}
if( RegQueryValueEx( i_key, p_reg_keys[ i ][ 1 ],
NULL, NULL, NULL, &i_size ) != ERROR_SUCCESS )
{
RegCloseKey( i_key );
continue;
}
p_reg_buf = malloc( i_size );
if( p_reg_buf != NULL )
{
if( RegQueryValueEx( i_key, p_reg_keys[ i ][ 1 ],
NULL, NULL, p_reg_buf,
&i_size ) == ERROR_SUCCESS )
{
AddMD5( &md5, (uint8_t *)p_reg_buf, i_size );
}
free( p_reg_buf );
}
RegCloseKey( i_key );
}
#else
InitMD5( &md5 );
i_ret = -1;
#endif
EndMD5( &md5 );
memcpy( p_system_hash, md5.p_digest, 16 );
return i_ret;
}
/*****************************************************************************
* GetiPodID: Get iPod ID
*****************************************************************************
* This function gets the iPod ID.
*****************************************************************************/
static int GetiPodID( int64_t *p_ipod_id )
{
int i_ret = -1;
#define PROD_NAME "iPod"
#define VENDOR_NAME "Apple Computer, Inc."
char *psz_ipod_id = getenv( "IPODID" );
if( psz_ipod_id != NULL )
{
#ifndef _WIN32
*p_ipod_id = strtoll( psz_ipod_id, NULL, 16 );
#else
*p_ipod_id = strtol( psz_ipod_id, NULL, 16 );
#endif
return 0;
}
#ifdef HAVE_IOKIT_IOKITLIB_H
CFTypeRef value;
mach_port_t port;
io_object_t device;
io_iterator_t iterator;
CFMutableDictionaryRef matching_dic;
if( IOMasterPort( MACH_PORT_NULL, &port ) == KERN_SUCCESS )
{
if( ( matching_dic = IOServiceMatching( "IOFireWireUnit" ) ) != NULL )
{
CFDictionarySetValue( matching_dic,
CFSTR("FireWire Vendor Name"),
CFSTR(VENDOR_NAME) );
CFDictionarySetValue( matching_dic,
CFSTR("FireWire Product Name"),
CFSTR(PROD_NAME) );
if( IOServiceGetMatchingServices( port, matching_dic,
&iterator ) == KERN_SUCCESS )
{
while( ( device = IOIteratorNext( iterator ) ) != NULL )
{
value = IORegistryEntryCreateCFProperty( device,
CFSTR("GUID"), kCFAllocatorDefault, kNilOptions );
if( value != NULL )
{
if( CFGetTypeID( value ) == CFNumberGetTypeID() )
{
int64_t i_ipod_id;
CFNumberGetValue( (CFNumberRef)value,
kCFNumberLongLongType,
&i_ipod_id );
*p_ipod_id = i_ipod_id;
i_ret = 0;
}
CFRelease( value );
}
IOObjectRelease( device );
if( !i_ret ) break;
}
IOObjectRelease( iterator );
}
}
mach_port_deallocate( mach_task_self(), port );
}
#elif HAVE_SYSFS_LIBSYSFS_H
struct sysfs_bus *bus = NULL;
struct dlist *devlist = NULL;
struct dlist *attributes = NULL;
struct sysfs_device *curdev = NULL;
struct sysfs_attribute *curattr = NULL;
bus = sysfs_open_bus( "ieee1394" );
if( bus != NULL )
{
devlist = sysfs_get_bus_devices( bus );
if( devlist != NULL )
{
dlist_for_each_data( devlist, curdev, struct sysfs_device )
{
attributes = sysfs_get_device_attributes( curdev );
if( attributes != NULL )
{
dlist_for_each_data( attributes, curattr,
struct sysfs_attribute )
{
if( ( strcmp( curattr->name, "model_name" ) == 0 ) &&
( strncmp( curattr->value, PROD_NAME,
sizeof(PROD_NAME) ) == 0 ) )
{
*p_ipod_id = strtoll( curdev->name, NULL, 16 );
i_ret = 0;
break;
}
}
}
if( !i_ret ) break;
}
}
sysfs_close_bus( bus );
}
#endif
return i_ret;
}
#endif