/***************************************************************************** * drms.c: DRMS ***************************************************************************** * Copyright (C) 2004 VideoLAN * $Id: drms.c,v 1.5 2004/01/16 18:26:57 sam Exp $ * * Authors: Jon Lech Johansen * Sam Hocevar * * 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 /* malloc(), free() */ #ifdef WIN32 # include #else # include #endif #include #ifdef HAVE_ERRNO_H # include #endif #ifdef WIN32 # include # include # include #endif #ifdef HAVE_SYS_STAT_H #include #endif #ifdef HAVE_SYS_TYPES_H #include #endif #include "drms.h" #include "drmstables.h" #include "libmp4.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 *, const uint32_t * ); static void InitShuffle ( struct shuffle_s *, uint32_t * ); static void DoShuffle ( struct shuffle_s *, uint8_t *, uint32_t ); static int GetSystemKey ( uint32_t * ); static int WriteUserKey ( void *, uint32_t * ); static int ReadUserKey ( void *, uint32_t * ); static int GetUserKey ( void *, uint32_t * ); static int GetSCIData ( uint32_t **, uint32_t * ); static int HashSystemInfo ( uint32_t * ); /***************************************************************************** * 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 ]; 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 ); 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 ); 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); 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<>(32-s), w += x ) /***************************************************************************** * Digest: update the MD5 digest with 64 bytes of data *****************************************************************************/ static void Digest( struct md5_s *p_md5, const uint32_t *p_input ) { uint32_t a, b, c, d; 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[] = "*!vT"; 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; /* Convert the secret to big endian */ uint32_t i_big_secret = U32_AT(p_secret1); int32_t i_hash; InitMD5( &md5 ); AddMD5( &md5, (uint8_t *)p_sys_key, 16 ); AddMD5( &md5, (uint8_t *)&i_big_secret, 4 ); EndMD5( &md5 ); p_secret1[ 0 ]++; 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 ); } } /***************************************************************************** * DoShuffle: shuffle i_len bytes of a 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, uint8_t *p_buffer, uint32_t i_len ) { 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 ); /* There are only 16 bytes in an MD5 hash */ if( i_len > 16 ) { i_len = 16; } /* XOR our buffer with the computed checksum */ for( i = 0; i < i_len; i++ ) { p_buffer[ i ] ^= ((uint8_t *)&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 ) { static char const p_secret1[ 8 ] = "YuaFlafu"; static char const p_secret2[ 8 ] = "zPif98ga"; struct md5_s md5; uint32_t p_system_hash[ 4 ]; /* Compute the MD5 hash of our system info */ if( HashSystemInfo( p_system_hash ) ) { 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 ); 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 ); 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 = 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 ]; snprintf( 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 p_sys_key[ 4 ]; uint32_t i_sci_size, i_blocks; uint32_t *p_sci0, *p_sci1, *p_buffer; uint32_t p_sci_key[ 4 ]; int i_ret = -1; if( !ReadUserKey( p_drms, p_user_key ) ) { return 0; } if( GetSystemKey( p_sys_key ) ) { return -1; } if( GetSCIData( &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; p_buffer = p_sci_data + 1; /* Decrypt and shuffle our data at the same time */ InitAES( &aes, p_sys_key ); InitShuffle( &shuffle, p_sys_key ); /* FIXME: check for endianness */ memcpy( p_sci_key, p_secret, 16 ); while( i_blocks-- ) { uint32_t p_tmp[ 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, (uint8_t *)p_tmp, 16 ); /* Copy this block back to p_buffer */ memcpy( p_buffer, p_tmp, 16 ); p_buffer += 4; } /* 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; 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; y = U32_AT( p_sci1 + 17 ); p_sci1 += 18; } if( !y ) { i--; p_sci0 = NULL; continue; } if( U32_AT( p_sci0 ) == p_drms->i_user && ( ( U32_AT( p_sci1 ) == p_drms->i_key ) || ( !p_drms->i_key ) || ( p_sci1 == (p_sci0 + 18) ) ) ) { memcpy( p_user_key, p_sci1 + 1, 16 ); WriteUserKey( p_drms, p_user_key ); 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( uint32_t **pp_sci, uint32_t *pi_sci_size ) { int i_ret = -1; #ifdef WIN32 HANDLE i_file; DWORD i_size, i_read; TCHAR p_path[ PATH_MAX ]; TCHAR *p_filename = _T("\\Apple Computer\\iTunes\\SC Info\\SC Info.sidb"); typedef HRESULT (WINAPI *SHGETFOLDERPATH)( HWND, int, HANDLE, DWORD, LPTSTR ); HINSTANCE shfolder_dll = NULL; SHGETFOLDERPATH dSHGetFolderPath = NULL; if( ( shfolder_dll = LoadLibrary( _T("SHFolder.dll") ) ) != NULL ) { dSHGetFolderPath = (SHGETFOLDERPATH)GetProcAddress( shfolder_dll, #ifdef _UNICODE _T("SHGetFolderPathW") ); #else _T("SHGetFolderPathA") ); #endif } if( dSHGetFolderPath != NULL && SUCCEEDED( dSHGetFolderPath( NULL, CSIDL_COMMON_APPDATA, NULL, 0, p_path ) ) ) { _tcsncat( p_path, p_filename, min( _tcslen( p_filename ), (PATH_MAX-1) - _tcslen( p_path ) ) ); i_file = CreateFile( p_path, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL ); if( i_file != INVALID_HANDLE_VALUE ) { i_size = GetFileSize( i_file, NULL ); if( i_size != INVALID_FILE_SIZE && i_size > (sizeof(uin32_t) * 22) ) { *pp_sci = malloc( i_size ); if( *pp_sci != NULL ) { if( ReadFile( i_file, *pp_sci, i_size, &i_read, NULL ) && i_read == i_size ) { *pi_sci_size = i_size; i_ret = 0; } else { free( (void *)*pp_sci ); *pp_sci = NULL; } } } CloseHandle( i_file ); } } if( shfolder_dll != NULL ) { FreeLibrary( shfolder_dll ); } #endif 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; InitMD5( &md5 ); #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") } }; 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 i_ret = -1; #endif EndMD5( &md5 ); memcpy( p_system_hash, md5.p_digest, 16 ); return i_ret; }