/*
| Copyright (C) 2007 Christophe Fergeau <teuf@gnome.org>
|
| The code in this file is heavily based on the proof-of-concept code
| written by wtbw
|
| Redistribution and use in source and binary forms, with or without
| modification, are permitted provided that the following conditions are met:
|
| 1. Redistributions of source code must retain the above copyright
| notice, this list of conditions and the following disclaimer.
| 2. Redistributions in binary form must reproduce the above copyright
| notice, this list of conditions and the following disclaimer in the
| documentation and/or other materials provided with the distribution.
| 3. The name of the author may not be used to endorse or promote
| products derived from this software without specific prior written
| permission.
|
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
| IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
| INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
| BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
| OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
| ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
| OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
| OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
| OF SUCH DAMAGE.
|
|
| iTunes and iPod are trademarks of Apple
|
| This product is not supported/written/published by Apple!
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <glib.h>
#include <string.h>
#include "itdb.h"
#include "db-itunes-parser.h"
#include "itdb_private.h"
static const unsigned char table1[256] = {
0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5,
0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC,
0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A,
0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B,
0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85,
0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17,
0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88,
0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9,
0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6,
0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94,
0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
};
static const unsigned char table2[256] = {
0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38,
0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87,
0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D,
0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2,
0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16,
0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA,
0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A,
0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02,
0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA,
0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85,
0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89,
0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20,
0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31,
0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D,
0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0,
0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26,
0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
};
static const unsigned char fixed[18] = {
0x67, 0x23, 0xFE, 0x30, 0x45, 0x33, 0xF8, 0x90, 0x99,
0x21, 0x07, 0xC1, 0xD0, 0x12, 0xB2, 0xA1, 0x07, 0x81
};
#ifndef HAVE_G_CHECKSUM_RESET
#define g_checksum_reset(checksum) \
G_STMT_START { \
g_checksum_free(checksum); \
(checksum) = g_checksum_new (G_CHECKSUM_SHA1); \
} G_STMT_END
#endif
static int gcd(int a, int b){
while (TRUE)
{
a = a % b;
if( a == 0 )
return b;
b = b % a;
if( b == 0 )
return a;
}
}
static int lcm(int a, int b)
{
if(a==0 || b==0)
return 1;
return (a*b)/gcd(a,b);
}
static unsigned char *generate_key (const unsigned char *firewire_id)
{
unsigned char *key;
unsigned char y[16];
GChecksum *checksum;
gsize checksum_len;
int i;
/* take LCM of each two bytes in the FWID in turn */
for (i=0; i<4; i++){
int a = firewire_id[i*2];
int b = firewire_id[i*2+1];
int cur_lcm = lcm(a,b);
unsigned char hi = (cur_lcm & 0xFF00) >> 8;
unsigned char lo = cur_lcm & 0xFF;
y[i*4 ] = table1[hi];
y[i*4 + 1] = table2[hi];
y[i*4 + 2] = table1[lo];
y[i*4 + 3] = table2[lo];
}
/* hash */
checksum = g_checksum_new (G_CHECKSUM_SHA1);
g_checksum_update (checksum, fixed, sizeof (fixed));
g_checksum_update (checksum, y, sizeof (y));
key = g_new0 (unsigned char, 64);
checksum_len = 64;
g_checksum_get_digest (checksum, key, &checksum_len);
g_checksum_free (checksum);
return key;
}
static unsigned char *itdb_compute_hash (const unsigned char *firewire_id,
const unsigned char *itdb,
unsigned long size,
gsize *len)
{
unsigned char *key;
unsigned char *hash;
GChecksum *checksum;
int i;
const gsize CHECKSUM_LEN = g_checksum_type_get_length (G_CHECKSUM_SHA1);
gsize digest_len;
key = generate_key(firewire_id);
if (key == NULL) {
return NULL;
}
/* hmac sha1 */
for (i=0; i < 64; i++)
{
key[i] ^= 0x36;
}
/* 20 bytes for the checksum, and 1 trailing \0 */
hash = g_new0 (unsigned char, CHECKSUM_LEN+1);
checksum = g_checksum_new (G_CHECKSUM_SHA1);
g_checksum_update (checksum, key, 64);
g_checksum_update (checksum, itdb, size);
digest_len = CHECKSUM_LEN;
g_checksum_get_digest (checksum, hash, &digest_len);
g_assert (digest_len == CHECKSUM_LEN);
for (i=0; i < 64; i++)
key[i] ^= 0x36 ^ 0x5c;
g_checksum_reset (checksum);
g_checksum_update (checksum, key, 64);
g_checksum_update (checksum, hash, digest_len);
g_checksum_get_digest (checksum, hash, &digest_len);
g_checksum_free (checksum);
g_assert (digest_len == CHECKSUM_LEN);
g_free (key);
if (len != NULL) {
*len = digest_len;
}
return hash;
}
gboolean itdb_hash58_write_hash (Itdb_Device *device,
unsigned char *itdb_data,
gsize itdb_len,
GError **error)
{
unsigned char firewire_id[20];
guchar backup18[8];
guchar backup32[20];
unsigned char *checksum;
gsize len;
MhbdHeader *header;
g_assert (itdb_device_get_checksum_type (device) == ITDB_CHECKSUM_HASH58);
if (!itdb_device_get_hex_uuid(device, firewire_id)) {
g_set_error (error, 0, -1, "Couldn't find the iPod firewire ID");
return FALSE;
}
if (itdb_len < 0x6c) {
g_set_error (error, 0, -1, "iTunesDB file too small to write checksum");
return FALSE;
}
header = (MhbdHeader *)itdb_data;
g_assert (strncmp (header->header_id, "mhbd", strlen ("mhbd")) == 0);
memcpy (backup18, &header->db_id, sizeof (backup18));
memcpy (backup32, &header->unk_0x32, sizeof (backup32));
/* Those fields must be zero'ed out for the sha1 calculation */
memset(&header->db_id, 0, sizeof (header->db_id));
memset(&header->unk_0x32, 0, sizeof (header->unk_0x32));
memset(&header->hash58, 0, sizeof (header->hash58));
header->hashing_scheme = GUINT16_FROM_LE (ITDB_CHECKSUM_HASH58);
checksum = itdb_compute_hash (firewire_id, itdb_data, itdb_len, &len);
if (checksum == NULL) {
g_set_error (error, 0, -1, "Failed to compute checksum");
return FALSE;
}
g_assert (len <= sizeof (header->hash58));
memcpy (&header->hash58, checksum, len);
g_free (checksum);
memcpy (&header->db_id, backup18, sizeof (backup18));
memcpy (&header->unk_0x32, backup32, sizeof (backup32));
return TRUE;
}