XDVDFS
XDVDFS (Also known as XISO) is the image format used for Xbox Game Discs. It is stored in the data area.
Format
Each sector is 2048 bytes.
Filesystem
[FIXME]
Volume descriptor
32 sectors which are zero-filled. The Volume descriptor is 4096 bytes, but split into 2x 2048 sections.
- Section 1: The first data is the magic at sector 32. It is always "MICROSOFT*XBOX*MEDIA". [FIXME]
- Section 2: The first data is the magic at sector 32. It is always "MICROSOFT*XBOX*MEDIA". [FIXME]
Examples
[FIXME] [FIXME] [FIXME]
Wave 1
Developers used xblayout to create DVD layout. Then generated the final image using xbpremaster. The final image was submitted to Microsoft.
- Azurik - Rise of Perathia (NTSC)
- xblayout version: 1.0.3926.1
- xbpremaster version: 1.0.3926.1
- Genma Onimusha (PAL)
- xblayout version: 1.0.4039.1
- xbpremaster version: 1.0.4039.2
- Max Payne (PAL)
- xblayout version: 1.0.4134.1
- xbpremaster version: 1.0.4242.1
- Petit Copter (Japanese)
- xblayout version: 1.0.4361.1
- xbpremaster version: 1.0.4361.2
- 007 - Agent Under Fire (PAL)
- xblayout version: 1.0.4432.1
- xbpremaster version: 1.0.4432.1
Wave 2
[FIXME]. Developers used a new version of xblayout and submitted the layout + content to Microsoft Microsoft generated the final image.
- Metal Gear Solid 2 - Substance (NTSC)
- xblayout version: 1.0.4721.1
- Battle Engine Aquila (PAL)
- xblayout version: 1.0.4831.1
Wave 3
[FIXME]. Same as wave 2, but Microsoft upgraded their tool to use new random padding.
- Metal Gear Solid 2 - Substance (PAL)
- xblayout version: 1.0.5120.1
- Shenmue II (PAL)
- xblayout version: 1.0.5120.1
Wave 4
[FIXME]. Same as wave 3, but developers now had to use the xbgamedisc tool instead of xblayout. The mastering tool used by microsoft also leaves a version identifier now.
- Star Wars - Knights of the Old Republic (PAL)
- xbgamedisc version: 2.1.0.5233.1
- mastering tool version: 2.1.0.5233.1
- Indiana Jones and the Emperor's Tomb (PAL)
- xbgamedisc version: 2.1.0.5233.1
- mastering tool version: 2.1.0.5233.1
- Dynasty Warriors 4 (PAL)
- xbgamedisc version: 2.1.0.5344.1
- mastering tool version: 2.1.0.5344.1
- The Matrix - Path of Neo (PAL)
- xbgamedisc version: 2.1.0.5849.1
- mastering tool version: 2.1.0.5849.1
- The Suffering - Ties That Bind
- xbgamedisc version: 2.1.0.5849.1
- mastering tool version: 2.1.0.5849.1
- Reservoir Dogs (PAL)
- xbgamedisc version: 2.1.0.5849.1
- mastering tool version: 2.1.0.5849.1
Directory Entry
Version 4361
File entry flags:
- READONLY = 0x01
- HIDDEN = 0x02
- SYSTEM = 0x04
- DIRECTORY = 0x10
- ARCHIVE = 0x20
- NORMAL = 0x80
File data blocks
Version 4361
Incomplete sectors are padded with 0x00 bytes.
Random blocks
Version 3926 - 4721
Seeded and then starting to emit bytes in data area. Filled with the following algorithm:
// State
uint32_t a;
uint32_t b;
uint32_t c;
// Helper
static uint32_t Value(void) {
uint64_t result;
result = c;
result += 1;
result *= b;
result %= 0xFFFFFFFB;
c = result & 0xFFFFFFFF;
return c ^ a;
}
// buffer must be at even address, length must be multiple of 2
void Fill(uint16_t* buffer, size_t length) {
while(length >= 2) {
*buffer++ = Value() >> 8;
length -= 2;
}
}
void Seed() {
const uint32_t b_seeds[8] = {
0x52F690D5,
0x534D7DDE,
0x5B71A70F,
0x66793320,
0x9B7E5ED5,
0xA465265E,
0xA53F1D11,
0xB154430F
};
FILETIME ft;
GetSystemTimeAsFileTime(&ft);
uint32_t seed = ft.dwLowDateTime ^ ft.dwHighDateTime;
a = 0;
b = b_seeds[seed & 7];
c = seed;
a = Value();
}
The RNG is seeded when the mastering tool / wizard is started. The first portion of the code to use this random number generator is the code which generates layer 0 and layer 1.
Version 4831 - 5849
The algorithm was switched to RC4-256-drop-2048.
#include <openssl/rc4.h>
RC4_KEY rc4key;
void Fill(uint8_t* buffer, size_t length) {
// We need a zero buffer as OpenSSL will want to XOR the keystream with data.
// The XDVDFS random data is the keystream without changes, so we let XOR OpenSSL XOR with 0x00 bytes.
uint8_t zero_buffer[length];
memset(zero_buffer, 0x00, length);
RC4(&rc4key, length, zero_buffer, buffer);
}
void Seed() {
union {
uint8_t raw[16];
struct {
struct _FILETIME SystemTimeAsFileTime; // first 8 bytes, little-endian
uint64_t tsc; // later 8 bytes, little-endian
};
} key;
// Initialize seed
key.tsc = rdtsc();
GetSystemTimeAsFileTime(&key.SystemTimeAsFileTime);
RC4_set_key(&rc4key, 16, &key);
// Drop the first 2048 bytes of the RC4 keystream
uint8_t discard_buffer[2048];
Fill(discard_buffer, 2048);
}
The RNG is seeded when the mastering tool / wizard is started. The first portion of the code to use this random number generator is the code which generates layer 0 and layer 1.
Security blocks
Version 4361
Treated like random block.
