Editing Bluray disc

== Overview ==

* [http://www.osta.org/specs/pdf/udf260.pdf UDF] filesystem (a profile of [http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-167.pdf ECMA-167]) in cleartext
* File entries are not encrypted, some files are not encrypted
* Some regions of the disc are encrypted (sector by sector)
* One sector is 2048 bytes

== Encryption ==

The first sector of the disc tells which parts of the disc are unencrypted and which one are encoded.

For example, this is the beginning of "The Last of Us" disc:

<pre>
00000000: 0000 0003 0000 0000 0000 0000 0000 099f  ................
00000010: 00a2 6160 00ba 73ff 011d dda0 011f ddbf  ..a`..s.........
00000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
</pre>

* 0x00000003 is the number of unencrypted regions
* The first unencrypted region is from sector 0x00000000 to sector 0x0000099f
* The first encrypted region is from sector 0x0000099f to sector 0x00a26160
* The second unencrypted region is from sector 0x00a26160 to sector 0x00ba73ff
* The second encrypted region is from sector 0x00ba73ff to sector 0x011ddda0 
* The third unencrypted region is from sector 0x011ddda0 to sector 0x011fddbf
* 0x011fddbf sectors is 38636746752 bytes whereas the file is 38636748800 bytes : the last sector is not included for some reason.

=== Deriving the disc key ===

The disc key is obtained by encrypting "data1" with AES CBC:

* with the secret 0x380bcf0b53455b3c7817ab4fa3ba90ed
* with the IV 0x69474772af6fdab342743aefaa186287
* no padding
* data1 is available in the IRD file
* it can be found on the disc with a bunch of SCSI commands.

=== Sector encryption ===

Each sector is encrypted with AES CBC:

* using the disc key
* no padding

The IV is derived from the sector number with:

<pre>
int num = sectorNumber;
byte[] iv = new byte[16];
for (int j = 0; j < 16; j++)
{
	iv[16 - j - 1] = (byte)(num & 0xFF);
	num >>= 8;
}
</pre>

== File system layout ==
* PS3_DISC.SFB
* PS3_GAME/ICON0.PNG
* PS3_GAME/LICDIR/LIC.DAT
* PS3_GAME/PARAM.SFO
* PS3_GAME/PIC1.PNG
* PS3_GAME/PS3LOGO.DAT
* PS3_GAME/SND0.AT3
* PS3_GAME/TROPDIR/
* PS3_GAME/USRDIR/build/
* PS3_GAME/USRDIR/data/
* PS3_GAME/USRDIR/EBOOT.BIN
* PS3_UPDATE/PS3UPDAT.PUP

{{PS3 Disc Game Structure}}
See also [[Content Information Files]]

== Extra "tracks" ==

=== Blu-ray Disc Information ===

See http://www.t10.org/ftp/t10/document.04/04-328r0.pdf#page=43:

<blockquote>A DI unit is 112 bytes in PIC on a BD-RE disc.  The DI unit that contains physical information shall 
be returned.  The information for layer 0 shall be returned when the Layer field of the CDB is set 
to zero.  The information for layer 1 shall be returned when the Layer field of the CDB is set to 1.  
See 
System Description Blu-ray Disc Rewritable Format, Part 1 Basic Format Specifications 
for 
DI unit detailed definition.</blockquote>

AFAIU, the description of its content is in a spec under NDA.

Exemple from "The Last Of Us":

<pre>
00000000: 1002 0000 4449 0110 0000 2000 4244 4f01  ....DI.... .BDO.
00000010: 2101 0300 0000 0000 019a f5bf 0010 0000  !...............
00000020: 00ca 73fe 0000 0000 0000 0000 0000 0000  ..s.............
00000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000040: 0000 0000 4449 0111 0001 2000 4244 4f01  ....DI.... .BDO.
00000050: 2101 0300 0000 0000 019a f5bf 0135 8c00  !............5..
00000060: 01ef fffe 0000 0000 0000 0000 0000 0000  ................
</pre>

It can be read with the [http://www.t10.org/ftp/t10/document.04/04-328r0.pdf#page=43 READ DISC STRUCTURE] SCSI command.

Reading it (in C on Linux):

<pre>
#define PIC_SIZE 112

  unsigned char read_pic_command[12] = {
    173, // Operation Code=READ_DISC_STRUCTURE
    1,   // Reserved=0, MediaType=1 (BD)
    0,
    0,
    0,
    0,
    0,
    0, // FormatCode=0 (Disc Information)
    pic_size / 256,
    pic_size % 256,
    0,
    0
  };

  int drive = open(drive_filename, 0, O_RDONLY);
  if (drive == -1) {
    fputs("Can't open file\n", stderr);
    return 1;
  }

  unsigned char sense_data[12];

  // Actually there is a lot more than that:
  unsigned char* pic = malloc(pic_size);
  memset(pic, 0, pic_size);

  struct sg_io_hdr header;
  memset(&header, 0, sizeof(header));
  header.interface_id = 'S'; // SCSI
  header.dxfer_direction = SG_DXFER_FROM_DEV;
  header.cmd_len = sizeof(read_pic_command);
  header.mx_sb_len = sizeof(sense_data);
  header.iovec_count = 0;
  header.dxfer_len = pic_size;
  header.dxferp = pic;
  header.cmdp = (unsigned char*) read_pic_command;
  header.sbp = sense_data;
  header.timeout = 60 * 1000;
  header.flags = 0;
  header.pack_id = 0;
  header.usr_ptr = NULL;
  header.status = 0;
  header.msg_status = 0;
  header.sb_len_wr = 0;
  header.host_status = 0;
  header.driver_status = 0;
  header.resid = 0;
  header.duration = 0;
  header.info = 0;

  if (ioctl(drive, SG_IO, &header) < 0) {
    fputs("ioctl failed\n", stderr);
    return 1;
  }

  if ((header.info & SG_INFO_OK_MASK) != SG_INFO_OK) {
    fputs("SCSI failed\n", stderr);
    return 1;
  }
</pre>

=== "Data1" and "Data2" ===

Read after authentication with some undocumented SCSI commands. Not sure if those are PS3-specific SCSI commands.

== IRD file ==

3k3y generates [http://jonnysp.bplaced.net/ IRD files] which contains some information about the disc. In particular, it contains "data1" which is used to derived the disc AES encryption key.

The file is:

* either uncompressed (magic string "3IRD");
* or gzipped (gzip magic string 0x1f8b) with a (4 bytes) CRC afterwards.

The format is based on .NET BinaryReader/BinaryWriter:

* Integer are in little endian format:
* Variable length strings use a [https://msdn.microsoft.com/fr-fr/library/system.io.binaryreader.readstring(v=vs.110).aspx compressed length prefix].

Compressed data are compressed with gzipped and prefixed with a length (uint32).

The format is (v6 to v9):

{|class="wikitable"
!Size
!Format
!Description
!Example
!Versions
|-
|4B
|string
|Magic string ("3IRD")
|3IRD
|
|-
|1B
|uint
|Version
|6, 7, 8, 9
|
|-
|9B
|string
|Game ID
|BCES01584
|
|-
|var
|string
|Game name
|The Last Of Us
|
|-
|4B
|string
|Update version
|4.41
|
|-
|5B
|string
|Game version
|4.41
|
|-
|5B
|string
|App version
|01.00
|
|-
|4B
|uint
|ID
|
|v=7
|-
|var
|compressed
|Header
|
|
|-
|var
|compressed
|Footer
|
|
|-
|1B
|uint
|Region count
|
|
|-
|16B
|bytes
|Region 1 hash
|
|
|-
|…
|…
|…
|…
|…
|-
|4B
|uint
|File count
|
|
|-
|8B
|uint
|File 1 key
|
|
|-
|16B
|bytes
|File 1 hash
|
|
|-
|…
|…
|…
|…
|…
|-
|115B
|bytes
|PIC
|
|v=9
|-
|16B
|bytes
|Data 1
|
|
|-
|16B
|bytes
|Data 2
|
|
|-
|115B
|bytes
|PIC
|
|v<9
|-
|2B
|uint/bytes
|UID
|
|
|}

== References ==

* 3k3y IsoTools, this is a .NET program available in binary form. The [https://github.com/icsharpcode/ILSpy ILspy] decompiler produces a very readable output.
* PS3 ISO Patcher by BlackDaemon, is a .NET program available in source code

{{Reverse engineering}}<noinclude>[[Category:Main]]</noinclude>