Linux Unified Key Setup: JavaScript parsing library

Linux Unified Key Setup (LUKS) is a format specification for storing disk encryption parameters and up to 8 user keys (which can unlock the master key).

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of Linux Unified Key Setup using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.

The JavaScript runtime library is available at npm:

npm install kaitai-struct

Code

See the usage examples in the JavaScript notes.

Parse structure from an ArrayBuffer:

var arrayBuffer = ...;
var data = new Luks(new KaitaiStream(arrayBuffer));

After that, one can get various attributes from the structure by accessing fields or properties like:

data.partitionHeader // => get partition header

JavaScript source code to parse Linux Unified Key Setup

Luks.js

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['kaitai-struct/KaitaiStream'], factory);
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory(require('kaitai-struct/KaitaiStream'));
  } else {
    root.Luks = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
/**
 * Linux Unified Key Setup (LUKS) is a format specification for storing disk
 * encryption parameters and up to 8 user keys (which can unlock the master key).
 * @see {@link https://gitlab.com/cryptsetup/cryptsetup/wikis/LUKS-standard/on-disk-format.pdf|Source}
 */

var Luks = (function() {
  function Luks(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  Luks.prototype._read = function() {
    this.partitionHeader = new PartitionHeader(this._io, this, this._root);
  }

  var PartitionHeader = Luks.PartitionHeader = (function() {
    function PartitionHeader(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PartitionHeader.prototype._read = function() {
      this.magic = this._io.readBytes(6);
      if (!((KaitaiStream.byteArrayCompare(this.magic, [76, 85, 75, 83, 186, 190]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([76, 85, 75, 83, 186, 190], this.magic, this._io, "/types/partition_header/seq/0");
      }
      this.version = this._io.readBytes(2);
      if (!((KaitaiStream.byteArrayCompare(this.version, [0, 1]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([0, 1], this.version, this._io, "/types/partition_header/seq/1");
      }
      this.cipherNameSpecification = KaitaiStream.bytesToStr(this._io.readBytes(32), "ASCII");
      this.cipherModeSpecification = KaitaiStream.bytesToStr(this._io.readBytes(32), "ASCII");
      this.hashSpecification = KaitaiStream.bytesToStr(this._io.readBytes(32), "ASCII");
      this.payloadOffset = this._io.readU4be();
      this.numberOfKeyBytes = this._io.readU4be();
      this.masterKeyChecksum = this._io.readBytes(20);
      this.masterKeySaltParameter = this._io.readBytes(32);
      this.masterKeyIterationsParameter = this._io.readU4be();
      this.uuid = KaitaiStream.bytesToStr(this._io.readBytes(40), "ASCII");
      this.keySlots = new Array(8);
      for (var i = 0; i < 8; i++) {
        this.keySlots[i] = new KeySlot(this._io, this, this._root);
      }
    }

    var KeySlot = PartitionHeader.KeySlot = (function() {
      KeySlot.KeySlotStates = Object.freeze({
        DISABLED_KEY_SLOT: 57005,
        ENABLED_KEY_SLOT: 11301363,

        57005: "DISABLED_KEY_SLOT",
        11301363: "ENABLED_KEY_SLOT",
      });

      function KeySlot(_io, _parent, _root) {
        this._io = _io;
        this._parent = _parent;
        this._root = _root || this;

        this._read();
      }
      KeySlot.prototype._read = function() {
        this.stateOfKeySlot = this._io.readU4be();
        this.iterationParameter = this._io.readU4be();
        this.saltParameter = this._io.readBytes(32);
        this.startSectorOfKeyMaterial = this._io.readU4be();
        this.numberOfAntiForensicStripes = this._io.readU4be();
      }
      Object.defineProperty(KeySlot.prototype, 'keyMaterial', {
        get: function() {
          if (this._m_keyMaterial !== undefined)
            return this._m_keyMaterial;
          var _pos = this._io.pos;
          this._io.seek((this.startSectorOfKeyMaterial * 512));
          this._m_keyMaterial = this._io.readBytes((this._parent.numberOfKeyBytes * this.numberOfAntiForensicStripes));
          this._io.seek(_pos);
          return this._m_keyMaterial;
        }
      });

      return KeySlot;
    })();

    return PartitionHeader;
  })();
  Object.defineProperty(Luks.prototype, 'payload', {
    get: function() {
      if (this._m_payload !== undefined)
        return this._m_payload;
      var _pos = this._io.pos;
      this._io.seek((this.partitionHeader.payloadOffset * 512));
      this._m_payload = this._io.readBytesFull();
      this._io.seek(_pos);
      return this._m_payload;
    }
  });

  return Luks;
})();
return Luks;
}));