// GPG4Browsers - An OpenPGP implementation in javascript // Copyright (C) 2011 Recurity Labs GmbH // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Lesser General Public // License as published by the Free Software Foundation; either // version 2.1 of the License, or (at your option) any later version. // // This library 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 // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public // License along with this library; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA /** * @class * @classdesc Implementation of the Compressed Data Packet (Tag 8) * * RFC4880 5.6: * The Compressed Data packet contains compressed data. Typically, this * packet is found as the contents of an encrypted packet, or following * a Signature or One-Pass Signature packet, and contains a literal data * packet. */ function openpgp_packet_compressed() { this.tagType = 8; /** * parsing function for the packet. * @param {string} input payload of a tag 8 packet * @param {integer} position position to start reading from the input string * @param {integer} len length of the packet or the remaining length of input at position * @return {openpgp_packet_compressed} object representation */ function read_packet (input, position, len) { this.packetLength = len; var mypos = position; // One octet that gives the algorithm used to compress the packet. this.type = input.charCodeAt(mypos++); // Compressed data, which makes up the remainder of the packet. this.compressedData = input.substring(position+1, position+len); return this; } /** * decompression method for decompressing the compressed data * read by read_packet * @return {String} the decompressed data */ function decompress() { if (this.decompressedData != null) return this.decompressedData; if (this.type == null) return null; switch (this.type) { case 0: // - Uncompressed this.decompressedData = this.compressedData; break; case 1: // - ZIP [RFC1951] var compData = this.compressedData; var radix = s2r(compData).replace(/\n/g,""); // no header in this case, directly call deflate var jxg_obj = new JXG.Util.Unzip(JXG.Util.Base64.decodeAsArray(radix)); var outputString = unescape(jxg_obj.deflate()[0][0]); var packet = openpgp_packet.read_packet(outputString, 0, outputString.length); util.print_info('Decompressed packet [Type 1-ZIP]: ' + packet); this.decompressedData = packet.data; break; case 2: // - ZLIB [RFC1950] var compressionMethod = this.compressedData.charCodeAt(0) % 0x10; //RFC 1950. Bits 0-3 Compression Method //Bits 4-7 RFC 1950 are LZ77 Window. Generally this value is 7 == 32k window size. //2nd Byte in RFC 1950 is for "FLAGs" Allows for a Dictionary (how is this defined). Basic checksum, and compression level. if (compressionMethod == 8) { //CM 8 is for DEFLATE, RFC 1951 // remove 4 bytes ADLER32 checksum from the end var compData = this.compressedData.substring(0, this.compressedData.length - 4); var radix = s2r(compData).replace(/\n/g,""); var outputString = JXG.decompress(radix); //TODO check ADLER32 checksum var packet = openpgp_packet.read_packet(outputString, 0, outputString.length); util.print_info('Decompressed packet [Type 2-ZLIB]: ' + packet); this.decompressedData = packet.data; } else { util.print_error("Compression algorithm ZLIB only supports DEFLATE compression method."); } break; case 3: // - BZip2 [BZ2] // TODO: need to implement this util.print_error("Compression algorithm BZip2 [BZ2] is not implemented."); break; default: util.print_error("Compression algorithm unknown :"+this.type); break; } util.print_debug("decompressed:"+util.hexstrdump(this.decompressedData)); return this.decompressedData; } /** * Compress the packet data (member decompressedData) * @param {integer} type algorithm to be used // See RFC 4880 9.3 * @param {String} data data to be compressed * @return {String} The compressed data stored in attribute compressedData */ function compress(type, data) { this.type = type; this.decompressedData = data; switch (this.type) { case 0: // - Uncompressed this.compressedData = this.decompressedData; break; case 1: // - ZIP [RFC1951] util.print_error("Compression algorithm ZIP [RFC1951] is not implemented."); break; case 2: // - ZLIB [RFC1950] // TODO: need to implement this util.print_error("Compression algorithm ZLIB [RFC1950] is not implemented."); break; case 3: // - BZip2 [BZ2] // TODO: need to implement this util.print_error("Compression algorithm BZip2 [BZ2] is not implemented."); break; default: util.print_error("Compression algorithm unknown :"+this.type); break; } this.packetLength = this.compressedData.length +1; return this.compressedData; } /** * creates a string representation of the packet * @param {integer} algorithm algorithm to be used // See RFC 4880 9.3 * @param {String} data data to be compressed * @return {String} string-representation of the packet */ function write_packet(algorithm, data) { this.decompressedData = data; if (algorithm == null) { this.type = 1; } var result = String.fromCharCode(this.type)+this.compress(this.type); return openpgp_packet.write_packet_header(8, result.length)+result; } /** * pretty printing the packet (useful for debug purposes) * @return {String} */ function toString() { return '5.6. Compressed Data Packet (Tag 8)\n'+ ' length: '+this.packetLength+'\n'+ ' Compression Algorithm = '+this.type+'\n'+ ' Compressed Data: Byte ['+util.hexstrdump(this.compressedData)+']\n'; } this.read_packet = read_packet; this.toString = toString; this.compress = compress; this.decompress = decompress; this.write_packet = write_packet; };