DeDRMS.cs

Dieses Script knackt den Copyright Schutz der Tauschbörse Itones von Appel. Es ist in C# Geschrieben.

Script:

/***************************************************************************** * DeDRMS.cs: DeDRMS 0.1 ***************************************************************************** * Copyright (C) 2004 Jon Lech Johansen <jon-vl@nanocrew.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. *****************************************************************************/ using System; using System.IO; using System.Text; using System.Security.Cryptography; class M4PStream { private Rijndael alg; private BinaryReader br; private BinaryWriter bw; private byte [] sbuffer; private string AtomDRMS = "drms"; private string AtomMP4A = "mp4a"; private string AtomSINF = "sinf"; private string AtomUSER = "user"; private string AtomKEY = "key "; private string AtomIVIV = "iviv"; private string AtomNAME = "name"; private string AtomPRIV = "priv"; private string AtomSTSZ = "stsz"; private string AtomMDAT = "mdat"; public M4PStream( FileStream fs ) { br = new BinaryReader( fs ); bw = new BinaryWriter( fs ); sbuffer = br.ReadBytes( Convert.ToInt32( fs.Length ) ); alg = Rijndael.Create(); alg.Mode = CipherMode.CBC; alg.Padding = PaddingMode.None; } byte [] NetToHost( byte [] Input, int Pos, int Count ) { if( BitConverter.IsLittleEndian ) { for( int i = 0; i < Count; i++ ) { Array.Reverse( Input, Pos + (i * 4), 4 ); } } return Input; } int GetAtomPos( string Atom ) { byte [] Bytes = Encoding.ASCII.GetBytes( Atom ); for( int i = 0; i < (sbuffer.Length - 3); i++ ) { if( sbuffer[ i + 0 ] == Bytes[ 0 ] && sbuffer[ i + 1 ] == Bytes[ 1 ] && sbuffer[ i + 2 ] == Bytes[ 2 ] && sbuffer[ i + 3 ] == Bytes[ 3 ] ) { return i; } } throw new Exception( String.Format( "Atom '{0}' not found", Atom ) ); } uint GetAtomSize( int Pos ) { byte [] Bytes = new byte[ 4 ]; Buffer.BlockCopy( sbuffer, Pos - 4, Bytes, 0, 4 ); return BitConverter.ToUInt32( NetToHost( Bytes, 0, 1 ), 0 ); } byte [] GetAtomData( int Pos, bool bNetToHost ) { uint Size; byte [] Bytes; Size = GetAtomSize( Pos ); Bytes = new byte[ Size - 8 ]; Buffer.BlockCopy( sbuffer, Pos + 4, Bytes, 0, Bytes.Length ); return bNetToHost ? NetToHost( Bytes, 0, Bytes.Length / 4 ) : Bytes; } public void Decrypt( byte [] CipherText, int Offset, int Count, byte [] Key, byte [] IV ) { MemoryStream ms = new MemoryStream(); ICryptoTransform ct = alg.CreateDecryptor( Key, IV ); CryptoStream cs = new CryptoStream( ms, ct, CryptoStreamMode.Write ); cs.Write( CipherText, Offset, (Count / 16) * 16 ); cs.Close(); ms.ToArray().CopyTo( CipherText, Offset ); } public byte [] GetUserKey( uint UserID, uint KeyID ) { byte [] UserKey; BinaryReader bruk; string strHome = Environment.GetFolderPath( Environment.SpecialFolder.ApplicationData ); bool bUnix = Environment.OSVersion.ToString().IndexOf( "Unix" ) != -1; string strFile = String.Format( "{0}{1}{2}drms{3}{4:X8}.{5:D3}", strHome, Path.DirectorySeparatorChar, bUnix ? "." : "", Path.DirectorySeparatorChar, UserID, KeyID ); bruk = new BinaryReader( File.OpenRead( strFile ) ); UserKey = bruk.ReadBytes( Convert.ToInt32( bruk.BaseStream.Length ) ); bruk.Close(); return UserKey; } public int [] GetSampleTable() { byte [] adSTSZ = GetAtomData( GetAtomPos( AtomSTSZ ), true ); int SampleCount = BitConverter.ToInt32( adSTSZ, 8 ); int [] SampleTable = new int[ SampleCount ]; for( int i = 0; i < SampleCount; i++ ) { SampleTable[ i ] = BitConverter.ToInt32( adSTSZ, 12 + (i * 4) ); } return SampleTable; } public void DeDRMS() { byte [] IV = new byte[ 16 ]; byte [] Key = new byte[ 16 ]; int apDRMS = GetAtomPos( AtomDRMS ); int apSINF = GetAtomPos( AtomSINF ); int apMDAT = GetAtomPos( AtomMDAT ); int [] SampleTable = GetSampleTable(); byte [] adUSER = GetAtomData( GetAtomPos( AtomUSER ), true ); byte [] adKEY = GetAtomData( GetAtomPos( AtomKEY ), true ); byte [] adIVIV = GetAtomData( GetAtomPos( AtomIVIV ), false ); byte [] adNAME = GetAtomData( GetAtomPos( AtomNAME ), false ); byte [] adPRIV = GetAtomData( GetAtomPos( AtomPRIV ), false ); uint UserID = BitConverter.ToUInt32( adUSER, 0 ); uint KeyID = BitConverter.ToUInt32( adKEY, 0 ); string strName = Encoding.ASCII.GetString( adNAME ); byte [] UserKey = GetUserKey( UserID, KeyID ); MD5CryptoServiceProvider MD5 = new MD5CryptoServiceProvider(); MD5.TransformBlock( adNAME, 0, strName.IndexOf( '\0' ), adNAME, 0 ); MD5.TransformFinalBlock( adIVIV, 0, adIVIV.Length ); Decrypt( adPRIV, 0, adPRIV.Length, UserKey, MD5.Hash ); if( Encoding.ASCII.GetString( adPRIV, 0, 4 ) != "itun" ) { throw new Exception( "Decryption of 'priv' atom failed" ); } Buffer.BlockCopy( adPRIV, 24, Key, 0, Key.Length ); Buffer.BlockCopy( adPRIV, 48, IV, 0, IV.Length ); for( int i = 0, Pos = apMDAT + 4; i < SampleTable.Length; Pos += SampleTable[ i ], i++ ) { Decrypt( sbuffer, Pos, SampleTable[ i ], Key, IV ); } Encoding.ASCII.GetBytes( AtomMP4A ).CopyTo( sbuffer, apDRMS ); Encoding.ASCII.GetBytes( AtomSINF.ToUpper() ).CopyTo( sbuffer, apSINF ); bw.Seek( 0, SeekOrigin.Begin ); bw.Write( sbuffer ); } } class DeDRMS { public static void Main( string [] Args ) { FileStream fs; M4PStream m4p; if( Args.Length != 1 ) { Console.WriteLine( "Usage: DeDRMS file.m4p" ); return; } try { fs = new FileStream( Args[ 0 ], FileMode.Open, FileAccess.Read | FileAccess.Write ); m4p = new M4PStream( fs ); m4p.DeDRMS(); fs.Close(); } catch( Exception e ) { Console.WriteLine( "Exception: {0}", e.Message ); return; } } }