146 lines
4.2 KiB
C#
146 lines
4.2 KiB
C#
/*
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Copyright (C) 2011-2014 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System;
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using System.Collections.Generic;
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using System.IO;
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using dnlib.DotNet;
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using de4dot.blocks;
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using de4dot.blocks.cflow;
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namespace de4dot.code.deobfuscators.dotNET_Reactor.v3 {
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class MemoryPatcher {
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DecryptMethod decryptMethod = new DecryptMethod();
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List<PatchInfo> patchInfos = new List<PatchInfo>();
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class PatchInfo {
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public int[] offsets;
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public int[] values;
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public PatchInfo(int[] offsets, int[] values) {
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this.offsets = offsets;
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this.values = values;
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}
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}
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public bool Detected {
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get { return decryptMethod.Detected; }
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}
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public MemoryPatcher(TypeDef type, ICflowDeobfuscator cflowDeobfuscator) {
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Find(type, cflowDeobfuscator);
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}
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void Find(TypeDef type, ICflowDeobfuscator cflowDeobfuscator) {
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var additionalTypes = new List<string> {
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"System.IO.BinaryWriter",
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};
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foreach (var method in type.Methods) {
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if (!DotNetUtils.IsMethod(method, "System.Void", "(System.Int32[],System.UInt32[])"))
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continue;
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if (!DecryptMethod.CouldBeDecryptMethod(method, additionalTypes))
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continue;
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cflowDeobfuscator.Deobfuscate(method);
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if (!decryptMethod.GetKey(method))
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continue;
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FindPatchData(type, cflowDeobfuscator);
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return;
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}
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}
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void FindPatchData(TypeDef type, ICflowDeobfuscator cflowDeobfuscator) {
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var locals = new List<string> {
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"System.Int32[]",
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"System.UInt32[]",
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};
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foreach (var method in type.Methods) {
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if (method.Attributes != MethodAttributes.Private)
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continue;
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if (!DotNetUtils.IsMethod(method, "System.Void", "()"))
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continue;
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if (!new LocalTypes(method).Exactly(locals))
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continue;
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cflowDeobfuscator.Deobfuscate(method);
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var patchInfo = GetPatchInfo(method);
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if (patchInfo == null)
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continue;
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patchInfos.Add(patchInfo);
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}
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}
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PatchInfo GetPatchInfo(MethodDef method) {
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int index1 = 0, index2, index3, size1, size2, size3;
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if (!ArrayFinder.FindNewarr(method, ref index1, out size1))
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return null;
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index2 = index1 + 1;
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if (!ArrayFinder.FindNewarr(method, ref index2, out size2))
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return null;
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index3 = index2 + 1;
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if (ArrayFinder.FindNewarr(method, ref index3, out size3))
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return null;
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if (size1 <= 0 || size1 > 35)
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return null;
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var ary1 = ArrayFinder.GetInitializedInt32Array(size1, method, ref index1);
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var ary2 = ArrayFinder.GetInitializedInt32Array(size2, method, ref index2);
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if (ary1 == null || ary2 == null)
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return null;
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ary2 = Decrypt(ary2);
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if (ary2 == null || ary1.Length != ary2.Length)
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return null;
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for (int i = 0; i < ary1.Length; i++)
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ary1[i] = -ary1[i];
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return new PatchInfo(ary1, ary2);
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}
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int[] Decrypt(int[] data) {
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var memStream = new MemoryStream();
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var writer = new BinaryWriter(memStream);
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foreach (var value in data)
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writer.Write(value);
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byte[] decrypted;
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try {
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decrypted = DeobUtils.AesDecrypt(memStream.ToArray(), decryptMethod.Key, decryptMethod.Iv);
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}
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catch {
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return null;
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}
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if (decrypted.Length / 4 * 4 != decrypted.Length)
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return null;
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var newData = new int[decrypted.Length / 4];
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for (int i = 0; i < newData.Length; i++)
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newData[i] = BitConverter.ToInt32(decrypted, i * 4);
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return newData;
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}
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public void Patch(byte[] peImageData) {
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using (var peImage = new MyPEImage(peImageData)) {
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foreach (var info in patchInfos) {
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for (int i = 0; i < info.offsets.Length; i++)
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peImage.DotNetSafeWriteOffset((uint)info.offsets[i], BitConverter.GetBytes(info.values[i]));
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}
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}
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}
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}
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}
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