515 lines
16 KiB
C#
515 lines
16 KiB
C#
/*
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Copyright (C) 2011-2012 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 System.Text;
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using Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.Confuser {
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class ConstantsDecrypterV15 {
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ModuleDefinition module;
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ISimpleDeobfuscator simpleDeobfuscator;
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MethodDefinition decryptMethod;
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EmbeddedResource resource;
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uint key0, key1, key2, key3;
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byte doubleType, singleType, int32Type, int64Type, stringType;
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BinaryReader reader;
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ConfuserVersion version = ConfuserVersion.Unknown;
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enum ConfuserVersion {
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Unknown,
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v15_r60785_normal,
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v15_r60785_dynamic,
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v17_r73404_normal,
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v17_r73740_dynamic,
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}
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public MethodDefinition Method {
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get { return decryptMethod; }
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}
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public EmbeddedResource Resource {
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get { return resource; }
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}
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public bool Detected {
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get { return decryptMethod != null; }
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}
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public ConstantsDecrypterV15(ModuleDefinition module, ISimpleDeobfuscator simpleDeobfuscator) {
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this.module = module;
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this.simpleDeobfuscator = simpleDeobfuscator;
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}
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static readonly string[] requiredLocals = new string[] {
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"System.Byte[]",
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"System.Collections.Generic.Dictionary`2<System.UInt32,System.Object>",
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"System.IO.BinaryReader",
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"System.IO.Compression.DeflateStream",
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"System.IO.MemoryStream",
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"System.Reflection.Assembly",
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};
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public void find() {
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var type = DotNetUtils.getModuleType(module);
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if (type == null)
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return;
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foreach (var method in type.Methods) {
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if (!method.IsStatic || method.Body == null)
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continue;
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if (!DotNetUtils.isMethod(method, "System.Object", "(System.UInt32)"))
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continue;
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var localTypes = new LocalTypes(method);
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if (!localTypes.all(requiredLocals))
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continue;
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if (localTypes.exists("System.Collections.BitArray")) // or System.Random
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version = ConfuserVersion.v15_r60785_normal;
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else if (DeobUtils.hasInteger(method, 0x100) &&
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DeobUtils.hasInteger(method, 0x10000) &&
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DeobUtils.hasInteger(method, 0xFFFF))
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version = ConfuserVersion.v17_r73404_normal;
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else if (findInstruction(method.Body.Instructions, 0, Code.Conv_I8) >= 0)
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version = ConfuserVersion.v15_r60785_dynamic;
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else
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version = ConfuserVersion.v17_r73740_dynamic;
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decryptMethod = method;
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break;
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}
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}
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public void initialize() {
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if ((resource = findResource(decryptMethod)) == null)
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throw new ApplicationException("Could not find encrypted consts resource");
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simpleDeobfuscator.deobfuscate(decryptMethod);
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if (!initializeKeys())
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throw new ApplicationException("Could not find all keys");
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if (!initializeTypeCodes())
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throw new ApplicationException("Could not find all type codes");
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var constants = DeobUtils.inflate(resource.GetResourceData(), true);
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reader = new BinaryReader(new MemoryStream(constants));
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}
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bool initializeKeys() {
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if (!findKey0(decryptMethod, out key0))
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return false;
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if (!findKey1(decryptMethod, out key1))
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return false;
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if (!findKey2Key3(decryptMethod, out key2, out key3))
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return false;
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return true;
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}
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static bool findKey0(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 5; i++) {
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if (!DotNetUtils.isLdloc(instrs[i]))
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continue;
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if (instrs[i + 1].OpCode.Code != Code.Or)
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continue;
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var ldci4 = instrs[i + 2];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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if (instrs[i + 3].OpCode.Code != Code.Xor)
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continue;
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if (instrs[i + 4].OpCode.Code != Code.Add)
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 5]))
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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static bool findKey1(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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int index = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Int32 System.Reflection.MemberInfo::get_MetadataToken()");
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if (index < 0)
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break;
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if (index + 2 > instrs.Count)
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break;
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if (!DotNetUtils.isStloc(instrs[index + 1]))
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continue;
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var ldci4 = instrs[index + 2];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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static bool findKey2Key3(MethodDefinition method, out uint key2, out uint key3) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 3; i++) {
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var ldci4_1 = instrs[i];
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if (!DotNetUtils.isLdcI4(ldci4_1))
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 1]))
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continue;
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var ldci4_2 = instrs[i + 2];
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if (!DotNetUtils.isLdcI4(ldci4_2))
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 3]))
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continue;
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key2 = (uint)DotNetUtils.getLdcI4Value(ldci4_1);
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key3 = (uint)DotNetUtils.getLdcI4Value(ldci4_2);
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return true;
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}
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key2 = 0;
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key3 = 0;
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return false;
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}
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bool initializeTypeCodes() {
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var allBlocks = new Blocks(decryptMethod).MethodBlocks.getAllBlocks();
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if (!findTypeCode(allBlocks, out doubleType, Code.Call, "System.Double System.BitConverter::ToDouble(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out singleType, Code.Call, "System.Single System.BitConverter::ToSingle(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out int32Type, Code.Call, "System.Int32 System.BitConverter::ToInt32(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out int64Type, Code.Call, "System.Int64 System.BitConverter::ToInt64(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out stringType, Code.Callvirt, "System.String System.Text.Encoding::GetString(System.Byte[])"))
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return false;
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return true;
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}
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static bool findTypeCode(IList<Block> allBlocks, out byte typeCode, Code callCode, string bitConverterMethod) {
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foreach (var block in allBlocks) {
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if (block.Sources.Count != 1)
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continue;
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int index = ConfuserUtils.findCallMethod(block.Instructions, 0, callCode, bitConverterMethod);
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if (index < 0)
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continue;
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if (!findTypeCode(block.Sources[0], out typeCode))
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continue;
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return true;
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}
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typeCode = 0;
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return false;
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}
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static Block fixBlock(Block block) {
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if (block.Sources.Count != 1)
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return block;
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if (block.getOnlyTarget() == null)
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return block;
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if (block.Instructions.Count == 0) {
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}
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else if (block.Instructions.Count == 1 && block.Instructions[0].OpCode.Code == Code.Nop) {
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}
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else
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return block;
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return block.Sources[0];
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}
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static bool findTypeCode(Block block, out byte typeCode) {
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block = fixBlock(block);
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var instrs = block.Instructions;
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int numCeq = 0;
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for (int i = instrs.Count - 1; i >= 0; i--) {
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var instr = instrs[i];
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if (instr.OpCode.Code == Code.Ceq) {
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numCeq++;
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continue;
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}
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if (!DotNetUtils.isLdcI4(instr.Instruction))
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continue;
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if (numCeq != 0 && numCeq != 2)
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continue;
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typeCode = (byte)DotNetUtils.getLdcI4Value(instr.Instruction);
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return true;
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}
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typeCode = 0;
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return false;
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}
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EmbeddedResource findResource(MethodDefinition method) {
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return DotNetUtils.getResource(module, DotNetUtils.getCodeStrings(method)) as EmbeddedResource;
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}
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public object decryptInt32(MethodDefinition caller, uint magic) {
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byte typeCode;
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var data = decryptData(caller, magic, out typeCode);
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if (typeCode != int32Type)
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return null;
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if (data.Length != 4)
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throw new ApplicationException("Invalid data length");
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return BitConverter.ToInt32(data, 0);
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}
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public object decryptInt64(MethodDefinition caller, uint magic) {
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byte typeCode;
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var data = decryptData(caller, magic, out typeCode);
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if (typeCode != int64Type)
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return null;
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if (data.Length != 8)
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throw new ApplicationException("Invalid data length");
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return BitConverter.ToInt64(data, 0);
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}
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public object decryptSingle(MethodDefinition caller, uint magic) {
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byte typeCode;
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var data = decryptData(caller, magic, out typeCode);
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if (typeCode != singleType)
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return null;
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if (data.Length != 4)
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throw new ApplicationException("Invalid data length");
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return BitConverter.ToSingle(data, 0);
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}
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public object decryptDouble(MethodDefinition caller, uint magic) {
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byte typeCode;
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var data = decryptData(caller, magic, out typeCode);
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if (typeCode != doubleType)
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return null;
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if (data.Length != 8)
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throw new ApplicationException("Invalid data length");
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return BitConverter.ToDouble(data, 0);
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}
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public string decryptString(MethodDefinition caller, uint magic) {
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byte typeCode;
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var data = decryptData(caller, magic, out typeCode);
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if (typeCode != stringType)
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return null;
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return Encoding.UTF8.GetString(data);
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}
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byte[] decryptData(MethodDefinition caller, uint magic, out byte typeCode) {
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uint offs = calcHash(caller.MetadataToken.ToUInt32()) ^ magic;
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reader.BaseStream.Position = offs;
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typeCode = reader.ReadByte();
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if (typeCode != int32Type && typeCode != int64Type &&
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typeCode != singleType && typeCode != doubleType &&
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typeCode != stringType)
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throw new ApplicationException("Invalid type code");
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var encrypted = reader.ReadBytes(reader.ReadInt32());
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return decryptConstant(encrypted, offs);
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}
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byte[] decryptConstant(byte[] encrypted, uint offs) {
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switch (version) {
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case ConfuserVersion.v15_r60785_normal: return decryptConstant_v15_r60785_normal(encrypted, offs);
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case ConfuserVersion.v15_r60785_dynamic: return decryptConstant_v15_r60785_dynamic(encrypted, offs);
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case ConfuserVersion.v17_r73404_normal: return decryptConstant_v17_r73404_normal(encrypted, offs);
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case ConfuserVersion.v17_r73740_dynamic: return decryptConstant_v17_r73740_dynamic(encrypted, offs);
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default: throw new ApplicationException("Invalid version");
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}
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}
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byte[] decryptConstant_v15_r60785_normal(byte[] encrypted, uint offs) {
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var rand = new Random((int)(key0 ^ offs));
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var decrypted = new byte[encrypted.Length];
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rand.NextBytes(decrypted);
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for (int i = 0; i < decrypted.Length; i++)
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decrypted[i] ^= encrypted[i];
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return decrypted;
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}
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byte[] decryptConstant_v15_r60785_dynamic(byte[] encrypted, uint offs) {
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var instrs = decryptMethod.Body.Instructions;
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int startIndex = getDynamicStartIndex_v15_r60785(instrs);
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int endIndex = getDynamicEndIndex_v15_r60785(instrs, startIndex);
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if (endIndex < 0)
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throw new ApplicationException("Could not find start/endIndex");
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var dataReader = new BinaryReader(new MemoryStream(encrypted));
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var decrypted = new byte[dataReader.ReadInt32()];
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var constReader = new Arg64ConstantsReader(instrs, false);
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ConfuserUtils.decryptCompressedInt32Data(constReader, startIndex, endIndex, dataReader, decrypted);
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return decrypted;
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}
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static int getDynamicStartIndex_v15_r60785(IList<Instruction> instrs) {
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int index = findInstruction(instrs, 0, Code.Conv_I8);
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if (index < 0)
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return -1;
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if (findInstruction(instrs, index + 1, Code.Conv_I8) >= 0)
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return -1;
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return index;
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}
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static int getDynamicEndIndex_v15_r60785(IList<Instruction> instrs, int index) {
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if (index < 0)
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return -1;
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for (int i = index; i < instrs.Count; i++) {
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var instr = instrs[i];
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if (instr.OpCode.FlowControl != FlowControl.Next)
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break;
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if (instr.OpCode.Code == Code.Conv_U1)
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return i;
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}
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return -1;
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}
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static int findInstruction(IList<Instruction> instrs, int index, Code code) {
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for (int i = index; i < instrs.Count; i++) {
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if (instrs[i].OpCode.Code == code)
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return i;
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}
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return -1;
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}
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byte[] decryptConstant_v17_r73404_normal(byte[] encrypted, uint offs) {
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return ConfuserUtils.decrypt(key0 ^ offs, encrypted);
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}
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static VariableDefinition getDynamicLocal_v17_r73740(MethodDefinition method) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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i = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Byte System.IO.BinaryReader::ReadByte()");
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if (i < 0 || i + 5 >= instrs.Count)
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break;
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if (!DotNetUtils.isStloc(instrs[i + 1]))
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continue;
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var ldloc = instrs[i + 2];
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if (!DotNetUtils.isLdloc(ldloc))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 3]))
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continue;
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var ldci4 = instrs[i + 4];
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if (!DotNetUtils.isLdcI4(ldci4) || DotNetUtils.getLdcI4Value(ldci4) != 0x7F)
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continue;
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if (instrs[i + 5].OpCode.Code != Code.And)
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continue;
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return DotNetUtils.getLocalVar(method.Body.Variables, ldloc);
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}
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return null;
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}
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static int getDynamicEndIndex_v17_r73740(MethodDefinition method, VariableDefinition local) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 5; i++) {
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var stloc = instrs[i];
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if (!DotNetUtils.isStloc(stloc) || DotNetUtils.getLocalVar(method.Body.Variables, stloc) != local)
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 1]))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 2]))
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continue;
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var ldloc = instrs[i + 3];
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if (!DotNetUtils.isLdloc(ldloc) || DotNetUtils.getLocalVar(method.Body.Variables, ldloc) != local)
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continue;
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if (instrs[i + 4].OpCode.Code != Code.Conv_U1)
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continue;
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if (instrs[i + 5].OpCode.Code != Code.Stelem_I1)
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continue;
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return i;
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}
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return -1;
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}
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static int getDynamicStartIndex_v17_r73740(MethodDefinition method, int endIndex) {
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if (endIndex < 0)
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return -1;
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var instrs = method.Body.Instructions;
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for (int i = endIndex; i >= 0; i--) {
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if (i == 0)
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return i == endIndex ? -1 : i + 1;
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if (instrs[i].OpCode.FlowControl == FlowControl.Next)
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continue;
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return i + 1;
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}
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return -1;
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}
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byte[] decryptConstant_v17_r73740_dynamic(byte[] encrypted, uint offs) {
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var local = getDynamicLocal_v17_r73740(decryptMethod);
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if (local == null)
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throw new ApplicationException("Could not find local");
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int endIndex = getDynamicEndIndex_v17_r73740(decryptMethod, local);
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int startIndex = getDynamicStartIndex_v17_r73740(decryptMethod, endIndex);
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if (startIndex < 0)
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throw new ApplicationException("Could not find start/end index");
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var constReader = new ConstantsReader(decryptMethod);
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var dataReader = new BinaryReader(new MemoryStream(encrypted));
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var decrypted = new byte[dataReader.ReadInt32()];
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return decryptCompressedInt32Data(constReader, local, startIndex, endIndex, dataReader, decrypted);
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}
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static byte[] decryptCompressedInt32Data(ConstantsReader constReader, VariableDefinition local, int exprStart, int exprEnd, BinaryReader reader, byte[] decrypted) {
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for (int i = 0; i < decrypted.Length; i++) {
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constReader.setConstantInt32(local, Utils.readEncodedInt32(reader));
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int index = exprStart, result;
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if (!constReader.getNextInt32(ref index, out result) || index != exprEnd)
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throw new ApplicationException("Could not decrypt integer");
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decrypted[i] = (byte)result;
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}
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return decrypted;
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}
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uint calcHash(uint x) {
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uint h0 = key1 ^ x;
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uint h1 = key2;
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uint h2 = key3;
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for (uint i = 1; i <= 64; i++) {
|
|
h0 = (h0 << 8) | (h0 >> 24);
|
|
uint n = h0 & 0x3F;
|
|
if (n >= 0 && n < 16) {
|
|
h1 |= ((byte)(h0 >> 8) & (h0 >> 16)) ^ (byte)~h0;
|
|
h2 ^= (h0 * i + 1) & 0xF;
|
|
h0 += (h1 | h2) ^ key0;
|
|
}
|
|
else if (n >= 16 && n < 32) {
|
|
h1 ^= ((h0 & 0x00FF00FF) << 8) ^ (ushort)((h0 >> 8) | ~h0);
|
|
h2 += (h0 * i) & 0x1F;
|
|
h0 |= (h1 + ~h2) & key0;
|
|
}
|
|
else if (n >= 32 && n < 48) {
|
|
h1 += (byte)(h0 | (h0 >> 16)) + (~h0 & 0xFF);
|
|
h2 -= ~(h0 + n) % 48;
|
|
h0 ^= (h1 % h2) | key0;
|
|
}
|
|
else if (n >= 48 && n < 64) {
|
|
h1 ^= ((byte)(h0 >> 16) | ~(h0 & 0xFF)) * (~h0 & 0x00FF0000);
|
|
h2 += (h0 ^ (i - 1)) % n;
|
|
h0 -= ~(h1 ^ h2) + key0;
|
|
}
|
|
}
|
|
return h0;
|
|
}
|
|
}
|
|
}
|