161 lines
5.5 KiB
C#
161 lines
5.5 KiB
C#
/*
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Copyright (C) 2011 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 Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.code.AssemblyClient;
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using de4dot.blocks;
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namespace de4dot.code {
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abstract class StringDecrypter : MethodReturnValueInliner {
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protected override void inlineReturnValues(IList<CallResult> callResults) {
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foreach (var callResult in callResults) {
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var block = callResult.block;
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int num = callResult.callEndIndex - callResult.callStartIndex + 1;
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int ldstrIndex = callResult.callStartIndex;
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block.replace(ldstrIndex, num, Instruction.Create(OpCodes.Ldstr, (string)callResult.returnValue));
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// If it's followed by String.Intern(), then nop out that call
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if (ldstrIndex + 1 < block.Instructions.Count) {
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var instr = block.Instructions[ldstrIndex + 1];
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if (instr.OpCode.Code == Code.Call) {
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var calledMethod = instr.Operand as MethodReference;
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if (calledMethod != null &&
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calledMethod.FullName == "System.String System.String::Intern(System.String)") {
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block.remove(ldstrIndex + 1, 1);
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}
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}
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}
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Log.v("Decrypted string: {0}", Utils.toCsharpString((string)callResult.returnValue));
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}
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}
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}
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class DynamicStringDecrypter : StringDecrypter {
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IAssemblyClient assemblyClient;
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Dictionary<int, int> methodTokenToId = new Dictionary<int, int>();
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class MyCallResult : CallResult {
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public int methodId;
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public MyCallResult(Block block, int callEndIndex, int methodId)
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: base(block, callEndIndex) {
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this.methodId = methodId;
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}
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}
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public DynamicStringDecrypter(IAssemblyClient assemblyClient) {
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this.assemblyClient = assemblyClient;
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}
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public void init(IEnumerable<int> methodTokens) {
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methodTokenToId.Clear();
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foreach (var methodToken in methodTokens) {
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if (methodTokenToId.ContainsKey(methodToken))
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continue;
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methodTokenToId[methodToken] = assemblyClient.Service.defineStringDecrypter(methodToken);
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}
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}
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protected override CallResult createCallResult(MethodReference method, Block block, int callInstrIndex) {
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int methodId;
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if (!methodTokenToId.TryGetValue(method.MetadataToken.ToInt32(), out methodId))
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return null;
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return new MyCallResult(block, callInstrIndex, methodId);
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}
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protected override void inlineAllCalls() {
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var sortedCalls = new Dictionary<int, List<MyCallResult>>();
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foreach (var tmp in callResults) {
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var callResult = (MyCallResult)tmp;
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List<MyCallResult> list;
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if (!sortedCalls.TryGetValue(callResult.methodId, out list))
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sortedCalls[callResult.methodId] = list = new List<MyCallResult>(callResults.Count);
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list.Add(callResult);
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}
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foreach (var methodId in sortedCalls.Keys) {
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var list = sortedCalls[methodId];
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var args = new object[list.Count];
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for (int i = 0; i < list.Count; i++) {
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AssemblyData.SimpleData.pack(list[i].args);
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args[i] = list[i].args;
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}
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var decryptedStrings = assemblyClient.Service.decryptStrings(methodId, args);
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if (decryptedStrings.Length != args.Length)
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throw new ApplicationException("Invalid decrypted strings array length");
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AssemblyData.SimpleData.unpack(decryptedStrings);
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for (int i = 0; i < list.Count; i++) {
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var s = decryptedStrings[i];
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if (s == null)
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throw new ApplicationException(string.Format("Decrypted string is null. Method: {0}", list[i].getMethodReference()));
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list[i].returnValue = (string)s;
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}
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}
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}
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}
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class StaticStringDecrypter : StringDecrypter {
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MethodDefinitionAndDeclaringTypeDict<Func<MethodDefinition, object[], string>> stringDecrypters = new MethodDefinitionAndDeclaringTypeDict<Func<MethodDefinition, object[], string>>();
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public bool HasHandlers {
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get { return stringDecrypters.Count != 0; }
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}
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public IEnumerable<MethodDefinition> Methods {
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get {
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var list = new List<MethodDefinition>(stringDecrypters.Count);
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foreach (var method in stringDecrypters.getKeys())
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list.Add(method);
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return list;
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}
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}
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class MyCallResult : CallResult {
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public MethodReference methodReference;
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public MyCallResult(Block block, int callEndIndex, MethodReference method)
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: base(block, callEndIndex) {
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this.methodReference = method;
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}
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}
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public void add(MethodDefinition method, Func<MethodDefinition, object[], string> handler) {
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if (method != null)
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stringDecrypters.add(method, handler);
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}
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protected override void inlineAllCalls() {
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foreach (var tmp in callResults) {
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var callResult = (MyCallResult)tmp;
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var handler = stringDecrypters.find(callResult.methodReference);
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callResult.returnValue = handler((MethodDefinition)callResult.methodReference, callResult.args);
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}
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}
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protected override CallResult createCallResult(MethodReference method, Block block, int callInstrIndex) {
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if (stringDecrypters.find(method) == null)
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return null;
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return new MyCallResult(block, callInstrIndex, method);
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}
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}
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}
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