169 lines
4.9 KiB
C#
169 lines
4.9 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.Collections.Generic;
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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.deobfuscators.SmartAssembly {
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abstract class ResolverInfoBase {
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protected ModuleDefinition module;
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ISimpleDeobfuscator simpleDeobfuscator;
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IDeobfuscator deob;
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TypeDefinition resolverType;
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TypeDefinition callResolverType;
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MethodDefinition callResolverMethod;
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public TypeDefinition ResolverType {
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get { return resolverType; }
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}
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public TypeDefinition CallResolverType {
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get { return callResolverType; }
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}
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public MethodDefinition CallResolverMethod {
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get { return callResolverMethod; }
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}
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public ResolverInfoBase(ModuleDefinition module, ISimpleDeobfuscator simpleDeobfuscator, IDeobfuscator deob) {
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this.module = module;
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this.simpleDeobfuscator = simpleDeobfuscator;
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this.deob = deob;
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findTypes();
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}
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public bool findTypes() {
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if (resolverType != null)
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return true;
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var cctor = DotNetUtils.getMethod(DotNetUtils.getModuleType(module), ".cctor");
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if (cctor == null)
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return false;
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foreach (var tuple in DotNetUtils.getCalledMethods(module, cctor)) {
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var method = tuple.Item2;
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if (method.Name == ".cctor" || method.Name == ".ctor")
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continue;
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if (!method.IsStatic || !DotNetUtils.isMethod(method, "System.Void", "()"))
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continue;
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if (checkAttachAppType(tuple.Item1, method))
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return true;
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}
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return false;
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}
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bool checkAttachAppType(TypeDefinition type, MethodDefinition attachAppMethod) {
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callResolverType = null;
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if (!attachAppMethod.HasBody)
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return false;
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if (type.Fields.Count > 0 || type.Properties.Count > 0 || type.Events.Count > 0)
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return false;
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foreach (var m in type.Methods) {
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if (m.Name == ".cctor" || m.Name == ".ctor")
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continue;
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if (m == attachAppMethod)
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continue;
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return false;
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}
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foreach (var tuple in DotNetUtils.getCalledMethods(module, attachAppMethod)) {
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var method = tuple.Item2;
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if (method.Name == ".cctor" || method.Name == ".ctor")
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continue;
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if (!method.IsStatic || !DotNetUtils.isMethod(method, "System.Void", "()"))
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continue;
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if (!checkResolverType(tuple.Item1, method))
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continue;
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callResolverMethod = attachAppMethod;
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callResolverType = type;
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return true;
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}
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return false;
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}
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bool checkResolverType(TypeDefinition type, MethodDefinition initMethod) {
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resolverType = null;
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if (!initMethod.HasBody)
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return false;
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if (type.Properties.Count > 0 || type.Events.Count > 0)
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return false;
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if (!checkResolverType(type))
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return false;
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deobfuscate(initMethod);
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foreach (var handlerDef in getResolverHandlers(type, initMethod)) {
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deobfuscate(handlerDef);
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if (checkHandlerMethod(handlerDef)) {
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resolverType = type;
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return true;
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}
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}
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return false;
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}
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void deobfuscate(MethodDefinition method) {
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simpleDeobfuscator.deobfuscate(method);
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simpleDeobfuscator.decryptStrings(method, deob);
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}
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protected abstract bool checkResolverType(TypeDefinition type);
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protected abstract bool checkHandlerMethod(MethodDefinition handler);
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static IEnumerable<MethodDefinition> getResolverHandlers(TypeDefinition type, MethodDefinition method) {
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int numHandlers = 0;
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var instructions = method.Body.Instructions;
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for (int i = 0; i < instructions.Count; i++) {
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var instrs = DotNetUtils.getInstructions(instructions, i, OpCodes.Call, OpCodes.Ldnull, OpCodes.Ldftn, OpCodes.Newobj, OpCodes.Callvirt);
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if (instrs == null)
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continue;
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var call = instrs[0];
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if (!DotNetUtils.isMethod(call.Operand as MethodReference, "System.AppDomain", "()"))
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continue;
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var ldftn = instrs[2];
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var handlerDef = DotNetUtils.getMethod(type, ldftn.Operand as MethodReference);
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if (handlerDef == null)
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continue;
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var newobj = instrs[3];
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if (!DotNetUtils.isMethod(newobj.Operand as MethodReference, "System.Void", "(System.Object,System.IntPtr)"))
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continue;
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var callvirt = instrs[4];
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if (!DotNetUtils.isMethod(callvirt.Operand as MethodReference, "System.Void", "(System.ResolveEventHandler)"))
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continue;
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numHandlers++;
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yield return handlerDef;
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}
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// If no handlers found, it's possible that the method itself is the handler.
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if (numHandlers == 0)
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yield return method;
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}
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}
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}
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