119 lines
3.1 KiB
C#
119 lines
3.1 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 Mono.Cecil;
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using Mono.Cecil.Cil;
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using Mono.Cecil.Metadata;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.CliSecure.vm {
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// Tries to restore the operands of the following CIL instructions:
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// ldelema
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// ldobj
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// stobj
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class CilOperandInstructionRestorer {
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MethodDefinition method;
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// Returns true if something was restored
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public bool restore(MethodDefinition method) {
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this.method = method;
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bool changed = false;
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if (method == null || method.Body == null)
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return changed;
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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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var instr = instrs[i];
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if (instr.Operand != null)
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continue;
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TypeReference operandType = null;
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switch (instr.OpCode.Code) {
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case Code.Ldelema:
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var arrayType = MethodStack.getLoadedType(method, instrs, i, 1) as ArrayType;
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if (arrayType == null)
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break;
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operandType = arrayType.ElementType;
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break;
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case Code.Ldobj:
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operandType = MethodStack.getLoadedType(method, instrs, i, 0);
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break;
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case Code.Stobj:
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operandType = MethodStack.getLoadedType(method, instrs, i, 1);
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if (operandType == null)
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operandType = MethodStack.getLoadedType(method, instrs, i, 0);
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break;
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default:
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continue;
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}
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if (!isValidType(operandType))
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continue;
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instr.Operand = operandType;
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changed = true;
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}
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return changed;
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}
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bool isValidType(TypeReference type) {
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if (type == null)
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return false;
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if (type.EType == ElementType.Void)
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return false;
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while (type != null) {
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switch (MemberReferenceHelper.getMemberReferenceType(type)) {
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case CecilType.ArrayType:
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case CecilType.GenericInstanceType:
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case CecilType.PointerType:
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case CecilType.TypeDefinition:
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case CecilType.TypeReference:
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case CecilType.FunctionPointerType:
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break;
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case CecilType.GenericParameter:
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var gp = (GenericParameter)type;
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if (method.DeclaringType != gp.Owner && method != gp.Owner)
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return false;
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break;
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case CecilType.ByReferenceType:
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case CecilType.OptionalModifierType:
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case CecilType.PinnedType:
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case CecilType.RequiredModifierType:
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case CecilType.SentinelType:
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default:
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return false;
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}
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if (!(type is TypeSpecification))
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break;
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type = ((TypeSpecification)type).ElementType;
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}
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return type != null;
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}
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}
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}
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