130 lines
4.0 KiB
C#
130 lines
4.0 KiB
C#
/*
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Copyright (C) 2011-2015 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.IO;
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using System.Security.Cryptography;
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using System.Text;
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using dnlib.IO;
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using dnlib.DotNet;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.Agile_NET {
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class ResourceDecrypter {
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ModuleDefMD module;
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TypeDef rsrcType;
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MethodDef rsrcRrrMethod;
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MethodDef rsrcResolveMethod;
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public bool Detected {
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get { return rsrcType != null; }
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}
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public TypeDef Type {
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get { return rsrcType; }
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}
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public MethodDef RsrcRrrMethod {
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get { return rsrcRrrMethod; }
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}
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public ResourceDecrypter(ModuleDefMD module) {
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this.module = module;
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}
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public ResourceDecrypter(ModuleDefMD module, ResourceDecrypter oldOne) {
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this.module = module;
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rsrcType = Lookup(oldOne.rsrcType, "Could not find rsrcType");
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rsrcRrrMethod = Lookup(oldOne.rsrcRrrMethod, "Could not find rsrcRrrMethod");
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rsrcResolveMethod = Lookup(oldOne.rsrcResolveMethod, "Could not find rsrcResolveMethod");
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}
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T Lookup<T>(T def, string errorMessage) where T : class, ICodedToken {
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return DeobUtils.Lookup(module, def, errorMessage);
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}
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public void Find() {
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FindResourceType();
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}
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static readonly string[] requiredFields1 = new string[] {
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"System.Reflection.Assembly",
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"System.String[]",
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};
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static readonly string[] requiredFields2 = new string[] {
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"System.Reflection.Assembly",
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"System.String[]",
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"System.Collections.Hashtable",
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};
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void FindResourceType() {
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var cctor = DotNetUtils.GetModuleTypeCctor(module);
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if (cctor == null)
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return;
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foreach (var calledMethod in DotNetUtils.GetCalledMethods(module, cctor)) {
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if (!calledMethod.IsStatic || calledMethod.Body == null)
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continue;
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if (!DotNetUtils.IsMethod(calledMethod, "System.Void", "()"))
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continue;
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var type = calledMethod.DeclaringType;
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var fieldTypes = new FieldTypes(type);
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if (!fieldTypes.Exactly(requiredFields1) &&
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!fieldTypes.Exactly(requiredFields2))
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continue;
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var resolveHandler = DotNetUtils.GetMethod(type, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)");
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var decryptMethod = DotNetUtils.GetMethod(type, "System.Byte[]", "(System.IO.Stream)");
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if (resolveHandler == null || !resolveHandler.IsStatic)
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continue;
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if (decryptMethod == null || !decryptMethod.IsStatic)
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continue;
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rsrcType = type;
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rsrcRrrMethod = calledMethod;
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rsrcResolveMethod = resolveHandler;
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return;
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}
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}
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public EmbeddedResource MergeResources() {
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if (rsrcResolveMethod == null)
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return null;
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var resource = DotNetUtils.GetResource(module, DotNetUtils.GetCodeStrings(rsrcResolveMethod)) as EmbeddedResource;
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if (resource == null)
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return null;
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DeobUtils.DecryptAndAddResources(module, resource.Name.String, () => DecryptResource(resource));
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return resource;
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}
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byte[] DecryptResource(EmbeddedResource resource) {
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var reader = resource.Data;
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reader.Position = 0;
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var key = reader.ReadString();
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var data = reader.ReadRemainingBytes();
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var cryptoTransform = new DESCryptoServiceProvider {
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Key = Encoding.ASCII.GetBytes(key),
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IV = Encoding.ASCII.GetBytes(key),
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}.CreateDecryptor();
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var memStream = new MemoryStream(data);
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using (var reader2 = new BinaryReader(new CryptoStream(memStream, cryptoTransform, CryptoStreamMode.Read))) {
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return reader2.ReadBytes((int)memStream.Length);
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}
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}
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}
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}
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