Implement SkidSuite2 transformer (java-deobfuscator#143)

src/main/java/com/javadeobfuscator/deobfuscator/transformers/Transformers.java

@@ -60,6 +60,10 @@ public static class Zelix {
         public static final Class<? extends Transformer> FLOW_OBFUSCATION = com.javadeobfuscator.deobfuscator.transformers.zelix.FlowObfuscationTransformer.class;
     }
 
+    public static class SkidSuite {
+        public static final Class<? extends Transformer> STRING_ENCRYPTION = com.javadeobfuscator.deobfuscator.transformers.skidsuite2.StringEncryptionTransformer.class;
+    }
+
     public static class Normalizer {
         public static final Class<? extends Transformer> PACKAGE_NORMALIZER = com.javadeobfuscator.deobfuscator.transformers.normalizer.PackageNormalizer.class;
         public static final Class<? extends Transformer> CLASS_NORMALIZER = com.javadeobfuscator.deobfuscator.transformers.normalizer.ClassNormalizer.class;

src/main/java/com/javadeobfuscator/deobfuscator/transformers/skidsuite2/StringEncryptionTransformer.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2017 Sam Sun <[email protected]>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.javadeobfuscator.deobfuscator.transformers.skidsuite2;
+
+import com.javadeobfuscator.deobfuscator.analyzer.AnalyzerResult;
+import com.javadeobfuscator.deobfuscator.analyzer.MethodAnalyzer;
+import com.javadeobfuscator.deobfuscator.analyzer.frame.*;
+import com.javadeobfuscator.deobfuscator.config.TransformerConfig;
+import com.javadeobfuscator.deobfuscator.executor.Context;
+import com.javadeobfuscator.deobfuscator.executor.MethodExecutor;
+import com.javadeobfuscator.deobfuscator.executor.defined.JVMComparisonProvider;
+import com.javadeobfuscator.deobfuscator.executor.defined.JVMMethodProvider;
+import com.javadeobfuscator.deobfuscator.executor.providers.DelegatingProvider;
+import com.javadeobfuscator.deobfuscator.executor.values.JavaInteger;
+import com.javadeobfuscator.deobfuscator.executor.values.JavaObject;
+import com.javadeobfuscator.deobfuscator.executor.values.JavaValue;
+import com.javadeobfuscator.deobfuscator.transformers.Transformer;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.*;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
+// I can't believe this has to exist
+public class StringEncryptionTransformer extends Transformer<TransformerConfig> {
+    @Override
+    public boolean transform() throws Throwable {
+
+        AtomicInteger counter = new AtomicInteger();
+
+        DelegatingProvider provider = new DelegatingProvider();
+        provider.register(new JVMMethodProvider());
+        provider.register(new JVMComparisonProvider());
+
+        classNodes().forEach(wrappedClassNode -> {
+            wrappedClassNode.classNode.methods.forEach(methodNode -> {
+                AnalyzerResult result = MethodAnalyzer.analyze(wrappedClassNode.classNode, methodNode);
+
+                Map<AbstractInsnNode, InsnList> replacements = new HashMap<>();
+
+                insns:
+                for (int index = 0; index < methodNode.instructions.size(); index++) {
+                    AbstractInsnNode current = methodNode.instructions.get(index);
+                    if (!(current instanceof MethodInsnNode))
+                        continue;
+
+                    MethodInsnNode methodInsnNode = (MethodInsnNode) current;
+                    if (methodInsnNode.getOpcode() != Opcodes.INVOKESTATIC)
+                        continue;
+
+                    if (!methodInsnNode.desc.equals("([CLjava/lang/String;I)Ljava/lang/String;"))
+                        continue;
+
+                    MethodFrame frame = (MethodFrame) result.getFrames().get(methodInsnNode).get(0);
+
+                    List<JavaValue> args = new ArrayList<>();
+                    Map<AbstractInsnNode, InsnList> localReplacements = new HashMap<>();
+
+                    for (Frame arg : frame.getArgs()) {
+                        if (arg instanceof LdcFrame) {
+                            Object cst = ((LdcFrame) arg).getConstant();
+                            if (cst == null) {
+                                continue insns;
+                            }
+                            if (cst instanceof String) {
+                                args.add(new JavaObject(cst, "java/lang/String"));
+                            } else {
+                                args.add(new JavaInteger(((Number) cst).intValue()));
+                            }
+                        } else if (arg instanceof NewArrayFrame) {
+                            NewArrayFrame newArrayFrame = (NewArrayFrame) arg;
+
+                            {
+                                InsnList list = new InsnList();
+                                list.add(new InsnNode(Opcodes.POP));
+                                list.add(new InsnNode(Opcodes.ACONST_NULL));
+                                localReplacements.put(result.getMapping().get(newArrayFrame), list);
+                            }
+
+                            if (newArrayFrame.getLength() instanceof LdcFrame) {
+                                char[] arr = new char[((Number) ((LdcFrame) newArrayFrame.getLength()).getConstant()).intValue()];
+                                JavaObject obj = new JavaObject(arr, "[C");
+                                for (Frame child0 : arg.getChildren()) {
+                                    if (child0 instanceof ArrayStoreFrame) {
+                                        ArrayStoreFrame arrayStoreFrame = (ArrayStoreFrame) child0;
+                                        if (arrayStoreFrame.getIndex() instanceof LdcFrame && arrayStoreFrame.getObject() instanceof LdcFrame) {
+                                            {
+                                                InsnList list = new InsnList();
+                                                list.add(new InsnNode(Opcodes.POP2));
+                                                list.add(new InsnNode(Opcodes.POP));
+                                                localReplacements.put(result.getMapping().get(arrayStoreFrame), list);
+                                            }
+                                            arr[((Number) ((LdcFrame) arrayStoreFrame.getIndex()).getConstant()).intValue()] = (char) ((Number) ((LdcFrame) arrayStoreFrame.getObject()).getConstant()).intValue();
+                                        } else {
+                                            continue insns;
+                                        }
+                                    }
+                                }
+                                args.add(obj);
+                            } else {
+                                continue insns;
+                            }
+                        }
+                    }
+
+                    if (classes.containsKey(methodInsnNode.owner)) {
+                        Context context = new Context(provider);
+                        context.push(wrappedClassNode.classNode.name, methodNode.name, wrappedClassNode.constantPoolSize);
+                        ClassNode innerClassNode = classes.get(methodInsnNode.owner).classNode;
+                        MethodNode decrypterNode = innerClassNode.methods.stream().filter(mn -> mn.name.equals(methodInsnNode.name) && mn.desc.equals(methodInsnNode.desc)).findFirst().orElse(null);
+                        try {
+                            Object o = MethodExecutor.execute(wrappedClassNode, decrypterNode, args, null, context);
+                            InsnList list = new InsnList();
+                            for (int i = 0; i < args.size(); i++) {
+                                list.add(new InsnNode(Opcodes.POP));
+                            }
+                            list.add(new LdcInsnNode(o));
+                            methodNode.instructions.insertBefore(methodInsnNode, list);
+                            methodNode.instructions.remove(methodInsnNode);
+                            replacements.putAll(localReplacements);
+                            counter.getAndIncrement();
+                        } catch (Throwable t) {
+                            System.out.println("Error while decrypting string. " + methodInsnNode.owner + " " + methodInsnNode.name + methodInsnNode.desc);
+                            t.printStackTrace(System.out);
+                        }
+                    }
+                }
+
+                replacements.forEach((k, v) -> {
+                    methodNode.instructions.insertBefore(k, v);
+                    methodNode.instructions.remove(k);
+                });
+            });
+        });
+
+        System.out.println("[SkidSuite2] [StringEncryptionTransformer] Decrypted " + counter + " strings");
+        return true;
+    }
+}