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Add ExitVisitor to the TerminalTransformer that finds and intercepts any calls to Runtime.exit or System.exit.

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This commit is contained in:
Lex Manos 2014-07-12 17:20:01 -07:00
parent 87dde51b8d
commit b1ec7b420c
1 changed files with 103 additions and 2 deletions
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105
fml/src/main/java/cpw/mods/fml/common/asm/transformers/TerminalTransformer.java
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@ -1,12 +1,113 @@
package cpw.mods.fml.common.asm.transformers;
import org.objectweb.asm.*;
import cpw.mods.fml.relauncher.FMLRelaunchLog;
import cpw.mods.fml.relauncher.FMLSecurityManager.ExitTrappedException;
import net.minecraft.launchwrapper.IClassTransformer;
public class TerminalTransformer implements IClassTransformer {
public class TerminalTransformer implements IClassTransformer
{
@Override
public byte[] transform(String name, String transformedName, byte[] basicClass)
{
return basicClass;
ClassReader reader = new ClassReader(basicClass);
ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS);
ClassVisitor visitor = writer;
visitor = new ExitVisitor(visitor);
reader.accept(visitor, 0);
return writer.toByteArray();
}
public static class ExitVisitor extends ClassVisitor
{
private String clsName = null;
private static final String callbackOwner = org.objectweb.asm.Type.getInternalName(ExitVisitor.class);
private ExitVisitor(ClassVisitor cv)
{
super(Opcodes.ASM4, cv);
}
@Override
public void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
{
super.visit(version, access, name, signature, superName, interfaces);
this.clsName = name;
}
@Override
public MethodVisitor visitMethod(int mAccess, final String mName, final String mDesc, String mSignature, String[] mExceptions)
{
final boolean warn = !clsName.equals("net/minecraft/client/Minecraft") &&
!clsName.equals("net/minecraft/server/dedicated/DedicatedServer") &&
!clsName.equals("cpw/mods/fml/common/FMLCommonHandler");
return new MethodVisitor(Opcodes.ASM4, super.visitMethod(mAccess, mName, mDesc, mSignature, mExceptions))
{
public void visitMethodInsn(int opcode, String owner, String name, String desc)
{
if (opcode == Opcodes.INVOKESTATIC && owner.equals("java/lang/System") && name.equals("exit") && desc.equals("(I)V"))
{
if (warn)
{
FMLRelaunchLog.warning("=============================================================");
FMLRelaunchLog.warning("MOD HAS DIRECT REFERENCE System.exit() THIS IS NOT ALLOWED REROUTING TO FMLCommonHandler!");
FMLRelaunchLog.warning("Offendor: %s.%s%s", ExitVisitor.this.clsName, mName, mDesc);
FMLRelaunchLog.warning("=============================================================");
}
owner = ExitVisitor.callbackOwner;
name = "systemExitCalled";
}
else if (opcode == Opcodes.INVOKEVIRTUAL && owner.equals("java/lang/Runtime") && name.equals("exit") && desc.equals("(I)V"))
{
if (warn)
{
FMLRelaunchLog.warning("=============================================================");
FMLRelaunchLog.warning("MOD HAS DIRECT REFERENCE Runtime.exit() THIS IS NOT ALLOWED REROUTING TO FMLCommonHandler!");
FMLRelaunchLog.warning("Offendor: %s.%s%s", ExitVisitor.this.clsName, mName, mDesc);
FMLRelaunchLog.warning("=============================================================");
}
opcode = Opcodes.INVOKESTATIC;
owner = ExitVisitor.callbackOwner;
name = "runtimeExitCalled";
desc = "(Ljava/lang/Runtime;I)V";
}
super.visitMethodInsn(opcode, owner, name, desc);
}
};
}
// Intercept System.exit, and check if the caller is allowed to use it, if not wrap it in a ExitTrappedException
public static void systemExitCalled(int status)
{
ExitVisitor.checkAccess();
System.exit(status);
}
// Intercept Runtime.getRuntime().exit, and check if the caller is allowed to use it, if not wrap it in a ExitTrappedException
public static void runtimeExitCalled(Runtime runtime, int status)
{
ExitVisitor.checkAccess();
runtime.exit(status);
}
private static void checkAccess()
{
StackTraceElement[] cause = Thread.currentThread().getStackTrace();
String callingClass = cause.length > 2 ? cause[3].getClassName() : "none";
String callingParent = cause.length > 3 ? cause[4].getClassName() : "none";
// FML is allowed to call system exit and the Minecraft applet (from the quit button), and the dedicated server (from itself)
if (!(callingClass.startsWith("cpw.mods.fml.") ||
("net.minecraft.client.Minecraft".equals(callingClass) && "net.minecraft.client.Minecraft".equals(callingParent)) ||
("net.minecraft.server.dedicated.DedicatedServer".equals(callingClass) && "net.minecraft.server.MinecraftServer".equals(callingParent)))
)
{
throw new ExitTrappedException();
}
}
}
}