jtaint.RuntimeAdapter.java Source code

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Here is the source code for jtaint.RuntimeAdapter.java

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/*
 *  Copyright 2009-2012 Michael Dalton
 *
 *  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 jtaint;

import org.objectweb.asm.ClassAdapter;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

import org.objectweb.asm.commons.SimpleAdviceAdapter;

import java.util.ArrayList;
import java.util.List;

/** Instrument java.lang.Runtime to prevent command injection attacks.
 * Forbid the pathname of the program to be tainted. Tainted arguments, however,
 * are allowed. Validation checks are inserted into the exec methods.
 */

public class RuntimeAdapter extends StubAdapter implements Opcodes {
    private static final List methodList;
    private String className;

    static {
        List l = new ArrayList();
        l.add(new MethodDecl(ACC_PUBLIC, "exec", "(Ljava/lang/String;)Ljava/lang/Process;"));
        l.add(new MethodDecl(ACC_PUBLIC, "exec", "(Ljava/lang/String;[Ljava/lang/String;)Ljava/lang/Process;"));
        l.add(new MethodDecl(ACC_PUBLIC, "exec",
                "(Ljava/lang/String;[Ljava/lang/String;Ljava/io/File;)Ljava/lang/Process;"));

        l.add(new MethodDecl(ACC_PUBLIC, "exec", "([Ljava/lang/String;)Ljava/lang/Process;"));
        l.add(new MethodDecl(ACC_PUBLIC, "exec", "([Ljava/lang/String;[Ljava/lang/String;)Ljava/lang/Process;"));
        l.add(new MethodDecl(ACC_PUBLIC, "exec",
                "([Ljava/lang/String;[Ljava/lang/String;Ljava/io/File;)Ljava/lang/Process;"));
        methodList = l;
    }

    public RuntimeAdapter(ClassVisitor cv) {
        super(cv, methodList);
    }

    public void visit(int version, int access, String name, String signature, String superName,
            String[] interfaces) {
        className = name;
        super.visit(version, access, name, signature, superName, interfaces);
    }

    public MethodVisitor visitMethod(final int access, final String name, final String desc, String signature,
            String[] exceptions) {

        final MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
        if (!methodList.contains(new MethodDecl(access, name, desc)))
            return mv;
        return new SimpleAdviceAdapter(mv, className, access, name, desc) {
            public void onMethodEnter() {
                Type cmdType = Type.getArgumentTypes(desc)[0];

                mv.visitVarInsn(ALOAD, 1);
                mv.visitMethodInsn(INVOKESTATIC, "jtaint/ExecUtil", "validateExec",
                        "(" + cmdType.getDescriptor() + ")V");
            }
        };
    }

    public static InstrumentationBuilder builder() {
        return Builder.getInstance();
    }

    private static class Builder implements InstrumentationBuilder {
        private static final Builder b = new Builder();

        public static InstrumentationBuilder getInstance() {
            return b;
        }

        public ClassVisitor build(ClassVisitor cv) {
            return new RuntimeAdapter(cv);
        }
    }
}