com.h3xstream.findsecbugs.password.HashUnsafeEqualsDetector Maven / Gradle / Ivy

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Core module of the project. It include all the FindBugs detectors. The resulting jar is the published plugin.
There is a newer version: 1.13.0
/**
 * Find Security Bugs
 * Copyright (c) Philippe Arteau, All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3.0 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.
 */
package com.h3xstream.findsecbugs.password;

import com.h3xstream.findsecbugs.common.StackUtils;
import com.h3xstream.findsecbugs.common.matcher.InvokeMatcherBuilder;
import com.h3xstream.findsecbugs.injection.BasicInjectionDetector;
import com.h3xstream.findsecbugs.injection.InjectionPoint;
import com.h3xstream.findsecbugs.taintanalysis.Taint;
import com.h3xstream.findsecbugs.taintanalysis.TaintFrame;
import com.h3xstream.findsecbugs.taintanalysis.TaintFrameAdditionalVisitor;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Priorities;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import org.apache.bcel.generic.*;

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

import static com.h3xstream.findsecbugs.common.matcher.InstructionDSL.invokeInstruction;

/**
 * 
 *     Detect:
 * 
 *
 *  * if(hashInput.equals(actualHash)) {
 *     ....
 * }
 * 
 */
public class HashUnsafeEqualsDetector extends BasicInjectionDetector implements TaintFrameAdditionalVisitor {

    private static final String UNSAFE_HASH_EQUALS_TYPE = "UNSAFE_HASH_EQUALS";

    private static final InvokeMatcherBuilder STRING_EQUALS_METHOD = invokeInstruction() //
            .atClass("java/lang/String").atMethod("equals").withArgs("(Ljava/lang/Object;)Z");

    private static final InvokeMatcherBuilder ARRAYS_EQUALS_METHOD = invokeInstruction() //
            .atClass("java/util/Arrays").atMethod("equals").withArgs("([B[B)Z");
    private static final boolean DEBUG = false;


    public static List HASH_WORDS = new ArrayList();
    static {
        HASH_WORDS.add("hash");
        HASH_WORDS.add("md5");
        HASH_WORDS.add("sha");
        HASH_WORDS.add("digest");

    }

    public HashUnsafeEqualsDetector(BugReporter bugReporter) {
        super(bugReporter);
        registerVisitor(this);
    }

    @Override
    protected int getPriorityFromTaintFrame(TaintFrame fact, int offset) throws DataflowAnalysisException {

        Taint rightValue = fact.getStackValue(offset);
        Taint leftValue = fact.getStackValue(offset == 0 ? 1 : 0);

        boolean passwordVariableLeft = leftValue.isUnknown() && leftValue.hasTag(Taint.Tag.HASH_VARIABLE);
        boolean passwordVariableRight = rightValue.isUnknown() && rightValue.hasTag(Taint.Tag.HASH_VARIABLE);

        //Is a constant value that was tag because the value was place in a variable name "password" at some point.
        if (passwordVariableLeft  || passwordVariableRight) {
            return Priorities.NORMAL_PRIORITY;
        } else {
            return Priorities.IGNORE_PRIORITY;
        }
    }

    @Override
    protected InjectionPoint getInjectionPoint(InvokeInstruction invoke, ConstantPoolGen cpg,
                                               InstructionHandle handle) {
        if(STRING_EQUALS_METHOD.matches(invoke,cpg) || ARRAYS_EQUALS_METHOD.matches(invoke,cpg)) {
            return new InjectionPoint(new int[]{0,1}, UNSAFE_HASH_EQUALS_TYPE);
        }
        return InjectionPoint.NONE;
    }

    @Override
    public void visitInvoke(InvokeInstruction invoke, MethodGen methodGen, TaintFrame frameType, List parameters, ConstantPoolGen cpg) {

    }

    @Override
    public void visitReturn(MethodGen methodGen, Taint returnValue, ConstantPoolGen cpg) throws Exception {

    }

    @Override
    public void visitLoad(LoadInstruction instruction, MethodGen methodGen, TaintFrame frameType, int numProduced, ConstantPoolGen cpg) {
        //Extract the name of the variable
        int index = instruction.getIndex();
        LocalVariableGen var = StackUtils.getLocalVariable(methodGen, index);
        if(var == null) {
            if(DEBUG) System.out.println("Unable to get field name for index "+ index + " in "+methodGen);
            return;
        }
        String fieldName = var.getName();

        boolean isHashVariable = false;
        String fieldNameLower = fieldName.toLowerCase();
        for (String password : HASH_WORDS) {
            if (fieldNameLower.contains(password)) {
                isHashVariable = true;
            }
        }

        if(!isHashVariable) {return;}

        //Mark local variable
        Taint passwordValue = frameType.getValue(index);
        passwordValue.addTag(Taint.Tag.HASH_VARIABLE);

        if(numProduced <= 0) {return;}

        //Mark the stack value
        try {
            for(int indexStack=0;indexStack