/*

  * This file is part of dependency-check-core.

  *

  * 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.

  *

  * Copyright (c) 2012 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.analyzer;

 import java.io.UnsupportedEncodingException;

 import java.net.URLEncoder;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Iterator;

 import java.util.List;

 import java.util.ListIterator;

 import java.util.Set;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import org.owasp.dependencycheck.Engine;

 import org.owasp.dependencycheck.dependency.Dependency;

 import org.owasp.dependencycheck.dependency.Identifier;

 import org.owasp.dependencycheck.dependency.VulnerableSoftware;

 /**

  * This analyzer attempts to remove some well known false positives - specifically regarding the java runtime.

  *

  * @author Jeremy Long <jeremy.long@owasp.org>

  */

 public class FalsePositiveAnalyzer extends AbstractAnalyzer {

     //<editor-fold defaultstate="collapsed" desc="All standard implmentation details of Analyzer">

     /**

      * The set of file extensions supported by this analyzer.

      */

     private static final Set<String> EXTENSIONS = null;

     /**

      * The name of the analyzer.

      */

     private static final String ANALYZER_NAME = "False Positive Analyzer";

     /**

      * The phase that this analyzer is intended to run in.

      */

     private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.POST_IDENTIFIER_ANALYSIS;

     /**

      * Returns a list of file EXTENSIONS supported by this analyzer.

      *

      * @return a list of file EXTENSIONS supported by this analyzer.

      */

     public Set<String> getSupportedExtensions() {

         return EXTENSIONS;

     }

     /**

      * Returns the name of the analyzer.

      *

      * @return the name of the analyzer.

      */

     public String getName() {

         return ANALYZER_NAME;

     }

     /**

      * Returns whether or not this analyzer can process the given extension.

      *

      * @param extension the file extension to test for support

      * @return whether or not the specified file extension is supported by this analyzer.

      */

     public boolean supportsExtension(String extension) {

         return true;

     }

     /**

      * Returns the phase that the analyzer is intended to run in.

      *

      * @return the phase that the analyzer is intended to run in.

      */

     public AnalysisPhase getAnalysisPhase() {

         return ANALYSIS_PHASE;

     }

     //</editor-fold>

     /**

      * Analyzes the dependencies and removes bad/incorrect CPE associations based on various heuristics.

      *

      * @param dependency the dependency to analyze.

      * @param engine the engine that is scanning the dependencies

      * @throws AnalysisException is thrown if there is an error reading the JAR file.

      */

     @Override

     public void analyze(Dependency dependency, Engine engine) throws AnalysisException {

         removeJreEntries(dependency);

         removeBadMatches(dependency);

         removeWrongVersionMatches(dependency);

         removeSpuriousCPE(dependency);

         addFalseNegativeCPEs(dependency);

     }

     /**

      * <p>

      * Intended to remove spurious CPE entries. By spurious we mean duplicate, less specific CPE entries.</p>

      * <p>

      * Example:</p>

      * <code>

      * cpe:/a:some-vendor:some-product

      * cpe:/a:some-vendor:some-product:1.5

      * cpe:/a:some-vendor:some-product:1.5.2

      * </code>

      * <p>

      * Should be trimmed to:</p>

      * <code>

      * cpe:/a:some-vendor:some-product:1.5.2

      * </code>

      *

      * @param dependency the dependency being analyzed

      */

     @SuppressWarnings("null")

     private void removeSpuriousCPE(Dependency dependency) {

         final List<Identifier> ids = new ArrayList<Identifier>();

         ids.addAll(dependency.getIdentifiers());

         Collections.sort(ids);

         final ListIterator<Identifier> mainItr = ids.listIterator();

         while (mainItr.hasNext()) {

             final Identifier currentId = mainItr.next();

             final VulnerableSoftware currentCpe = parseCpe(currentId.getType(), currentId.getValue());

             if (currentCpe == null) {

                 continue;

             }

             final ListIterator<Identifier> subItr = ids.listIterator(mainItr.nextIndex());

             while (subItr.hasNext()) {

                 final Identifier nextId = subItr.next();

                 final VulnerableSoftware nextCpe = parseCpe(nextId.getType(), nextId.getValue());

                 if (nextCpe == null) {

                     continue;

                 }

                 //TODO fix the version problem below

                 if (currentCpe.getVendor().equals(nextCpe.getVendor())) {

                     if (currentCpe.getProduct().equals(nextCpe.getProduct())) {

                         // see if one is contained in the other.. remove the contained one from dependency.getIdentifier

                         final String currentVersion = currentCpe.getVersion();

                         final String nextVersion = nextCpe.getVersion();

                         if (currentVersion == null && nextVersion == null) {

                             //how did we get here?

                             Logger.getLogger(FalsePositiveAnalyzer.class

                                     .getName()).log(Level.FINE, "currentVersion and nextVersion are both null?");

                         } else if (currentVersion == null && nextVersion != null) {

                             dependency.getIdentifiers().remove(currentId);

                         } else if (nextVersion == null && currentVersion != null) {

                             dependency.getIdentifiers().remove(nextId);

                         } else if (currentVersion.length() < nextVersion.length()) {

                             if (nextVersion.startsWith(currentVersion) || "-".equals(currentVersion)) {

                                 dependency.getIdentifiers().remove(currentId);

                             }

                         } else {

                             if (currentVersion.startsWith(nextVersion) || "-".equals(nextVersion)) {

                                 dependency.getIdentifiers().remove(nextId);

                             }

                         }

                     }

                 }

             }

         }

     }

     /**

      * Regex to identify core java libraries and a few other commonly misidentified ones.

      */

     public static final Pattern CORE_JAVA = Pattern.compile("^cpe:/a:(sun|oracle|ibm):(j2[ems]e|"

             + "java(_platfrom_micro_edition|_runtime_environment|_se|virtual_machine|se_development_kit|fx)?|"

             + "jdk|jre|jsf|jsse)($|:.*)");

     /**

      * Regex to identify core java library files. This is currently incomplete.

      */

     public static final Pattern CORE_FILES = Pattern.compile("^((alt[-])?rt|jsf[-].*|jsse|jfxrt|jfr|jce|javaws|deploy|charsets)\\.jar$");

     /**

      * Removes any CPE entries for the JDK/JRE unless the filename ends with rt.jar

      *

      * @param dependency the dependency to remove JRE CPEs from

      */

     private void removeJreEntries(Dependency dependency) {

         final Set<Identifier> identifiers = dependency.getIdentifiers();

         final Iterator<Identifier> itr = identifiers.iterator();

         while (itr.hasNext()) {

             final Identifier i = itr.next();

             final Matcher coreCPE = CORE_JAVA.matcher(i.getValue());

             final Matcher coreFiles = CORE_FILES.matcher(dependency.getFileName());

             if (coreCPE.matches() && !coreFiles.matches()) {

                 itr.remove();

             }

             //replacecd with the regex above.

             //            if (("cpe:/a:sun:java".equals(i.getValue())

             //                    || "cpe:/a:oracle:java".equals(i.getValue())

             //                    || "cpe:/a:ibm:java".equals(i.getValue())

             //                    || "cpe:/a:sun:j2se".equals(i.getValue())

             //                    || "cpe:/a:oracle:j2se".equals(i.getValue())

             //                    || i.getValue().startsWith("cpe:/a:sun:java:")

             //                    || i.getValue().startsWith("cpe:/a:sun:j2se:")

             //                    || i.getValue().startsWith("cpe:/a:sun:java:jre")

             //                    || i.getValue().startsWith("cpe:/a:sun:java:jdk")

             //                    || i.getValue().startsWith("cpe:/a:sun:java_se")

             //                    || i.getValue().startsWith("cpe:/a:oracle:java_se")

             //                    || i.getValue().startsWith("cpe:/a:oracle:java:")

             //                    || i.getValue().startsWith("cpe:/a:oracle:j2se:")

             //                    || i.getValue().startsWith("cpe:/a:oracle:jre")

             //                    || i.getValue().startsWith("cpe:/a:oracle:jdk")

             //                    || i.getValue().startsWith("cpe:/a:ibm:java:"))

             //                    && !dependency.getFileName().toLowerCase().endsWith("rt.jar")) {

             //                itr.remove();

             //            }

         }

     }

     /**

      * Parses a CPE string into an IndexEntry.

      *

      * @param type the type of identifier

      * @param value the cpe identifier to parse

      * @return an VulnerableSoftware object constructed from the identifier

      */

     private VulnerableSoftware parseCpe(String type, String value) {

         if (!"cpe".equals(type)) {

             return null;

         }

         final VulnerableSoftware cpe = new VulnerableSoftware();

         try {

             cpe.parseName(value);

         } catch (UnsupportedEncodingException ex) {

             Logger.getLogger(FalsePositiveAnalyzer.class.getName()).log(Level.FINEST, null, ex);

             return null;

         }

         return cpe;

     }

     /**

      * Removes bad CPE matches for a dependency. Unfortunately, right now these are hard-coded patches for specific

      * problems identified when testing this on a LARGE volume of jar files.

      *

      * @param dependency the dependency to analyze

      */

     private void removeBadMatches(Dependency dependency) {

         final Set<Identifier> identifiers = dependency.getIdentifiers();

         final Iterator<Identifier> itr = identifiers.iterator();

         /* TODO - can we utilize the pom's groupid and artifactId to filter??? most of

          * these are due to low quality data.  Other idea would be to say any CPE

          * found based on LOW confidence evidence should have a different CPE type? (this

          * might be a better solution then just removing the URL for "best-guess" matches).

          */

         //Set<Evidence> groupId = dependency.getVendorEvidence().getEvidence("pom", "groupid");

         //Set<Evidence> artifactId = dependency.getVendorEvidence().getEvidence("pom", "artifactid");

         while (itr.hasNext()) {

             final Identifier i = itr.next();

             //TODO move this startswith expression to a configuration file?

             if ("cpe".equals(i.getType())) {

                 if ((i.getValue().matches(".*c\\+\\+.*")

                         || i.getValue().startsWith("cpe:/a:jquery:jquery")

                         || i.getValue().startsWith("cpe:/a:prototypejs:prototype")

                         || i.getValue().startsWith("cpe:/a:yahoo:yui")

                         || i.getValue().startsWith("cpe:/a:file:file")

                         || i.getValue().startsWith("cpe:/a:mozilla:mozilla")

                         || i.getValue().startsWith("cpe:/a:cvs:cvs")

                         || i.getValue().startsWith("cpe:/a:ftp:ftp")

                         || i.getValue().startsWith("cpe:/a:ssh:ssh"))

                         && (dependency.getFileName().toLowerCase().endsWith(".jar")

                         || dependency.getFileName().toLowerCase().endsWith("pom.xml"))) {

                     itr.remove();

                 } else if (i.getValue().startsWith("cpe:/a:apache:maven")

                         && !dependency.getFileName().toLowerCase().matches("maven-core-[\\d\\.]+\\.jar")) {

                     itr.remove();

                 }

             }

         }

     }

     /**

      * Removes CPE matches for the wrong version of a dependency. Currently, this only covers Axis 1 & 2.

      *

      * @param dependency the dependency to analyze

      */

     private void removeWrongVersionMatches(Dependency dependency) {

         final Set<Identifier> identifiers = dependency.getIdentifiers();

         final Iterator<Identifier> itr = identifiers.iterator();

         final String fileName = dependency.getFileName();

         if (fileName != null && fileName.contains("axis2")) {

             while (itr.hasNext()) {

                 final Identifier i = itr.next();

                 if ("cpe".equals(i.getType())) {

                     final String cpe = i.getValue();

                     if (cpe != null && (cpe.startsWith("cpe:/a:apache:axis:") || "cpe:/a:apache:axis".equals(cpe))) {

                         itr.remove();

                     }

                 }

             }

         } else if (fileName != null && fileName.contains("axis")) {

             while (itr.hasNext()) {

                 final Identifier i = itr.next();

                 if ("cpe".equals(i.getType())) {

                     final String cpe = i.getValue();

                     if (cpe != null && (cpe.startsWith("cpe:/a:apache:axis2:") || "cpe:/a:apache:axis2".equals(cpe))) {

                         itr.remove();

                     }

                 }

             }

         }

     }

     /**

      * There are some known CPE entries, specifically regarding sun and oracle products due to the acquisition and

      * changes in product names, that based on given evidence we can add the related CPE entries to ensure a complete

      * list of CVE entries.

      *

      * @param dependency the dependency being analyzed

      */

     private void addFalseNegativeCPEs(Dependency dependency) {

         final Iterator<Identifier> itr = dependency.getIdentifiers().iterator();

         while (itr.hasNext()) {

             final Identifier i = itr.next();

             if ("cpe".equals(i.getType()) && i.getValue() != null

                     && (i.getValue().startsWith("cpe:/a:oracle:opensso:")

                     || i.getValue().startsWith("cpe:/a:oracle:opensso_enterprise:")

                     || i.getValue().startsWith("cpe:/a:sun:opensso_enterprise:")

                     || i.getValue().startsWith("cpe:/a:sun:opensso:"))) {

                 final String newCpe = String.format("cpe:/a:sun:opensso_enterprise:%s", i.getValue().substring(22));

                 final String newCpe2 = String.format("cpe:/a:oracle:opensso_enterprise:%s", i.getValue().substring(22));

                 final String newCpe3 = String.format("cpe:/a:sun:opensso:%s", i.getValue().substring(22));

                 final String newCpe4 = String.format("cpe:/a:oracle:opensso:%s", i.getValue().substring(22));

                 try {

                     dependency.addIdentifier("cpe",

                             newCpe,

                             String.format("http://web.nvd.nist.gov/view/vuln/search?cpe=%s", URLEncoder.encode(newCpe, "UTF-8")));

                     dependency.addIdentifier("cpe",

                             newCpe2,

                             String.format("http://web.nvd.nist.gov/view/vuln/search?cpe=%s", URLEncoder.encode(newCpe2, "UTF-8")));

                     dependency.addIdentifier("cpe",

                             newCpe3,

                             String.format("http://web.nvd.nist.gov/view/vuln/search?cpe=%s", URLEncoder.encode(newCpe3, "UTF-8")));

                     dependency.addIdentifier("cpe",

                             newCpe4,

                             String.format("http://web.nvd.nist.gov/view/vuln/search?cpe=%s", URLEncoder.encode(newCpe4, "UTF-8")));

                 } catch (UnsupportedEncodingException ex) {

                     Logger.getLogger(FalsePositiveAnalyzer.class

                             .getName()).log(Level.FINE, null, ex);

                 }

             }

         }

     }

 }