/*

  * 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.File;

 import java.io.FileFilter;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import org.apache.commons.io.IOUtils;

 import org.apache.commons.io.output.NullOutputStream;

 import org.owasp.dependencycheck.Engine;

 import org.owasp.dependencycheck.analyzer.exception.AnalysisException;

 import org.owasp.dependencycheck.dependency.Confidence;

 import org.owasp.dependencycheck.dependency.Dependency;

 import org.owasp.dependencycheck.dependency.Evidence;

 import org.owasp.dependencycheck.utils.FileFilterBuilder;

 import org.owasp.dependencycheck.utils.Settings;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import org.w3c.dom.Document;

 import org.xml.sax.SAXException;

 import javax.xml.parsers.DocumentBuilder;

 import javax.xml.parsers.DocumentBuilderFactory;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathExpressionException;

 import javax.xml.xpath.XPathFactory;

 import java.util.ArrayList;

 import java.util.List;

 import javax.xml.parsers.ParserConfigurationException;

 import org.owasp.dependencycheck.exception.InitializationException;

 import org.apache.commons.lang3.SystemUtils;

 /**

  * Analyzer for getting company, product, and version information from a .NET

  * assembly.

  *

  * @author colezlaw

  *

  */

 public class AssemblyAnalyzer extends AbstractFileTypeAnalyzer {

     /**

      * The analyzer name

      */

     private static final String ANALYZER_NAME = "Assembly Analyzer";

     /**

      * The analysis phase

      */

     private static final AnalysisPhase ANALYSIS_PHASE = AnalysisPhase.INFORMATION_COLLECTION;

     /**

      * The list of supported extensions

      */

     private static final String[] SUPPORTED_EXTENSIONS = {"dll", "exe"};

     /**

      * The temp value for GrokAssembly.exe

      */

     private File grokAssemblyExe = null;

     /**

      * Logger

      */

     private static final Logger LOGGER = LoggerFactory.getLogger(AssemblyAnalyzer.class);

     /**

      * Builds the beginnings of a List for ProcessBuilder

      *

      * @return the list of arguments to begin populating the ProcessBuilder

      */

     protected List<String> buildArgumentList() {

         // Use file.separator as a wild guess as to whether this is Windows

         final List<String> args = new ArrayList<String>();

         if (!SystemUtils.IS_OS_WINDOWS) {

             if (Settings.getString(Settings.KEYS.ANALYZER_ASSEMBLY_MONO_PATH) != null) {

                 args.add(Settings.getString(Settings.KEYS.ANALYZER_ASSEMBLY_MONO_PATH));

             } else if (isInPath("mono")) {

                 args.add("mono");

             } else {

                 return null;

             }

         }

         args.add(grokAssemblyExe.getPath());

         return args;

     }

     /**

      * Performs the analysis on a single Dependency.

      *

      * @param dependency the dependency to analyze

      * @param engine the engine to perform the analysis under

      * @throws AnalysisException if anything goes sideways

      */

     @Override

     public void analyzeFileType(Dependency dependency, Engine engine)

             throws AnalysisException {

         if (grokAssemblyExe == null) {

             LOGGER.warn("GrokAssembly didn't get deployed");

             return;

         }

         final List<String> args = buildArgumentList();

         if (args == null) {

             LOGGER.warn("Assembly Analyzer was unable to execute");

             return;

         }

         args.add(dependency.getActualFilePath());

         final ProcessBuilder pb = new ProcessBuilder(args);

         Document doc = null;

         try {

             final Process proc = pb.start();

             final DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();

             doc = builder.parse(proc.getInputStream());

             // Try evacuating the error stream

             final String errorStream = IOUtils.toString(proc.getErrorStream(), "UTF-8");

             if (null != errorStream && !errorStream.isEmpty()) {

                 LOGGER.warn("Error from GrokAssembly: {}", errorStream);

             }

             int rc = 0;

             try {

                 rc = proc.waitFor();

             } catch (InterruptedException ie) {

                 return;

             }

             if (rc == 3) {

                 LOGGER.debug("{} is not a .NET assembly or executable and as such cannot be analyzed by dependency-check",

                         dependency.getActualFilePath());

                 return;

             } else if (rc != 0) {

                 LOGGER.warn("Return code {} from GrokAssembly", rc);

             }

             final XPath xpath = XPathFactory.newInstance().newXPath();

             // First, see if there was an error

             final String error = xpath.evaluate("/assembly/error", doc);

             if (error != null && !error.isEmpty()) {

                 throw new AnalysisException(error);

             }

             final String version = xpath.evaluate("/assembly/version", doc);

             if (version != null) {

                 dependency.getVersionEvidence().addEvidence(new Evidence("grokassembly", "version",

                         version, Confidence.HIGHEST));

             }

             final String vendor = xpath.evaluate("/assembly/company", doc);

             if (vendor != null) {

                 dependency.getVendorEvidence().addEvidence(new Evidence("grokassembly", "vendor",

                         vendor, Confidence.HIGH));

             }

             final String product = xpath.evaluate("/assembly/product", doc);

             if (product != null) {

                 dependency.getProductEvidence().addEvidence(new Evidence("grokassembly", "product",

                         product, Confidence.HIGH));

             }

         } catch (ParserConfigurationException pce) {

             throw new AnalysisException("Error initializing the assembly analyzer", pce);

         } catch (IOException ioe) {

             throw new AnalysisException(ioe);

         } catch (SAXException saxe) {

             throw new AnalysisException("Couldn't parse GrokAssembly result", saxe);

         } catch (XPathExpressionException xpe) {

             // This shouldn't happen

             throw new AnalysisException(xpe);

         }

     }

     /**

      * Initialize the analyzer. In this case, extract GrokAssembly.exe to a

      * temporary location.

      *

      * @throws InitializationException thrown if anything goes wrong

      */

     @Override

     public void initializeFileTypeAnalyzer() throws InitializationException {

         final File tempFile;

         try {

             tempFile = File.createTempFile("GKA", ".exe", Settings.getTempDirectory());

         } catch (IOException ex) {

             setEnabled(false);

             throw new InitializationException("Unable to create temporary file for the assembly analyzerr", ex);

         }

         FileOutputStream fos = null;

         InputStream is = null;

         try {

             fos = new FileOutputStream(tempFile);

             is = AssemblyAnalyzer.class.getClassLoader().getResourceAsStream("GrokAssembly.exe");

             IOUtils.copy(is, fos);

             grokAssemblyExe = tempFile;

             LOGGER.debug("Extracted GrokAssembly.exe to {}", grokAssemblyExe.getPath());

         } catch (IOException ioe) {

             this.setEnabled(false);

             LOGGER.warn("Could not extract GrokAssembly.exe: {}", ioe.getMessage());

             throw new InitializationException("Could not extract GrokAssembly.exe", ioe);

         } finally {

             if (fos != null) {

                 try {

                     fos.close();

                 } catch (Throwable e) {

                     LOGGER.debug("Error closing output stream");

                 }

             }

             if (is != null) {

                 try {

                     is.close();

                 } catch (Throwable e) {

                     LOGGER.debug("Error closing input stream");

                 }

             }

         }

         // Now, need to see if GrokAssembly actually runs from this location.

         final List<String> args = buildArgumentList();

         //TODO this creates an "unreported" error - if someone doesn't look

         // at the command output this could easily be missed (especially in an

         // Ant or Maven build.

         //

         // We need to create a non-fatal warning error type that will

         // get added to the report.

         //TOOD this idea needs to get replicated to the bundle audit analyzer.

         if (args == null) {

             setEnabled(false);

             LOGGER.error("----------------------------------------------------");

             LOGGER.error(".NET Assembly Analyzer could not be initialized and at least one "

                     + "'exe' or 'dll' was scanned. The 'mono' executable could not be found on "

                     + "the path; either disable the Assembly Analyzer or configure the path mono.");

             LOGGER.error("----------------------------------------------------");

             return;

         }

         try {

             final ProcessBuilder pb = new ProcessBuilder(args);

             final Process p = pb.start();

             // Try evacuating the error stream

             IOUtils.copy(p.getErrorStream(), NullOutputStream.NULL_OUTPUT_STREAM);

             final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

             factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);

             final DocumentBuilder builder = factory.newDocumentBuilder();

             final Document doc = builder.parse(p.getInputStream());

             final XPath xpath = XPathFactory.newInstance().newXPath();

             final String error = xpath.evaluate("/assembly/error", doc);

             if (p.waitFor() != 1 || error == null || error.isEmpty()) {

                 LOGGER.warn("An error occurred with the .NET AssemblyAnalyzer, please see the log for more details.");

                 LOGGER.debug("GrokAssembly.exe is not working properly");

                 grokAssemblyExe = null;

                 setEnabled(false);

                 throw new InitializationException("Could not execute .NET AssemblyAnalyzer");

             }

         } catch (InitializationException e) {

             setEnabled(false);

             throw e;

         } catch (Throwable e) {

             LOGGER.warn("An error occurred with the .NET AssemblyAnalyzer;\n"

                     + "this can be ignored unless you are scanning .NET DLLs. Please see the log for more details.");

             LOGGER.debug("Could not execute GrokAssembly {}", e.getMessage());

             setEnabled(false);

             throw new InitializationException("An error occurred with the .NET AssemblyAnalyzer", e);

         }

     }

     /**

      * Removes resources used from the local file system.

      *

      * @throws Exception thrown if there is a problem closing the analyzer

      */

     @Override

     public void close() throws Exception {

         super.close();

         try {

             if (grokAssemblyExe != null && !grokAssemblyExe.delete()) {

                 LOGGER.debug("Unable to delete temporary GrokAssembly.exe; attempting delete on exit");

                 grokAssemblyExe.deleteOnExit();

             }

         } catch (SecurityException se) {

             LOGGER.debug("Can't delete temporary GrokAssembly.exe");

             grokAssemblyExe.deleteOnExit();

         }

     }

     /**

      * The File Filter used to filter supported extensions.

      */

     private static final FileFilter FILTER = FileFilterBuilder.newInstance().addExtensions(

             SUPPORTED_EXTENSIONS).build();

     @Override

     protected FileFilter getFileFilter() {

         return FILTER;

     }

     /**

      * Gets this analyzer's name.

      *

      * @return the analyzer name

      */

     @Override

     public String getName() {

         return ANALYZER_NAME;

     }

     /**

      * Returns the phase this analyzer runs under.

      *

      * @return the phase this runs under

      */

     @Override

     public AnalysisPhase getAnalysisPhase() {

         return ANALYSIS_PHASE;

     }

     /**

      * Returns the key used in the properties file to reference the analyzer's

      * enabled property.

      *

      * @return the analyzer's enabled property setting key

      */

     @Override

     protected String getAnalyzerEnabledSettingKey() {

         return Settings.KEYS.ANALYZER_ASSEMBLY_ENABLED;

     }

     /**

      * Tests to see if a file is in the system path. <b>Note</b> - the current

      * implementation only works on non-windows platforms. For purposes of the

      * AssemblyAnalyzer this is okay as this is only needed on Mac/*nix.

      *

      * @param file the executable to look for

      * @return <code>true</code> if the file exists; otherwise

      * <code>false</code>

      */

     private boolean isInPath(String file) {

         final ProcessBuilder pb = new ProcessBuilder("which", file);

         try {

             final Process proc = pb.start();

             final int retCode = proc.waitFor();

             if (retCode == 0) {

                 return true;

             }

         } catch (IOException ex) {

             LOGGER.debug("Path seach failed for " + file);

         } catch (InterruptedException ex) {

             LOGGER.debug("Path seach failed for " + file);

         }

         return false;

     }

 }