Loading classes from the plugin archive

(cherry picked from commit 2adf04c)

src/main/java/org/owasp/webgoat/plugins/Plugin.java

@@ -0,0 +1,61 @@
+package org.owasp.webgoat.plugins;
+
+import org.owasp.webgoat.lessons.AbstractLesson;
+
+import java.nio.file.Path;
+
+public class Plugin {
+
+    private final Class<AbstractLesson> lesson;
+    private final String lessonPlanHtml;
+    private final String lessonSolutionHtml;
+
+    public static class Builder {
+
+        private Path pluginDirectory;
+        private Class lesson;
+
+        public Builder loadClass(String name, byte[] classFile) {
+            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+            PluginClassLoader pluginClassLoader = new PluginClassLoader(contextClassLoader, classFile);
+            try {
+                String realClassName = name.replace("/lesson_plans/", "").replaceAll("/", ".").replaceAll(".class", "");
+                Class clazz = pluginClassLoader.loadClass(realClassName);
+                if (AbstractLesson.class.isAssignableFrom(clazz)) {
+                    this.lesson = clazz;
+                }
+            } catch (ClassNotFoundException e) {
+                e.printStackTrace();
+            }
+            return this;
+        }
+
+        public Builder setBaseDirectory(Path pluginDirectory) {
+            this.pluginDirectory = pluginDirectory;
+            return this;
+        }
+
+        public Plugin build() {
+            return new Plugin(this.lesson, null, null);
+        }
+    }
+
+    public Plugin(Class<AbstractLesson> lesson, String lessonPlanHtml, String lessonSolutionHtml) {
+        this.lesson = lesson;
+        this.lessonPlanHtml = lessonPlanHtml;
+        this.lessonSolutionHtml = lessonSolutionHtml;
+    }
+
+
+    public String getLessonPlanHtml() {
+        return lessonPlanHtml;
+    }
+
+    public Class<AbstractLesson> getLesson() {
+        return lesson;
+    }
+
+    public String getLessonSolutionHtml() {
+        return lessonSolutionHtml;
+    }
+}

src/main/java/org/owasp/webgoat/plugins/PluginClassLoader.java

@@ -0,0 +1,18 @@
+package org.owasp.webgoat.plugins;
+
+public class PluginClassLoader extends ClassLoader {
+
+    private final byte[] classFile;
+
+    public PluginClassLoader(ClassLoader parent, byte[] classFile) {
+        super(parent);
+        this.classFile = classFile;
+    }
+
+    public Class findClass(String name) {
+        return defineClass(name, classFile, 0, classFile.length);
+    }
+
+
+}
+

src/main/java/org/owasp/webgoat/plugins/PluginExtractor.java

@@ -0,0 +1,79 @@
+package org.owasp.webgoat.plugins;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.net.URI;
+import java.nio.file.FileSystem;
+import java.nio.file.FileSystems;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.HashMap;
+
+/**
+ * Extract the zip file and place the files in a temp directory
+ */
+public class PluginExtractor {
+
+    private static final String DIRECTORY = "plugins";
+    private final Path pluginArchive;
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+
+    public PluginExtractor(Path pluginArchive) {
+        this.pluginArchive = pluginArchive;
+    }
+
+
+    public Plugin extract() {
+        final Plugin.Builder pluginBuilder = new Plugin.Builder();
+        FileSystem zip = null;
+        try {
+            zip = createZipFileSystem();
+            final Path root = zip.getPath("/");
+            final Path tempDirectory = Files.createTempDirectory(DIRECTORY);
+            pluginBuilder.setBaseDirectory(tempDirectory);
+            Files.walkFileTree(root, new SimpleFileVisitor<Path>() {
+                @Override
+                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                    if (file.toString().endsWith(".class")) {
+                        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                        Files.copy(file, bos);
+                        pluginBuilder.loadClass(file.toString(), bos.toByteArray());
+                    }
+                    Files.copy(file, tempDirectory, StandardCopyOption.REPLACE_EXISTING);
+                    return FileVisitResult.CONTINUE;
+                }
+            });
+            return pluginBuilder.build();
+        } catch (IOException io) {
+            logger.error(String.format("Unable to extract: %s", pluginArchive.getFileName()), io);
+        } finally {
+            closeZipFileSystem(zip);
+        }
+
+        return pluginBuilder.build();
+    }
+
+    private FileSystem createZipFileSystem() throws IOException {
+        final URI uri = URI.create("jar:file:" + pluginArchive.toUri().getPath());
+        return FileSystems.newFileSystem(uri, new HashMap<String, Object>());
+    }
+
+    private void closeZipFileSystem(FileSystem zip) {
+        if (zip != null) {
+            try {
+                zip.close();
+            } catch (IOException e) {
+                //ignore
+            }
+        }
+    }
+
+
+}

src/main/java/org/owasp/webgoat/plugins/PluginsLoader.java

@@ -0,0 +1,39 @@
+package org.owasp.webgoat.plugins;
+
+import java.io.IOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.ArrayList;
+import java.util.List;
+
+public class PluginsLoader {
+
+    private final Path path;
+
+    public PluginsLoader(Path path) {
+        this.path = path;
+    }
+
+    public List<Plugin> loadPlugins() {
+        final List<Plugin> plugins = new ArrayList<Plugin>();
+        try {
+            Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
+
+                @Override
+                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                    plugins.add(new PluginExtractor(file).extract());
+                    return FileVisitResult.CONTINUE;
+                }
+
+            });
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return plugins;
+    }
+
+
+}