+ * The AccessControlContext of the thread that created the instance of + * URLClassLoader will be used when subsequently loading classes and + * resources. + *
+ * The classes that are loaded are by default granted permission only to + * access the URLs specified when the URLClassLoader was created. + * + * @author David Connelly + * @since 1.2 + */ +public class URLClassLoader extends SecureClassLoader { + /* The search path for classes and resources */ + URLClassPath ucp; + + /* The context to be used when loading classes and resources */ + private AccessControlContext acc; + + /** + * Constructs a new URLClassLoader for the given URLs. The URLs will be + * searched in the order specified for classes and resources after first + * searching in the specified parent class loader. Any URL that ends with + * a '/' is assumed to refer to a directory. Otherwise, the URL is assumed + * to refer to a JAR file which will be downloaded and opened as needed. + * + *
If there is a security manager, this method first
+ * calls the security manager's checkCreateClassLoader method
+ * to ensure creation of a class loader is allowed.
+ *
+ * @param urls the URLs from which to load classes and resources
+ * @param parent the parent class loader for delegation
+ * @exception SecurityException if a security manager exists and its
+ * checkCreateClassLoader method doesn't allow
+ * creation of a class loader.
+ * @see SecurityManager#checkCreateClassLoader
+ */
+ public URLClassLoader(URL[] urls, ClassLoader parent) {
+ super(parent);
+ // this is to make the stack depth consistent with 1.1
+ SecurityManager security = System.getSecurityManager();
+ if (security != null) {
+ security.checkCreateClassLoader();
+ }
+ ucp = new URLClassPath(urls);
+ acc = AccessController.getContext();
+ }
+
+ /**
+ * Constructs a new URLClassLoader for the specified URLs using the
+ * default delegation parent ClassLoader. The URLs will
+ * be searched in the order specified for classes and resources after
+ * first searching in the parent class loader. Any URL that ends with
+ * a '/' is assumed to refer to a directory. Otherwise, the URL is
+ * assumed to refer to a JAR file which will be downloaded and opened
+ * as needed.
+ *
+ *
If there is a security manager, this method first
+ * calls the security manager's checkCreateClassLoader method
+ * to ensure creation of a class loader is allowed.
+ *
+ * @param urls the URLs from which to load classes and resources
+ *
+ * @exception SecurityException if a security manager exists and its
+ * checkCreateClassLoader method doesn't allow
+ * creation of a class loader.
+ * @see SecurityManager#checkCreateClassLoader
+ */
+ public URLClassLoader(URL[] urls) {
+ super();
+ // this is to make the stack depth consistent with 1.1
+ SecurityManager security = System.getSecurityManager();
+ if (security != null) {
+ security.checkCreateClassLoader();
+ }
+ ucp = new URLClassPath(urls);
+ acc = AccessController.getContext();
+ }
+
+ /**
+ * Constructs a new URLClassLoader for the specified URLs, parent
+ * class loader, and URLStreamHandlerFactory. The parent argument
+ * will be used as the parent class loader for delegation. The
+ * factory argument will be used as the stream handler factory to
+ * obtain protocol handlers when creating new jar URLs.
+ *
+ *
If there is a security manager, this method first
+ * calls the security manager's checkCreateClassLoader method
+ * to ensure creation of a class loader is allowed.
+ *
+ * @param urls the URLs from which to load classes and resources
+ * @param parent the parent class loader for delegation
+ * @param factory the URLStreamHandlerFactory to use when creating URLs
+ *
+ * @exception SecurityException if a security manager exists and its
+ * checkCreateClassLoader method doesn't allow
+ * creation of a class loader.
+ * @see SecurityManager#checkCreateClassLoader
+ */
+ public URLClassLoader(URL[] urls, ClassLoader parent,
+ URLStreamHandlerFactory factory) {
+ super(parent);
+ // this is to make the stack depth consistent with 1.1
+ SecurityManager security = System.getSecurityManager();
+ if (security != null) {
+ security.checkCreateClassLoader();
+ }
+ ucp = new URLClassPath(urls, factory);
+ acc = AccessController.getContext();
+ }
+
+ /**
+ * Appends the specified URL to the list of URLs to search for
+ * classes and resources.
+ *
+ * If the URL specified is
+ * If the protocol of this URL is "jar", then the permission granted
+ * is based on the permission that is required by the URL of the Jar
+ * file.
+ *
+ * If the protocol is "file" and there is an authority component, then
+ * permission to connect to and accept connections from that authority
+ * may be granted. If the protocol is "file"
+ * and the path specifies a file, then permission to read that
+ * file is granted. If protocol is "file" and the path is
+ * a directory, permission is granted to read all files
+ * and (recursively) all files and subdirectories contained in
+ * that directory.
+ *
+ * If the protocol is not "file", then permission
+ * to connect to and accept connections from the URL's host is granted.
+ * @param codesource the codesource
+ * @return the permissions granted to the codesource
+ */
+ protected PermissionCollection getPermissions(CodeSource codesource)
+ {
+ PermissionCollection perms = super.getPermissions(codesource);
+
+ URL url = codesource.getLocation();
+
+ Permission p;
+ URLConnection urlConnection;
+
+ try {
+ urlConnection = url.openConnection();
+ p = urlConnection.getPermission();
+ } catch (java.io.IOException ioe) {
+ p = null;
+ urlConnection = null;
+ }
+
+ if (p instanceof FilePermission) {
+ // if the permission has a separator char on the end,
+ // it means the codebase is a directory, and we need
+ // to add an additional permission to read recursively
+ String path = p.getName();
+ if (path.endsWith(File.separator)) {
+ path += "-";
+ p = new FilePermission(path, SecurityConstants.FILE_READ_ACTION);
+ }
+ } else if ((p == null) && (url.getProtocol().equals("file"))) {
+ String path = url.getFile().replace('/', File.separatorChar);
+ path = ParseUtil.decode(path);
+ if (path.endsWith(File.separator))
+ path += "-";
+ p = new FilePermission(path, SecurityConstants.FILE_READ_ACTION);
+ } else {
+ /**
+ * Not loading from a 'file:' URL so we want to give the class
+ * permission to connect to and accept from the remote host
+ * after we've made sure the host is the correct one and is valid.
+ */
+ URL locUrl = url;
+ if (urlConnection instanceof JarURLConnection) {
+ locUrl = ((JarURLConnection)urlConnection).getJarFileURL();
+ }
+ String host = locUrl.getHost();
+ if (host != null && (host.length() > 0))
+ p = new SocketPermission(host,
+ SecurityConstants.SOCKET_CONNECT_ACCEPT_ACTION);
+ }
+
+ // make sure the person that created this class loader
+ // would have this permission
+
+ if (p != null) {
+ final SecurityManager sm = System.getSecurityManager();
+ if (sm != null) {
+ final Permission fp = p;
+ AccessController.doPrivileged(new PrivilegedAction() {
+ public Object run() throws SecurityException {
+ sm.checkPermission(fp);
+ return null;
+ }
+ }, acc);
+ }
+ perms.add(p);
+ }
+ return perms;
+ }
+
+ /**
+ * Creates a new instance of URLClassLoader for the specified
+ * URLs and parent class loader. If a security manager is
+ * installed, the null or is already in the
+ * list of URLs, then invoking this method has no effect.
+ *
+ * @param url the URL to be added to the search path of URLs
+ */
+ protected void addURL(URL url) {
+ ucp.addURL(url);
+ }
+
+ /**
+ * Returns the search path of URLs for loading classes and resources.
+ * This includes the original list of URLs specified to the constructor,
+ * along with any URLs subsequently appended by the addURL() method.
+ * @return the search path of URLs for loading classes and resources.
+ */
+ public URL[] getURLs() {
+ return ucp.getURLs();
+ }
+
+ /**
+ * Finds and loads the class with the specified name from the URL search
+ * path. Any URLs referring to JAR files are loaded and opened as needed
+ * until the class is found.
+ *
+ * @param name the name of the class
+ * @return the resulting class
+ * @exception ClassNotFoundException if the class could not be found
+ */
+ protected Class findClass(final String name)
+ throws ClassNotFoundException
+ {
+ try {
+ return (Class)
+ AccessController.doPrivileged(new PrivilegedExceptionAction() {
+ public Object run() throws ClassNotFoundException {
+ String path = name.replace('.', '/').concat(".class");
+ Resource res = ucp.getResource(path, false);
+ if (res != null) {
+ try {
+ return defineClass(name, res);
+ } catch (IOException e) {
+ throw new ClassNotFoundException(name, e);
+ }
+ } else {
+ throw new ClassNotFoundException(name);
+ }
+ }
+ }, acc);
+ } catch (java.security.PrivilegedActionException pae) {
+ throw (ClassNotFoundException) pae.getException();
+ }
+ }
+
+ /*
+ * Defines a Class using the class bytes obtained from the specified
+ * Resource. The resulting Class must be resolved before it can be
+ * used.
+ */
+ private Class defineClass(String name, Resource res) throws IOException {
+ int i = name.lastIndexOf('.');
+ URL url = res.getCodeSourceURL();
+ if (i != -1) {
+ String pkgname = name.substring(0, i);
+ // Check if package already loaded.
+ Package pkg = getPackage(pkgname);
+ Manifest man = res.getManifest();
+ if (pkg != null) {
+ // Package found, so check package sealing.
+ if (pkg.isSealed()) {
+ // Verify that code source URL is the same.
+ if (!pkg.isSealed(url)) {
+ throw new SecurityException(
+ "sealing violation: package " + pkgname + " is sealed");
+ }
+
+ } else {
+ // Make sure we are not attempting to seal the package
+ // at this code source URL.
+ if ((man != null) && isSealed(pkgname, man)) {
+ throw new SecurityException(
+ "sealing violation: can't seal package " + pkgname +
+ ": already loaded");
+ }
+ }
+ } else {
+ if (man != null) {
+ definePackage(pkgname, man, url);
+ } else {
+ definePackage(pkgname, null, null, null, null, null, null, null);
+ }
+ }
+ }
+ // Now read the class bytes and define the class
+ java.nio.ByteBuffer bb = res.getByteBuffer();
+ if (bb != null) {
+ // Use (direct) ByteBuffer:
+ CodeSigner[] signers = res.getCodeSigners();
+ CodeSource cs = new CodeSource(url, signers);
+ return defineClass(name, bb, cs);
+ } else {
+ byte[] b = res.getBytes();
+ // must read certificates AFTER reading bytes.
+ CodeSigner[] signers = res.getCodeSigners();
+ CodeSource cs = new CodeSource(url, signers);
+ return defineClass(name, b, 0, b.length, cs);
+ }
+ }
+
+ /**
+ * Defines a new package by name in this ClassLoader. The attributes
+ * contained in the specified Manifest will be used to obtain package
+ * version and sealing information. For sealed packages, the additional
+ * URL specifies the code source URL from which the package was loaded.
+ *
+ * @param name the package name
+ * @param man the Manifest containing package version and sealing
+ * information
+ * @param url the code source url for the package, or null if none
+ * @exception IllegalArgumentException if the package name duplicates
+ * an existing package either in this class loader or one
+ * of its ancestors
+ * @return the newly defined Package object
+ */
+ protected Package definePackage(String name, Manifest man, URL url)
+ throws IllegalArgumentException
+ {
+ String path = name.replace('.', '/').concat("/");
+ String specTitle = null, specVersion = null, specVendor = null;
+ String implTitle = null, implVersion = null, implVendor = null;
+ String sealed = null;
+ URL sealBase = null;
+
+ Attributes attr = man.getAttributes(path);
+ if (attr != null) {
+ specTitle = attr.getValue(Name.SPECIFICATION_TITLE);
+ specVersion = attr.getValue(Name.SPECIFICATION_VERSION);
+ specVendor = attr.getValue(Name.SPECIFICATION_VENDOR);
+ implTitle = attr.getValue(Name.IMPLEMENTATION_TITLE);
+ implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION);
+ implVendor = attr.getValue(Name.IMPLEMENTATION_VENDOR);
+ sealed = attr.getValue(Name.SEALED);
+ }
+ attr = man.getMainAttributes();
+ if (attr != null) {
+ if (specTitle == null) {
+ specTitle = attr.getValue(Name.SPECIFICATION_TITLE);
+ }
+ if (specVersion == null) {
+ specVersion = attr.getValue(Name.SPECIFICATION_VERSION);
+ }
+ if (specVendor == null) {
+ specVendor = attr.getValue(Name.SPECIFICATION_VENDOR);
+ }
+ if (implTitle == null) {
+ implTitle = attr.getValue(Name.IMPLEMENTATION_TITLE);
+ }
+ if (implVersion == null) {
+ implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION);
+ }
+ if (implVendor == null) {
+ implVendor = attr.getValue(Name.IMPLEMENTATION_VENDOR);
+ }
+ if (sealed == null) {
+ sealed = attr.getValue(Name.SEALED);
+ }
+ }
+ if ("true".equalsIgnoreCase(sealed)) {
+ sealBase = url;
+ }
+ return definePackage(name, specTitle, specVersion, specVendor,
+ implTitle, implVersion, implVendor, sealBase);
+ }
+
+ /*
+ * Returns true if the specified package name is sealed according to the
+ * given manifest.
+ */
+ private boolean isSealed(String name, Manifest man) {
+ String path = name.replace('.', '/').concat("/");
+ Attributes attr = man.getAttributes(path);
+ String sealed = null;
+ if (attr != null) {
+ sealed = attr.getValue(Name.SEALED);
+ }
+ if (sealed == null) {
+ if ((attr = man.getMainAttributes()) != null) {
+ sealed = attr.getValue(Name.SEALED);
+ }
+ }
+ return "true".equalsIgnoreCase(sealed);
+ }
+
+ /**
+ * Finds the resource with the specified name on the URL search path.
+ *
+ * @param name the name of the resource
+ * @return a URL for the resource, or null
+ * if the resource could not be found.
+ */
+ public URL findResource(final String name) {
+ /*
+ * The same restriction to finding classes applies to resources
+ */
+ URL url =
+ (URL) AccessController.doPrivileged(new PrivilegedAction() {
+ public Object run() {
+ return ucp.findResource(name, true);
+ }
+ }, acc);
+
+ return url != null ? ucp.checkURL(url) : null;
+ }
+
+ /**
+ * Returns an Enumeration of URLs representing all of the resources
+ * on the URL search path having the specified name.
+ *
+ * @param name the resource name
+ * @exception IOException if an I/O exception occurs
+ * @return an Enumeration of URLs
+ */
+ public EnumerationloadClass method of the URLClassLoader
+ * returned by this method will invoke the
+ * SecurityManager.checkPackageAccess method before
+ * loading the class.
+ *
+ * @param urls the URLs to search for classes and resources
+ * @param parent the parent class loader for delegation
+ * @return the resulting class loader
+ */
+ public static URLClassLoader newInstance(final URL[] urls,
+ final ClassLoader parent) {
+ // Save the caller's context
+ AccessControlContext acc = AccessController.getContext();
+ // Need a privileged block to create the class loader
+ URLClassLoader ucl =
+ (URLClassLoader) AccessController.doPrivileged(new PrivilegedAction() {
+ public Object run() {
+ return new FactoryURLClassLoader(urls, parent);
+ }
+ });
+ // Now set the context on the loader using the one we saved,
+ // not the one inside the privileged block...
+ ucl.acc = acc;
+ return ucl;
+ }
+
+ /**
+ * Creates a new instance of URLClassLoader for the specified
+ * URLs and default parent class loader. If a security manager is
+ * installed, the loadClass method of the URLClassLoader
+ * returned by this method will invoke the
+ * SecurityManager.checkPackageAccess before
+ * loading the class.
+ *
+ * @param urls the URLs to search for classes and resources
+ * @return the resulting class loader
+ */
+ public static URLClassLoader newInstance(final URL[] urls) {
+ // Save the caller's context
+ AccessControlContext acc = AccessController.getContext();
+ // Need a privileged block to create the class loader
+ URLClassLoader ucl = (URLClassLoader)
+ AccessController.doPrivileged(new PrivilegedAction() {
+ public Object run() {
+ return new FactoryURLClassLoader(urls);
+ }
+ });
+
+ // Now set the context on the loader using the one we saved,
+ // not the one inside the privileged block...
+ ucl.acc = acc;
+ return ucl;
+ }
+
+ static {
+ sun.misc.SharedSecrets.setJavaNetAccess (
+ new sun.misc.JavaNetAccess() {
+ public URLClassPath getURLClassPath (URLClassLoader u) {
+ return u.ucp;
+ }
+ }
+ );
+ }
+}
+
+final class FactoryURLClassLoader extends URLClassLoader {
+
+ FactoryURLClassLoader(URL[] urls, ClassLoader parent) {
+ super(urls, parent);
+ }
+
+ FactoryURLClassLoader(URL[] urls) {
+ super(urls);
+ }
+
+ public final synchronized Class loadClass(String name, boolean resolve)
+ throws ClassNotFoundException
+ {
+ // First check if we have permission to access the package. This
+ // should go away once we've added support for exported packages.
+ SecurityManager sm = System.getSecurityManager();
+ if (sm != null) {
+ int i = name.lastIndexOf('.');
+ if (i != -1) {
+ sm.checkPackageAccess(name.substring(0, i));
+ }
+ }
+ return super.loadClass(name, resolve);
+ }
+}