--- /dev/null 2020-01-02 04:43:18.583999853 +0000 +++ new/src/share/classes/jdk/jfr/internal/WriteableUserPath.java 2020-01-30 06:26:49.278071927 +0000 @@ -0,0 +1,129 @@ +/* + * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the LICENSE file that accompanied this code. + * + * This code 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 General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +package jdk.jfr.internal; + +import java.io.BufferedWriter; +import java.io.FileNotFoundException; +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.security.AccessControlContext; +import java.security.AccessController; +import java.security.PrivilegedExceptionAction; +import java.util.concurrent.Callable; + +/** + * Purpose of this class is to simplify analysis of security risks. + *
+ * Paths in the public API should be wrapped in this class so we + * at all time know what kind of paths we are dealing with. + *
+ * A user supplied path must never be used in an unsafe context, such as a + * shutdown hook or any other thread created by JFR. + *
+ * All operation using this path must happen in {@link #doPriviligedIO(Callable)}
+ */
+public final class WriteableUserPath {
+ private final AccessControlContext controlContext;
+ private final Path original;
+ private final Path real;
+ private final String text;
+
+ // Not to ensure security, but to help
+ // against programming errors
+ private volatile boolean inPrivileged;
+
+ public WriteableUserPath(Path path) throws IOException {
+ controlContext = AccessController.getContext();
+ // verify that the path is writeable
+ if (Files.exists(path) && !Files.isWritable(path)) {
+ // throw same type of exception as FileOutputStream
+ // constructor, if file can't be opened.
+ throw new FileNotFoundException("Could not write to file: " + path.toAbsolutePath());
+ }
+ // will throw if non-writeable
+ BufferedWriter fw = Files.newBufferedWriter(path);
+ fw.close();
+ this.original = path;
+ this.real = path.toRealPath();
+ this.text = real.toString();
+ }
+
+ /**
+ * Returns a potentially malicious path where the user may have implemented
+ * their own version of Path. This method should never be called in an
+ * unsafe context and the Path value should never be passed along to other
+ * methods.
+ *
+ * @return path from a potentially malicious user
+ */
+ public Path getPotentiallyMaliciousOriginal() {
+ return original;
+ }
+
+ /**
+ * Returns a string representation of the path.
+ *
+ * @return path as text
+ */
+ public String getText() {
+ return text;
+ }
+
+ /**
+ * Returns a potentially malicious path where the user may have implemented
+ * their own version of Path. This method should never be called in an
+ * unsafe context and the Path value should never be passed along to other
+ * methods.
+ *
+ * @return path from a potentially malicious user
+ */
+ public Path getReal() {
+ if (!inPrivileged) {
+ throw new InternalError("A user path was accessed outside the context it was supplied in");
+ }
+ return real;
+ }
+
+ public void doPriviligedIO(Callable> function) throws IOException {
+ try {
+ inPrivileged = true;
+ AccessController.doPrivileged(new PrivilegedExceptionAction