vuln-fix: Zip Slip Vulnerability

This fixes a Zip-Slip vulnerability.

This change does one of two things. This change either

1. Inserts a guard to protect against Zip Slip.
OR
2. Replaces `dir.getCanonicalPath().startsWith(parent.getCanonicalPath())`, which is vulnerable to partial path traversal attacks, with the more secure `dir.getCanonicalFile().toPath().startsWith(parent.getCanonicalFile().toPath())`.

For number 2, consider `"/usr/outnot".startsWith("/usr/out")`.
The check is bypassed although `/outnot` is not under the `/out` directory.
It's important to understand that the terminating slash may be removed when using various `String` representations of the `File` object.
For example, on Linux, `println(new File("/var"))` will print `/var`, but `println(new File("/var", "/")` will print `/var/`;
however, `println(new File("/var", "/").getCanonicalPath())` will print `/var`.

Weakness: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Severity: High
CVSSS: 7.4
Detection: CodeQL (https://codeql.github.com/codeql-query-help/java/java-zipslip/) & OpenRewrite (https://public.moderne.io/recipes/org.openrewrite.java.security.ZipSlip)

Reported-by: Jonathan Leitschuh <[email protected]>
Signed-off-by: Jonathan Leitschuh <[email protected]>

Bug-tracker: JLLeitschuh/security-research#16


Co-authored-by: Moderne <[email protected]>

marytts-common/src/main/java/marytts/util/io/FileUtils.java

@@ -749,6 +749,10 @@ private static void unzipEntry(ZipFile zipfile, ZipEntry entry, File outputDir)
 		}
 
 		File outputFile = new File(outputDir, entry.getName());
+
+		if (!outputFile.toPath().normalize().startsWith(outputDir.toPath())) {
+			throw new RuntimeException("Bad zip entry");
+		}
 		if (!outputFile.getParentFile().exists()) {
 			createDir(outputFile.getParentFile());
 		}

marytts-runtime/src/main/java/marytts/tools/install/ComponentDescription.java

@@ -832,7 +832,10 @@ public void run() {
 				while (entries.hasMoreElements()) {
 					ZipEntry entry = entries.nextElement();
 					files.add(entry.getName()); // add to installed filelist; rely on uninstaller retaining shared files
-					File newFile = new File(maryBase + "/" + entry.getName());
+					File newFile = new File(maryBase, entry.getName());
+					if (!newFile.toPath().normalize().startsWith(maryBase)) {
+						throw new RuntimeException("Bad zip entry");
+					}
 					if (entry.isDirectory()) {
 						System.err.println("Extracting directory: " + entry.getName());
 						newFile.mkdir();