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]>

xmppserver/src/main/java/org/jivesoftware/openfire/container/PluginMonitor.java

@@ -479,7 +479,10 @@ private boolean unzipPlugin( String pluginName, Path file, Path dir )
                 for ( Enumeration e = zipFile.entries(); e.hasMoreElements(); )
                 {
                     JarEntry entry = (JarEntry) e.nextElement();
-                    Path entryFile = dir.resolve( entry.getName() ); // ignore possibility for zipslip as this is sanitized for if property is enabled lgtm [java/zipslip]
+                    Path entryFile = dir.resolve( entry.getName() );
+                 if (!entryFile.normalize().startsWith(dir.normalize())) {
+                  throw new IOException("Bad zip entry");
+                 } // ignore possibility for zipslip as this is sanitized for if property is enabled lgtm [java/zipslip]
                     // Ignore any manifest.mf entries.
                     if ( entry.getName().toLowerCase().endsWith( "manifest.mf" ) )
                     {