vuln-fix: Zip Slip Vulnerability (#10)

Issue #18: Fix Zip Slip Vulnerability in test code

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]>


Bug-tracker: JLLeitschuh/security-research#16

Co-authored-by: Moderne <[email protected]>
Co-authored-by: Richard Eckart de Castilho <[email protected]>

src/test/java/org/apache/uima/json/jsoncas2/Fixtures.java

@@ -94,6 +94,10 @@ public static Path materializeTestSuite()
                         }
 
                         Path target = targetBase.resolve(name);
+
+                      if (!target.normalize().startsWith(targetBase.normalize())) {
+                        throw new RuntimeException("Bad zip entry");
+                      }
                         Files.createDirectories(target.getParent());
 
                         try (InputStream eis = zipFile.getInputStream(entry);