vuln-fix: Partial Path Traversal Vulnerability

This fixes a partial path traversal vulnerability.

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())`.

To demonstrate this vulnerability, 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: Medium
CVSSS: 6.1
Detection: CodeQL & OpenRewrite (https://public.moderne.io/recipes/org.openrewrite.java.security.PartialPathTraversalVulnerability)

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

Bug-tracker: JLLeitschuh/security-research#13

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

src/main/java/org/whitesource/agent/utils/FilesScanner.java

@@ -126,7 +126,7 @@ private Map<String, Set<String>> getTopFoldersWithIncludedFiles(String rootFolde
                     Path folderPath = Paths.get(folder);
                     boolean shouldRemove = false;
                     try {
-                        shouldRemove = otherFolderPath.toFile().getCanonicalPath().startsWith(folderPath.toFile().getCanonicalPath());
+                        shouldRemove = otherFolderPath.toFile().getCanonicalFile().toPath().startsWith(folderPath.toFile().getCanonicalFile().toPath());
                     } catch (Exception e) {
                         logger.debug("could not get file path " + otherFolderPath + folderPath, e.getStackTrace());
                         logger.warn("could not get file path " + otherFolderPath + folderPath, e.getMessage());
@@ -152,4 +152,4 @@ public boolean isIncluded(File file, String[] includes, String[] excludes, boole
         scanner.setCaseSensitive(globCaseSensitive);
         return scanner.isIncluded(file);
     }
-}
+}