From 47a8352fb229d4ddd70b3b2fd6394f9a81d03099 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Fri, 29 Jul 2022 13:38:28 +0000 Subject: [PATCH] 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 Signed-off-by: Jonathan Leitschuh Bug-tracker: https://github.com/JLLeitschuh/security-research/issues/13 Co-authored-by: Moderne --- src/main/java/io/vertx/core/file/impl/FileCache.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/main/java/io/vertx/core/file/impl/FileCache.java b/src/main/java/io/vertx/core/file/impl/FileCache.java index 377c0e9ebcc..6500ab8c6a6 100644 --- a/src/main/java/io/vertx/core/file/impl/FileCache.java +++ b/src/main/java/io/vertx/core/file/impl/FileCache.java @@ -216,7 +216,7 @@ void cacheDir(String fileName) throws IOException { private void fileNameCheck(File file) throws IOException { String fileName = file.getCanonicalPath(); String cachePath = getCacheDir().getPath(); - if (fileName.startsWith(cachePath)) { + if (file.getCanonicalFile().toPath().startsWith(cachePath)) { int cachePathLen = cachePath.length(); if (fileName.length() == cachePathLen) { return;