From a5d213c2ecbefdb5ea931d71938abf45cda4f2aa Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Wed, 21 Sep 2022 15:25:43 +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 --- byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java b/byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java index fa200c0723a..68da09da61e 100644 --- a/byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java +++ b/byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java @@ -3397,7 +3397,7 @@ public void retain(Source.Element element) throws IOException { String name = element.getName(); if (!name.endsWith("/")) { File target = new File(folder, name), resolved = element.resolveAs(File.class); - if (!target.getCanonicalPath().startsWith(folder.getCanonicalPath())) { + if (!target.getCanonicalFile().toPath().startsWith(folder.getCanonicalFile().toPath())) { throw new IllegalArgumentException(target + " is not a subdirectory of " + folder); } else if (!target.getParentFile().isDirectory() && !target.getParentFile().mkdirs()) { throw new IOException("Could not create directory: " + target.getParent());