From 94871e2b1e537782b53efcbb93c4796c13e8e6a2 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Fri, 9 Sep 2022 03:02:03 +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 --- .../com/turn/ttorrent/client/storage/FileCollectionStorage.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ttorrent-client/src/main/java/com/turn/ttorrent/client/storage/FileCollectionStorage.java b/ttorrent-client/src/main/java/com/turn/ttorrent/client/storage/FileCollectionStorage.java index 083e3e48..b8bfc901 100644 --- a/ttorrent-client/src/main/java/com/turn/ttorrent/client/storage/FileCollectionStorage.java +++ b/ttorrent-client/src/main/java/com/turn/ttorrent/client/storage/FileCollectionStorage.java @@ -76,7 +76,7 @@ public static FileCollectionStorage create(TorrentMetadata metadata, File parent for (TorrentFile file : metadata.getFiles()) { File actual = new File(parent, file.getRelativePathAsString()); - if (!actual.getCanonicalPath().startsWith(parent.getCanonicalPath())) { + if (!actual.getCanonicalFile().toPath().startsWith(parent.getCanonicalFile().toPath())) { throw new SecurityException("Torrent file path attempted " + "to break directory jail!"); }