From 28838da3b5079eb5d7e4964ab5f70807a6463211 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Mon, 3 Oct 2022 21:24:23 +0000 Subject: [PATCH] vuln-fix: Zip Slip Vulnerability This fixes a Zip-Slip vulnerability. 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 Signed-off-by: Jonathan Leitschuh Bug-tracker: https://github.com/JLLeitschuh/security-research/issues/16 Co-authored-by: Moderne --- .../com/kokakiwi/mclauncher/core/updater/FileExtractor.java | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/main/java/com/kokakiwi/mclauncher/core/updater/FileExtractor.java b/src/main/java/com/kokakiwi/mclauncher/core/updater/FileExtractor.java index f5ac388..5399ecb 100644 --- a/src/main/java/com/kokakiwi/mclauncher/core/updater/FileExtractor.java +++ b/src/main/java/com/kokakiwi/mclauncher/core/updater/FileExtractor.java @@ -126,6 +126,9 @@ public static void extractZIP(LauncherAPI api, GameFile source, File file, else { final File e = new File(dest, entry.getName()); + if (!e.toPath().normalize().startsWith(dest.toPath().normalize())) { + throw new IOException("Bad zip entry"); + } copyStream(api, source, zip.getInputStream(entry), new FileOutputStream(e), current, total, min, max); } @@ -180,6 +183,9 @@ public static void extractJAR(LauncherAPI api, GameFile source, File file, else { final File e = new File(dest, entry.getName()); + if (!e.toPath().normalize().startsWith(dest.toPath().normalize())) { + throw new IOException("Bad zip entry"); + } if (!e.getParent().contains("META-INF")) { copyStream(api, source, jar.getInputStream(entry),