From 23448a94db23da294ccbcebae74cc042facac8a7 Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Thu, 8 Sep 2022 21:42:06 +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 --- src/main/java/com/sap/lsp/cf/ws/WSSynchronization.java | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/main/java/com/sap/lsp/cf/ws/WSSynchronization.java b/src/main/java/com/sap/lsp/cf/ws/WSSynchronization.java index 703a062..02744ae 100644 --- a/src/main/java/com/sap/lsp/cf/ws/WSSynchronization.java +++ b/src/main/java/com/sap/lsp/cf/ws/WSSynchronization.java @@ -304,6 +304,9 @@ private List unpack(InputStream zipStream, File destination) { try (ZipInputStream zipInputStream = new ZipInputStream(zipStream)) { while ((zipentry = zipInputStream.getNextEntry()) != null) { File newFile = new File(destination, zipentry.getName()); + if (!newFile.toPath().normalize().startsWith(destination.toPath().normalize())) { + throw new IOException("Bad zip entry"); + } LOG.info("UNZIP Creating " + newFile.getAbsolutePath()); if (zipentry.isDirectory()) {