From cb680aed73093bcefe86ac87574da8dd36d7b34a Mon Sep 17 00:00:00 2001 From: Jonathan Leitschuh Date: Fri, 29 Jul 2022 19:16:22 +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/perye/dokit/utils/ZipUtils.java | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/main/java/com/perye/dokit/utils/ZipUtils.java b/src/main/java/com/perye/dokit/utils/ZipUtils.java index 13fd48e..0159387 100644 --- a/src/main/java/com/perye/dokit/utils/ZipUtils.java +++ b/src/main/java/com/perye/dokit/utils/ZipUtils.java @@ -32,7 +32,10 @@ public static void unZipIt(String zipFilePath, String outputFolder) { ZipEntry ze = zis.getNextEntry(); while (ze != null) { String fileName = ze.getName(); - File newFile = new File(outputFolder + File.separator + fileName); + File newFile = new File(outputFolder, fileName); + if (!newFile.toPath().normalize().startsWith(outputFolder)) { + throw new RuntimeException("Bad zip entry"); + } System.out.println("file unzip : " + newFile.getAbsoluteFile()); //大部分网络上的源码，这里没有判断子目录 if (ze.isDirectory()) { @@ -69,6 +72,10 @@ public static void unzip(File source, String out) throws IOException { File file = new File(out, entry.getName()); + if (!file.toPath().normalize().startsWith(out)) { + throw new RuntimeException("Bad zip entry"); + } + if (entry.isDirectory()) { if (!file.mkdirs()) { System.out.println("was not successful.");