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Fix zip slip check in StructContext on Windows #22

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Fix zip slip check in StructContext on Windows #22

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4 changes: 2 additions & 2 deletions src/org/jetbrains/java/decompiler/struct/StructContext.java
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Original file line number Diff line number Diff line change
Expand Up @@ -139,8 +139,8 @@ private void addArchive(String path, File file, int type, boolean isOwn) throws
}

String name = entry.getName();
File test = new File(file.getAbsolutePath(), name);
if (!test.getCanonicalPath().startsWith(file.getCanonicalPath() + File.separator)) { // check for zip slip exploit
String normalizedName = name.replace('\\', '/');
if (normalizedName.startsWith("/") || normalizedName.startsWith("../") || normalizedName.contains("/../")) {
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Copilot AI Dec 10, 2025

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The zip-slip protection is incomplete. It doesn't handle cases where a path ends with .. (e.g., foo/..) or contains multiple consecutive slashes that could be normalized away. Consider using a more robust path normalization approach or additional checks for these edge cases.

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Copilot AI Dec 10, 2025

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The check should also reject paths that start with .. without a slash (e.g., ..foo), as startsWith(\"../\") only catches cases with a trailing slash. Consider changing to startsWith(\"..\") to catch all cases where the path begins with two dots.

Suggested change
if (normalizedName.startsWith("/") || normalizedName.startsWith("../") || normalizedName.contains("/../")) {
if (normalizedName.startsWith("/") || normalizedName.startsWith("..") || normalizedName.contains("/../")) {

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throw new RuntimeException("Zip entry '" + entry.getName() + "' tries to escape target directory");
}

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