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fix(security): add extraction size limit to prevent decompression bomb [DEVA11Y-484] #22

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fix(security): add extraction size limit to prevent decompression bomb [DEVA11Y-484] #22

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25 changes: 25 additions & 0 deletions Plugins/BrowserStackAccessibilityLint/BrowserStackAccessibilityLint.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -285,6 +285,8 @@ private struct BrowserStackCLIDownloader {
let message = String(data: tarError.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8)?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
forwardExit(code: bsdtar.terminationStatus, message: message.isEmpty ? "bsdtar failed to extract BrowserStack CLI." : message)
}

try validateExtractedSize(of: directory)
}

private func extractLocalArchive(at archiveURL: URL, into directory: URL) throws {
Expand All @@ -301,6 +303,11 @@ private struct BrowserStackCLIDownloader {
throw PluginError("Failed to launch bsdtar: \(error.localizedDescription)")
}

if process.terminationReason == .exit && process.terminationStatus == 0 {
try validateExtractedSize(of: directory)
return
}

if process.terminationReason != .exit || process.terminationStatus != 0 {
// Fall back to copying the file directly if it's already an executable.
let message = String(data: errorPipe.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8)?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
Expand All @@ -315,6 +322,24 @@ private struct BrowserStackCLIDownloader {
}
}
}

private func validateExtractedSize(of directory: URL, maxBytes: UInt64 = 100 * 1024 * 1024) throws {
var totalSize: UInt64 = 0
let enumerator = fileManager.enumerator(
at: directory,
includingPropertiesForKeys: [.fileSizeKey],
options: [.skipsHiddenFiles]
)
while let fileURL = enumerator?.nextObject() as? URL {
if let size = try? fileURL.resourceValues(forKeys: [.fileSizeKey]).fileSize {
totalSize += UInt64(size)
if totalSize > maxBytes {
try? fileManager.removeItem(at: directory)
throw PluginError("Extracted archive exceeds maximum allowed size (\(maxBytes / (1024 * 1024)) MB). Possible decompression bomb.")
}
}
}
}
#endif

private func resolveOverrideArtifact(from url: URL) async throws -> ArtifactInfo {
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