75 lines
2.6 KiB
TypeScript
75 lines
2.6 KiB
TypeScript
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import { dirname, isAbsolute, relative, resolve, sep } from "node:path"
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export type ArchiveEntry = {
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path: string
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type: "file" | "directory" | "symlink"
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linkPath?: string
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}
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function normalizeArchivePath(filePath: string): string {
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return filePath.replaceAll("\\", "/")
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}
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function containsTraversalSegment(filePath: string): boolean {
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return normalizeArchivePath(filePath)
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.split("/")
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.some(segment => segment === "..")
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}
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function isArchiveAbsolutePath(filePath: string): boolean {
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const normalizedPath = normalizeArchivePath(filePath)
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return isAbsolute(normalizedPath) || /^[A-Za-z]:\//.test(normalizedPath) || normalizedPath.startsWith("//")
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}
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function escapesDirectory(rootDir: string, candidatePath: string): boolean {
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const relativePath = relative(rootDir, candidatePath)
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return relativePath === ".." || relativePath.startsWith(`..${sep}`) || isAbsolute(relativePath)
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}
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function resolveContainedPath(rootDir: string, filePath: string, errorLabel: string): string {
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const normalizedPath = normalizeArchivePath(filePath)
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if (isArchiveAbsolutePath(normalizedPath)) {
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throw new Error(`Unsafe archive entry: ${errorLabel} uses an absolute path (${filePath})`)
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}
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if (containsTraversalSegment(normalizedPath)) {
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throw new Error(`Unsafe archive entry: ${errorLabel} contains path traversal (${filePath})`)
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}
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const resolvedPath = resolve(rootDir, normalizedPath)
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if (escapesDirectory(rootDir, resolvedPath)) {
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throw new Error(`Unsafe archive entry: ${errorLabel} contains path traversal (${filePath})`)
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}
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return resolvedPath
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}
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export function validateArchiveEntries(entries: ArchiveEntry[], destDir: string): void {
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const resolvedDestDir = resolve(destDir)
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for (const entry of entries) {
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const resolvedEntryPath = resolveContainedPath(resolvedDestDir, entry.path, "path")
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if (entry.type !== "symlink") {
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continue
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}
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if (!entry.linkPath) {
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throw new Error(`Unsafe archive entry: symlink target missing for ${entry.path}`)
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}
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const normalizedLinkPath = normalizeArchivePath(entry.linkPath)
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if (isArchiveAbsolutePath(normalizedLinkPath)) {
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throw new Error(`Unsafe archive entry: symlink target uses an absolute path (${entry.linkPath})`)
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}
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if (containsTraversalSegment(normalizedLinkPath)) {
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throw new Error(`Unsafe archive entry: symlink target contains path traversal (${entry.linkPath})`)
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}
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const resolvedLinkPath = resolve(dirname(resolvedEntryPath), normalizedLinkPath)
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if (escapesDirectory(resolvedDestDir, resolvedLinkPath)) {
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throw new Error(`Unsafe archive entry: symlink target escapes extraction directory (${entry.linkPath})`)
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}
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}
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}
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