can1357/oh-my-pi · error · ArchiveError

Invalid tar member path '${formatArchivePathForError(rawPath

Error message

Invalid tar member path '${formatArchivePathForError(rawPath)}'

What it means

normalizeArchiveEntryPath sanitizes a tar member path (resolving ., .., drive/backslash forms); when it returns empty the raw path was invalid (e.g. only traversal segments, null bytes, or nothing usable). The library throws rather than writing a header for an unusable path, and includes the formatted raw path in the message.

Source

Thrown at packages/utils/src/ar/tar.ts:745

			effectiveSplit[1],
			size <= MAX_OCTAL_SIZE ? size : 0,
			mtime,
			directory ? 0o755 : 0o644,
			directory ? 0x35 : 0x30,
		),
	);
	if (!directory) appendPayload(parts, payload);
}

/** Encode files as a deterministic ustar archive, using PAX records for overflow paths. */
export async function encodeTar(members: Iterable<readonly [string, Uint8Array]>): Promise<Uint8Array> {
	const parts: Uint8Array[] = [];
	const kinds = new Map<string, "directory" | "file">();
	let sequence = 0;
	for (const [rawPath, bytes] of members) {
		const directory = rawPath.endsWith("/") || rawPath.endsWith("\\");
		const normalized = normalizeArchiveEntryPath(rawPath);
		if (!normalized) throw new ArchiveError(`Invalid tar member path '${formatArchivePathForError(rawPath)}'`);
		const pathBytes = TEXT_ENCODER.encode(normalized);
		if (pathBytes.byteLength === 0) throw new ArchiveError("Invalid empty tar member path");
		if (directory && bytes.byteLength !== 0) {
			throw new ArchiveError(`Tar directory '${formatArchivePathForError(normalized)}' cannot contain file data`);
		}
		const segments = normalized.split("/");
		for (let index = 1; index < segments.length; index++) {
			const parent = segments.slice(0, index).join("/");
			const kind = kinds.get(parent);
			if (kind === "file")
				throw new ArchiveError(`Tar member '${formatArchivePathForError(parent)}' is not a directory`);
			if (kind === "directory") continue;
			kinds.set(parent, "directory");
			appendTarEntry(parts, parent, new Uint8Array(0), true, sequence++);
		}
		const existing = kinds.get(normalized);
		if (existing) {
			if (directory && existing === "directory") continue;

View on GitHub (pinned to 9690622007)

Solutions

1. Sanitize or re-key members to clean relative paths like 'dir/file.txt' before calling createTar
2. Strip leading slashes and resolve '..' segments yourself
3. Skip empty, '.', '..', and null-containing keys

Example fix

// before
const members = new Map([["../escape.txt", data]]);
await createTar(members);
// after
const members = new Map([["safe/escape.txt", data]]);
await createTar(members);

function isSafeMemberPath(p: string): boolean {
	if (p.length === 0 || p.includes("\0")) return false;
	const parts = p.replace(/\\/g, "/").split("/");
	return !parts.some((s) => s === ".." || s === "." || s === "");
}

function isSafeMemberPath(p: string): boolean {
	if (p.length === 0 || p.includes("\0")) return false;
	const parts = p.replace(/\\/g, "/").split("/");
	return !parts.some((s) => s === ".." || s === "." || s === "");
}

try {
	return await createTar(members);
} catch (err) {
	if (err instanceof ArchiveError && err.message.startsWith("Invalid tar member path")) {
		// log rejected path from err.message and sanitize keys
	}
	throw err;
}

When it happens

Trigger: createTar called with a key like '../etc/passwd', '.', '..', an empty string, a path containing NUL, or a backslash-only/Windows-style path that normalizes to nothing.

Common situations: Building archives from untrusted ZIP-style entry names; copying an in-memory virtual FS where root or '.' was included as a member; joining paths so a key became '..'.

Related errors

• Invalid old-GNU ${field}
• Invalid empty tar member path
• Tar directory '${formatArchivePathForError(normalized)}' can
• Archive write path must target a file inside the archive
• Archive write path must target a file, not a directory

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/e6d276fbdb60b4ff. Report an issue: GitHub.