gstack/browse/scripts/extension-id.ts

46 lines
1.7 KiB
TypeScript
Executable File

#!/usr/bin/env bun
/**
* Derive the Chrome extension ID from the "key" field in
* extension/manifest.json.
*
* Chrome computes an extension's ID as the first 16 bytes of the SHA-256
* hash of the DER-encoded public key, with each hex nibble mapped from
* 0-9a-f to a-p (the "mpdecimal" alphabet). Pinning the public key in the
* manifest pins the ID, which lets the browse server verify the Origin
* header on POST /extension-token against a single known extension
* identity (GSTACK_EXTENSION_ID in browse/src/server.ts).
*
* The private half of the keypair is intentionally NOT in the repo — the
* extension is loaded unpacked (or baked into Browser.app), so only the
* public key is needed to pin the ID. Regenerating the keypair changes
* the ID and requires updating both the manifest "key" and the
* GSTACK_EXTENSION_ID constant.
*
* Usage: bun browse/scripts/extension-id.ts [path/to/manifest.json]
*/
import { createHash } from 'node:crypto';
import * as fs from 'node:fs';
import * as path from 'node:path';
const manifestPath = process.argv[2]
?? path.join(import.meta.dir, '../../extension/manifest.json');
const manifest = JSON.parse(fs.readFileSync(manifestPath, 'utf-8'));
if (typeof manifest.key !== 'string' || manifest.key.length === 0) {
console.error(`No "key" field in ${manifestPath}`);
process.exit(1);
}
export function extensionIdFromPublicKey(publicKeyBase64: string): string {
const der = Buffer.from(publicKeyBase64, 'base64');
const hex = createHash('sha256').update(der).digest('hex').slice(0, 32);
let id = '';
for (const c of hex) {
id += String.fromCharCode('a'.charCodeAt(0) + parseInt(c, 16));
}
return id;
}
console.log(extensionIdFromPublicKey(manifest.key));