App lock: unlock with security keys via the built-in CTAP2 client on Linux too (Chromium returned no PRF result, so adding a YubiKey failed with "does not support hmac-secret"); updates: show only one update dialog at a time (startup and manual check stacked two)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main/ctap2.js

@@ -210,4 +210,48 @@ async function makeCredential(ui, { timeoutMs = 60000 } = {}) {
   }
 }
 
-module.exports = { makeCredential, CtapError, CANCEL_CODES, PIN };
+// Entspricht WebAuthn-PRF (evalByCredential) über hmac-secret, ohne PIN (wie Chromium mit
+// userVerification "discouraged"). creds: [{ credId: Buffer, salt: Buffer }] – salt ist der rohe PRF-Eingabewert.
+// Liefert { credId: Buffer, secret: Buffer(32) }, oder null, wenn kein FIDO2-Gerät per hidraw erreichbar ist.
+async function getHmacSecret(ui, creds, { timeoutMs = 60000 } = {}) {
+  let dev;
+  try { dev = Device.open(); } catch { return null; }
+  if (!dev) return null;
+  let timer;
+  try {
+    await dev.init();
+    const info = await dev.cbor(0x04);
+    if (!(info.get(1) || []).some((v) => String(v).startsWith('FIDO_2'))) return null;
+    const rpId = 'localhost';
+    const desc = (c) => new Map([['id', c.credId], ['type', 'public-key']]);
+    // Welches Credential liegt auf diesem Schlüssel? (Vorabprüfung ohne Berühren, up=false)
+    let cred = null;
+    for (const c of creds) {
+      try {
+        await dev.cbor(0x02, new Map([[1, rpId], [2, crypto.randomBytes(32)], [3, [desc(c)]], [5, new Map([['up', false]])]]));
+        cred = c; break;
+      } catch (e) { if (e.code !== 0x2e) throw e; }
+    }
+    if (!cred) throw new CtapError(0x2e);
+    const { key, platformKey } = await sharedSecret(dev);
+    const salt = crypto.createHash('sha256').update(Buffer.concat([Buffer.from('WebAuthn PRF\0', 'latin1'), cred.salt])).digest();
+    const saltEnc = aes('enc', key, salt);
+    const saltAuth = crypto.createHmac('sha256', key).update(saltEnc).digest().subarray(0, 16);
+    ui.touch(() => dev.cancel());
+    timer = setTimeout(() => dev.cancel(), timeoutMs);
+    const r = await dev.cbor(0x02, new Map([
+      [1, rpId], [2, crypto.randomBytes(32)], [3, [desc(cred)]],
+      [4, new Map([['hmac-secret', new Map([[1, platformKey], [2, saltEnc], [3, saltAuth]])]])],
+    ]));
+    const authData = r.get(2);
+    if (!(authData[32] & 0x80)) throw new CtapError(-1);
+    const ext = dec(authData, 37)[0].get('hmac-secret');
+    if (!ext) throw new CtapError(-1);
+    return { credId: Buffer.from(cred.credId), secret: aes('dec', key, ext).subarray(0, 32) };
+  } finally {
+    clearTimeout(timer);
+    dev.close();
+  }
+}
+
+module.exports = { makeCredential, getHmacSecret, CtapError, CANCEL_CODES, PIN };