| 1 | // The enrolment page. An instance (e.g. family.example.com) navigates here (same |
| 2 | // tab) to add itself to the user's passkey-protected backup. Passkeys are bound |
| 3 | // to THIS origin, so the instance can't run the ceremony — it hands us the |
| 4 | // server entry (its URL + the user's session) in our URL FRAGMENT, which never |
| 5 | // reaches any server (same model as invite secrets). We show exactly what's |
| 6 | // being added, run the passkey ceremony here (a plain top-level page — Safari |
| 7 | // blocks WebAuthn in a cross-origin-opened popup, which is why this is a |
| 8 | // navigation, not window.open), merge it into the encrypted blob, and redirect |
| 9 | // back to the instance with a one-time nonce it can verify. |
| 10 | // |
| 11 | // No inbound postMessage listener and no secret ever leaves here — the handoff |
| 12 | // in is one-way via the fragment, the handoff back is a redirect carrying only |
| 13 | // the nonce. The single trust control on the entry is the confirmation card |
| 14 | // below — the user sees what's being added before anything is written. |
| 15 | |
| 16 | import { |
| 17 | b64urlToBytes, kekFromPRF, generateDEK, importDEK, wrapDEK, unwrapDEK, |
| 18 | sealBlob, unpackBlob, openBlob, |
| 19 | } from "/static/crypto.js"; |
| 20 | import { beginRegister, beginLogin, runRegister, runLogin, fetchBlob, putBlob } from "/static/backup-core.js"; |
| 21 | import { reuseCandidate } from "/static/sessionreuse.js"; |
| 22 | import { formatCeremonyError } from "/static/ceremony-errors.js"; |
| 23 | import { clearTombstone } from "/static/serverlist.js"; |
| 24 | |
| 25 | const $ = (id) => document.getElementById(id); |
| 26 | function setStatus(msg, kind) { |
| 27 | const el = $("status"); |
| 28 | el.textContent = msg || ""; |
| 29 | el.className = "status" + (kind ? " " + kind : ""); |
| 30 | } |
| 31 | |
| 32 | // ---- read the entry from our fragment ---------------------------------------- |
| 33 | |
| 34 | function readPayload() { |
| 35 | const raw = location.hash.slice(1); |
| 36 | if (!raw) return null; |
| 37 | try { |
| 38 | const json = new TextDecoder().decode(b64urlToBytes(raw)); |
| 39 | const p = JSON.parse(json); |
| 40 | if (!p || !p.entry || typeof p.entry.url !== "string") return null; |
| 41 | // The entry URL must parse — it's where we send the user back to. |
| 42 | new URL(p.entry.url); |
| 43 | return p; |
| 44 | } catch { |
| 45 | return null; |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | const payload = readPayload(); |
| 50 | // Drop the secret-bearing fragment from the address bar as soon as we've read it. |
| 51 | try { history.replaceState(null, "", location.pathname); } catch {} |
| 52 | |
| 53 | // The instance may pass a small branding photo for the confirmation card. It's |
| 54 | // display-only chrome and untrusted (anyone can craft a fragment), so we accept |
| 55 | // it only if it's an inline image data: URI, render it via .src (never innerHTML), |
| 56 | // and keep it OUT of the persisted entry — the backup blob is size-capped, and the |
| 57 | // photo is public branding, not part of the credentials. |
| 58 | let entryIcon = null; |
| 59 | if (payload && payload.entry) { |
| 60 | if (typeof payload.entry.icon === "string" && |
| 61 | /^data:image\/(png|jpeg|webp);base64,/.test(payload.entry.icon)) { |
| 62 | entryIcon = payload.entry.icon; |
| 63 | } |
| 64 | delete payload.entry.icon; |
| 65 | } |
| 66 | |
| 67 | // Where to send the user back to. The instance passes its origin as `ret`; fall |
| 68 | // back to the entry URL's origin. Only ever a bare origin, and we append only a |
| 69 | // non-secret nonce marker — never blob contents, tokens, or keys leave here. |
| 70 | const returnOrigin = payload ? new URL(payload.ret || payload.entry.url).origin : null; |
| 71 | |
| 72 | // goBack returns to the chat. On success we carry the one-time nonce the |
| 73 | // instance gave us, so it can trust the redirect is genuine; on cancel, nothing. |
| 74 | // In the native case there's no useful redirect target (this opened in the |
| 75 | // system browser, which has no session for the instance), so we just end here. |
| 76 | function goBack(withNonce) { |
| 77 | if (payload && payload.native) { |
| 78 | setStatus(withNonce |
| 79 | ? "All saved. You can close this tab and return to Eleven." |
| 80 | : "You can close this tab and return to Eleven.", withNonce ? "ok" : ""); |
| 81 | return; |
| 82 | } |
| 83 | if (!returnOrigin) return; |
| 84 | const frag = withNonce && payload.nonce ? "#lchat_backup=" + encodeURIComponent(payload.nonce) : ""; |
| 85 | location.replace(returnOrigin + "/" + frag); |
| 86 | } |
| 87 | |
| 88 | // ---- merge one entry into the (possibly new) blob ---------------------------- |
| 89 | |
| 90 | // Upsert the entry into a servers list by url (last-writer-wins per url), |
| 91 | // replacing IN PLACE — enrolment must never shuffle a curated list, and the |
| 92 | // starred flag survives the upgrade. |
| 93 | function upsert(servers, entry) { |
| 94 | const list = (servers || []).slice(); |
| 95 | const i = list.findIndex((s) => s.url === entry.url); |
| 96 | if (i < 0) return [...list, entry]; |
| 97 | list[i] = list[i].starred ? { ...entry, starred: true } : entry; |
| 98 | return list; |
| 99 | } |
| 100 | |
| 101 | // The credentials that actually grant access to an instance — what a replace |
| 102 | // would swap out. Compared to decide whether an incoming entry is a benign |
| 103 | // re-save (identical) or a genuine change worth an explicit confirmation. |
| 104 | function credFingerprint(entry) { |
| 105 | const c = entry.credentials || {}; |
| 106 | return JSON.stringify([c.token || "", c.userPub || "", c.userPriv || ""]); |
| 107 | } |
| 108 | |
| 109 | // Ceremony options are pre-fetched on load (see boot) so a button click reaches |
| 110 | // navigator.credentials.* WITHOUT an intervening network await — Safari drops |
| 111 | // transient activation across a fetch and then rejects the ceremony. Held as |
| 112 | // resolved values; refreshed after any failure so a retry has a fresh challenge. |
| 113 | let regBegin = null, loginBegin = null; |
| 114 | function prefetch() { |
| 115 | beginRegister().then((v) => { regBegin = v; }).catch(() => { regBegin = null; }); |
| 116 | beginLogin().then((v) => { loginBegin = v; }).catch(() => { loginBegin = null; }); |
| 117 | } |
| 118 | |
| 119 | // saveSecurely is the primary path: sign in to the account you already have and |
| 120 | // add this chat to it. Sign-in stays first so a returning user always adds to |
| 121 | // their one account instead of accidentally starting a second — but someone who |
| 122 | // KNOWS they're new never has to fail a ceremony to find their path: the |
| 123 | // up-front "I'm new" button (createAndAdd) runs the register path directly. |
| 124 | async function saveSecurely() { |
| 125 | disable(); |
| 126 | // The live-session fast path (#1378): the create→setup→enrol journey is |
| 127 | // same-tab by design, so the tab that just created this space usually still |
| 128 | // holds a live session — the link token plus the tab-scoped DEK |
| 129 | // (home.js § session state). Both were minted by a full ceremony in this |
| 130 | // very tab, and both are validated against the server below, so reusing |
| 131 | // them grants nothing a fresh assertion wouldn't — it just spares the user |
| 132 | // a Face ID for an account this tab is already signed into, and closes the |
| 133 | // second-account trapdoor a dismissed assertion opened (offerCreate). |
| 134 | if (await trySessionReuse()) return; |
| 135 | setStatus("Looking for your sign-in…", "busy"); |
| 136 | let login; |
| 137 | try { |
| 138 | login = await runLogin(loginBegin); |
| 139 | } catch (e) { |
| 140 | // NotAllowedError here means no sign-in on an authenticator (or the prompt |
| 141 | // was dismissed). Offer to create one — with a way back to sign-in so a |
| 142 | // returning user who dismissed doesn't accidentally start a second account. |
| 143 | if (e && e.name === "NotAllowedError") { offerCreate(); return; } |
| 144 | throw e; |
| 145 | } |
| 146 | await addWithLogin(login); |
| 147 | } |
| 148 | |
| 149 | // trySessionReuse: false = no usable live session, run the ceremony. True = |
| 150 | // the save was handled end-to-end (or genuinely failed — those errors |
| 151 | // propagate to onError like the ceremony path's). Every soft failure — |
| 152 | // missing halves, a dead token, a stale DEK that can't open the blob — falls |
| 153 | // back to the ceremony rather than guessing. |
| 154 | async function trySessionReuse() { |
| 155 | let cand = null; |
| 156 | try { cand = reuseCandidate(sessionStorage); } catch { return false; } |
| 157 | if (!cand) return false; |
| 158 | let got, dek, opened; |
| 159 | try { |
| 160 | setStatus("Checking your sign-in…", "busy"); |
| 161 | got = await fetchBlob(cand.token); // throws on a dead token (401) |
| 162 | // Signed in but no backup yet (a fresh sign-up — the first blob needs a |
| 163 | // ceremony's PRF, which reuse can't supply). Clear the busy status before |
| 164 | // falling back: in auto mode nothing else repaints, so "Checking your |
| 165 | // sign-in…" would sit under the re-enabled buttons like a stuck spinner. |
| 166 | if (!got) { setStatus("", ""); return false; } |
| 167 | dek = await importDEK(cand.dek); |
| 168 | opened = await openBlob(got.bytes, dek); |
| 169 | } catch { |
| 170 | setStatus("", ""); |
| 171 | return false; |
| 172 | } |
| 173 | await applyEntry({ token: cand.token, dek, got, opened }); |
| 174 | return true; |
| 175 | } |
| 176 | |
| 177 | // createBlobFor writes a fresh backup whose only server is this entry, keyed to |
| 178 | // the given credential. Shared by "create a new passkey" and the "signed in but |
| 179 | // no backup yet" case, so both start a backup rather than fragmenting. |
| 180 | async function createBlobFor({ token, credId, prf }) { |
| 181 | const kek = await kekFromPRF(prf); |
| 182 | const dek = await generateDEK(); |
| 183 | const vault = { |
| 184 | obj: { v: 1, servers: [payload.entry] }, |
| 185 | keys: { [credId]: await wrapDEK(dek, kek) }, |
| 186 | version: "0", |
| 187 | }; |
| 188 | const sealed = await sealBlob(vault.obj, dek, vault.keys); |
| 189 | const v = await putBlob(token, sealed, vault.version); |
| 190 | if (v === null) throw new Error("That's already set up — sign in instead."); |
| 191 | succeed(); |
| 192 | } |
| 193 | |
| 194 | // createAndAdd: register a brand-new sign-in, then save this chat under it. |
| 195 | async function createAndAdd() { |
| 196 | disable(); |
| 197 | setStatus("Creating your sign-in…", "busy"); |
| 198 | let reg; |
| 199 | try { |
| 200 | reg = await runRegister(regBegin); |
| 201 | } catch (e) { |
| 202 | if (e.message === "no-prf") { |
| 203 | setStatus("This device can't protect your sign-in here (no PRF support). You can still use add-device links to move between devices.", "error"); |
| 204 | enable(); |
| 205 | return; |
| 206 | } |
| 207 | throw e; |
| 208 | } |
| 209 | await createBlobFor(reg); |
| 210 | } |
| 211 | |
| 212 | // addWithLogin adds this chat to the backup behind an already-signed-in passkey. |
| 213 | async function addWithLogin({ token, credId, prf }) { |
| 214 | if (!prf) { |
| 215 | setStatus("Signed in, but this browser couldn't unlock your saved spaces here (no PRF result).", "error"); |
| 216 | enable(); |
| 217 | return; |
| 218 | } |
| 219 | const got = await fetchBlob(token); |
| 220 | if (!got) { |
| 221 | // A passkey that has no backup yet — start one under it (don't send the user |
| 222 | // off to make a second passkey). |
| 223 | await createBlobFor({ token, credId, prf }); |
| 224 | return; |
| 225 | } |
| 226 | const kek = await kekFromPRF(prf); |
| 227 | const { keys } = unpackBlob(got.bytes); |
| 228 | const wrapped = keys[credId]; |
| 229 | if (!wrapped) { |
| 230 | setStatus("That sign-in can't unlock these spaces.", "error"); |
| 231 | enable(); |
| 232 | return; |
| 233 | } |
| 234 | const dek = await unwrapDEK(wrapped, kek); |
| 235 | await applyEntry({ token, dek, got, opened: await openBlob(got.bytes, dek) }); |
| 236 | } |
| 237 | |
| 238 | // applyEntry merges the payload entry into an unlocked blob and saves it — |
| 239 | // the shared tail of the ceremony path (addWithLogin) and the live-session |
| 240 | // fast path (trySessionReuse). Ends in succeed(), a terminal keep-what-I-have |
| 241 | // message, or a thrown error for onError. |
| 242 | async function applyEntry({ token, dek, got, opened }) { |
| 243 | // If an entry with DIFFERENT credentials already exists for this host, adding |
| 244 | // would overwrite the credentials the user already trusts. Anyone can open |
| 245 | // this page with an arbitrary fragment, so a page that knows the host could |
| 246 | // try to clobber a real saved entry with junk — a silent add wouldn't reveal |
| 247 | // that. Require an explicit, host-specific replace confirmation. |
| 248 | // Two cases merge silently instead: an identical re-save (harmless no-op), |
| 249 | // and an existing entry with NO credentials — the address-only stub the |
| 250 | // create-a-space flow saves. There's nothing to clobber; enrolment upgrades |
| 251 | // the stub with this space's key (and its real name). |
| 252 | let cur = got; |
| 253 | const existing = (opened.obj.servers || []).find((s) => s.url === payload.entry.url); |
| 254 | if (existing && existing.credentials && credFingerprint(existing) !== credFingerprint(payload.entry)) { |
| 255 | const ok = await confirmReplace(existing); |
| 256 | if (!ok) { |
| 257 | // The replace prompt replaced the action buttons, so this is terminal: |
| 258 | // leave a clear message; the user goes back / closes the window. |
| 259 | $("actions").classList.add("hidden"); |
| 260 | setStatus("Kept your existing access to this chat — nothing changed.", "ok"); |
| 261 | return; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | // Add the entry and save, retrying once on a version race. An explicit save |
| 266 | // beats a removal tombstone (serverlist.js): re-enrolling a space the user |
| 267 | // deleted on the home page must actually bring it back. |
| 268 | for (let attempt = 0; attempt < 2; attempt++) { |
| 269 | const obj = { ...opened.obj, servers: upsert(opened.obj.servers, payload.entry) }; |
| 270 | obj.removed = clearTombstone(obj.removed, payload.entry.url); |
| 271 | if (!obj.removed) delete obj.removed; |
| 272 | const sealed = await sealBlob(obj, dek, opened.keys); |
| 273 | const v = await putBlob(token, sealed, cur.version); |
| 274 | if (v !== null) return succeed(); |
| 275 | cur = await fetchBlob(token); |
| 276 | if (!cur) throw new Error("backup disappeared"); |
| 277 | opened = await openBlob(cur.bytes, dek); |
| 278 | } |
| 279 | throw new Error("couldn't save after a version conflict — try again"); |
| 280 | } |
| 281 | |
| 282 | // ---- UI plumbing -------------------------------------------------------------- |
| 283 | |
| 284 | // Disable/enable every button currently in #actions — the set changes as the |
| 285 | // flow morphs (save → create/retry, or the replace prompt), so target them all. |
| 286 | function setBusy(busy) { |
| 287 | $("actions").querySelectorAll("button").forEach((b) => { b.disabled = busy; }); |
| 288 | } |
| 289 | function disable() { setBusy(true); } |
| 290 | function enable() { setBusy(false); } |
| 291 | |
| 292 | // offerCreate: the fallback after a sign-in that found nothing (the up-front |
| 293 | // "I'm new" button skips straight to createAndAdd). Creating leads here — the |
| 294 | // sign-in just came back empty — with a way back to sign-in so a returning |
| 295 | // user who dismissed the prompt can't fragment into a second account. |
| 296 | function offerCreate() { |
| 297 | const actions = $("actions"); |
| 298 | actions.textContent = ""; |
| 299 | setStatus("No sign-in was found on this device — or the prompt was cancelled."); |
| 300 | |
| 301 | const create = document.createElement("button"); |
| 302 | create.id = "create-fallback"; |
| 303 | create.textContent = "Create my sign-in"; |
| 304 | create.addEventListener("click", () => createAndAdd().catch((e) => onError(e, "create"))); |
| 305 | |
| 306 | const retry = document.createElement("button"); |
| 307 | retry.className = "secondary"; |
| 308 | retry.textContent = "I already have a sign-in — try again"; |
| 309 | retry.addEventListener("click", () => saveSecurely().catch((e) => onError(e, "signin"))); |
| 310 | |
| 311 | const back = document.createElement("button"); |
| 312 | back.className = "secondary"; |
| 313 | back.textContent = "Cancel"; |
| 314 | back.addEventListener("click", () => goBack(false)); |
| 315 | |
| 316 | actions.append(create, retry, back); |
| 317 | } |
| 318 | |
| 319 | // confirmReplace shows a distinct, host-specific prompt before overwriting an |
| 320 | // existing entry (never the generic "add" copy), and resolves the user's choice. |
| 321 | // All text is set via textContent — the names come from the attacker-influenced |
| 322 | // fragment, so they must never be interpolated as HTML. |
| 323 | function confirmReplace(existing) { |
| 324 | return new Promise((resolve) => { |
| 325 | const host = new URL(payload.entry.url).host; |
| 326 | const actions = $("actions"); |
| 327 | actions.textContent = ""; |
| 328 | setStatus(""); |
| 329 | |
| 330 | const q = document.createElement("p"); |
| 331 | q.textContent = `You already have "${existing.name || host}" saved for ${host}. ` + |
| 332 | `Replace it with "${payload.entry.name || host}"? Your current saved access for this chat will be overwritten.`; |
| 333 | |
| 334 | const replace = document.createElement("button"); |
| 335 | replace.textContent = "Replace my saved access"; |
| 336 | |
| 337 | const cancel = document.createElement("button"); |
| 338 | cancel.className = "secondary"; |
| 339 | cancel.textContent = "Keep what I have"; |
| 340 | |
| 341 | // Disable both so a double-click can't resolve twice; these replaced the |
| 342 | // action buttons, so setBusy/enable won't touch them anyway. |
| 343 | const settle = (v) => { replace.disabled = true; cancel.disabled = true; resolve(v); }; |
| 344 | replace.addEventListener("click", () => settle(true)); |
| 345 | cancel.addEventListener("click", () => settle(false)); |
| 346 | |
| 347 | actions.append(q, replace, cancel); |
| 348 | }); |
| 349 | } |
| 350 | |
| 351 | function succeed() { |
| 352 | $("actions").classList.add("hidden"); |
| 353 | // Seal the tile's key badge (→ green check) and hold a short beat before |
| 354 | // leaving, so success is legible instead of a flash before the redirect. |
| 355 | $("badge").classList.add("sealed"); |
| 356 | // Report completion to the oracle (enrolstatus.go): the page that launched |
| 357 | // this enrolment may never receive the redirect (iOS home-screen apps open |
| 358 | // cross-origin links in an in-app overlay; the native wrapper hands off to |
| 359 | // the system browser) — it polls /api/enroll-status with this same nonce |
| 360 | // instead. Fire-and-forget, keepalive so it survives the redirect below. |
| 361 | if (payload.nonce) { |
| 362 | try { |
| 363 | fetch("/api/enroll-done", { |
| 364 | method: "POST", |
| 365 | headers: { "Content-Type": "application/json" }, |
| 366 | body: JSON.stringify({ nonce: String(payload.nonce) }), |
| 367 | keepalive: true, |
| 368 | }).catch(() => {}); |
| 369 | } catch {} |
| 370 | } |
| 371 | setStatus("Saved. Taking you back to your chat…", "ok"); |
| 372 | setTimeout(() => goBack(true), 700); // returns with the one-time nonce so the instance trusts it |
| 373 | } |
| 374 | |
| 375 | // onError renders a friendly, specific sentence for whichever ceremony the |
| 376 | // user was in (ceremony-errors.js), keeping the name+phase crumb parenthesised |
| 377 | // — that detail is deliberate; a bland "dismissed" hid the real signal. |
| 378 | const onError = (err, ceremony) => { |
| 379 | try { console.error("[enrol] error", err && err.phase, err); } catch {} |
| 380 | setStatus(formatCeremonyError(err, ceremony), "error"); |
| 381 | enable(); |
| 382 | prefetch(); // a used/failed ceremony's options are spent — refresh for a retry |
| 383 | }; |
| 384 | |
| 385 | // ---- boot --------------------------------------------------------------------- |
| 386 | |
| 387 | if (!payload) { |
| 388 | setStatus("This page was opened without a valid request. Go back to your chat and try again.", "error"); |
| 389 | $("actions").classList.add("hidden"); |
| 390 | $("entry").classList.add("hidden"); // no entry to show — a placeholder tile would mislead |
| 391 | } else { |
| 392 | // The payload is valid, so the tile can name the chat even when the ceremony |
| 393 | // can't run (a placeholder "This chat" under an error would mislead). |
| 394 | const host = new URL(payload.entry.url).host; |
| 395 | $("entry-name").textContent = payload.entry.name || host; |
| 396 | $("entry-host").textContent = host; |
| 397 | if (entryIcon) { |
| 398 | const img = $("entry-icon"); |
| 399 | img.src = entryIcon; // validated data:image URI; set via .src, never innerHTML |
| 400 | img.classList.remove("hidden"); |
| 401 | $("entry-glyph").classList.add("hidden"); // the photo takes the glyph's spot |
| 402 | } |
| 403 | } |
| 404 | if (payload && !window.PublicKeyCredential) { |
| 405 | setStatus("This browser can't sign you in — try another browser.", "error"); |
| 406 | $("actions").classList.add("hidden"); |
| 407 | } else if (payload) { |
| 408 | // Pre-fetch ceremony options now, while the user reads the card — so either |
| 409 | // button's click reaches the authenticator inside the gesture (Safari |
| 410 | // activation, see prefetch): regBegin covers "I'm new", loginBegin the sign-in. |
| 411 | prefetch(); |
| 412 | $("save").addEventListener("click", () => saveSecurely().catch((e) => onError(e, "signin"))); |
| 413 | $("create-new").addEventListener("click", () => createAndAdd().catch((e) => onError(e, "create"))); |
| 414 | |
| 415 | // A way back without saving (same-tab navigation replaced the chat). |
| 416 | const back = document.createElement("button"); |
| 417 | back.className = "secondary"; |
| 418 | back.textContent = "Cancel"; |
| 419 | back.addEventListener("click", () => goBack(false)); |
| 420 | $("actions").append(back); |
| 421 | |
| 422 | // A post-claim handoff from the signup-first join (payload.auto): the tab |
| 423 | // signed in at home moments ago, so try the live-session fast path without |
| 424 | // a tap. Auto NEVER runs a ceremony and never skips the replace guard — if |
| 425 | // the session can't complete the save silently, the normal card stands and |
| 426 | // the buttons above do their usual work. |
| 427 | if (payload.auto) { |
| 428 | disable(); |
| 429 | trySessionReuse() |
| 430 | .then((done) => { if (!done) enable(); }) |
| 431 | .catch((e) => onError(e, "signin")); |
| 432 | } |
| 433 | } |
| 434 | |
amadan