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[codex] Add hidden GitHub auth canary entry #72

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Merged
mberman84 merged 1 commit into from
Jun 23, 2026
+64 −2
Merged

[codex] Add hidden GitHub auth canary entry #72

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54 changes: 53 additions & 1 deletion worker/src/auth-votes.js
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Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,11 @@ async function startOAuth(requestUrl, env) {
return unavailable("Login is not configured.");
}

const clientNonce = requestUrl.searchParams.get("client_nonce") || "";
const requestedNonce = requestUrl.searchParams.get("client_nonce");
if (requestedNonce === null) {
return oauthStartBridge(requestUrl, env);
}
const clientNonce = requestedNonce;
if (!OAUTH_NONCE_PATTERN.test(clientNonce)) {
return jsonResponse(
{ error: "Invalid OAuth nonce", code: "invalid_oauth_nonce" },
Expand Down Expand Up @@ -161,6 +165,54 @@ async function startOAuth(requestUrl, env) {
return jsonResponse({ authorizationUrl: authorizationUrl.toString() });
}

function oauthStartBridge(requestUrl, env) {
const startUrl = new URL(
`${canonicalOrigin(env)}${normalizeBasePath(
env.PUBLIC_SITE_PATH || "/loop-library",
)}/auth/github`,
);
startUrl.searchParams.set(
"return_to",
safeReturnTo(requestUrl.searchParams.get("return_to"), env),
);
const bridge = scriptJson({ startUrl: startUrl.toString() });
const body = `<!doctype html>
<html lang="en"><head><meta charset="utf-8"><meta name="robots" content="noindex"><meta name="referrer" content="no-referrer"><title>Starting GitHub sign-in</title></head>
<body><p data-auth-status>Starting GitHub sign-in…</p>
<script>
const bridge = ${bridge};
try {
const bytes = new Uint8Array(32);
crypto.getRandomValues(bytes);
let binary = "";
bytes.forEach((byte) => { binary += String.fromCharCode(byte); });
const nonce = btoa(binary).replace(/\\+/g, "-").replace(/\\//g, "_").replace(/=+$/, "");
sessionStorage.setItem("ll_oauth_nonce", nonce);
const url = new URL(bridge.startUrl);
url.searchParams.set("client_nonce", nonce);
fetch(url, { headers: { Accept: "application/json" } })
.then(async (response) => {
const result = await response.json();
if (!response.ok || !result.authorizationUrl) throw new Error("GitHub sign-in is unavailable.");
location.replace(result.authorizationUrl);
})
.catch(() => { document.querySelector("[data-auth-status]").textContent = "GitHub sign-in is unavailable. Please try again."; });
} catch {
document.querySelector("[data-auth-status]").textContent = "GitHub sign-in is unavailable in this browser.";
}
</script></body></html>`;
return new Response(body, {
status: 200,
headers: {
"Cache-Control": "no-store",
"Content-Security-Policy": `default-src 'none'; script-src 'unsafe-inline'; connect-src 'self' ${canonicalOrigin(env)}; base-uri 'none'; frame-ancestors 'none'`,
"Content-Type": "text/html; charset=utf-8",
"Referrer-Policy": "no-referrer",
"X-Content-Type-Options": "nosniff",
},
});
}

async function finishOAuth(request, requestUrl, env, fetcher) {
const state = requestUrl.searchParams.get("state") || "";
const oauth = await readSignedValue(state, env.SESSION_SECRET);
Expand Down
12 changes: 11 additions & 1 deletion worker/test/auth-votes.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -291,7 +291,17 @@ test("GitHub OAuth state is verified and X routes are absent", async () => {
new Request(`${BASE}/auth/github?return_to=%2Floop-library%2F`),
env,
);
assert.equal(missingNonce.status, 400);
assert.equal(missingNonce.status, 200);
const startBridge = await missingNonce.text();
assert.match(startBridge, /sessionStorage\.setItem\("ll_oauth_nonce"/);
assert.match(startBridge, /client_nonce/);
assert.match(startBridge, /GitHub sign-in/);

const malformedNonce = await handleAuthVoteRoute(
new Request(`${BASE}/auth/github?client_nonce=too-short`),
env,
);
assert.equal(malformedNonce.status, 400);

assert.equal(
await handleAuthVoteRoute(new Request(`${BASE}/auth/x`), env),
Expand Down
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