fix(git): WAC preHandler 401/402/403 responses carry the git CORS headers (JavaScriptSolidServer#548) (JavaScriptSolidServer#550)

melvincarvalho · web-flow · commit 666f7dbdd343 · 2026-06-10T21:04:14.000+02:00
The 401/403 for an unauthorized git operation is emitted by the WAC preHandler in src/server.js — before handleGit runs — and that path set WAC-Allow / WWW-Authenticate but not the git CORS headers. A browser-based git client (e.g. jss.live/git/) hitting an auth-gated repo therefore saw a generic CORS/network error instead of the 401 auth challenge — the exact failure mode JavaScriptSolidServer#371 fixed for handleGit's own paths. Fix: export setGitCorsHeaders from src/handlers/git.js (it was module-private) and apply it on the preHandler's early returns — the 402 paymentRequired branch and the 401/403 unauthorized branch. The GIT_CORS_HEADERS doc comment is updated to name the new caller so it stays the single source of truth. The 402 branch gets the same one-line helper call as the tested 401/403 path; a dedicated 402 test would need a pay-gated git fixture, which is disproportionate to an identical mechanical call — the 401 test pins the helper's output. Test: the deliberately-scoped 401 test from JavaScriptSolidServer#549 (which asserted WWW-Authenticate but NOT CORS, with a pointer comment at this issue) now asserts the full contract via assertGitCors. Test title, inline comment, and the file docstring all updated to match the new behaviour. Full suite: 934/934 passing. Closes JavaScriptSolidServer#548.
diff --git a/src/handlers/git.js b/src/handlers/git.js
@@ -167,16 +167,18 @@ function tryAutoInitRepo(repoAbs, log) {
 
 // CORS headers for git responses. Single source of truth — used by the
 // success path (Fastify reply on the OPTIONS preflight, raw stream on
-// http-backend output) and by every 4xx early-return. Without these,
-// browser-based git clients (e.g. jss.live/git/) see a generic
-// CORS/network error instead of the actual status, undermining #371.
+// http-backend output), by every 4xx early-return in this module, and
+// by the WAC preHandler's 401/402/403 returns in src/server.js (#548).
+// Without these, browser-based git clients (e.g. jss.live/git/) see a
+// generic CORS/network error instead of the actual status,
+// undermining #371.
 const GIT_CORS_HEADERS = {
   'Access-Control-Allow-Origin': '*',
   'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
   'Access-Control-Allow-Headers': 'Content-Type, Authorization, Git-Protocol',
 };
 
-function setGitCorsHeaders(reply) {
+export function setGitCorsHeaders(reply) {
   for (const [k, v] of Object.entries(GIT_CORS_HEADERS)) {
     reply.header(k, v);
   }
diff --git a/src/server.js b/src/server.js
@@ -17,7 +17,7 @@ import { idpPlugin } from './idp/index.js';
 // below so non-IdP deployments don't pull in the IdP accounts module
 // (bcryptjs etc.) just to register Fastify routes. The same lazy-load
 // pattern is used in src/auth/nostr.js for the NIP-98 verifier.
-import { isGitRequest, isGitWriteOperation, handleGit } from './handlers/git.js';
+import { isGitRequest, isGitWriteOperation, handleGit, setGitCorsHeaders } from './handlers/git.js';
 import { handleCorsProxy, isCorsProxyRequest, setProxyCorsHeaders } from './handlers/cors-proxy.js';
 import { AccessMode } from './wac/parser.js';
 import { registerNostrRelay } from './nostr/relay.js';
@@ -533,11 +533,20 @@ export function createServer(options = {}) {
       request.wacAllow = wacAllow;
 
       if (paymentRequired) {
+        // Git CORS headers on the early return — same reasoning as the
+        // 401/403 below: a browser git client must see the 402, not a
+        // generic CORS/network error. See #548 / #371.
+        setGitCorsHeaders(reply);
         return reply.code(402).send({ type: 'PaymentRequired', ...paymentRequired });
       }
 
       if (!authorized) {
         const message = needsWrite ? 'Write access required for push' : 'Read access required for clone';
+        // Without the git CORS headers, browser-based git clients (e.g.
+        // jss.live/git/) hitting an auth-gated repo saw a generic CORS
+        // error instead of this 401/403 — the same failure mode #371
+        // fixed inside handleGit. See #548.
+        setGitCorsHeaders(reply);
         reply.header('WAC-Allow', wacAllow);
         if (!webId) {
           // No authentication - request Basic auth for git clients
diff --git a/test/git-handler.test.js b/test/git-handler.test.js
@@ -13,10 +13,10 @@
  *     them a browser git client sees a CORS error, not the 404)
  *   - path traversal attempts are blocked (never 200, never 500)
  *     with CORS headers
- *   - unauthenticated push advertise → 401 + WWW-Authenticate
- *     (NOTE: this 401 is emitted by the server.js WAC preHandler,
- *     which does NOT currently set the git CORS headers — that gap is
- *     tracked separately; the test asserts what is true today)
+ *   - unauthenticated push advertise → 401 + WWW-Authenticate + the
+ *     git CORS headers (the preHandler's 401/403 path lacked them
+ *     until #548; this 401 is emitted by the server.js WAC
+ *     preHandler, not by handleGit)
  *   - a real end-to-end `git push` succeeds and the pushed file is
  *     served as a static resource (receive-pack POST through
  *     http-backend + updateInstead extraction)
@@ -179,7 +179,7 @@ describe('git handler HTTP contract (#375)', () => {
     assertGitCors(res, 'traversal block');
   });
 
-  it('unauthenticated push advertise returns 401 with WWW-Authenticate (non-public server)', async () => {
+  it('unauthenticated push advertise returns 401 with WWW-Authenticate and git CORS headers (non-public server, #548)', async () => {
     // Second server WITHOUT public:true so the WAC preHandler gates
     // the push. Snapshot/restore DATA_ROOT — createServer({ root })
     // mutates it process-wide and the main suite's server reads it
@@ -198,9 +198,10 @@ describe('git handler HTTP contract (#375)', () => {
         `unauthenticated push advertise must be 401, got ${res.status}`);
       assert.ok(res.headers.get('www-authenticate'),
         'WWW-Authenticate must be present so git CLI clients prompt for credentials');
-      // Deliberately NOT asserting CORS here: the WAC preHandler's
-      // 401 path does not currently set the git CORS headers (tracked
-      // as a follow-up). Assert truth, not aspiration.
+      // #548: the WAC preHandler's 401/403 path must carry the git
+      // CORS headers, or browser git clients see a generic CORS error
+      // instead of the auth challenge.
+      assertGitCors(res, 'unauthenticated push 401');
     } finally {
       await authServer.close();
       if (originalDataRoot === undefined) delete process.env.DATA_ROOT;
