Merge pull request #247 from copenhagentruckwash/fix-information-disclosure-in-websocket-upgrades

Sanitize websocket upgrade error responses

services/edge-broker/server.mjs

@@ -576,7 +576,7 @@ export function createBrokerServer(options = {}) {
           gatewayInfo = await validateAgent({ gatewayId, token, headers: req.headers });
         } catch (error) {
           const status = Number(error?.status) === 403 ? 403 : Number(error?.status) === 401 ? 401 : 503;
-          rejectUpgrade(socket, status, error?.code || "agent_validation_failed", normalizeErrorMessage(error, "Gateway agent could not be validated."), {
+          rejectUpgrade(socket, status, error?.code || "agent_validation_failed", "Gateway agent could not be validated.", {
             stage: "agent_validate",
           });
           return;
@@ -643,7 +643,7 @@ export function createBrokerServer(options = {}) {
         try {
           session = await validateShellSession({ token, headers: req.headers });
         } catch (error) {
-          rejectUpgrade(socket, Number(error?.status) === 403 ? 403 : 401, error?.code || "shell_session_invalid", normalizeErrorMessage(error, "Shell session could not be validated."), {
+          rejectUpgrade(socket, Number(error?.status) === 403 ? 403 : 401, error?.code || "shell_session_invalid", "Shell session could not be validated.", {
             stage: "shell_session_validate",
           });
           return;
@@ -744,7 +744,7 @@ export function createBrokerServer(options = {}) {
         return;
       }
     } catch (error) {
-      rejectUpgrade(socket, 500, "websocket_upgrade_failed", normalizeErrorMessage(error, "WebSocket upgrade failed."));
+      rejectUpgrade(socket, 500, "websocket_upgrade_failed", "WebSocket upgrade failed.");
       return;
     }
 

services/edge-broker/test/broker.test.mjs

@@ -95,13 +95,15 @@ test("broker defaults to strict auth and fails closed when manager URL is missin
     assert.doesNotMatch(shellResponse, /101 Switching Protocols/);
     assert.match(shellResponse, /^HTTP\/1\.1 401 Unauthorized/m);
     assert.match(shellResponse, /"error_code":"shell_session_invalid"/);
-    assert.match(shellResponse, /Edge manager URL is not configured/);
+    assert.match(shellResponse, /"message":"Shell session could not be validated\."/);
+    assert.doesNotMatch(shellResponse, /Edge manager URL is not configured/);
 
     assert.doesNotMatch(agentResponse, /101 Switching Protocols/);
     assert.match(agentResponse, /^HTTP\/1\.1 503 Service Unavailable/m);
     assert.match(agentResponse, /"error_code":"agent_validation_failed"/);
     assert.match(agentResponse, /"stage":"agent_validate"/);
-    assert.match(agentResponse, /Edge manager URL is not configured/);
+    assert.match(agentResponse, /"message":"Gateway agent could not be validated\."/);
+    assert.doesNotMatch(agentResponse, /Edge manager URL is not configured/);
   } finally {
     if (broker) {
       await broker.close();
@@ -397,11 +399,34 @@ test("broker rejects invalid browser shell upgrades without leaking the token",
 
   assert.match(response, /^HTTP\/1\.1 401 Unauthorized/m);
   assert.match(response, /"error_code":"shell_session_expired"/);
+  assert.match(response, /"message":"Shell session could not be validated\."/);
+  assert.doesNotMatch(response, /Shell session expired/);
   assert.doesNotMatch(response, new RegExp(rawToken));
 
   await broker.close();
 });
 
+test("broker rejects websocket upgrade errors without exposing exception text", async () => {
+  const broker = createBrokerServer({
+    authMode: "stub",
+    validateBrowserStream: async () => {
+      throw new Error("UPSTREAM-SENSITIVE: redis://cache.internal:6379 timeout");
+    },
+  });
+  const address = await broker.listen(0);
+  const port = address.port;
+
+  const response = await rawUpgradeRequest(port, "/ws/browser-gateway-stream?token=session-token");
+
+  assert.match(response, /^HTTP\/1\.1 500 Internal Server Error/m);
+  assert.match(response, /"error_code":"websocket_upgrade_failed"/);
+  assert.match(response, /"message":"WebSocket upgrade failed\."/);
+  assert.doesNotMatch(response, /UPSTREAM-SENSITIVE/);
+  assert.doesNotMatch(response, /redis:\/\/cache\.internal/);
+
+  await broker.close();
+});
+
 test("broker closes browser shell sessions when the agent never reports shell opened", async () => {
   const closedSessions = [];
   const broker = createBrokerServer({