fix(console): secure server action redirects (#45374)

packages/console/app/src/lib/server-action.ts

@@ -0,0 +1,11 @@
+export function sanitizeServerActionRequest(request: Request) {
+  const requestUrl = new URL(request.url)
+  if (requestUrl.pathname !== "/_server") return request
+
+  const referer = request.headers.get("referer")
+  if (referer && URL.canParse(referer) && new URL(referer).origin === requestUrl.origin) return request
+
+  const sanitized = new Request(request)
+  sanitized.headers.set("referer", requestUrl.origin)
+  return sanitized
+}

packages/console/app/src/middleware.ts

@@ -1,9 +1,12 @@
 import { createMiddleware } from "@solidjs/start/middleware"
 import { LOCALE_HEADER, cookie, fromPathname, strip } from "~/lib/language"
 import { normalizeReferralCode, referralCookie } from "~/lib/referral-invite"
+import { sanitizeServerActionRequest } from "~/lib/server-action"
 
 export default createMiddleware({
   onRequest(event) {
+    event.request = sanitizeServerActionRequest(event.request)
+
     const url = new URL(event.request.url)
     const locale = fromPathname(url.pathname)
     if (locale) {

packages/console/app/test/serverAction.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, test } from "bun:test"
+import { sanitizeServerActionRequest } from "../src/lib/server-action"
+
+describe("server action referer", () => {
+  test("preserves same-origin return locations", () => {
+    const request = new Request("https://dev.opencode.ai/_server?id=action", {
+      headers: { referer: "https://dev.opencode.ai/auth?next=%2Fconsole" },
+    })
+
+    expect(sanitizeServerActionRequest(request)).toBe(request)
+  })
+
+  test("replaces unsafe return locations with the request origin", () => {
+    const referers = ["https://evil.example/phishing-login", "not a url", undefined]
+
+    expect(
+      referers.map((referer) =>
+        sanitizeServerActionRequest(
+          new Request("https://dev.opencode.ai/_server?id=action", {
+            headers: referer === undefined ? undefined : { referer },
+          }),
+        ).headers.get("referer"),
+      ),
+    ).toEqual(["https://dev.opencode.ai", "https://dev.opencode.ai", "https://dev.opencode.ai"])
+  })
+
+  test("does not change other routes", () => {
+    const request = new Request("https://dev.opencode.ai/auth", {
+      headers: { referer: "https://evil.example/phishing-login" },
+    })
+
+    expect(sanitizeServerActionRequest(request)).toBe(request)
+  })
+})