fix(desktop): constrain renderer navigation

packages/desktop/src/main/external-url.test.ts

@@ -0,0 +1,18 @@
+import { describe, expect, test } from "bun:test"
+import { isSafeExternalUrl } from "./external-url"
+
+describe("external URL policy", () => {
+  test.each(["https://opencode.ai", "http://127.0.0.1:4096", "mailto:hello@opencode.ai"])("allows %s", (url) =>
+    expect(isSafeExternalUrl(url)).toBe(true),
+  )
+
+  test.each(["file:///tmp/test", "javascript:alert(1)", "data:text/html,test", "vscode://file/tmp/test", "nope"])(
+    "rejects %s",
+    (url) => expect(isSafeExternalUrl(url)).toBe(false),
+  )
+
+  test("rejects non-string values", () => {
+    expect(isSafeExternalUrl(null)).toBe(false)
+    expect(isSafeExternalUrl({ toString: () => "https://opencode.ai" })).toBe(false)
+  })
+})

packages/desktop/src/main/external-url.ts

@@ -0,0 +1,6 @@
+const protocols = new Set(["http:", "https:", "mailto:"])
+
+export function isSafeExternalUrl(value: unknown) {
+  if (typeof value !== "string" || !URL.canParse(value)) return false
+  return protocols.has(new URL(value).protocol)
+}

packages/desktop/src/main/ipc.ts

@@ -8,6 +8,7 @@ import type { DesktopMenuAction } from "@opencode-ai/app/desktop-menu"
 import type { FatalRendererError, ServerReadyData, TitlebarTheme } from "../preload/types"
 import { runDesktopMenuAction } from "./desktop-menu-actions"
 import { setForceFocus } from "./debug"
+import { isSafeExternalUrl } from "./external-url"
 import { assertAttachmentBudget, createPickedFileAuthorizations } from "./attachment-picker"
 import { getStore, removeStoreFileIfEmpty } from "./store"
 import { getPinchZoomEnabled, getWindowID, setPinchZoomEnabled, setTitlebar, updateTitlebar } from "./windows"
@@ -178,6 +179,7 @@ export function registerIpcHandlers(deps: Deps) {
   )
 
   ipcMain.on("open-link", (_event: IpcMainEvent, url: string) => {
+    if (!isSafeExternalUrl(url)) return
     void shell.openExternal(url)
   })
 

packages/desktop/src/main/windows.ts

@@ -220,6 +220,11 @@ export function createMainWindow(id: string = randomUUID()) {
   state.manage(win)
   registerWindow(win, id)
   wireFullscreen(win)
+  win.webContents.on("will-frame-navigate", (event) => {
+    if (isRendererUrl(event.url)) return
+    event.preventDefault()
+  })
+  win.webContents.setWindowOpenHandler(() => ({ action: "deny" }))
   loadWindow(win, "index.html")
   wireZoom(win)