fix: enforce origin isolation on subdomain gws (#60)

* fix: enforce origin isolation on subdomain gws

Towards #30

* chore: undo ts fixup

* refactor: apply suggestions from code review

Co-authored-by: Russell Dempsey <1173416+SgtPooki@users.noreply.github.com>

* fix: config page redirect

* chore: empty out redirects

* chore: config page check supports hash routing

* chore: html title

* Revert "chore: empty out redirects"

This reverts commit 1a6d25c.

* Revert "fix: config page redirect"

This reverts commit 2fee3ce.

* fix: redirects file doesnt bork config requests

---------

Co-authored-by: Russell Dempsey <1173416+SgtPooki@users.noreply.github.com>

public/_redirects

@@ -1 +1,2 @@
+/config /#/config 302
 /* /?helia-sw=/:splat 302

src/app.tsx

@@ -2,15 +2,14 @@ import React, { useContext } from 'react'
 import Config from './components/config.tsx'
 import { ConfigContext } from './context/config-context.tsx'
 import HelperUi from './helper-ui.tsx'
+import { isConfigPage } from './lib/is-config-page.ts'
 import { isPathOrSubdomainRequest } from './lib/path-or-subdomain.ts'
 import RedirectPage from './redirectPage.tsx'
 
 function App (): JSX.Element {
   const { isConfigExpanded, setConfigExpanded } = useContext(ConfigContext)
-  if (window.location.pathname === '/config') {
+  if (isConfigPage()) {
     setConfigExpanded(true)
-  }
-  if (window.location.pathname === '/config') {
     return <Config />
   }
 

src/components/config.tsx

@@ -44,6 +44,7 @@ export default (): JSX.Element | null => {
       return
     }
     // we get the iframe origin from a query parameter called 'origin', if this is loaded in an iframe
+    // TODO: why we need this origin here? where is targetOrigin used?
     const targetOrigin = decodeURIComponent(window.location.search.split('origin=')[1])
     const config = await getConfig()
 

src/context/config-context.tsx

@@ -1,4 +1,5 @@
 import React, { createContext, useState } from 'react'
+import { isConfigPage } from '../lib/is-config-page.ts'
 
 const isLoadedInIframe = window.self !== window.top
 
@@ -9,7 +10,7 @@ export const ConfigContext = createContext({
 
 export const ConfigProvider = ({ children, expanded = isLoadedInIframe }: { children: JSX.Element[] | JSX.Element, expanded?: boolean }): JSX.Element => {
   const [isConfigExpanded, setConfigExpanded] = useState(expanded)
-  const isExplicitlyLoadedConfigPage = window.location.pathname === '/config'
+  const isExplicitlyLoadedConfigPage = isConfigPage()
 
   const setConfigExpandedWrapped = (value: boolean): void => {
     if (isLoadedInIframe || isExplicitlyLoadedConfigPage) {

src/index.tsx

@@ -5,6 +5,7 @@ import App from './app.tsx'
 import { ConfigProvider } from './context/config-context.tsx'
 import { ServiceWorkerProvider } from './context/service-worker-context.tsx'
 import { loadConfigFromLocalStorage } from './lib/config-db.ts'
+import { isConfigPage } from './lib/is-config-page.ts'
 
 await loadConfigFromLocalStorage()
 
@@ -16,7 +17,7 @@ const root = ReactDOMClient.createRoot(container)
 root.render(
   <React.StrictMode>
     <ServiceWorkerProvider>
-      <ConfigProvider expanded={window.location.pathname === '/config'}>
+      <ConfigProvider expanded={isConfigPage()}>
           <App />
       </ConfigProvider>
     </ServiceWorkerProvider>

src/lib/is-config-page.ts

@@ -0,0 +1,5 @@
+export function isConfigPage (): boolean {
+  const isConfigPathname = window.location.pathname === '/config'
+  const isConfigHashPath = window.location.hash === '#/config' // needed for _redirects and IPFS hosted sw gateways
+  return isConfigPathname || isConfigHashPath
+}

src/lib/path-or-subdomain.ts

@@ -1,14 +1,84 @@
+import { base32 } from 'multiformats/bases/base32'
+import { base36 } from 'multiformats/bases/base36'
+import { CID } from 'multiformats/cid'
+import { dnsLinkLabelEncoder } from './dns-link-labels.ts'
+
 // TODO: dry, this is same regex code  as in  getSubdomainParts
 const subdomainRegex = /^(?<id>[^/]+)\.(?<protocol>ip[fn]s)\.[^/]+$/
 const pathRegex = /^\/(?<protocol>ip[fn]s)\/(?<path>.*)$/
 
-export const isPathOrSubdomainRequest = (location: Pick<Location, 'hostname' | 'pathname'>): boolean => {
-  const subdomain = location.hostname
-  const subdomainMatch = subdomain.match(subdomainRegex)
+export const isPathOrSubdomainRequest = (location: Pick<Location, 'host' | 'pathname'>): boolean => {
+  return isPathGatewayRequest(location) || isSubdomainGatewayRequest(location)
+}
 
+export const isSubdomainGatewayRequest = (location: Pick<Location, 'host' | 'pathname'>): boolean => {
+  const subdomainMatch = location.host.match(subdomainRegex)
+  return subdomainMatch?.groups != null
+}
+
+export const isPathGatewayRequest = (location: Pick<Location, 'host' | 'pathname'>): boolean => {
   const pathMatch = location.pathname.match(pathRegex)
-  const isPathBasedRequest = pathMatch?.groups != null
-  const isSubdomainRequest = subdomainMatch?.groups != null
+  return pathMatch?.groups != null
+}
+
+/**
+ * Origin isolation check and enforcement
+ * https://github.com/ipfs-shipyard/helia-service-worker-gateway/issues/30
+ */
+export const findOriginIsolationRedirect = async (location: Pick<Location, 'protocol' | 'host' | 'pathname' | 'search' | 'hash' >): Promise<string | null> => {
+  if (isPathGatewayRequest(location) && !isSubdomainGatewayRequest(location)) {
+    const redirect = await isSubdomainIsolationSupported(location)
+    if (redirect) {
+      return toSubdomainRequest(location)
+    }
+  }
+  return null
+}
+
+const isSubdomainIsolationSupported = async (location: Pick<Location, 'protocol' | 'host' | 'pathname'>): Promise<boolean> => {
+  // TODO: do this test once and expose it as cookie / config flag somehow
+  const testUrl = `${location.protocol}//bafkqaaa.ipfs.${location.host}`
+  try {
+    const response: Response = await fetch(testUrl)
+    return response.status === 200
+  } catch (_) {
+    return false
+  }
+}
+
+const toSubdomainRequest = (location: Pick<Location, 'protocol' | 'host' | 'pathname' | 'search' | 'hash'>): string => {
+  const segments = location.pathname.split('/').filter(segment => segment !== '')
+  const ns = segments[0]
+  let id = segments[1]
 
-  return isPathBasedRequest || isSubdomainRequest
+  // DNS labels are case-insensitive, and the length limit is 63.
+  // We ensure base32 if CID, base36 if ipns,
+  // or inlined according to https://specs.ipfs.tech/http-gateways/subdomain-gateway/#host-request-header if DNSLink name
+  try {
+    switch (ns) {
+      case 'ipfs':
+        // Base32 is case-insensitive and allows CID with popular hashes like sha2-256 to fit in a single DNS label
+        id = CID.parse(id).toV1().toString(base32)
+        break
+      case 'ipns':
+        // IPNS Names are represented as Base36 CIDv1 with libp2p-key codec
+        // https://specs.ipfs.tech/ipns/ipns-record/#ipns-name
+        // eslint-disable-next-line no-case-declarations
+        const ipnsName = CID.parse(id).toV1()
+        // /ipns/ namespace uses Base36 instead of 32 because ED25519 keys need to fit in DNS label of max length 63
+        id = ipnsName.toString(base36)
+        break
+      default:
+        throw new Error('Unknown namespace: ' + ns)
+    }
+  } catch (_) {
+    // not a CID, so we assume a DNSLink name and inline it according to
+    // https://specs.ipfs.tech/http-gateways/subdomain-gateway/#host-request-header
+    if (id.includes('.')) {
+      id = dnsLinkLabelEncoder(id)
+    }
+  }
+  const remainingPath = `/${segments.slice(2).join('/')}`
+  const newLocation = new URL(`${location.protocol}//${id}.${ns}.${location.host}${remainingPath}${location.search}${location.hash}`)
+  return newLocation.href
 }

src/sw.ts

@@ -4,6 +4,7 @@ import { HeliaServiceWorkerCommsChannel, type ChannelMessage } from './lib/chann
 import { getSubdomainParts } from './lib/get-subdomain-parts.ts'
 import { heliaFetch } from './lib/heliaFetch.ts'
 import { error, log, trace } from './lib/logger.ts'
+import { findOriginIsolationRedirect } from './lib/path-or-subdomain.ts'
 import type { Helia } from '@helia/interface'
 
 declare let self: ServiceWorkerGlobalScope
@@ -49,6 +50,19 @@ interface FetchHandlerArg {
 }
 
 const fetchHandler = async ({ path, request }: FetchHandlerArg): Promise<Response> => {
+  // test and enforce origin isolation before anything else is executed
+  const originLocation = await findOriginIsolationRedirect(new URL(request.url))
+  if (originLocation !== null) {
+    const body = 'Gateway supports subdomain mode, redirecting to ensure Origin isolation..'
+    return new Response(body, {
+      status: 301,
+      headers: {
+        'Content-Type': 'text/plain',
+        Location: originLocation
+      }
+    })
+  }
+
   if (helia == null) {
     helia = await getHelia()
   }

tests/path-or-subdomain.spec.ts

@@ -5,44 +5,44 @@ import { isPathOrSubdomainRequest } from '../src/lib/path-or-subdomain.ts'
 describe('isPathOrSubdomainRequest', () => {
   it('returns true for path-based request', () => {
     expect(isPathOrSubdomainRequest({
-      hostname: 'example.com',
+      host: 'example.com',
       pathname: '/ipfs/bafyFoo'
     })).to.equal(true)
     expect(isPathOrSubdomainRequest({
-      hostname: 'example.com',
+      host: 'example.com',
       pathname: '/ipns/specs.ipfs.tech'
     })).to.equal(true)
   })
 
   it('returns true for subdomain request', () => {
     expect(isPathOrSubdomainRequest({
-      hostname: 'bafyFoo.ipfs.example.com',
+      host: 'bafyFoo.ipfs.example.com',
       pathname: '/'
     })).to.equal(true)
     expect(isPathOrSubdomainRequest({
-      hostname: 'docs.ipfs.tech.ipns.example.com',
+      host: 'docs.ipfs.tech.ipns.example.com',
       pathname: '/'
     })).to.equal(true)
   })
 
   it('returns true for inlined dnslink subdomain request', () => {
     expect(isPathOrSubdomainRequest({
-      hostname: 'bafyFoo.ipfs.example.com',
+      host: 'bafyFoo.ipfs.example.com',
       pathname: '/'
     })).to.equal(true)
     expect(isPathOrSubdomainRequest({
-      hostname: 'specs-ipfs-tech.ipns.example.com',
+      host: 'specs-ipfs-tech.ipns.example.com',
       pathname: '/'
     })).to.equal(true)
   })
 
   it('returns false for non-path and non-subdomain request', () => {
     expect(isPathOrSubdomainRequest({
-      hostname: 'example.com',
+      host: 'example.com',
       pathname: '/foo/bar'
     })).to.equal(false)
     expect(isPathOrSubdomainRequest({
-      hostname: 'foo.bar.example.com',
+      host: 'foo.bar.example.com',
       pathname: '/'
     })).to.equal(false)
   })

webpack.config.js

@@ -106,6 +106,10 @@ const dev = {
     // Only update what has changed on hot reload
     hot: true,
     port: 3000,
+    headers: {
+      'access-control-allow-origin': '*',
+      'access-control-allow-methods': 'GET'
+    },
     allowedHosts: ['helia-sw-gateway.localhost', 'localhost']
   },
 
@@ -170,7 +174,7 @@ const common = {
     // Generates an HTML file from a template
     // Generates deprecation warning: https://github.com/jantimon/html-webpack-plugin/issues/1501
     new HtmlWebpackPlugin({
-      title: 'Helia bundle by Webpack',
+      title: 'Helia service worker gateway',
       favicon: paths.public + '/favicon.ico',
       template: paths.public + '/index.html', // template file
       filename: 'index.html', // output file,