fix: csp SHA hashes accumulate when using custom script-src rules (#4519)

[skip ci]

packages/server/src/middleware/nuxt.js

@@ -15,7 +15,7 @@ export default ({ options, nuxt, renderRoute, resources }) => async function nux
     await nuxt.callHook('render:route', url, result, context)
     const {
       html,
-      cspScriptSrcHashSet,
+      cspScriptSrcHashes,
       error,
       redirected,
       getPreloadFiles
@@ -66,7 +66,7 @@ export default ({ options, nuxt, renderRoute, resources }) => async function nux
       const { allowedSources, policies } = options.render.csp
       const cspHeader = options.render.csp.reportOnly ? 'Content-Security-Policy-Report-Only' : 'Content-Security-Policy'
 
-      res.setHeader(cspHeader, getCspString({ cspScriptSrcHashSet, allowedSources, policies, isDev: options.dev }))
+      res.setHeader(cspHeader, getCspString({ cspScriptSrcHashes, allowedSources, policies, isDev: options.dev }))
     }
 
     // Send response
@@ -114,9 +114,9 @@ const defaultPushAssets = (preloadFiles, shouldPush, publicPath, options) => {
   return links
 }
 
-const getCspString = ({ cspScriptSrcHashSet, allowedSources, policies, isDev }) => {
+const getCspString = ({ cspScriptSrcHashes, allowedSources, policies, isDev }) => {
-  const joinedHashSet = Array.from(cspScriptSrcHashSet).join(' ')
+  const joinedHashes = cspScriptSrcHashes.join(' ')
-  const baseCspStr = `script-src 'self'${isDev ? ` 'unsafe-eval'` : ''} ${joinedHashSet}`
+  const baseCspStr = `script-src 'self'${isDev ? ` 'unsafe-eval'` : ''} ${joinedHashes}`
 
   if (Array.isArray(allowedSources)) {
     return `${baseCspStr} ${allowedSources.join(' ')}`
@@ -125,7 +125,7 @@ const getCspString = ({ cspScriptSrcHashSet, allowedSources, policies, isDev })
   const policyObjectAvailable = typeof policies === 'object' && policies !== null && !Array.isArray(policies)
 
   if (policyObjectAvailable) {
-    const transformedPolicyObject = transformPolicyObject(policies, cspScriptSrcHashSet)
+    const transformedPolicyObject = transformPolicyObject(policies, cspScriptSrcHashes)
 
     return Object.entries(transformedPolicyObject).map(([k, v]) => `${k} ${v.join(' ')}`).join('; ')
   }
@@ -133,22 +133,13 @@ const getCspString = ({ cspScriptSrcHashSet, allowedSources, policies, isDev })
   return baseCspStr
 }
 
-const transformPolicyObject = (policies, cspScriptSrcHashSet) => {
+const transformPolicyObject = (policies, cspScriptSrcHashes) => {
   const userHasDefinedScriptSrc = policies['script-src'] && Array.isArray(policies['script-src'])
 
+  const additionalPolicies = userHasDefinedScriptSrc ? policies['script-src'] : []
+
   // Self is always needed for inline-scripts, so add it, no matter if the user specified script-src himself.
+  const hashAndPolicyList = cspScriptSrcHashes.concat(`'self'`, additionalPolicies)
 
-  const hashAndPolicySet = cspScriptSrcHashSet
+  return { ...policies, 'script-src': hashAndPolicyList }
-  hashAndPolicySet.add(`'self'`)
-
-  if (!userHasDefinedScriptSrc) {
-    policies['script-src'] = Array.from(hashAndPolicySet)
-    return policies
-  }
-
-  new Set(policies['script-src']).forEach(src => hashAndPolicySet.add(src))
-
-  policies['script-src'] = Array.from(hashAndPolicySet)
-
-  return policies
 }

packages/vue-renderer/src/renderer.js

@@ -365,12 +365,12 @@ export default class VueRenderer {
 
     const serializedSession = `window.${this.context.globals.context}=${devalue(context.nuxt)};`
 
-    const cspScriptSrcHashSet = new Set()
+    const cspScriptSrcHashes = []
     if (this.context.options.render.csp) {
       const { hashAlgorithm } = this.context.options.render.csp
       const hash = crypto.createHash(hashAlgorithm)
       hash.update(serializedSession)
-      cspScriptSrcHashSet.add(`'${hashAlgorithm}-${hash.digest('base64')}'`)
+      cspScriptSrcHashes.push(`'${hashAlgorithm}-${hash.digest('base64')}'`)
     }
 
     APP += `<script>${serializedSession}</script>`
@@ -390,7 +390,7 @@ export default class VueRenderer {
 
     return {
       html,
-      cspScriptSrcHashSet,
+      cspScriptSrcHashes,
       getPreloadFiles: this.getPreloadFiles.bind(this, context),
       error: context.nuxt.error,
       redirected: context.redirected

test/unit/basic.ssr.csp.test.js

@@ -312,5 +312,30 @@ describe('basic ssr csp', () => {
         expect(uniqueHashes.length).toBe(hashes.length)
       }
     )
+    test(
+      'Not contain old hashes when loading new page',
+      async () => {
+        const cspOption = {
+          enabled: true,
+          policies: {
+            'default-src': [`'self'`],
+            'script-src': ['https://example.com', 'https://example.io']
+          }
+        }
+        nuxt = await startCspDevServer(cspOption)
+        const { headers: user1Header } = await rp(url('/users/1'), {
+          resolveWithFullResponse: true
+        })
+        const user1Hashes = user1Header[reportOnlyHeader].split(' ').filter(s => s.startsWith('\'sha256-'))
+
+        const { headers: user2Header } = await rp(url('/users/2'), {
+          resolveWithFullResponse: true
+        })
+        const user2Hashes = new Set(user2Header[reportOnlyHeader].split(' ').filter(s => s.startsWith('\'sha256-')))
+
+        const intersection = new Set(user1Hashes.filter(x => user2Hashes.has(x)))
+        expect(intersection.size).toBe(0)
+      }
+    )
   })
 })