From 2fdbb1e4827bc8f4f82b469aea5fbcc13d347824 Mon Sep 17 00:00:00 2001
From: Gabe Kangas <gabek@real-ity.com>
Date: Mon, 12 Dec 2022 16:57:17 -0800
Subject: [PATCH] Support CSP nonce for webv2. Closes #2127

---
 controllers/index.go                          | 19 ++++++++++++-------
 router/middleware/headers.go                  | 12 ++----------
 utils/accessTokens.go                         |  6 +++---
 .../ServerRenderedHydration.tsx               |  1 +
 4 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/controllers/index.go b/controllers/index.go
index 0dba20e92..f2beb3b93 100644
--- a/controllers/index.go
+++ b/controllers/index.go
@@ -2,6 +2,7 @@ package controllers
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"path/filepath"
 	"strings"
@@ -23,21 +24,23 @@ func IndexHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if isIndexRequest {
-		renderIndexHtml(w)
-		return
-	}
-
 	// Set a cache control max-age header
 	middleware.SetCachingHeaders(w, r)
 
+	nonceRandom, _ := utils.GenerateRandomString(5)
+
 	// Set our global HTTP headers
-	middleware.SetHeaders(w)
+	middleware.SetHeaders(w, fmt.Sprintf("nonce-%s", nonceRandom))
+
+	if isIndexRequest {
+		renderIndexHtml(w, nonceRandom)
+		return
+	}
 
 	serveWeb(w, r)
 }
 
-func renderIndexHtml(w http.ResponseWriter) {
+func renderIndexHtml(w http.ResponseWriter, nonce string) {
 	type serverSideContent struct {
 		Name             string
 		Summary          string
@@ -48,6 +51,7 @@ func renderIndexHtml(w http.ResponseWriter) {
 		Image            string
 		StatusJSON       string
 		ServerConfigJSON string
+		Nonce            string
 	}
 
 	status := getStatusResponse()
@@ -74,6 +78,7 @@ func renderIndexHtml(w http.ResponseWriter) {
 		Image:            "/logo/external",
 		StatusJSON:       string(sb),
 		ServerConfigJSON: string(cb),
+		Nonce:            nonce,
 	}
 
 	index, err := static.GetWebIndexTemplate()
diff --git a/router/middleware/headers.go b/router/middleware/headers.go
index f228c9b8a..62643d266 100644
--- a/router/middleware/headers.go
+++ b/router/middleware/headers.go
@@ -3,22 +3,14 @@ package middleware
 import (
 	"fmt"
 	"net/http"
-	"os"
 	"strings"
 )
 
 // SetHeaders will set our global headers for web resources.
-func SetHeaders(w http.ResponseWriter) {
-	// When running automated browser tests we must allow `unsafe-eval` in our CSP
-	// so we can explicitly add it only when needed.
-	inTest := os.Getenv("BROWSER_TEST") == "true"
-	unsafeEval := ""
-	if inTest {
-		unsafeEval = `'unsafe-eval'`
-	}
+func SetHeaders(w http.ResponseWriter, nonce string) {
 	// Content security policy
 	csp := []string{
-		fmt.Sprintf("script-src 'self' %s 'sha256-B5bOgtE39ax4J6RqDE93TVYrJeLAdxDOJFtF3hoWYDw=' 'sha256-PzXGlTLvNFZ7et6GkP2nD3XuSaAKQVBSYiHzU2ZKm8o=' 'sha256-/wqazZOqIpFSIrNVseblbKCXrezG73X7CMqRSTf+8zw=' 'sha256-jCj2f+ICtd8fvdb0ngc+Hkr/ZnZOMvNkikno/XR6VZs='", unsafeEval),
+		fmt.Sprintf("script-src '%s' 'self'", nonce),
 		"worker-src 'self' blob:", // No single quotes around blob:
 	}
 	w.Header().Set("Content-Security-Policy", strings.Join(csp, "; "))
diff --git a/utils/accessTokens.go b/utils/accessTokens.go
index 12f8afe90..77a1f06c4 100644
--- a/utils/accessTokens.go
+++ b/utils/accessTokens.go
@@ -9,7 +9,7 @@ const tokenLength = 32
 
 // GenerateAccessToken will generate and return an access token.
 func GenerateAccessToken() (string, error) {
-	return generateRandomString(tokenLength)
+	return GenerateRandomString(tokenLength)
 }
 
 // generateRandomBytes returns securely generated random bytes.
@@ -27,12 +27,12 @@ func generateRandomBytes(n int) ([]byte, error) {
 	return b, nil
 }
 
-// generateRandomString returns a URL-safe, base64 encoded
+// GenerateRandomString returns a URL-safe, base64 encoded
 // securely generated random string.
 // It will return an error if the system's secure random
 // number generator fails to function correctly, in which
 // case the caller should not continue.
-func generateRandomString(n int) (string, error) {
+func GenerateRandomString(n int) (string, error) {
 	b, err := generateRandomBytes(n)
 	return base64.URLEncoding.EncodeToString(b), err
 }
diff --git a/web/components/ServerRendered/ServerRenderedHydration.tsx b/web/components/ServerRendered/ServerRenderedHydration.tsx
index e0ada02a5..9c84e4cf1 100644
--- a/web/components/ServerRendered/ServerRenderedHydration.tsx
+++ b/web/components/ServerRendered/ServerRenderedHydration.tsx
@@ -4,6 +4,7 @@ import { FC } from 'react';
 export const ServerRenderedHydration: FC = () => (
   <script
     id="server-side-hydration"
+    nonce="{{.Nonce}}"
     dangerouslySetInnerHTML={{
       __html: `
 	window.configHydration = {{.ServerConfigJSON}};