add Content Security Policy (#1252)

* add Content Security Policy

* remove reflect-metadata on production builds to get rid of unsafe-eval

* fix baseCSP usage

* add SRI to CSP

* add blob: to media-src

* remove SRI

* CSP set to reportOnly

* adding data: to connect-src CSP

* remove block-all-mixed-content

* add report-uri support

1 files changed, 45 insertions, 0 deletions

diff --git a/server/middlewares/csp.ts b/server/middlewares/csp.ts
new file mode 100644
index 000000000..a0ed3710b
--- /dev/null
+++ b/server/middlewares/csp.ts
@@ -0,0 +1,45 @@
+import * as helmet from 'helmet'
+import { CONFIG } from '../initializers/constants'
+
+const baseDirectives = Object.assign({},
+  {
+    defaultSrc: ["'none'"], // by default, not specifying default-src = '*'
+    connectSrc: ['*', 'data:'],
+    mediaSrc: ["'self'", 'https:', 'blob:'],
+    fontSrc: ["'self'", 'data:'],
+    imgSrc: ["'self'", 'data:'],
+    scriptSrc: ["'self' 'unsafe-inline'"],
+    styleSrc: ["'self' 'unsafe-inline'"],
+    // objectSrc: ["'none'"], // only define to allow plugins, else let defaultSrc 'none' block it
+    formAction: ["'self'"],
+    frameAncestors: ["'none'"],
+    baseUri: ["'self'"],
+    pluginTypes: ["'none'"],
+    manifestSrc: ["'self'"],
+    frameSrc: ["'self'"], // instead of deprecated child-src / self because of test-embed
+    workerSrc: ["'self'"], // instead of deprecated child-src
+    upgradeInsecureRequests: true
+  },
+  (CONFIG.SERVICES['CSP-LOGGER'] != null) ? { reportUri: CONFIG.SERVICES['CSP-LOGGER'] } : {}
+)
+
+const baseCSP = helmet.contentSecurityPolicy({
+  directives: baseDirectives,
+  browserSniff: false,
+  reportOnly: true
+})
+
+const embedCSP = helmet.contentSecurityPolicy({
+  directives: Object.assign(baseDirectives, {
+    frameAncestors: ['*']
+  }),
+  browserSniff: false, // assumes a modern browser, but allows CDN in front
+  reportOnly: true
+})
+
+// ---------------------------------------------------------------------------
+
+export {
+  baseCSP,
+  embedCSP
+}