init

internal/security/headers.go

@@ -0,0 +1,27 @@
+package security
+
+import "net/http"
+
+// SecureHeaders adds a baseline of security headers.
+// CSP is intentionally conservative; adjust if you add external assets.
+func SecureHeaders(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("X-Content-Type-Options", "nosniff")
+		w.Header().Set("X-Frame-Options", "DENY")
+		w.Header().Set("Referrer-Policy", "no-referrer")
+		w.Header().Set("Permissions-Policy", "geolocation=(), microphone=(), camera=()")
+		w.Header().Set("Cross-Origin-Opener-Policy", "same-origin")
+		w.Header().Set("Cross-Origin-Resource-Policy", "same-origin")
+		w.Header().Set("Cross-Origin-Embedder-Policy", "require-corp")
+		w.Header().Set("Content-Security-Policy",
+			"default-src 'self'; "+
+				"script-src 'self'; "+
+				"style-src 'self'; "+
+				"img-src 'self' data:; "+
+				"object-src 'none'; "+
+				"base-uri 'none'; "+
+				"frame-ancestors 'none'; "+
+				"form-action 'self'")
+		next.ServeHTTP(w, r)
+	})
+}