First commit

server/middleware/csrf.go

@@ -0,0 +1,48 @@
+// Copyright 2017 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package middleware
+
+import (
+	"context"
+	"github.com/miniflux/miniflux2/helper"
+	"log"
+	"net/http"
+)
+
+func Csrf(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var csrfToken string
+
+		csrfCookie, err := r.Cookie("csrfToken")
+		if err == http.ErrNoCookie || csrfCookie.Value == "" {
+			csrfToken = helper.GenerateRandomString(64)
+			cookie := &http.Cookie{
+				Name:     "csrfToken",
+				Value:    csrfToken,
+				Path:     "/",
+				Secure:   r.URL.Scheme == "https",
+				HttpOnly: true,
+			}
+
+			http.SetCookie(w, cookie)
+		} else {
+			csrfToken = csrfCookie.Value
+		}
+
+		ctx := r.Context()
+		ctx = context.WithValue(ctx, "CsrfToken", csrfToken)
+
+		w.Header().Add("Vary", "Cookie")
+		isTokenValid := csrfToken == r.FormValue("csrf") || csrfToken == r.Header.Get("X-Csrf-Token")
+
+		if r.Method == "POST" && !isTokenValid {
+			log.Println("[Middleware:CSRF] Invalid or missing CSRF token!")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte("Invalid or missing CSRF token!"))
+		} else {
+			next.ServeHTTP(w, r.WithContext(ctx))
+		}
+	})
+}