Refactor CSRF protection modules, make sure CSRF tokens can be up-to-date. (#19337)

Do a refactoring to the CSRF related code, remove most unnecessary functions.
Parse the generated token's issue time, regenerate the token every a few minutes.

integrations/csrf_test.go

@@ -0,0 +1,52 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package integrations
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCsrfProtection(t *testing.T) {
+	defer prepareTestEnv(t)()
+
+	// test web form csrf via form
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2}).(*user_model.User)
+	session := loginUser(t, user.Name)
+	req := NewRequestWithValues(t, "POST", "/user/settings", map[string]string{
+		"_csrf": "fake_csrf",
+	})
+	session.MakeRequest(t, req, http.StatusSeeOther)
+
+	resp := session.MakeRequest(t, req, http.StatusSeeOther)
+	loc := resp.Header().Get("Location")
+	assert.Equal(t, setting.AppSubURL+"/", loc)
+	resp = session.MakeRequest(t, NewRequest(t, "GET", loc), http.StatusOK)
+	htmlDoc := NewHTMLParser(t, resp.Body)
+	assert.Equal(t, "Bad Request: invalid CSRF token",
+		strings.TrimSpace(htmlDoc.doc.Find(".ui.message").Text()),
+	)
+
+	// test web form csrf via header. TODO: should use an UI api to test
+	req = NewRequest(t, "POST", "/user/settings")
+	req.Header.Add("X-Csrf-Token", "fake_csrf")
+	session.MakeRequest(t, req, http.StatusSeeOther)
+
+	resp = session.MakeRequest(t, req, http.StatusSeeOther)
+	loc = resp.Header().Get("Location")
+	assert.Equal(t, setting.AppSubURL+"/", loc)
+	resp = session.MakeRequest(t, NewRequest(t, "GET", loc), http.StatusOK)
+	htmlDoc = NewHTMLParser(t, resp.Body)
+	assert.Equal(t, "Bad Request: invalid CSRF token",
+		strings.TrimSpace(htmlDoc.doc.Find(".ui.message").Text()),
+	)
+}