Move context from modules to services (#29440)

Since `modules/context` has to depend on `models` and many other
packages, it should be moved from `modules/context` to
`services/context` according to design principles. There is no logic
code change on this PR, only move packages.

- Move `code.gitea.io/gitea/modules/context` to
`code.gitea.io/gitea/services/context`
- Move `code.gitea.io/gitea/modules/contexttest` to
`code.gitea.io/gitea/services/contexttest` because of depending on
context
- Move `code.gitea.io/gitea/modules/upload` to
`code.gitea.io/gitea/services/context/upload` because of depending on
context

services/context/xsrf_test.go

@@ -0,0 +1,91 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+// Copyright 2014 The Macaron Authors
+// Copyright 2020 The Gitea Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
+
+package context
+
+import (
+	"encoding/base64"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	key      = "quay"
+	userID   = "12345678"
+	actionID = "POST /form"
+)
+
+var (
+	now              = time.Now()
+	oneMinuteFromNow = now.Add(1 * time.Minute)
+)
+
+func Test_ValidToken(t *testing.T) {
+	t.Run("Validate token", func(t *testing.T) {
+		tok := GenerateCsrfToken(key, userID, actionID, now)
+		assert.True(t, ValidCsrfToken(tok, key, userID, actionID, oneMinuteFromNow))
+		assert.True(t, ValidCsrfToken(tok, key, userID, actionID, now.Add(CsrfTokenTimeout-1*time.Nanosecond)))
+		assert.True(t, ValidCsrfToken(tok, key, userID, actionID, now.Add(-1*time.Minute)))
+	})
+}
+
+// Test_SeparatorReplacement tests that separators are being correctly substituted
+func Test_SeparatorReplacement(t *testing.T) {
+	t.Run("Test two separator replacements", func(t *testing.T) {
+		assert.NotEqual(t, GenerateCsrfToken("foo:bar", "baz", "wah", now),
+			GenerateCsrfToken("foo", "bar:baz", "wah", now))
+	})
+}
+
+func Test_InvalidToken(t *testing.T) {
+	t.Run("Test invalid tokens", func(t *testing.T) {
+		invalidTokenTests := []struct {
+			name, key, userID, actionID string
+			t                           time.Time
+		}{
+			{"Bad key", "foobar", userID, actionID, oneMinuteFromNow},
+			{"Bad userID", key, "foobar", actionID, oneMinuteFromNow},
+			{"Bad actionID", key, userID, "foobar", oneMinuteFromNow},
+			{"Expired", key, userID, actionID, now.Add(CsrfTokenTimeout)},
+			{"More than 1 minute from the future", key, userID, actionID, now.Add(-1*time.Nanosecond - 1*time.Minute)},
+		}
+
+		tok := GenerateCsrfToken(key, userID, actionID, now)
+		for _, itt := range invalidTokenTests {
+			assert.False(t, ValidCsrfToken(tok, itt.key, itt.userID, itt.actionID, itt.t))
+		}
+	})
+}
+
+// Test_ValidateBadData primarily tests that no unexpected panics are triggered during parsing
+func Test_ValidateBadData(t *testing.T) {
+	t.Run("Validate bad data", func(t *testing.T) {
+		badDataTests := []struct {
+			name, tok string
+		}{
+			{"Invalid Base64", "ASDab24(@)$*=="},
+			{"No delimiter", base64.URLEncoding.EncodeToString([]byte("foobar12345678"))},
+			{"Invalid time", base64.URLEncoding.EncodeToString([]byte("foobar:foobar"))},
+		}
+
+		for _, bdt := range badDataTests {
+			assert.False(t, ValidCsrfToken(bdt.tok, key, userID, actionID, oneMinuteFromNow))
+		}
+	})
+}