fix(cron): switch manual trigger to POST to defeat CSRF

GHSA-8qhj-4f8c-j8qg: GET /api/v1/cron/:id/manual changed shared state
on the agent stream, and the JWT cookie is SameSite=Lax so a victim's
browser would send the cookie on a top-level cross-site GET. An
attacker could trick a logged-in user into firing any of their own
cron commands.

Switch the route to POST: SameSite=Lax cookies are not sent on cross-
site POST, closing the CSRF window without introducing a new token.

Tests:
- TestCronManualTriggerRejectsCrossSiteGET locks in that GET no longer
  resolves.
- TestCronManualTriggerAcceptsSameSitePOST locks in the legitimate POST
  still works.

Frontend (admin-frontend) updated in a follow-up commit.

Co-authored-by: cloudcode <cloudcode@users.noreply.github.com>

cmd/dashboard/controller/cron_manual_csrf_test.go

@@ -0,0 +1,105 @@
+package controller
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/patrickmn/go-cache"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/pkg/i18n"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+func setupCronManualTriggerFixture(t *testing.T) {
+	t.Helper()
+
+	originalDB := singleton.DB
+	originalCache := singleton.Cache
+	originalLoc := singleton.Loc
+	originalLocalizer := singleton.Localizer
+	originalCron := singleton.CronShared
+	originalServer := singleton.ServerShared
+	originalUserInfo := singleton.UserInfoMap
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	require.NoError(t, err)
+	require.NoError(t, db.AutoMigrate(&model.Cron{}, &model.Server{}, &model.User{}))
+
+	singleton.DB = db
+	singleton.Loc = time.UTC
+	singleton.Cache = cache.New(time.Minute, time.Minute)
+	singleton.Localizer = i18n.NewLocalizer("en_US", "nezha", "translations", i18n.Translations)
+	singleton.CronShared = singleton.NewCronClass()
+	singleton.ServerShared = singleton.NewServerClass()
+	singleton.UserLock.Lock()
+	singleton.UserInfoMap = map[uint64]model.UserInfo{100: {Role: model.RoleMember}}
+	singleton.UserLock.Unlock()
+
+	cr := &model.Cron{
+		Common:   model.Common{ID: 7, UserID: 100},
+		Name:     "victim cron",
+		TaskType: model.CronTypeCronTask,
+		Command:  "echo csrf-poc",
+		Cover:    model.CronCoverIgnoreAll,
+	}
+	require.NoError(t, db.Create(cr).Error)
+	singleton.CronShared.Update(cr)
+
+	t.Cleanup(func() {
+		singleton.DB = originalDB
+		singleton.Cache = originalCache
+		singleton.Loc = originalLoc
+		singleton.Localizer = originalLocalizer
+		singleton.CronShared = originalCron
+		singleton.ServerShared = originalServer
+		singleton.UserLock.Lock()
+		singleton.UserInfoMap = originalUserInfo
+		singleton.UserLock.Unlock()
+	})
+}
+
+func newCronManualRouter() *gin.Engine {
+	gin.SetMode(gin.TestMode)
+	r := gin.New()
+	r.Use(func(c *gin.Context) {
+		c.Set(model.CtxKeyAuthorizedUser, &model.User{
+			Common: model.Common{ID: 100},
+			Role:   model.RoleMember,
+		})
+		c.Next()
+	})
+	r.POST("/api/v1/cron/:id/manual", commonHandler(manualTriggerCron))
+	return r
+}
+
+func TestCronManualTriggerRejectsCrossSiteGET(t *testing.T) {
+	setupCronManualTriggerFixture(t)
+	r := newCronManualRouter()
+
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/cron/7/manual", nil)
+	req.Header.Set("Origin", "https://attacker.example")
+	req.Header.Set("Sec-Fetch-Site", "cross-site")
+	r.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusNotFound, w.Code, "manual trigger must reject cross-site GET — the route is POST-only after the CSRF fix")
+}
+
+func TestCronManualTriggerAcceptsSameSitePOST(t *testing.T) {
+	setupCronManualTriggerFixture(t)
+	r := newCronManualRouter()
+
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/cron/7/manual", nil)
+	r.ServeHTTP(w, req)
+
+	success, errMsg := decodeCommonResponseError(t, w.Body.Bytes())
+	assert.True(t, success, "owner POST must succeed: error=%q", errMsg)
+}