[MM-37108] Fix possible nil dereference in team edition (#17933)

* Fix possible nil dereference

* Fix translation

* Switch to StatusForbidden

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

api4/license.go

@@ -181,6 +181,11 @@ func requestTrialLicense(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if c.App.Srv().LicenseManager == nil {
+		c.Err = model.NewAppError("requestTrialLicense", "api.license.upgrade_needed.app_error", nil, "", http.StatusForbidden)
+		return
+	}
+
 	canStartTrialLicense, err := c.App.Srv().LicenseManager.CanStartTrial()
 	if err != nil {
 		c.Err = model.NewAppError("requestTrialLicense", "api.license.request-trial.can-start-trial.error", nil, err.Error(), http.StatusInternalServerError)
@@ -278,6 +283,11 @@ func requestRenewalLink(c *Context, w http.ResponseWriter, r *http.Request) {
 }
 
 func getPrevTrialLicense(c *Context, w http.ResponseWriter, r *http.Request) {
+	if c.App.Srv().LicenseManager == nil {
+		c.Err = model.NewAppError("getPrevTrialLicense", "api.license.upgrade_needed.app_error", nil, "", http.StatusForbidden)
+		return
+	}
+
 	license, err := c.App.Srv().LicenseManager.GetPrevTrial()
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)

api4/license_test.go

@@ -229,4 +229,12 @@ func TestRequestTrialLicense(t *testing.T) {
 		require.Equal(t, "api.license.add_license.unique_users.app_error", resp.Error.Id)
 		require.False(t, ok)
 	})
+
+	th.App.Srv().LicenseManager = nil
+	t.Run("trial license should fail if LicenseManager is nil", func(t *testing.T) {
+		ok, resp := th.SystemAdminClient.RequestTrialLicense(1)
+		CheckForbiddenStatus(t, resp)
+		require.False(t, ok)
+		require.Equal(t, "api.license.upgrade_needed.app_error", resp.Error.Id)
+	})
 }

i18n/en.json

@@ -2000,6 +2000,10 @@
     "id": "api.license.request_trial_license.no-site-url.app_error",
     "translation": "Unable to request a trial license. Please configure a Site URL in the web server section of the Mattermost System Console."
   },
+  {
+    "id": "api.license.upgrade_needed.app_error",
+    "translation": "Feature requires an upgrade to Enterprise Edition."
+  },
   {
     "id": "api.marshal_error",
     "translation": "marshal error"