security: fix password log leak, getDb CSRF, cookie hardening

1. web/controller/index.go
   Stop logging the submitted plaintext password on failed login.
   Replace it with "***" in the Telegram notification too.

2. web/controller/server.go + web/html/index.html
   Convert /panel/api/server/getDb from GET to POST and require an
   X-Requested-With header. Prevents <img>/<a>/<form> CSRF that would
   otherwise let an attacker steal the SQLite DB by tricking a logged-in
   admin into loading a single URL.

3. web/web.go
   Set Secure=true on the session cookie when TLS cert/key are configured,
   and tighten SameSite from Lax to Strict for the panel session.

web/controller/index.go

@@ -74,11 +74,10 @@ func (a *IndexController) login(c *gin.Context) {
 	user := a.userService.CheckUser(form.Username, form.Password, form.TwoFactorCode)
 	timeStr := time.Now().Format("2006-01-02 15:04:05")
 	safeUser := template.HTMLEscapeString(form.Username)
-	safePass := template.HTMLEscapeString(form.Password)
 
 	if user == nil {
-		logger.Warningf("wrong username: \"%s\", password: \"%s\", IP: \"%s\"", safeUser, safePass, getRemoteIp(c))
-		a.tgbot.UserLoginNotify(safeUser, safePass, getRemoteIp(c), timeStr, 0)
+		logger.Warningf("wrong username: \"%s\", IP: \"%s\"", safeUser, getRemoteIp(c))
+		a.tgbot.UserLoginNotify(safeUser, "***", getRemoteIp(c), timeStr, 0)
 		pureJsonMsg(c, http.StatusOK, false, I18nWeb(c, "pages.login.toasts.wrongUsernameOrPassword"))
 		return
 	}

web/controller/server.go

@@ -44,7 +44,7 @@ func (a *ServerController) initRouter(g *gin.RouterGroup) {
 	g.GET("/cpuHistory/:bucket", a.getCpuHistoryBucket)
 	g.GET("/getXrayVersion", a.getXrayVersion)
 	g.GET("/getConfigJson", a.getConfigJson)
-	g.GET("/getDb", a.getDb)
+	g.POST("/getDb", a.getDb)
 	g.GET("/getNewUUID", a.getNewUUID)
 	g.GET("/getNewX25519Cert", a.getNewX25519Cert)
 	g.GET("/getNewmldsa65", a.getNewmldsa65)
@@ -252,7 +252,13 @@ func (a *ServerController) getConfigJson(c *gin.Context) {
 }
 
 // getDb downloads the database file.
+// CSRF mitigation: requires X-Requested-With header (cannot be sent cross-origin
+// from a simple form/img/anchor without a preflight, which SameSite=Strict blocks).
 func (a *ServerController) getDb(c *gin.Context) {
+	if c.GetHeader("X-Requested-With") != "XMLHttpRequest" {
+		c.AbortWithStatus(http.StatusForbidden)
+		return
+	}
 	db, err := a.serverService.GetDb()
 	if err != nil {
 		jsonMsg(c, I18nWeb(c, "pages.index.getDatabaseError"), err)

web/html/index.html

@@ -1067,8 +1067,28 @@
       openBackup() {
         backupModal.show();
       },
-      exportDatabase() {
-        window.location = basePath + 'panel/api/server/getDb';
+      async exportDatabase() {
+        try {
+          const resp = await fetch(basePath + 'panel/api/server/getDb', {
+            method: 'POST',
+            headers: { 'X-Requested-With': 'XMLHttpRequest' },
+            credentials: 'same-origin',
+          });
+          if (!resp.ok) {
+            throw new Error('HTTP ' + resp.status);
+          }
+          const blob = await resp.blob();
+          const url = URL.createObjectURL(blob);
+          const a = document.createElement('a');
+          a.href = url;
+          a.download = 'x-ui.db';
+          document.body.appendChild(a);
+          a.click();
+          document.body.removeChild(a);
+          URL.revokeObjectURL(url);
+        } catch (e) {
+          console.error('export db failed', e);
+        }
       },
       importDatabase() {
         const fileInput = document.createElement('input');

web/web.go

@@ -206,11 +206,15 @@ func (s *Server) initRouter() (*gin.Engine, error) {
 	store := cookie.NewStore(secret)
 	// Configure default session cookie options, including expiration (MaxAge)
 	if sessionMaxAge, err := s.settingService.GetSessionMaxAge(); err == nil {
+		certFile, _ := s.settingService.GetCertFile()
+		keyFile, _ := s.settingService.GetKeyFile()
+		secureCookie := certFile != "" && keyFile != ""
 		store.Options(sessions.Options{
 			Path:     "/",
 			MaxAge:   sessionMaxAge * 60, // minutes -> seconds
 			HttpOnly: true,
-			SameSite: http.SameSiteLaxMode,
+			Secure:   secureCookie,
+			SameSite: http.SameSiteStrictMode,
 		})
 	}
 	engine.Use(sessions.Sessions("3x-ui", store))