[Admin UI] Login not possible due to securecookie error (#7374)

* [Admin UI] Login not possible due to securecookie error

* avoid 404 favicon

* Update weed/admin/dash/auth_middleware.go

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* address comments

* avoid variable over shadowing

* log session save error

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/admin/dash/auth_middleware.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/gin-contrib/sessions"
 	"github.com/gin-gonic/gin"
+	"github.com/seaweedfs/seaweedfs/weed/glog"
 )
 
 // ShowLogin displays the login page
@@ -31,9 +32,16 @@ func (s *AdminServer) HandleLogin(username, password string) gin.HandlerFunc {
 
 		if loginUsername == username && loginPassword == password {
 			session := sessions.Default(c)
+			// Clear any existing invalid session data before setting new values
+			session.Clear()
 			session.Set("authenticated", true)
 			session.Set("username", loginUsername)
-			session.Save()
+			if err := session.Save(); err != nil {
+				// Log the detailed error server-side for diagnostics
+				glog.Errorf("Failed to save session for user %s: %v", loginUsername, err)
+				c.Redirect(http.StatusSeeOther, "/login?error=Unable to create session. Please try again or contact administrator.")
+				return
+			}
 
 			c.Redirect(http.StatusSeeOther, "/admin")
 			return
@@ -48,6 +56,8 @@ func (s *AdminServer) HandleLogin(username, password string) gin.HandlerFunc {
 func (s *AdminServer) HandleLogout(c *gin.Context) {
 	session := sessions.Default(c)
 	session.Clear()
-	session.Save()
+	if err := session.Save(); err != nil {
+		glog.Warningf("Failed to save session during logout: %v", err)
+	}
 	c.Redirect(http.StatusSeeOther, "/login")
 }

weed/admin/handlers/admin_handlers.go

@@ -48,6 +48,11 @@ func (h *AdminHandlers) SetupRoutes(r *gin.Engine, authRequired bool, username,
 	// Health check (no auth required)
 	r.GET("/health", h.HealthCheck)
 
+	// Favicon route (no auth required) - redirect to static version
+	r.GET("/favicon.ico", func(c *gin.Context) {
+		c.Redirect(http.StatusMovedPermanently, "/static/favicon.ico")
+	})
+
 	if authRequired {
 		// Authentication routes (no auth required)
 		r.GET("/login", h.authHandlers.ShowLogin)

weed/command/admin.go

@@ -191,31 +191,7 @@ func startAdminServer(ctx context.Context, options AdminOptions) error {
 	r := gin.New()
 	r.Use(gin.Logger(), gin.Recovery())
 
-	// Session store - always auto-generate session key
-	sessionKeyBytes := make([]byte, 32)
-	_, err := rand.Read(sessionKeyBytes)
-	if err != nil {
-		return fmt.Errorf("failed to generate session key: %w", err)
-	}
-	store := cookie.NewStore(sessionKeyBytes)
-
-	// Configure session options to ensure cookies are properly saved
-	store.Options(sessions.Options{
-		Path:   "/",
-		MaxAge: 3600 * 24, // 24 hours
-	})
-
-	r.Use(sessions.Sessions("admin-session", store))
-
-	// Static files - serve from embedded filesystem
-	staticFS, err := admin.GetStaticFS()
-	if err != nil {
-		log.Printf("Warning: Failed to load embedded static files: %v", err)
-	} else {
-		r.StaticFS("/static", http.FS(staticFS))
-	}
-
-	// Create data directory if specified
+	// Create data directory first if specified (needed for session key storage)
 	var dataDir string
 	if *options.dataDir != "" {
 		// Expand tilde (~) to home directory
@@ -236,6 +212,35 @@ func startAdminServer(ctx context.Context, options AdminOptions) error {
 		fmt.Printf("Data directory created/verified: %s\n", dataDir)
 	}
 
+	// Detect TLS configuration to set Secure cookie flag
+	cookieSecure := viper.GetString("https.admin.key") != ""
+
+	// Session store - load or generate session key
+	sessionKeyBytes, err := loadOrGenerateSessionKey(dataDir)
+	if err != nil {
+		return fmt.Errorf("failed to get session key: %w", err)
+	}
+	store := cookie.NewStore(sessionKeyBytes)
+
+	// Configure session options to ensure cookies are properly saved
+	store.Options(sessions.Options{
+		Path:     "/",
+		MaxAge:   3600 * 24,    // 24 hours
+		HttpOnly: true,         // Prevent JavaScript access
+		Secure:   cookieSecure, // Set based on actual TLS configuration
+		SameSite: http.SameSiteLaxMode,
+	})
+
+	r.Use(sessions.Sessions("admin-session", store))
+
+	// Static files - serve from embedded filesystem
+	staticFS, err := admin.GetStaticFS()
+	if err != nil {
+		log.Printf("Warning: Failed to load embedded static files: %v", err)
+	} else {
+		r.StaticFS("/static", http.FS(staticFS))
+	}
+
 	// Create admin server
 	adminServer := dash.NewAdminServer(*options.masters, nil, dataDir)
 
@@ -331,6 +336,46 @@ func GetAdminOptions() *AdminOptions {
 	return &AdminOptions{}
 }
 
+// loadOrGenerateSessionKey loads an existing session key from dataDir or generates a new one
+func loadOrGenerateSessionKey(dataDir string) ([]byte, error) {
+	const sessionKeyLength = 32
+	if dataDir == "" {
+		// No persistence, generate random key
+		log.Println("No dataDir specified, generating ephemeral session key")
+		key := make([]byte, sessionKeyLength)
+		_, err := rand.Read(key)
+		return key, err
+	}
+
+	sessionKeyPath := filepath.Join(dataDir, ".session_key")
+
+	// Try to load existing key
+	if data, err := os.ReadFile(sessionKeyPath); err == nil {
+		if len(data) == sessionKeyLength {
+			log.Printf("Loaded persisted session key from %s", sessionKeyPath)
+			return data, nil
+		}
+		log.Printf("Warning: Invalid session key file (expected %d bytes, got %d), generating new key", sessionKeyLength, len(data))
+	} else if !os.IsNotExist(err) {
+		log.Printf("Warning: Failed to read session key from %s: %v. A new key will be generated.", sessionKeyPath, err)
+	}
+
+	// Generate new key
+	key := make([]byte, sessionKeyLength)
+	if _, err := rand.Read(key); err != nil {
+		return nil, err
+	}
+
+	// Save key for future use
+	if err := os.WriteFile(sessionKeyPath, key, 0600); err != nil {
+		log.Printf("Warning: Failed to persist session key: %v", err)
+	} else {
+		log.Printf("Generated and persisted new session key to %s", sessionKeyPath)
+	}
+
+	return key, nil
+}
+
 // expandHomeDir expands the tilde (~) in a path to the user's home directory
 func expandHomeDir(path string) (string, error) {
 	if path == "" {