fix: verify unauthorized credentials before deleting accounts

iOSClient/Account/NCAccount.swift

@@ -8,6 +8,7 @@ import NextcloudKit
 
 @MainActor
 class NCAccount: NSObject {
+    private static var accountsCheckingRemoteUser: Set<String> = []
     let database = NCManageDatabase.shared
     let appDelegate = (UIApplication.shared.delegate as? AppDelegate)!
     let global = NCGlobal.shared
@@ -89,20 +90,10 @@ class NCAccount: NSObject {
 
     func changeAccount(_ account: String, userProfile: NKUserProfile?, controller: NCMainTabBarController?) async {
         if let tblAccount = await database.setAccountActiveAsync(account) {
-            // Set account
-            controller?.account = account
             // Set User Profile
             if let userProfile {
                 await database.setAccountUserProfileAsync(account: account, userProfile: userProfile)
             }
-            // Networking Certificate
-            NCNetworking.shared.activeAccountCertificate(account: account)
-            // Subscribing Push Notification
-            await NCPushNotification.shared.subscribingNextcloudServerPushNotification(account: tblAccount.account, urlBase: tblAccount.urlBase)
-            // Start the service
-            Task(priority: .utility) {
-                await NCService().startRequestServicesServer(account: account, controller: controller)
-            }
             // Capabilities
             if let capabilities = await self.database.getCapabilities(account: account) {
                 // set theming color
@@ -111,13 +102,24 @@ class NCAccount: NSObject {
             // Networking Process
             await NCNetworkingProcess.shared.setCurrentAccount(account)
 
+            // Update the account and the file context together, before starting network requests.
+            controller?.account = account
+            NCNetworking.shared.activeAccountCertificate(account: account)
+
             // Color
             NotificationCenter.default.postOnMainThread(name: self.global.notificationCenterChangeTheming, userInfo: ["account": account])
             // Notification
             if let controller {
-                NotificationCenter.default.postOnMainThread(name: self.global.notificationCenterChangeUser, userInfo: ["account": account, "controller": controller])
+                NotificationCenter.default.post(name: Notification.Name(self.global.notificationCenterChangeUser), object: nil, userInfo: ["account": account, "controller": controller])
             } else {
-                NotificationCenter.default.postOnMainThread(name: self.global.notificationCenterChangeUser, userInfo: ["account": account])
+                NotificationCenter.default.post(name: Notification.Name(self.global.notificationCenterChangeUser), object: nil, userInfo: ["account": account])
+            }
+
+            // Subscribing Push Notification
+            await NCPushNotification.shared.subscribingNextcloudServerPushNotification(account: tblAccount.account, urlBase: tblAccount.urlBase)
+            // Start the service
+            Task(priority: .utility) {
+                await NCService().startRequestServicesServer(account: account, controller: controller)
             }
         }
     }
@@ -189,10 +191,35 @@ class NCAccount: NSObject {
     }
 
     func checkRemoteUser(account: String, controller: NCMainTabBarController?) async {
+        guard Self.accountsCheckingRemoteUser.insert(account).inserted else {
+            return
+        }
+        defer { Self.accountsCheckingRemoteUser.remove(account) }
+
         let token = NCPreferences().getPassword(account: account)
         guard let tblAccount = await NCManageDatabase.shared.getTableAccountAsync(predicate: NSPredicate(format: "account == %@", account)) else {
             return
         }
+        guard let session = NextcloudKit.shared.nkCommonInstance.nksessions.session(forAccount: account),
+              session.password == token else {
+            return
+        }
+
+        // A stored 401 may belong to an inconsistent or outdated request. Verify with the server.
+        let result = await NextcloudKit.shared.getUserProfileAsync(account: account, options: NKRequestOptions(checkInterceptor: false))
+        guard !Task.isCancelled,
+              remoteUserCredentialsMatch(session, token: token) else {
+            return
+        }
+        if result.error == .success, result.userProfile?.userId == session.userId {
+            NCNetworking.shared.removeUnauthorizedAccount(account)
+            return
+        }
+        guard result.responseData?.response?.statusCode == NCGlobal.shared.errorUnauthorized else {
+            // Network failures and other responses do not confirm invalid credentials.
+            return
+        }
+
         let windowScene = SceneManager.shared.getWindowScene(controller: controller)
         await showErrorBanner(windowScene: windowScene, text: String(format: NSLocalizedString("_account_unauthorized_", comment: ""), account), errorCode: NCGlobal.shared.errorUnauthorized)
 
@@ -206,6 +233,10 @@ class NCAccount: NSObject {
         }
 
         // REMOVE ACCOUNT
+        guard !Task.isCancelled,
+              remoteUserCredentialsMatch(session, token: token) else {
+            return
+        }
         await NCAccount().deleteAccount(account, wipe: resultsWipe.wipe)
         if resultsWipe.wipe {
             let resultsSetWipe = await NextcloudKit.shared.setRemoteWipeCompletitionAsync(serverUrl: tblAccount.urlBase, token: token, account: tblAccount.account) { task in
@@ -219,11 +250,22 @@ class NCAccount: NSObject {
             nkLog(debug: "Set Remote Wipe Completition error code: \(resultsSetWipe.error.errorCode)")
         }
 
-        if account.count > 0 {
+        if !account.isEmpty, controller == nil || controller?.account == account {
             await switchToFirstAvailableAccount(controller: controller)
         }
     }
 
+    private func remoteUserCredentialsMatch(_ session: NKSession, token: String) -> Bool {
+        guard let currentSession = NextcloudKit.shared.nkCommonInstance.nksessions.session(forAccount: session.account) else {
+            return false
+        }
+        return currentSession.urlBase == session.urlBase
+            && currentSession.user == session.user
+            && currentSession.userId == session.userId
+            && currentSession.password == session.password
+            && NCPreferences().getPassword(account: session.account) == token
+    }
+
     /// Presents the login (or intro) screen if no account remains.
     func switchToFirstAvailableAccount(controller: NCMainTabBarController?) async {
         let accounts = await NCManageDatabase.shared.getAccountsAsync()

iOSClient/Files/NCFiles.swift

@@ -53,8 +53,8 @@ class NCFiles: NCCollectionViewCommon {
             self.serverUrl = utilityFileSystem.getHomeServer(session: session)
             self.titleCurrentFolder = getNavigationTitle()
 
-            NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: NCGlobal.shared.notificationCenterChangeUser), object: nil, queue: nil) { notification in
-                Task { @MainActor in
+            NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: NCGlobal.shared.notificationCenterChangeUser), object: nil, queue: .main) { notification in
+                MainActor.assumeIsolated {
                     guard let userInfo = notification.userInfo,
                           let account = userInfo["account"] as? String,
                           self.controller?.account == account else {
@@ -69,8 +69,8 @@ class NCFiles: NCCollectionViewCommon {
                     self.mainNavigationController?.menuPlusButton.menu = nil
                     self.mainNavigationController?.menuPlusButton.isEnabled = false
 
-                    self.navigationController?.popToRootViewController(animated: false)
                     self.serverUrl = self.utilityFileSystem.getHomeServer(session: session)
+                    self.navigationController?.popToRootViewController(animated: false)
                     self.isSearchingMode = false
                     self.isEditMode = false
                     self.fileSelect.removeAll()
@@ -87,10 +87,12 @@ class NCFiles: NCCollectionViewCommon {
                     self.titleCurrentFolder = self.getNavigationTitle()
                     self.navigationItem.title = self.titleCurrentFolder
 
-                    await self.mainNavigationController?.menuPlus?.create(session: session)
-                    await (self.navigationController as? NCMainNavigationController)?.setNavigationLeftItems()
-                    await self.reloadDataSource()
-                    await self.getServerData()
+                    Task { @MainActor in
+                        await self.mainNavigationController?.menuPlus?.create(session: session)
+                        await (self.navigationController as? NCMainNavigationController)?.setNavigationLeftItems()
+                        await self.reloadDataSource()
+                        await self.getServerData()
+                    }
                 }
             }
         }

iOSClient/Networking/NCNetworking+ServerError.swift

@@ -22,6 +22,15 @@ extension NCNetworking {
         return true
     }
 
+    func removeUnauthorizedAccount(_ account: String) {
+        guard let groupDefaults = UserDefaults(suiteName: NCBrandOptions.shared.capabilitiesGroup) else {
+            return
+        }
+        var accounts = groupDefaults.array(forKey: nkComm.groupDefaultsUnauthorized) as? [String] ?? []
+        accounts.removeAll { $0 == account }
+        groupDefaults.set(accounts, forKey: nkComm.groupDefaultsUnauthorized)
+    }
+
     func removeServerErrorAccount(_ account: String) {
         guard let groupDefaults = UserDefaults(suiteName: NCBrandOptions.shared.capabilitiesGroup) else {
             return