[PS-1219] Crash when login with SSO (#2023)

* PS-1219 Added null checks and improved error handling on SSO Login

* PS-1219 Improved code

* PS-1219 Improved const naming

Co-authored-by: Federico Maccaroni <fedemkr@gmail.com>

src/App/Pages/Accounts/LoginSsoPage.xaml.cs

@@ -69,12 +69,12 @@ namespace Bit.App.Pages
             }
         }
 
-        private async void LogIn_Clicked(object sender, EventArgs e)
+        private void LogIn_Clicked(object sender, EventArgs e)
         {
             if (DoOnce())
             {
                 CopyAppOptions();
-                await _vm.LogInAsync();
+                _vm.LogInCommand.Execute(null);
             }
         }
 

src/App/Pages/Accounts/LoginSsoPageViewModel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Threading.Tasks;
+using System.Windows.Input;
 using Bit.App.Abstractions;
 using Bit.App.Resources;
 using Bit.App.Utilities;
@@ -8,13 +9,15 @@ using Bit.Core.Enums;
 using Bit.Core.Exceptions;
 using Bit.Core.Models.Domain;
 using Bit.Core.Utilities;
+using Xamarin.CommunityToolkit.ObjectModel;
 using Xamarin.Essentials;
-using Xamarin.Forms;
 
 namespace Bit.App.Pages
 {
     public class LoginSsoPageViewModel : BaseViewModel
     {
+        private const string REDIRECT_URI = "bitwarden://sso-callback";
+
         private readonly IDeviceActionService _deviceActionService;
         private readonly IAuthService _authService;
         private readonly ISyncService _syncService;
@@ -23,6 +26,7 @@ namespace Bit.App.Pages
         private readonly ICryptoFunctionService _cryptoFunctionService;
         private readonly IPlatformUtilsService _platformUtilsService;
         private readonly IStateService _stateService;
+        private readonly ILogger _logger;
 
         private string _orgIdentifier;
 
@@ -37,9 +41,11 @@ namespace Bit.App.Pages
             _cryptoFunctionService = ServiceContainer.Resolve<ICryptoFunctionService>("cryptoFunctionService");
             _platformUtilsService = ServiceContainer.Resolve<IPlatformUtilsService>("platformUtilsService");
             _stateService = ServiceContainer.Resolve<IStateService>("stateService");
+            _logger = ServiceContainer.Resolve<ILogger>("logger");
+
 
             PageTitle = AppResources.Bitwarden;
-            LogInCommand = new Command(async () => await LogInAsync());
+            LogInCommand = new AsyncCommand(LogInAsync, allowsMultipleExecutions: false);
         }
 
         public string OrgIdentifier
@@ -48,7 +54,7 @@ namespace Bit.App.Pages
             set => SetProperty(ref _orgIdentifier, value);
         }
 
-        public Command LogInCommand { get; }
+        public ICommand LogInCommand { get; }
         public Action StartTwoFactorAction { get; set; }
         public Action StartSetPasswordAction { get; set; }
         public Action SsoAuthSuccessAction { get; set; }
@@ -65,81 +71,91 @@ namespace Bit.App.Pages
 
         public async Task LogInAsync()
         {
-            if (Connectivity.NetworkAccess == NetworkAccess.None)
-            {
-                await _platformUtilsService.ShowDialogAsync(AppResources.InternetConnectionRequiredMessage,
-                    AppResources.InternetConnectionRequiredTitle);
-                return;
-            }
-            if (string.IsNullOrWhiteSpace(OrgIdentifier))
-            {
-                await _platformUtilsService.ShowDialogAsync(
-                    string.Format(AppResources.ValidationFieldRequired, AppResources.OrgIdentifier),
-                    AppResources.AnErrorHasOccurred,
-                    AppResources.Ok);
-                return;
-            }
-
-            await _deviceActionService.ShowLoadingAsync(AppResources.LoggingIn);
-            string ssoToken;
-
             try
             {
+                if (Connectivity.NetworkAccess == NetworkAccess.None)
+                {
+                    await _platformUtilsService.ShowDialogAsync(AppResources.InternetConnectionRequiredMessage,
+                        AppResources.InternetConnectionRequiredTitle);
+                    return;
+                }
+                if (string.IsNullOrWhiteSpace(OrgIdentifier))
+                {
+                    await _platformUtilsService.ShowDialogAsync(
+                        string.Format(AppResources.ValidationFieldRequired, AppResources.OrgIdentifier),
+                        AppResources.AnErrorHasOccurred,
+                        AppResources.Ok);
+                    return;
+                }
+
+                await _deviceActionService.ShowLoadingAsync(AppResources.LoggingIn);
+
                 var response = await _apiService.PreValidateSso(OrgIdentifier);
-                ssoToken = response.Token;
+
+                if (string.IsNullOrWhiteSpace(response?.Token))
+                {
+                    _logger.Error(response is null ? "Login SSO Error: response is null" : "Login SSO Error: response.Token is null or whitespace");
+                    await _deviceActionService.HideLoadingAsync();
+                    await _platformUtilsService.ShowDialogAsync(AppResources.LoginSsoError);
+                    return;
+                }
+
+                var ssoToken = response.Token;
+
+
+                var passwordOptions = new PasswordGenerationOptions(true);
+                passwordOptions.Length = 64;
+
+                var codeVerifier = await _passwordGenerationService.GeneratePasswordAsync(passwordOptions);
+                var codeVerifierHash = await _cryptoFunctionService.HashAsync(codeVerifier, CryptoHashAlgorithm.Sha256);
+                var codeChallenge = CoreHelpers.Base64UrlEncode(codeVerifierHash);
+
+                var state = await _passwordGenerationService.GeneratePasswordAsync(passwordOptions);
+
+                var url = _apiService.IdentityBaseUrl + "/connect/authorize?" +
+                          "client_id=" + _platformUtilsService.GetClientType().GetString() + "&" +
+                          "redirect_uri=" + Uri.EscapeDataString(REDIRECT_URI) + "&" +
+                          "response_type=code&scope=api%20offline_access&" +
+                          "state=" + state + "&code_challenge=" + codeChallenge + "&" +
+                          "code_challenge_method=S256&response_mode=query&" +
+                          "domain_hint=" + Uri.EscapeDataString(OrgIdentifier) + "&" +
+                          "ssoToken=" + Uri.EscapeDataString(ssoToken);
+
+                WebAuthenticatorResult authResult = null;
+
+                authResult = await WebAuthenticator.AuthenticateAsync(new Uri(url),
+                    new Uri(REDIRECT_URI));
+
+
+                var code = GetResultCode(authResult, state);
+                if (!string.IsNullOrEmpty(code))
+                {
+                    await LogIn(code, codeVerifier, OrgIdentifier);
+                }
+                else
+                {
+                    await _deviceActionService.HideLoadingAsync();
+                    await _platformUtilsService.ShowDialogAsync(AppResources.LoginSsoError,
+                        AppResources.AnErrorHasOccurred);
+                }
             }
             catch (ApiException e)
             {
+                _logger.Exception(e);
                 await _deviceActionService.HideLoadingAsync();
-                await _platformUtilsService.ShowDialogAsync(
+                await _platformUtilsService.ShowDialogAsync(e?.Error?.GetSingleMessage() ?? AppResources.LoginSsoError,
-                    (e?.Error != null ? e.Error.GetSingleMessage() : AppResources.LoginSsoError),
                     AppResources.AnErrorHasOccurred);
-                return;
-            }
-
-            var passwordOptions = new PasswordGenerationOptions(true);
-            passwordOptions.Length = 64;
-
-            var codeVerifier = await _passwordGenerationService.GeneratePasswordAsync(passwordOptions);
-            var codeVerifierHash = await _cryptoFunctionService.HashAsync(codeVerifier, CryptoHashAlgorithm.Sha256);
-            var codeChallenge = CoreHelpers.Base64UrlEncode(codeVerifierHash);
-
-            var state = await _passwordGenerationService.GeneratePasswordAsync(passwordOptions);
-
-            var redirectUri = "bitwarden://sso-callback";
-
-            var url = _apiService.IdentityBaseUrl + "/connect/authorize?" +
-                      "client_id=" + _platformUtilsService.GetClientType().GetString() + "&" +
-                      "redirect_uri=" + Uri.EscapeDataString(redirectUri) + "&" +
-                      "response_type=code&scope=api%20offline_access&" +
-                      "state=" + state + "&code_challenge=" + codeChallenge + "&" +
-                      "code_challenge_method=S256&response_mode=query&" +
-                      "domain_hint=" + Uri.EscapeDataString(OrgIdentifier) + "&" +
-                      "ssoToken=" + Uri.EscapeDataString(ssoToken);
-
-            WebAuthenticatorResult authResult = null;
-            try
-            {
-                authResult = await WebAuthenticator.AuthenticateAsync(new Uri(url),
-                    new Uri(redirectUri));
             }
             catch (TaskCanceledException)
             {
                 // user canceled
                 await _deviceActionService.HideLoadingAsync();
-                return;
             }
-
+            catch (Exception ex)
-            var code = GetResultCode(authResult, state);
-            if (!string.IsNullOrEmpty(code))
-            {
-                await LogIn(code, codeVerifier, redirectUri, OrgIdentifier);
-            }
-            else
             {
+                _logger.Exception(ex);
                 await _deviceActionService.HideLoadingAsync();
-                await _platformUtilsService.ShowDialogAsync(AppResources.LoginSsoError,
+                await _platformUtilsService.ShowDialogAsync(AppResources.GenericErrorMessage, AppResources.AnErrorHasOccurred);
-                    AppResources.AnErrorHasOccurred);
             }
         }
 
@@ -158,11 +174,11 @@ namespace Bit.App.Pages
             return code;
         }
 
-        private async Task LogIn(string code, string codeVerifier, string redirectUri, string orgId)
+        private async Task LogIn(string code, string codeVerifier, string orgId)
         {
             try
             {
-                var response = await _authService.LogInSsoAsync(code, codeVerifier, redirectUri, orgId);
+                var response = await _authService.LogInSsoAsync(code, codeVerifier, REDIRECT_URI, orgId);
                 await AppHelpers.ResetInvalidUnlockAttemptsAsync();
                 await _stateService.SetRememberedOrgIdentifierAsync(OrgIdentifier);
                 await _deviceActionService.HideLoadingAsync();