PM-6685 Fix race condition issue where the biometrics check is being done before the iOS extension is being shown. So when we need the UI, we wait until ViewDidAppear happens. (#3078)

src/Core/Abstractions/IConditionedAwaiterManager.cs

@@ -1,12 +1,10 @@
-using System;
-using System.Threading.Tasks;
-
-namespace Bit.Core.Abstractions
+namespace Bit.Core.Abstractions
 {
     public enum AwaiterPrecondition
     {
         EnvironmentUrlsInited,
-        AndroidWindowCreated
+        AndroidWindowCreated,
+        AutofillIOSExtensionViewDidAppear
     }
 
     public interface IConditionedAwaiterManager
@@ -14,5 +12,6 @@ namespace Bit.Core.Abstractions
         Task GetAwaiterForPrecondition(AwaiterPrecondition awaiterPrecondition);
         void SetAsCompleted(AwaiterPrecondition awaiterPrecondition);
         void SetException(AwaiterPrecondition awaiterPrecondition, Exception ex);
+        void Recreate(AwaiterPrecondition awaiterPrecondition);
     }
 }

src/Core/Resources/Localization/AppResources.Designer.cs

@@ -7685,6 +7685,15 @@ namespace Bit.Core.Resources.Localization {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Verifying identity....
+        /// </summary>
+        public static string VerifyingIdentityEllipsis {
+            get {
+                return ResourceManager.GetString("VerifyingIdentityEllipsis", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Verify master password.
         /// </summary>

src/Core/Resources/Localization/AppResources.resx

@@ -2936,6 +2936,9 @@ Do you want to switch to this account?</value>
     <value>There was a problem reading your passkey for {0}. Try again later.</value>
     <comment>The parameter is the RpId</comment>
   </data>
+  <data name="VerifyingIdentityEllipsis" xml:space="preserve">
+    <value>Verifying identity...</value>
+  </data>
   <data name="Passwords" xml:space="preserve">
     <value>Passwords</value>
   </data>

src/Core/Services/ConditionedAwaiterManager.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Threading.Tasks;
+using System.Collections.Concurrent;
 using Bit.Core.Abstractions;
 
 namespace Bit.Core.Services
@@ -11,7 +8,8 @@ namespace Bit.Core.Services
         private readonly ConcurrentDictionary<AwaiterPrecondition, TaskCompletionSource<bool>> _preconditionsTasks = new ConcurrentDictionary<AwaiterPrecondition, TaskCompletionSource<bool>>
         {
             [AwaiterPrecondition.EnvironmentUrlsInited] = new TaskCompletionSource<bool>(),
-            [AwaiterPrecondition.AndroidWindowCreated] = new TaskCompletionSource<bool>()
+            [AwaiterPrecondition.AndroidWindowCreated] = new TaskCompletionSource<bool>(),
+            [AwaiterPrecondition.AutofillIOSExtensionViewDidAppear] = new TaskCompletionSource<bool>()
         };
 
         public Task GetAwaiterForPrecondition(AwaiterPrecondition awaiterPrecondition)
@@ -39,5 +37,15 @@ namespace Bit.Core.Services
                 tcs.TrySetException(ex);
             }
         }
+
+        public void Recreate(AwaiterPrecondition awaiterPrecondition)
+        {
+            if (_preconditionsTasks.TryRemove(awaiterPrecondition, out var oldTcs))
+            {
+                oldTcs.TrySetCanceled();
+
+                _preconditionsTasks.TryAdd(awaiterPrecondition, new TaskCompletionSource<bool>());
+            }
+        }
     }
 }

src/Core/Services/UserVerification/Fido2UserVerificationPreferredServiceStrategy.cs

@@ -19,7 +19,10 @@ namespace Bit.Core.Services.UserVerification
                 return true;
             }
 
-            options.OnNeedUI?.Invoke();
+            if (options.OnNeedUITask != null)
+            {
+                await options.OnNeedUITask();
+            }
 
             var (canPerformOSUnlock, isOSUnlocked) = await _userVerificationMediatorService.PerformOSUnlockAsync();
             if (canPerformOSUnlock)

src/Core/Services/UserVerification/Fido2UserVerificationRequiredServiceStrategy.cs

@@ -23,7 +23,10 @@ namespace Bit.Core.Services.UserVerification
                 return true;
             }
 
-            options.OnNeedUI?.Invoke();
+            if (options.OnNeedUITask != null)
+            {
+                await options.OnNeedUITask();
+            }
 
             var (canPerformOSUnlock, isOSUnlocked) = await _userVerificationMediatorService.PerformOSUnlockAsync();
             if (canPerformOSUnlock)

src/Core/Services/UserVerification/UserVerificationMediatorService.cs

@@ -39,7 +39,11 @@ namespace Bit.Core.Services.UserVerification
         {
             if (await ShouldPerformMasterPasswordRepromptAsync(options))
             {
-                options.OnNeedUI?.Invoke();
+                if (options.OnNeedUITask != null)
+                {
+                    await options.OnNeedUITask();
+                }
+
                 return await _passwordRepromptService.PromptAndCheckPasswordIfNeededAsync(Enums.CipherRepromptType.Password);
             }
 

src/Core/Utilities/Fido2/Fido2UserVerificationOptions.cs

@@ -6,19 +6,19 @@
             Fido2UserVerificationPreference userVerificationPreference,
             bool hasVaultBeenUnlockedInTransaction,
             string rpId = null,
-            Action onNeedUI = null)
+            Func<Task> onNeedUITask = null)
         {
             ShouldCheckMasterPasswordReprompt = shouldCheckMasterPasswordReprompt;
             UserVerificationPreference = userVerificationPreference;
             HasVaultBeenUnlockedInTransaction = hasVaultBeenUnlockedInTransaction;
             RpId = rpId;
-            OnNeedUI = onNeedUI;
+            OnNeedUITask = onNeedUITask;
         }
 
         public bool ShouldCheckMasterPasswordReprompt { get; }
         public Fido2UserVerificationPreference UserVerificationPreference { get; }
         public bool HasVaultBeenUnlockedInTransaction { get; }
         public string RpId { get; }
-        public Action OnNeedUI { get; }
+        public Func<Task> OnNeedUITask { get; }
     }
 }

src/iOS.Autofill/CredentialProviderViewController.Passkeys.cs

@@ -270,13 +270,21 @@ namespace Bit.iOS.Autofill
                         userVerificationPreference,
                         _context.VaultUnlockedDuringThisSession,
                         _context.PasskeyCredentialIdentity?.RelyingPartyIdentifier,
-                        () =>
+                        async () =>
                         {
                             if (_context.IsExecutingWithoutUserInteraction)
                             {
                                 CancelRequest(ASExtensionErrorCode.UserInteractionRequired);
                                 throw new InvalidOperationNeedsUIException();
                             }
+
+                            // HACK: [PM-6685] There are some devices that end up with a race condition when doing biometrics authentication
+                            // that the check is trying to be done before the iOS extension UI is shown, which cause the bio check to fail.
+                            // So a workaround is to show a toast which force the iOS extension UI to be shown and then awaiting for the
+                            // precondition that the view did appear before continuing with the verification.
+                            _platformUtilsService.Value.ShowToast(null, null, AppResources.VerifyingIdentityEllipsis);
+
+                            await _conditionedAwaiterManager.Value.GetAwaiterForPrecondition(AwaiterPrecondition.AutofillIOSExtensionViewDidAppear);
                         })
                     );
             }

src/iOS.Autofill/CredentialProviderViewController.cs

@@ -32,6 +32,7 @@ namespace Bit.iOS.Autofill
         private IAccountsManager _accountsManager;
 
         private readonly LazyResolve<IStateService> _stateService = new LazyResolve<IStateService>();
+        private readonly LazyResolve<IConditionedAwaiterManager> _conditionedAwaiterManager = new LazyResolve<IConditionedAwaiterManager>();
 
         public CredentialProviderViewController(IntPtr handle)
             : base(handle)
@@ -56,6 +57,8 @@ namespace Bit.iOS.Autofill
                 {
                     ExtContext = ExtensionContext
                 };
+
+                _conditionedAwaiterManager.Value.Recreate(AwaiterPrecondition.AutofillIOSExtensionViewDidAppear);
             }
             catch (Exception ex)
             {
@@ -63,6 +66,13 @@ namespace Bit.iOS.Autofill
             }
         }
 
+        public override void ViewDidAppear(bool animated)
+        {
+            base.ViewDidAppear(animated);
+
+            _conditionedAwaiterManager.Value.SetAsCompleted(AwaiterPrecondition.AutofillIOSExtensionViewDidAppear);
+        }
+
         public override async void PrepareCredentialList(ASCredentialServiceIdentifier[] serviceIdentifiers)
         {
             try