U2F (#1304)

* Delete U2F tokens alongside WebAuthn

* Bring back u2f apis

src/Core/Models/Api/Request/TwoFactorRequestModels.cs

@@ -224,6 +224,27 @@ namespace Bit.Core.Models.Api
         }
     }
 
+    public class TwoFactorU2fRequestModel : TwoFactorU2fDeleteRequestModel
+    {
+        [Required]
+        public string DeviceResponse { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class TwoFactorU2fDeleteRequestModel : TwoFactorRequestModel, IValidatableObject
+    {
+        [Required]
+        public int? Id { get; set; }
+
+        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        {
+            if (!Id.HasValue || Id < 0 || Id > 5)
+            {
+                yield return new ValidationResult("Invalid Key Id", new string[] { nameof(Id) });
+            }
+        }
+    }
+
     public class TwoFactorWebAuthnRequestModel : TwoFactorWebAuthnDeleteRequestModel
     {
         [Required]

src/Core/Models/Api/Response/TwoFactor/TwoFactorU2fResponseModel.cs

@@ -0,0 +1,59 @@
+using System;
+using Bit.Core.Models.Table;
+using Bit.Core.Models.Business;
+using Bit.Core.Enums;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Bit.Core.Models.Api
+{
+    public class TwoFactorU2fResponseModel : ResponseModel
+    {
+        public TwoFactorU2fResponseModel(User user)
+            : base("twoFactorU2f")
+        {
+            if (user == null)
+            {
+                throw new ArgumentNullException(nameof(user));
+            }
+
+            var provider = user.GetTwoFactorProvider(TwoFactorProviderType.U2f);
+            Enabled = provider?.Enabled ?? false;
+            Keys = provider?.MetaData?.Select(k => new KeyModel(k.Key,
+                new TwoFactorProvider.U2fMetaData((dynamic)k.Value)));
+        }
+
+        public bool Enabled { get; set; }
+        public IEnumerable<KeyModel> Keys { get; set; }
+
+        public class KeyModel
+        {
+            public KeyModel(string id, TwoFactorProvider.U2fMetaData data)
+            {
+                Name = data.Name;
+                Id = Convert.ToInt32(id.Replace("Key", string.Empty));
+                Compromised = data.Compromised;
+            }
+
+            public string Name { get; set; }
+            public int Id { get; set; }
+            public bool Compromised { get; set; }
+        }
+
+        public class ChallengeModel
+        {
+            public ChallengeModel(User user, U2fRegistration registration)
+            {
+                UserId = user.Id.ToString();
+                AppId = registration.AppId;
+                Challenge = registration.Challenge;
+                Version = registration.Version;
+            }
+
+            public string UserId { get; set; }
+            public string AppId { get; set; }
+            public string Challenge { get; set; }
+            public string Version { get; set; }
+        }
+    }
+}

src/Core/Models/Business/U2fRegistration.cs

@@ -0,0 +1,9 @@
+namespace Bit.Core.Models.Business
+{
+    public class U2fRegistration
+    {
+        public string AppId { get; set; }
+        public string Challenge { get; set; }
+        public string Version { get; set; }
+    }
+}