[PM-5731] Create C# WebAuthn authenticator to support maui apps

src/Core/Abstractions/ICryptoFunctionService.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Threading.Tasks;
 using Bit.Core.Enums;
+using Bit.Core.Models.Domain;
 
 namespace Bit.Core.Abstractions
 {

src/Core/Abstractions/IFido2AuthenticatorService.cs

@@ -0,0 +1,12 @@
+using Bit.Core.Utilities.Fido2;
+
+namespace Bit.Core.Abstractions
+{
+    public interface IFido2AuthenticatorService
+    {
+        Task<Fido2AuthenticatorMakeCredentialResult> MakeCredentialAsync(Fido2AuthenticatorMakeCredentialParams makeCredentialParams, IFido2MakeCredentialUserInterface userInterface);
+        Task<Fido2AuthenticatorGetAssertionResult> GetAssertionAsync(Fido2AuthenticatorGetAssertionParams assertionParams, IFido2GetAssertionUserInterface userInterface);
+        // TODO: Should this return a List? Or maybe IEnumerable?
+        Task<Fido2AuthenticatorDiscoverableCredentialMetadata[]> SilentCredentialDiscoveryAsync(string rpId);
+    }
+}

src/Core/Abstractions/IFido2ClientService.cs

@@ -0,0 +1,35 @@
+using Bit.Core.Utilities.Fido2;
+
+namespace Bit.Core.Abstractions
+{
+    /// <summary>
+    /// This class represents an abstraction of the WebAuthn Client as described by W3C:
+    /// https://www.w3.org/TR/webauthn-3/#webauthn-client
+    ///
+    /// The WebAuthn Client is an intermediary entity typically implemented in the user agent
+    /// (in whole, or in part). Conceptually, it underlies the Web Authentication API and embodies
+    /// the implementation of the Web Authentication API's operations.
+    ///
+    /// It is responsible for both marshalling the inputs for the underlying authenticator operations,
+    /// and for returning the results of the latter operations to the Web Authentication API's callers.
+    /// </summary>
+    public interface IFido2ClientService
+    {
+        /// <summary>
+        /// Allows WebAuthn Relying Party scripts to request the creation of a new public key credential source.
+        /// For more information please see: https://www.w3.org/TR/webauthn-3/#sctn-createCredential
+        /// </summary>
+        /// <param name="createCredentialParams">The parameters for the credential creation operation</param>
+        /// <returns>The new credential</returns>
+        Task<Fido2ClientCreateCredentialResult> CreateCredentialAsync(Fido2ClientCreateCredentialParams createCredentialParams);
+
+        /// <summary>
+        /// Allows WebAuthn Relying Party scripts to discover and use an existing public key credential, with the user’s consent.
+        /// Relying Party script can optionally specify some criteria to indicate what credential sources are acceptable to it.
+        /// For more information please see: https://www.w3.org/TR/webauthn-3/#sctn-getAssertion
+        /// </summary>
+        /// <param name="assertCredentialParams">The parameters for the credential assertion operation</param>
+        /// <returns>The asserted credential</returns>
+        Task<Fido2ClientAssertCredentialResult> AssertCredentialAsync(Fido2ClientAssertCredentialParams assertCredentialParams);
+    }
+}

src/Core/Abstractions/IFido2GetAssertionUserInterface.cs

@@ -0,0 +1,18 @@
+namespace Bit.Core.Abstractions 
+{
+    public struct Fido2GetAssertionUserInterfaceCredential
+    {
+        public string CipherId { get; set; }
+        public bool RequireUserVerification { get; set; }
+    }
+
+    public interface IFido2GetAssertionUserInterface : IFido2UserInterface
+    {
+        /// <summary>
+        /// Ask the user to pick a credential from a list of existing credentials.
+        /// </summary>
+        /// <param name="credentials">The credentials that the user can pick from, and if the user must be verified before completing the operation</param>
+        /// <returns>The ID of the cipher that contains the credentials the user picked, and if the user was verified before completing the operation</returns>
+        Task<(string CipherId, bool UserVerified)> PickCredentialAsync(Fido2GetAssertionUserInterfaceCredential[] credentials);
+    }
+}

src/Core/Abstractions/IFido2MakeCredentialUserInterface.cs

@@ -0,0 +1,37 @@
+namespace Bit.Core.Abstractions 
+{
+    public struct Fido2ConfirmNewCredentialParams
+    {
+        ///<summary>
+        /// The name of the credential.
+        ///</summary>
+        public string CredentialName { get; set; }
+
+        ///<summary>
+        /// The name of the user.
+        ///</summary>
+        public string UserName { get; set; }
+
+        /// <summary>
+        /// Whether or not the user must be verified before completing the operation.
+        /// </summary>
+        public bool UserVerification { get; set; }
+    }
+
+    public interface IFido2MakeCredentialUserInterface : IFido2UserInterface
+    {
+        /// <summary>
+        /// Inform the user that the operation was cancelled because their vault contains excluded credentials.
+        /// </summary>
+        /// <param name="existingCipherIds">The IDs of the excluded credentials.</param>
+        /// <returns>When user has confirmed the message</returns>
+        Task InformExcludedCredentialAsync(string[] existingCipherIds);
+
+        /// <summary>
+        /// Ask the user to confirm the creation of a new credential.
+        /// </summary>
+        /// <param name="confirmNewCredentialParams">The parameters to use when asking the user to confirm the creation of a new credential.</param>
+        /// <returns>The ID of the cipher where the new credential should be saved, and if the user was verified before completing the operation</returns>
+        Task<(string CipherId, bool UserVerified)> ConfirmNewCredentialAsync(Fido2ConfirmNewCredentialParams confirmNewCredentialParams);
+    }
+}

src/Core/Abstractions/IFido2UserInterface.cs

@@ -0,0 +1,12 @@
+namespace Bit.Core.Abstractions
+{
+    public interface IFido2UserInterface
+    {
+        /// <summary>
+        /// Make sure that the vault is unlocked.
+        /// This should open a window and ask the user to login or unlock the vault if necessary.
+        /// </summary>
+        /// <returns>When vault has been unlocked.</returns>
+        Task EnsureUnlockedVaultAsync();
+    }
+}

src/Core/Core.csproj

@@ -34,6 +34,7 @@
 	  <PackageReference Include="CsvHelper" Version="30.0.1" />
 	  <PackageReference Include="LiteDB" Version="5.0.17" />
 	  <PackageReference Include="PCLCrypto" Version="2.1.40-alpha" />
+	  <PackageReference Include="System.Formats.Cbor" Version="8.0.0" />
 	  <PackageReference Include="zxcvbn-core" Version="7.0.92" />
 	  <PackageReference Include="MessagePack.MSBuild.Tasks" Version="2.5.124">
 	    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

src/Core/Models/View/Fido2CredentialView.cs

@@ -1,5 +1,6 @@
 using Bit.Core.Enums;
 using Bit.Core.Models.Domain;
+using Bit.Core.Utilities;
 
 namespace Bit.Core.Models.View
 {
@@ -27,9 +28,28 @@ public Fido2CredentialView(Fido2Credential fido2Credential)
         public string Counter { get; set; }
         public DateTime CreationDate { get; set; }
 
+        public int CounterValue {
+            get => int.TryParse(Counter, out var counter) ? counter : 0;
+            set => Counter = value.ToString();
+        }
+
+        public byte[] UserHandleValue {
+            get => UserHandle == null ? null : CoreHelpers.Base64UrlDecode(UserHandle);
+            set => UserHandle = value == null ? null : CoreHelpers.Base64UrlEncode(value);
+        }
+
+        public byte[] KeyBytes {
+            get => KeyValue == null ? null : CoreHelpers.Base64UrlDecode(KeyValue);
+            set => KeyValue = value == null ? null : CoreHelpers.Base64UrlEncode(value);
+        }
+
+        public bool DiscoverableValue {
+            get => bool.TryParse(Discoverable, out var discoverable) && discoverable;
+            set => Discoverable = value.ToString().ToLower();
+        }
+
         public override string SubTitle => UserName;
         public override List<KeyValuePair<string, LinkedIdType>> LinkedFieldOptions => new List<KeyValuePair<string, LinkedIdType>>();
-        public bool IsDiscoverable => !string.IsNullOrWhiteSpace(Discoverable);
         public bool CanLaunch => !string.IsNullOrEmpty(RpId);
         public string LaunchUri => $"https://{RpId}";