email token provider

src/Core/Identity/EmailTokenProvider.cs

@@ -0,0 +1,86 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Identity;
+using Bit.Core.Models.Table;
+using Bit.Core.Enums;
+using Bit.Core.Services;
+using Microsoft.Extensions.DependencyInjection;
+using Bit.Core.Models;
+
+namespace Bit.Core.Identity
+{
+    public class EmailTokenProvider : IUserTwoFactorTokenProvider<User>
+    {
+        private readonly IServiceProvider _serviceProvider;
+
+        public EmailTokenProvider(IServiceProvider serviceProvider)
+        {
+            _serviceProvider = serviceProvider;
+        }
+
+        public async Task<bool> CanGenerateTwoFactorTokenAsync(UserManager<User> manager, User user)
+        {
+            var provider = user.GetTwoFactorProvider(TwoFactorProviderType.Email);
+            if(!HasProperMetaData(provider))
+            {
+                return false;
+            }
+
+            return await _serviceProvider.GetRequiredService<IUserService>().
+                TwoFactorProviderIsEnabledAsync(TwoFactorProviderType.Email, user);
+        }
+
+        public Task<string> GenerateAsync(string purpose, UserManager<User> manager, User user)
+        {
+            var provider = user.GetTwoFactorProvider(TwoFactorProviderType.Email);
+            if(!HasProperMetaData(provider))
+            {
+                return null;
+            }
+
+            return Task.FromResult(RedactEmail((string)provider.MetaData["Email"]));
+        }
+
+        public Task<bool> ValidateAsync(string purpose, string token, UserManager<User> manager, User user)
+        {
+            return _serviceProvider.GetRequiredService<IUserService>().VerifyTwoFactorEmailAsync(user, token);
+        }
+
+        private bool HasProperMetaData(TwoFactorProvider provider)
+        {
+            return provider?.MetaData != null && provider.MetaData.ContainsKey("Email") &&
+                !string.IsNullOrWhiteSpace((string)provider.MetaData["Email"]);
+        }
+
+        private static string RedactEmail(string email)
+        {
+            var emailParts = email.Split('@');
+
+            string shownPart = null;
+            if(emailParts[0].Length > 2 && emailParts[0].Length <= 4)
+            {
+                shownPart = emailParts[0].Substring(0, 1);
+            }
+            else if(emailParts[0].Length > 4)
+            {
+                shownPart = emailParts[0].Substring(0, 2);
+            }
+            else
+            {
+                shownPart = string.Empty;
+            }
+
+            string redactedPart = null;
+            if(emailParts[0].Length > 4)
+            {
+                redactedPart = new string('*', emailParts[0].Length - 2);
+            }
+            else
+            {
+                redactedPart = new string('*', emailParts[0].Length - shownPart.Length);
+            }
+
+            return $"{shownPart}{redactedPart}@{emailParts[1]}";
+        }
+    }
+}