PM-2035: PRF Unlock (#6401)

* Initial refactor

* Add WebauthnPRFOptions to syncResponse

* MAYBE: Use KM owned ResponseModel?

* REVERT ^- Keep using PrfUnlockOptions for simplicity

This reverts commit 5a34e7dfa8.

* UserDecryptionOptions: Only send one credential

* format

* Update UserDecryptionOptions.cs

* format

* Added feature flag (#6600)

src/Api/Vault/Controllers/SyncController.cs

@@ -6,6 +6,7 @@ using Bit.Core;
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.AdminConsole.Enums.Provider;
 using Bit.Core.AdminConsole.Repositories;
+using Bit.Core.Auth.Repositories;
 using Bit.Core.Auth.UserFeatures.TwoFactorAuth.Interfaces;
 using Bit.Core.Context;
 using Bit.Core.Entities;
@@ -44,6 +45,7 @@ public class SyncController : Controller
     private readonly IFeatureService _featureService;
     private readonly IApplicationCacheService _applicationCacheService;
     private readonly ITwoFactorIsEnabledQuery _twoFactorIsEnabledQuery;
+    private readonly IWebAuthnCredentialRepository _webAuthnCredentialRepository;
     private readonly IUserAccountKeysQuery _userAccountKeysQuery;
 
     public SyncController(
@@ -61,6 +63,7 @@ public class SyncController : Controller
         IFeatureService featureService,
         IApplicationCacheService applicationCacheService,
         ITwoFactorIsEnabledQuery twoFactorIsEnabledQuery,
+        IWebAuthnCredentialRepository webAuthnCredentialRepository,
         IUserAccountKeysQuery userAccountKeysQuery)
     {
         _userService = userService;
@@ -77,6 +80,7 @@ public class SyncController : Controller
         _featureService = featureService;
         _applicationCacheService = applicationCacheService;
         _twoFactorIsEnabledQuery = twoFactorIsEnabledQuery;
+        _webAuthnCredentialRepository = webAuthnCredentialRepository;
         _userAccountKeysQuery = userAccountKeysQuery;
     }
 
@@ -120,6 +124,9 @@ public class SyncController : Controller
         var organizationIdsClaimingActiveUser = organizationClaimingActiveUser.Select(o => o.Id);
 
         var organizationAbilities = await _applicationCacheService.GetOrganizationAbilitiesAsync();
+        var webAuthnCredentials = _featureService.IsEnabled(FeatureFlagKeys.PM2035PasskeyUnlock)
+            ? await _webAuthnCredentialRepository.GetManyByUserIdAsync(user.Id)
+            : [];
 
         UserAccountKeysData userAccountKeys = null;
         // JIT TDE users and some broken/old users may not have a private key.
@@ -130,7 +137,7 @@ public class SyncController : Controller
 
         var response = new SyncResponseModel(_globalSettings, user, userAccountKeys, userTwoFactorEnabled, userHasPremiumFromOrganization, organizationAbilities,
             organizationIdsClaimingActiveUser, organizationUserDetails, providerUserDetails, providerUserOrganizationDetails,
-            folders, collections, ciphers, collectionCiphersGroupDict, excludeDomains, policies, sends);
+            folders, collections, ciphers, collectionCiphersGroupDict, excludeDomains, policies, sends, webAuthnCredentials);
         return response;
     }
 

src/Api/Vault/Models/Response/SyncResponseModel.cs

@@ -6,6 +6,9 @@ using Bit.Api.Models.Response;
 using Bit.Api.Tools.Models.Response;
 using Bit.Core.AdminConsole.Entities;
 using Bit.Core.AdminConsole.Models.Data.Provider;
+using Bit.Core.Auth.Entities;
+using Bit.Core.Auth.Enums;
+using Bit.Core.Auth.Models.Api.Response;
 using Bit.Core.Entities;
 using Bit.Core.KeyManagement.Models.Api.Response;
 using Bit.Core.KeyManagement.Models.Data;
@@ -39,7 +42,8 @@ public class SyncResponseModel() : ResponseModel("sync")
         IDictionary<Guid, IGrouping<Guid, CollectionCipher>> collectionCiphersDict,
         bool excludeDomains,
         IEnumerable<Policy> policies,
-        IEnumerable<Send> sends)
+        IEnumerable<Send> sends,
+        IEnumerable<WebAuthnCredential> webAuthnCredentials)
         : this()
     {
         Profile = new ProfileResponseModel(user, userAccountKeysData, organizationUserDetails, providerUserDetails,
@@ -57,6 +61,16 @@ public class SyncResponseModel() : ResponseModel("sync")
         Domains = excludeDomains ? null : new DomainsResponseModel(user, false);
         Policies = policies?.Select(p => new PolicyResponseModel(p)) ?? new List<PolicyResponseModel>();
         Sends = sends.Select(s => new SendResponseModel(s));
+        var webAuthnPrfOptions = webAuthnCredentials
+            .Where(c => c.GetPrfStatus() == WebAuthnPrfStatus.Enabled)
+            .Select(c => new WebAuthnPrfDecryptionOption(
+                c.EncryptedPrivateKey,
+                c.EncryptedUserKey,
+                c.CredentialId,
+                [] // transports as empty array
+            ))
+            .ToArray();
+
         UserDecryption = new UserDecryptionResponseModel
         {
             MasterPasswordUnlock = user.HasMasterPassword()
@@ -72,7 +86,8 @@ public class SyncResponseModel() : ResponseModel("sync")
                     MasterKeyEncryptedUserKey = user.Key!,
                     Salt = user.Email.ToLowerInvariant()
                 }
-                : null
+                : null,
+            WebAuthnPrfOptions = webAuthnPrfOptions.Length > 0 ? webAuthnPrfOptions : null
         };
     }
 

src/Core/Auth/Models/Api/Response/UserDecryptionOptions.cs

@@ -45,13 +45,19 @@ public class WebAuthnPrfDecryptionOption
 {
     public string EncryptedPrivateKey { get; }
     public string EncryptedUserKey { get; }
+    public string CredentialId { get; }
+    public string[] Transports { get; }
 
     public WebAuthnPrfDecryptionOption(
         string encryptedPrivateKey,
-        string encryptedUserKey)
+        string encryptedUserKey,
+        string credentialId,
+        string[]? transports = null)
     {
         EncryptedPrivateKey = encryptedPrivateKey;
         EncryptedUserKey = encryptedUserKey;
+        CredentialId = credentialId;
+        Transports = transports ?? [];
     }
 }
 

src/Core/Constants.cs

@@ -160,6 +160,7 @@ public static class FeatureFlagKeys
     public const string PM24579_PreventSsoOnExistingNonCompliantUsers = "pm-24579-prevent-sso-on-existing-non-compliant-users";
     public const string DisableAlternateLoginMethods = "pm-22110-disable-alternate-login-methods";
     public const string MJMLBasedEmailTemplates = "mjml-based-email-templates";
+    public const string PM2035PasskeyUnlock = "pm-2035-passkey-unlock";
     public const string MjmlWelcomeEmailTemplates = "pm-21741-mjml-welcome-email";
     public const string OrganizationConfirmationEmail = "pm-28402-update-confirmed-to-org-email-template";
     public const string MarketingInitiatedPremiumFlow = "pm-26140-marketing-initiated-premium-flow";

src/Core/KeyManagement/Models/Api/Response/UserDecryptionResponseModel.cs

@@ -1,4 +1,7 @@
-namespace Bit.Core.KeyManagement.Models.Api.Response;
+using System.Text.Json.Serialization;
+using Bit.Core.Auth.Models.Api.Response;
+
+namespace Bit.Core.KeyManagement.Models.Api.Response;
 
 public class UserDecryptionResponseModel
 {
@@ -6,4 +9,10 @@ public class UserDecryptionResponseModel
     /// Returns the unlock data when the user has a master password that can be used to decrypt their vault.
     /// </summary>
     public MasterPasswordUnlockResponseModel? MasterPasswordUnlock { get; set; }
+
+    /// <summary>
+    /// Gets or sets the WebAuthn PRF decryption keys.
+    /// </summary>
+    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
+    public WebAuthnPrfDecryptionOption[]? WebAuthnPrfOptions { get; set; }
 }

src/Identity/IdentityServer/UserDecryptionOptionsBuilder.cs

@@ -64,8 +64,12 @@ public class UserDecryptionOptionsBuilder : IUserDecryptionOptionsBuilder
     {
         if (credential.GetPrfStatus() == WebAuthnPrfStatus.Enabled)
         {
-            _options.WebAuthnPrfOption =
-                new WebAuthnPrfDecryptionOption(credential.EncryptedPrivateKey, credential.EncryptedUserKey);
+            _options.WebAuthnPrfOption = new WebAuthnPrfDecryptionOption(
+                credential.EncryptedPrivateKey,
+                credential.EncryptedUserKey,
+                credential.CredentialId,
+                [] // Stored credentials currently lack Transports, just send an empty array for now
+            );
         }
 
         return this;

test/Identity.Test/IdentityServer/UserDecryptionOptionsBuilderTests.cs

@@ -60,6 +60,7 @@ public class UserDecryptionOptionsBuilderTests
         {
             Assert.NotNull(result.WebAuthnPrfOption);
             Assert.Equal(credential.EncryptedPrivateKey, result.WebAuthnPrfOption!.EncryptedPrivateKey);
+            Assert.Equal(credential.CredentialId, result.WebAuthnPrfOption!.CredentialId);
             Assert.Equal(credential.EncryptedUserKey, result.WebAuthnPrfOption!.EncryptedUserKey);
         }
         else