Fix issue w/iOS13 broker and nonce mismatch (#1667)

* update msbuild sdk extras
update ADAL broker error message
update logging for nonce

* add check for v3 broker

* add return ok

changelog.txt

@@ -1,7 +1,7 @@
 Version 5.2.2
 ==============
 Bug Fixes:
-- **Ensures that ADAL.NET works fine with brokers on iOS 13**. On iOS 13, iOS, the broker, may or may not return the source application, which is used by ADAL.NET to verify the response is coming from broker. To maintain secure calls, MSAL.NET will now also create a nonce to send in the broker request and will verify the same nonce is returned in the broker response in the case of a missing source application. [Issue](https://github.com/AzureAD/microsoft-authentication-library-for-dotnet/issues/1357)
+- **Ensures that ADAL.NET works with brokers on iOS 13**. On iOS 13, the iOS broker, may or may not return the source application, which will be used by ADAL.NET to verify that the response is coming from the iOS broker. To maintain secure calls, ADAL.NET will now also create a nonce to send in the broker request and will verify the same nonce is returned in the broker response in the case of a missing source application. [Issue](https://github.com/AzureAD/azure-activedirectory-library-for-dotnet/issues/1642)
 
 Version 5.2.1
 ==============

global.json

@@ -1,5 +1,5 @@
 {
   "msbuild-sdks": {
-    "MSBuild.Sdk.Extras": "1.6.61"
+    "MSBuild.Sdk.Extras": "2.0.41"
   }
 }

src/Microsoft.IdentityModel.Clients.ActiveDirectory/Exceptions/AdalErrorMessage.cs

@@ -89,7 +89,7 @@ internal static class AdalErrorMessage
         public const string RedirectUriContainsFragment = "'redirectUri' must NOT include a fragment component";
         public const string ServiceReturnedError = "Service returned error. Check InnerException for more details";
         public const string BrokerReponseHashMismatch = "Unencrypted broker response hash did not match the expected hash";
-        public const string BrokerNonceMismatch = "Broker response nonce does not match the request nonce sent by MSAL.NET." +
+        public const string BrokerNonceMismatch = "Broker response nonce does not match the request nonce sent by ADAL.NET." +
             "Please see https://aka.ms/adal-net-ios-13-broker for more details. ";
 
         public const string StsMetadataRequestFailed =

src/Microsoft.IdentityModel.Clients.ActiveDirectory/Platforms/iOS/iOSBroker.cs

@@ -39,6 +39,7 @@
 using Microsoft.Identity.Core.Cache;
 using Microsoft.Identity.Core.Helpers;
 using Microsoft.IdentityModel.Clients.ActiveDirectory.Internal.Broker;
+using System.Globalization;
 
 namespace Microsoft.IdentityModel.Clients.ActiveDirectory.Internal.Platform
 {
@@ -131,7 +132,6 @@ public async Task<AdalResultWrapper> AcquireTokenUsingBrokerAsync(IDictionary<st
 
             if (_brokerV3Installed)
             {
-                _brokerRequestNonce = string.Empty;
                 _brokerRequestNonce = Guid.NewGuid().ToString();
                 brokerPayload[BrokerParameter.BrokerNonce] = _brokerRequestNonce;
             }
@@ -224,8 +224,8 @@ private AdalResultWrapper ResultFromBrokerResponse(IDictionary<string, string> r
                 {
                     response = new TokenResponse
                     {
-                        Error = AdalError.BrokerReponseHashMismatch,
-                        ErrorDescription = AdalErrorMessage.BrokerReponseHashMismatch
+                        Error = AdalError.BrokerNonceMismatch,
+                        ErrorDescription = AdalErrorMessage.BrokerNonceMismatch
                     };
                 }
             }
@@ -237,15 +237,23 @@ private AdalResultWrapper ResultFromBrokerResponse(IDictionary<string, string> r
 
         private bool ValidateBrokerResponseNonceWithRequestNonce(IDictionary<string, string> brokerResponseDictionary)
         {
-            if (!string.IsNullOrEmpty(_brokerRequestNonce))
+            if (_brokerV3Installed)
             {
-                string brokerResponseNonce = brokerResponseDictionary.ContainsKey(BrokerParameter.BrokerNonce)
-                   ? brokerResponseDictionary[BrokerParameter.BrokerNonce]
-                   : null;
+                string brokerResponseNonce = brokerResponseDictionary[BrokerParameter.BrokerNonce];
+                bool ok = string.Equals(brokerResponseNonce, _brokerRequestNonce, StringComparison.InvariantCultureIgnoreCase);
 
-                return string.Equals(brokerResponseNonce, _brokerRequestNonce);
+                if (!ok)
+                {
+                    _logger.Error(
+                        string.Format(
+                            CultureInfo.CurrentCulture, 
+                            "Nonce check failed! Broker response nonce is:  {0}, \nBroker request nonce is: {1}", 
+                            brokerResponseNonce, 
+                            _brokerRequestNonce));
+                }
+                return ok;
             }
-            return false;
+            return true;
         }
 
         public static void SetBrokerResponse(NSUrl responseUrl)