GetWindowsVersionStringInternal Object reference not set to an instance of an object (in Linux/Mono with .net 4.8)

Logs and network traces This is the log of what I’m getting:

Azure.Identity.AuthenticationFailedException: ClientSecretCredential authentication failed: Object reference not set to an instance of an object ---> System.NullReferenceException: Object reference not set to an instance of an object
  at Microsoft.Identity.Client.Platforms.Features.DesktopOs.DesktopOsHelper.GetWindowsVersionStringInternal () [0x0000f] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.Platforms.Features.DesktopOs.DesktopOsHelper+<>c.<.cctor>b__16_2 () [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at System.Lazy`1[T].ViaFactory (System.Threading.LazyThreadSafetyMode mode) [0x00043] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].ExecutionAndPublication (System.LazyHelper executionAndPublication, System.Boolean useDefaultConstructor) [0x00022] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].CreateValue () [0x00074] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].get_Value () [0x0000a] in <533173d24dae460899d2b10975534bb0>:0 
  at Microsoft.Identity.Client.Platforms.Features.DesktopOs.DesktopOsHelper.GetWindowsVersionString () [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.Platforms.net45.NetDesktopPlatformProxy.InternalGetOperatingSystem () [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at System.Lazy`1[T].ViaFactory (System.Threading.LazyThreadSafetyMode mode) [0x00043] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].ExecutionAndPublication (System.LazyHelper executionAndPublication, System.Boolean useDefaultConstructor) [0x00022] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].CreateValue () [0x00074] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].get_Value () [0x0000a] in <533173d24dae460899d2b10975534bb0>:0 
  at Microsoft.Identity.Client.PlatformsCommon.Shared.AbstractPlatformProxy.GetOperatingSystem () [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.Internal.MsalIdHelper.GetMsalIdParameters (Microsoft.Identity.Client.Core.ICoreLogger logger) [0x00057] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.Internal.Logger.MsalLogger+<>c.<.cctor>b__44_2 () [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at System.Lazy`1[T].ViaFactory (System.Threading.LazyThreadSafetyMode mode) [0x00043] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].ExecutionAndPublication (System.LazyHelper executionAndPublication, System.Boolean useDefaultConstructor) [0x00022] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].CreateValue () [0x00074] in <533173d24dae460899d2b10975534bb0>:0 
  at System.Lazy`1[T].get_Value () [0x0000a] in <533173d24dae460899d2b10975534bb0>:0 
  at Microsoft.Identity.Client.Internal.Logger.MsalLogger.Log (Microsoft.Identity.Client.LogLevel logLevel, System.String messageWithPii, System.String messageScrubbed) [0x00057] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.Internal.Logger.MsalLogger.Info (System.String messageScrubbed) [0x00000] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.ApiConfig.Executors.AbstractExecutor.CreateRequestContextAndLogVersionInfo (System.Guid correlationId, System.Threading.CancellationToken userCancellationToken) [0x00043] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Microsoft.Identity.Client.ApiConfig.Executors.ConfidentialClientExecutor.ExecuteAsync (Microsoft.Identity.Client.ApiConfig.Parameters.AcquireTokenCommonParameters commonParameters, Microsoft.Identity.Client.ApiConfig.Parameters.AcquireTokenForClientParameters clientParameters, System.Threading.CancellationToken cancellationToken) [0x00020] in <bf76092abc204c3b87b8ffb18ff15aa1>:0 
  at Azure.Identity.AbstractAcquireTokenParameterBuilderExtensions.ExecuteAsync[T] (Microsoft.Identity.Client.AbstractAcquireTokenParameterBuilder`1[T] builder, System.Boolean async, System.Threading.CancellationToken cancellationToken) [0x00078] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.MsalConfidentialClient.AcquireTokenForClientAsync (System.String[] scopes, System.String tenantId, System.Boolean async, System.Threading.CancellationToken cancellationToken) [0x00140] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.ClientSecretCredential.GetTokenAsync (Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x000c3] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
   --- End of inner exception stack trace ---
  at Azure.Identity.CredentialDiagnosticScope.FailWrapAndThrow (System.Exception ex, System.String additionalMessage) [0x0001d] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.ClientSecretCredential.GetTokenAsync (Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x000ef] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.EnvironmentCredential.GetTokenImplAsync (System.Boolean async, Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x000d5] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.CredentialDiagnosticScope.FailWrapAndThrow (System.Exception ex, System.String additionalMessage) [0x00018] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.EnvironmentCredential.GetTokenImplAsync (System.Boolean async, Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x0010d] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.EnvironmentCredential.GetTokenAsync (Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x0007d] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.DefaultAzureCredential.GetTokenFromSourcesAsync (Azure.Core.TokenCredential[] sources, Azure.Core.TokenRequestContext requestContext, System.Boolean async, System.Threading.CancellationToken cancellationToken) [0x000aa] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.DefaultAzureCredential.GetTokenImplAsync (System.Boolean async, Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x001ed] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.CredentialDiagnosticScope.FailWrapAndThrow (System.Exception ex, System.String additionalMessage) [0x00018] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.DefaultAzureCredential.GetTokenImplAsync (System.Boolean async, Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x00253] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Identity.DefaultAzureCredential.GetTokenAsync (Azure.Core.TokenRequestContext requestContext, System.Threading.CancellationToken cancellationToken) [0x0007d] in <b1ff7d3abac2485b914a6579d21f78c2>:0 
  at Azure.Core.Pipeline.BearerTokenAuthenticationPolicy+AccessTokenCache.GetHeaderValueFromCredentialAsync (Azure.Core.TokenRequestContext context, System.Boolean async, System.Threading.CancellationToken cancellationToken) [0x00092] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.BearerTokenAuthenticationPolicy+AccessTokenCache.GetHeaderValueAsync (Azure.Core.HttpMessage message, Azure.Core.TokenRequestContext context, System.Boolean async) [0x0024f] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.BearerTokenAuthenticationPolicy+AccessTokenCache.GetHeaderValueAsync (Azure.Core.HttpMessage message, Azure.Core.TokenRequestContext context, System.Boolean async) [0x003d0] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.BearerTokenAuthenticationPolicy.AuthenticateAndAuthorizeRequestAsync (Azure.Core.HttpMessage message, Azure.Core.TokenRequestContext context) [0x00082] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Security.KeyVault.ChallengeBasedAuthenticationPolicy.AuthorizeRequestOnChallengeAsyncInternal (Azure.Core.HttpMessage message, System.Boolean async) [0x0018b] in <cf13f41e36fd4a94b87ece865a0bbfd5>:0 
  at Azure.Core.Pipeline.BearerTokenAuthenticationPolicy.ProcessAsync (Azure.Core.HttpMessage message, System.ReadOnlyMemory`1[T] pipeline, System.Boolean async) [0x0020e] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.RedirectPolicy.ProcessAsync (Azure.Core.HttpMessage message, System.ReadOnlyMemory`1[T] pipeline, System.Boolean async) [0x00090] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.RetryPolicy.ProcessAsync (Azure.Core.HttpMessage message, System.ReadOnlyMemory`1[T] pipeline, System.Boolean async) [0x000b4] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.RetryPolicy.ProcessAsync (Azure.Core.HttpMessage message, System.ReadOnlyMemory`1[T] pipeline, System.Boolean async) [0x00193] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Core.Pipeline.HttpPipeline.SendRequestAsync (Azure.Core.Request request, System.Threading.CancellationToken cancellationToken) [0x00093] in <056f6eea93f94d71966248c0a1937819>:0 
  at Azure.Security.KeyVault.KeyVaultPipeline.SendRequestAsync (Azure.Core.Request request, System.Threading.CancellationToken cancellationToken) [0x0008e] in <cf13f41e36fd4a94b87ece865a0bbfd5>:0 
  at Azure.Security.KeyVault.KeyVaultPipeline.SendRequestAsync[TResult] (Azure.Core.RequestMethod method, System.Func`1[TResult] resultFactory, System.Threading.CancellationToken cancellationToken, System.String[] path) [0x0009a] in <cf13f41e36fd4a94b87ece865a0bbfd5>:0 
  at Azure.Security.KeyVault.Secrets.SecretClient.GetSecretAsync (System.String name, System.String version, System.Threading.CancellationToken cancellationToken) [0x00131] in <cf13f41e36fd4a94b87ece865a0bbfd5>:0

Which version of MSAL.NET are you using? Not exactly sure. I was using Azure.Security.KeyVault.Secrets 4.3.0 which internally uses MSAL

Platform .NET 4.8 Mono/Ubuntu 18.4

What authentication flow has the issue?

• Desktop / Mobile
  • Interactive
  • Integrated Windows Authentication
  • Username Password
  • Device code flow (browserless)
• Web app
  • Authorization code
  • On-Behalf-Of
• Daemon app
  • Service to Service calls

Is this a new or existing app? New app

Repro I was following the instructions here https://github.com/Azure/azure-sdk-for-net/blob/main/sdk/identity/Azure.Identity/README.md to use Azure Key Vault in my program, particularly using the “Service Principal with Secret”. I got everything setup (registered the app, got a secret, granted access in key vault to the app, setup the environment variables) but it always failed with the error above

Using Mono because the feature will be implemented in a .Net 4.8 application and the unit/integration tests will be executed from an Ubuntu machine. Same tutorial above in a .net core (still in Ubuntu) worked without any issues.

string keyVaultUrl = ".... key vault URL here ...";
var client = new SecretClient(new Uri(keyVaultUrl), new DefaultAzureCredential());
var kvresult = await Client.GetSecretAsync("secretname");

Expected behavior Program should authenticate and retrieve the secret

Actual behavior Program crashes when is trying to log (the MSAL library) something and it’s trying to figure out the OS

Additional context / logs / screenshots / links to code Originally posted this in the Azure SDK project and they redirect me to this project. This is the issue I created there: https://github.com/Azure/azure-sdk-for-net/issues/26368

[ngcdev]

Hi @bgavrilMS Thanks for your response. Yes, I understand about Mono. Fortunately, I was able to make the code change with .Net Core and that worked perfectly. So for me this is not an emergency, just something that you could consider fixing if you have time. This is the code I used, which is basically the sample in the documentation about using Azure Secrets:

using System;
using Azure.Security.KeyVault.Secrets;
using Azure.Identity;
using System.Threading.Tasks;

namespace TestSecrets
{
	class MainClass
	{
		public static void Main(string[] args)
		{
			MainRun().GetAwaiter().GetResult();
		}

		public static async Task MainRun()
		{
			string keyVaultUrl = "https://<account here>.vault.azure.net/";

			// Using DeafultAzureCredentials with env vars for:
			// AZURE_CLIENT_ID, AZURE_TENANT_ID and AZURE_CLIENT_SECRET 
			var client = new SecretClient(new Uri(keyVaultUrl), new DefaultAzureCredential());

			var kvresult = await client.GetSecretAsync("abc-secret");

			Console.WriteLine(kvresult.Value);
		}
	}
}

Thank you!

[bgavrilMS]

Won’t fix. Please use .NET