GetWindowsVersionStringInternal Object reference not set to an instance of an object

Hello,

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 when I run my code:

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

I get the following error (I’m running under Ubuntu with Mono and using .NET Framework 4.8 in my project, because that’s the version of the system where I need to implement this):

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

Any help will be appreciated. Thanks!

[ngcdev]

Final comment: Did the integration test in .Net Core (5.0) and everything worked fine from an Ubuntu machine. Thanks for the quick responses!

[christothes]

@ngcdev would you mind creating an issue for this over in the MSAL repo here?:

https://github.com/AzureAD/microsoft-authentication-library-for-dotnet/issues