[Bug] SemaphoreFullException in ClientCredentialRequest when cancellation token is canceled

[pmaytak]

Library version used

4.56.0

.NET version

Scenario

ManagedIdentityClient - managed identity

Is this a new or an existing app?

None

Issue description and reproduction steps

microsoft-authentication-library-for-dotnet/src/client/Microsoft.Identity.Client/Internal/Requests/ClientCredentialRequest.cs

Line 121 in 546d00f

await s_semaphoreSlim.WaitAsync(cancellationToken).ConfigureAwait(false);

The semaphore.Wait is called inside a try. When the cancellation token is cancelled, a TaskCancelledException is thrown without the semaphore being acquired, and finally is called trying to release the semaphore which was not acquired causing a SemaphoreFullException.

Relevant code snippets

No response

Expected behavior

When cancellation token is cancelled, the request should be cancelled. The semaphore.Wait should be called outside of the try statement.

Identity provider

Microsoft Entra ID (Work and School accounts and Personal Microsoft accounts)

Regression

Regression in 4.56.0 - #4309

Solution and workarounds

No response

[pmaytak]

The fix is released in MSAL 4.59.0