Possible memory leak in IIS when StartupHook initializes

[leeriorio]

I was analyzing ASP.NET Core using Svace static analyer. It has found HANDLE_LEAK category error with the following message:

new PhysicalFileProvider(contentRoot) is not disposed at the end of the function

in method Initialize(). Here's the source code:

aspnetcore/src/Servers/IIS/IIS/src/StartupHook.cs

Lines 19 to 71 in 3fe0618

	public static void Initialize()
	{
	if (!NativeMethods.IsAspNetCoreModuleLoaded())
	{
	// This means someone set the startup hook for Microsoft.AspNetCore.Server.IIS
	// but are not running inprocess. Return at this point.
	return;
	}
	var detailedErrors = Environment.GetEnvironmentVariable("ASPNETCORE_DETAILEDERRORS");
	var enableStartupErrorPage = detailedErrors?.Equals("1", StringComparison.OrdinalIgnoreCase) ?? false;
	enableStartupErrorPage |= detailedErrors?.Equals("true", StringComparison.OrdinalIgnoreCase) ?? false;
	var aspnetCoreEnvironment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
	enableStartupErrorPage |= aspnetCoreEnvironment?.Equals("Development", StringComparison.OrdinalIgnoreCase) ?? false;
	var dotnetEnvironment = Environment.GetEnvironmentVariable("DOTNET_ENVIRONMENT");
	enableStartupErrorPage |= dotnetEnvironment?.Equals("Development", StringComparison.OrdinalIgnoreCase) ?? false;
	if (!enableStartupErrorPage)
	{
	// Not running in development or detailed errors aren't enabled
	return;
	}
	AppDomain.CurrentDomain.UnhandledException += (sender, eventArgs) =>
	{
	var exception = (Exception)eventArgs.ExceptionObject;
	// Get the content root from IIS.
	var iisConfigData = NativeMethods.HttpGetApplicationProperties();
	var contentRoot = iisConfigData.pwzFullApplicationPath.TrimEnd(Path.DirectorySeparatorChar);
	var model = ErrorPageModelBuilder.CreateErrorPageModel(
	new PhysicalFileProvider(contentRoot),
	logger: null,
	showDetailedErrors: true,
	exception);
	var errorPage = new ErrorPage(model);
	var stream = new MemoryStream();
	// Never will go async because we are writing to a memory stream.
	errorPage.ExecuteAsync(stream).GetAwaiter().GetResult();
	// Get the raw content and set the error page.
	stream.Position = 0;
	var content = stream.ToArray();
	NativeMethods.HttpSetStartupErrorPageContent(content);
	};
	}

I know, that it seems to be minor leak because of IIS startup specific, but how about to add using statement to ensure proper disposal?

    using var fileProvider = new PhysicalFileProvider(contentRoot);

    var model = ErrorPageModelBuilder.CreateErrorPageModel(
        fileProvider,
        logger: null,
        showDetailedErrors: true,
        exception);

---

Found by Linux Verification Center (linuxtesting.org) with SVACE.

[danmoseley]

thanks @leeriorio - want to offer a PR?

[danmoseley]

ah, let's try copilot