InvalidOperationException in AuthenticationMiddleware while AuthenticationSchemeProvider.RemoveScheme #3619
Description
In case of simultaneous execution AuthenticationSchemeProvider.RemoveScheme from background Task and any request, which uses AuthenticationMiddleware may get
System.InvalidOperationException: Collection was modified; enumeration operation may not execute. at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) at System.Collections.Generic.List`1.Enumerator.MoveNextRare() at System.Collections.Generic.List`1.Enumerator.MoveNext() at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.<Invoke>d__6.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.<Invoke>d__8.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at IdentityServer4.Hosting.BaseUrlMiddleware.<Invoke>d__3.MoveNext() By default AuthenticationMiddleware using AuthenticationSchemeProvider.GetRequestHandlerSchemesAsync() for retrieving all schemes and enumerate results via foreach.
Problem occurs when removing scheme from _requestHandlers at the moment when enumeration in process from foreach (without any locks)
Microsoft.AspNetCore.Authentication.dll version 2.1.1
Microsoft.AspNetCore.Html.Abstractions.dll 2.1.1
dotnet info:
.NET Core SDK (reflecting any global.json): Version: 2.1.403 Commit: 04e15494b6 Runtime Environment: OS Name: Windows OS Version: 10.0.17134 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\2.1.403\ Host (useful for support): Version: 2.1.5 Commit: 290303f510 .NET Core SDKs installed: 2.1.401 [C:\Program Files\dotnet\sdk] 2.1.402 [C:\Program Files\dotnet\sdk] 2.1.403 [C:\Program Files\dotnet\sdk] .NET Core runtimes installed: Microsoft.AspNetCore.All 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.All 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.1.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]