WinHttp buffer supplied to the function was too small error should not be exposed

[stephentoub]

http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/80/consoleFull

07:27:26      System.Net.Http.Functional.Tests.HttpClientHandler_ServerCertificates_Test.UseCallback_BadCertificate_ExpectedPolicyErrors(url: "https://wrong.host.badssl.com/", expectedErrors: RemoteCertificateNameMismatch) [FAIL]
07:27:26         System.Net.Http.HttpRequestException : An error occurred while sending the request.
07:27:26         ---- System.Net.Http.WinHttpException : A security error occurred
07:27:26         Stack Trace:
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http\src\System\Net\Http\HttpClient.cs(392,0): at System.Net.Http.HttpClient.<FinishSendAsync>d__58.MoveNext()
07:27:26            --- End of stack trace from previous location where exception was thrown ---
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http\tests\FunctionalTests\HttpClientHandlerTest.ServerCertificates.cs(174,0): at System.Net.Http.Functional.Tests.HttpClientHandler_ServerCertificates_Test.<UseCallback_BadCertificate_ExpectedPolicyErrors>d__9.MoveNext()
07:27:26            --- End of stack trace from previous location where exception was thrown ---
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            --- End of stack trace from previous location where exception was thrown ---
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            --- End of stack trace from previous location where exception was thrown ---
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            ----- Inner Stack Trace -----
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
07:27:26               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
07:27:26            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http.WinHttpHandler\src\System\Net\Http\WinHttpHandler.cs(843,0): at System.Net.Http.WinHttpHandler.<StartRequest>d__102.MoveNext()

[stephentoub]

Also here:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/74/console

[stephentoub]

Failed again, but this time with a different exception message:
"The buffers supplied to a function was too small"
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/92/consoleFull

04:25:45      System.Net.Http.Functional.Tests.HttpClientHandler_ServerCertificates_Test.UseCallback_BadCertificate_ExpectedPolicyErrors(url: "https://wrong.host.badssl.com/", expectedErrors: RemoteCertificateNameMismatch) [FAIL]
04:25:45         System.Net.Http.HttpRequestException : An error occurred while sending the request.
04:25:45         ---- System.Net.Http.WinHttpException : The buffers supplied to a function was too small
04:25:45         Stack Trace:
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http\src\System\Net\Http\HttpClient.cs(392,0): at System.Net.Http.HttpClient.<FinishSendAsync>d__58.MoveNext()
04:25:45            --- End of stack trace from previous location where exception was thrown ---
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http\tests\FunctionalTests\HttpClientHandlerTest.ServerCertificates.cs(174,0): at System.Net.Http.Functional.Tests.HttpClientHandler_ServerCertificates_Test.<UseCallback_BadCertificate_ExpectedPolicyErrors>d__9.MoveNext()
04:25:45            --- End of stack trace from previous location where exception was thrown ---
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            --- End of stack trace from previous location where exception was thrown ---
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            --- End of stack trace from previous location where exception was thrown ---
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            ----- Inner Stack Trace -----
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
04:25:45               at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
04:25:45            D:\j\workspace\windows_nt_re---37265eab\src\System.Net.Http.WinHttpHandler\src\System\Net\Http\WinHttpHandler.cs(843,0): at System.Net.Http.WinHttpHandler.<StartRequest>d__102.MoveNext()

[stephentoub]

From https://github.com/dotnet/corefx/issues/8038:

The exception of "The buffers supplied to a function was too small" doesn't seem like something due to just network vagaries.

http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_debug_prtest/408/

[stephentoub]

Again:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_debug_prtest/517/consoleText

"The buffers supplied to a function was too small"

[davidsh]

---- System.Net.Http.WinHttpException : The buffers supplied to a function was too small

That particular WinHTTP error is never supposed to bubble out. It means that we called WinHTTP and didn't give it a buffer big enough to return information. That would mean there is a bug in our code.

We didn't start seeing these errors until we added HttpClientHandler properties to expose server certificate validation callbacks. While this error doesn't repro very often, that is the area of code I'll start looking at.

[stephentoub]

Again here:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_debug_prtest/1026/consoleText

[stephentoub]

Again here:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/1025/consoleText

[stephentoub]

Again here:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/998/

[stephentoub]

Again here:
http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/windows_nt_release_prtest/1021/consoleText

[tmds]

I also occasionally get this error using System.Net.Http 4.1.0 on Windows with a custom ServerCertificateCustomValidationCallback.

[jacksontbryan]

This error is happening to me in a production environment. Packet capture shows the error happens during key exchange. The certificate is valid. I am doing no custom validation. When it happens it is intermittent with ~30% of requests failing for approx. hour period of time.

HttpClient client = new HttpClient();
client.BaseAddress = new Uri(baseUri);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var response = await client.PostAsJsonAsync("LabelService.svc/generateLabel", labelRequest);
--exception is blown here while sending the http request
An error occurred while sending the request -- The buffers supplied to a function was too small

[davidsh]

Packet capture shows the error happens during key exchange. The certificate is valid. I am doing no custom validation. When it happens it is intermittent with ~30% of requests failing for approx. hour period of time.

Thanks for the updated info. It sounds like this is a problem with the low-level windows WinHTTP component.

Do you have a stack trace for where the error "The buffers supplied to a function was too small" is coming from? It would be useful to catch this bug in a debugger since that is the only way to get actionable information to diagnose.

[jacksontbryan]

How would you advise setting up the debugger? This happens once every 2-3 days at seemly random times of day.

Stack:

at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
at System.Net.Http.HttpClient.<FinishSendAsync>d__58.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 Newgistics.Shipping.Service.Repositories.IntellicoreRepository.<CallIntellicoreApi>d__2.MoveNext() in C:\\Users\\Bjackson\\source\\newgistics.shipping.service\\src\\Newgistics.Shipping.Service\\Repositories\\IntellicoreRepository.cs:line 142
inner exception >>    
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
at System.Net.Http.WinHttpHandler.<StartRequest>d__101.MoveNext()",
"error":"An error occurred while sending the request.
inner exception >> The buffers supplied to a function was too small

[EDIT] Format call stack by @karelz

[davidsh]

If the exception is unhandled,then normally your process was crash. If so, you can use "windbg /I" to set up post-mortem debugging. When the process crashes, Windbg will launch automatically and you'll be able to debug and see threads, stack, etc.