I'm having a difficult time finding out how to fix this issue as it only happens in a Azure Linux app service. Locally (win10) and in Azure Windows app service, no problems.
The app is ASP.NET Core 3.1 and I've created a custom service as an HttpClient:
private readonly HttpClient _client;
public NPIApiService(HttpClient client)
{
_client = client;
_client.BaseAddress = new Uri("https://npiregistry.cms.hhs.gov/api/");
}
public class AllowCertsMessageHandler : HttpClientHandler
{
public AllowCertsMessageHandler()
{
this.ClientCertificateOptions = ClientCertificateOption.Manual;
this.ServerCertificateCustomValidationCallback = (requestMessage, cert, certChain, policyErrors) =>
{
return true;
};
}
}
public async Task<NPIResult> LoadNPI(string npi)
{
var response = await _client.GetAsync(new Uri($"?version=2.1&number={npi}", UriKind.Relative), HttpCompletionOption.ResponseContentRead);
if (response.IsSuccessStatusCode)
{
var rawstring = await response.Content.ReadAsStringAsync();
return System.Text.Json.JsonSerializer.Deserialize<NPIResult>(rawstring);
}
return null;
}
Note the AllowCertsMessageHandler: I've added this as a hopeful workaround but to no avail.
services.AddHttpClient<Services.NPIApiService>()
.ConfigurePrimaryHttpMessageHandler(() =>
{
return new HttpClientHandler()
{
ClientCertificateOptions = ClientCertificateOption.Manual,
ServerCertificateCustomValidationCallback = (requestMessage, cert, certChain, policyErrors) =>
{
return true;
}
};
});
The code above works well everywhere I've tried, except specifically in Azure Linux App Service.
Stack trace of exception:
2020-06-10T19:18:31.232053228Z: [INFO] [40m[32minfo[39m[22m[49m: System.Net.Http.HttpClient.NPIApiService.LogicalHandler[100]
2020-06-10T19:18:31.232121130Z: [INFO] Start processing HTTP request GET https://npiregistry.cms.hhs.gov/api/?version=2.1&number=1316923212
2020-06-10T19:18:31.233564068Z: [INFO] [40m[32minfo[39m[22m[49m: System.Net.Http.HttpClient.NPIApiService.ClientHandler[100]
2020-06-10T19:18:31.233584268Z: [INFO] Sending HTTP request GET https://npiregistry.cms.hhs.gov/api/?version=2.1&number=1316923212
2020-06-10T19:18:31.387040818Z: [INFO] [41m[30mfail[39m[22m[49m: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
2020-06-10T19:18:31.387088119Z: [INFO] An unhandled exception has occurred while executing the request.
2020-06-10T19:18:31.388164847Z: [INFO] System.Net.Http.HttpRequestException: **The SSL connection could not be established, see inner exception.**
2020-06-10T19:18:31.388184048Z: [INFO] ---> System.Security.Authentication.AuthenticationException: **Authentication failed, see inner exception.**
2020-06-10T19:18:31.388194148Z: [INFO] ---> Interop+OpenSsl+SslException: **SSL Handshake failed with OpenSSL error - SSL_ERROR_SSL.**
2020-06-10T19:18:31.389275477Z: [INFO] ---> Interop+Crypto+OpenSslCryptographicException: **error:141A318A:SSL routines:tls_process_ske_dhe:dh key too small**
2020-06-10T19:18:31.389293777Z: [INFO] --- End of inner exception stack trace ---
2020-06-10T19:18:31.394673519Z: [INFO] at Interop.OpenSsl.DoSslHandshake(SafeSslHandle context, Byte[] recvBuf, Int32 recvOffset, Int32 recvCount, Byte[]& sendBuf, Int32& sendCount)
2020-06-10T19:18:31.394697020Z: [INFO] at System.Net.Security.SslStreamPal.HandshakeInternal(SafeFreeCredentials credential, SafeDeleteContext& context, ArraySegment`1 inputBuffer, Byte[]& outputBuffer, SslAuthenticationOptions sslAuthenticationOptions)
2020-06-10T19:18:31.394708120Z: [INFO] --- End of inner exception stack trace ---
I've tried making some changes to openssl.conf as well, but didn't seem to make any difference.
This is my first go at an app that was presumably x-platform compatible, so I'm still learning. I'm pretty sure this is environment related, but I welcome any suggestions.
Thanks in advance...
