Web Requests fail due to failure to validate certificate

Unity 2017.1.0f3

Any attempt to get the package list causes the exception below. On project open, opening the explorer, and clicking refresh all result in the same.

The Exception:

System.Net.WebException: Error getting response stream (Write: The authentication or decryption has failed.): SendFailure ---> System.IO.IOException: The authentication or decryption has failed. ---> Mono.Security.Protocol.Tls.TlsException: Invalid certificate received from server. Error code: 0xffffffff800b010a
  at Mono.Security.Protocol.Tls.Handshake.Client.TlsServerCertificate.validateCertificates (Mono.Security.X509.X509CertificateCollection certificates) [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.Handshake.Client.TlsServerCertificate.ProcessAsTls1 () [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.Handshake.HandshakeMessage.Process () [0x00000] in <filename unknown>:0 
  at (wrapper remoting-invoke-with-check) Mono.Security.Protocol.Tls.Handshake.HandshakeMessage:Process ()
  at Mono.Security.Protocol.Tls.ClientRecordProtocol.ProcessHandshakeMessage (Mono.Security.Protocol.Tls.TlsStream handMsg) [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.RecordProtocol.InternalReceiveRecordCallback (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  --- End of inner exception stack trace ---
  at Mono.Security.Protocol.Tls.SslStreamBase.AsyncHandshakeCallback (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  --- End of inner exception stack trace ---
  at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0 
  at NugetForUnity.NugetPackageSource.GetPackagesFromUrl (System.String url) [0x0004b] in C:\Users\jowitt\Source\NuGetForUnity\Assets\NuGet\Editor\NugetPackageSource.cs:301 
UnityEngine.Debug:LogErrorFormat(String, Object[])
NugetForUnity.NugetPackageSource:GetPackagesFromUrl(String) (at Assets/NuGet/Editor/NugetPackageSource.cs:313)
NugetForUnity.NugetPackageSource:Search(String, Boolean, Boolean, Int32, Int32) (at Assets/NuGet/Editor/NugetPackageSource.cs:207)
NugetForUnity.NugetHelper:Search(String, Boolean, Boolean, Int32, Int32) (at Assets/NuGet/Editor/NugetHelper.cs:777)
NugetForUnity.NugetWindow:UpdateOnlinePackages() (at Assets/NuGet/Editor/NugetWindow.cs:279)
NugetForUnity.NugetWindow:OnEnable() (at Assets/NuGet/Editor/NugetWindow.cs:253)
UnityEditor.EditorWindow:GetWindow()
NugetForUnity.NugetWindow:DisplayNugetWindow() (at Assets/NuGet/Editor/NugetWindow.cs:117)

@alankemp gave me the quick fix to ignore the cert: In NugetPackageSource.cs, GetPackageFroUrl(string url), before the try/catch:

ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, errors) => true;

and hinted that the root cert of the system can be imported into Mono, which seems much safer.

Is this the suggested solution? Can we extend this tooling to support doing this?

[GlitchEnzo]

I added the unsafe way for now, just to make it work: https://github.com/GlitchEnzo/NuGetForUnity/commit/ca9d63233c3e8e63409316793046e1f30b476282

[GlitchEnzo]

No worries, I didn’t take any offense to your comment. I just realized I had only mentioned the unsafe option. I’d prefer a safer approach that didn’t allow everything, but I never got around to figuring out how best to do it.