Log a warning when using an untrusted developer certificate

src/Servers/Kestrel/Core/src/Internal/LoggerExtensions.cs

@@ -37,4 +37,7 @@ internal static partial class LoggerExtensions
 
     [LoggerMessage(7, LogLevel.Error, "The certificate key file at '{CertificateKeyFilePath}' can not be found, contains malformed data or does not contain a PEM encoded key in PKCS8 format.", EventName = "MissingOrInvalidCertificateKeyFile")]
     public static partial void FailedToLoadCertificateKey(this ILogger<KestrelServer> logger, string certificateKeyFilePath);
+
+    [LoggerMessage(8, LogLevel.Warning, "The ASP.NET Core developer certificate is not trusted. For information about trusting the ASP.NET Core developer certificate, see https://aka.ms/aspnet/https-trust-dev-cert.", EventName = "DeveloperCertificateNotTrusted")]
+    public static partial void DeveloperCertificateNotTrusted(this ILogger<KestrelServer> logger);
 }

src/Servers/Kestrel/Core/src/KestrelServerOptions.cs

@@ -295,6 +295,11 @@ private void EnsureDefaultCert()
                     }
 
                     logger.LocatedDevelopmentCertificate(DefaultCertificate);
+
+                    if (!CertificateManager.Instance.IsTrusted(DefaultCertificate))
+                    {
+                        logger.DeveloperCertificateNotTrusted();
+                    }
                 }
                 else
                 {

src/Shared/CertificateGeneration/WindowsCertificateManager.cs

@@ -41,7 +41,6 @@ protected override bool IsExportable(X509Certificate2 c)
 
     internal override CheckCertificateStateResult CheckCertificateState(X509Certificate2 candidate, bool interactive)
     {
-        // Return true as we don't perform any check.
         return new CheckCertificateStateResult(true, null);
     }