问题描述
.NET 6 MVC应用，代码中要求客户端访问时候必须携带正确的证书，如果不携带或者携带错误的证书，都会得到 HTTP ERROR 403 Forbidden 错误
在App Service中，客户端访问不携带证书时的错误页面为
在App Service中客户端访问携带了证书，但是证书验证失败的错误页面为
问题解决
在App Service的配置页面 (General Settings)中，可以开启Client Certificate Mode为Require（它的默认值为Ignore）。这样在第一次访问时候，客户端会要求从本地选择一个客户端证书。
配置截图
当访问App Service时，浏览器就会自动弹出选择证书窗口：
代码参考
验证客户端上传证书的 Thumbprints 的片段代码
builder.Services.AddAuthentication(CertificateAuthenticationDefaults.AuthenticationScheme) .AddCertificate(options => { options.AllowedCertificateTypes = CertificateTypes.All; options.Events = new CertificateAuthenticationEvents { OnCertificateValidated = context => { string[] allowedThumbprints = { "9bded811e9852f3cb6b347529f78b1f4be5bcf50", "5d6d791a9284628203a5b3e238e5ee7448d57f2b", "41b3906fa93c50d2cce35132d8853fdf29d7d539", "3109b0222269b47cd8190252f5f1adb06751103a" }; if (allowedThumbprints.Contains(context.ClientCertificate.Thumbprint.ToLower())) { context.Success(); } else { context.Fail("Invalid certificate: " + context.ClientCertificate.Thumbprint); } return Task.CompletedTask; }, OnAuthenticationFailed = context => { context.Fail("Invalid certificate"); return Task.CompletedTask; } }; });
参考资料
Configure certificate authentication in ASP.NET Core： https://docs.microsoft.com/en-us/aspnet/core/security/authentication/certauth?view=aspnetcore-6.0
CERTIFICATE AUTHENTICATION IN ASP.NET CORE 3.1：https://damienbod.com/2019/06/13/certificate-authentication-in-asp-net-core-3-0/
Using Certificates For API Authentication In .NET 5: https://www.c-sharpcorner.com/article/using-certificates-for-api-authentication-in-net-5/
