Merge pull request 'Hardened certificate loading' (#129) from dataprotection into master

Reviewed-on: #129

LiteCharms.Features/Extensions/Api.cs

@@ -54,12 +54,22 @@ public static class Api
 
     public static IServiceCollection AddLiteCharmsWebSecurity(this IServiceCollection services, IConfiguration configuration)
     {
-        var certificate = X509CertificateLoader.LoadPkcs12(Convert.FromBase64String(configuration["DataProtection:Certificate"]!), configuration["DataProtection:Password"]);
+        var certString = configuration["DataProtection:Certificate"] ?? configuration["DataProtection__Certificate"];
+        var certPassword = configuration["DataProtection:Password"] ?? configuration["DataProtection__Password"];
+
+        if (string.IsNullOrEmpty(certString))
+            throw new InvalidOperationException("Data Protection Certificate configuration is missing.");
+
+        var certificate = X509CertificateLoader.LoadPkcs12(Convert.FromBase64String(certString), certPassword);
 
         services.AddDataProtection().PersistKeysToDbContext<DataProtectionDbContext>()
             .ProtectKeysWithCertificate(certificate)
             .SetApplicationName("LiteCharmsApp");
 
+        services.Configure<DataProtectionOptions>(options => options.ApplicationDiscriminator = "LiteCharmsApp");
+
+        services.ConfigureCookieOidcSameSiteSupport();
+
         var configSection = configuration.GetSection(nameof(LiteCharmsSettings));
 
         var authOptions = new LiteCharmsSettings();
@@ -124,6 +134,30 @@ public static class Api
         return services;
     }
 
+    private static void ConfigureCookieOidcSameSiteSupport(this IServiceCollection services) =>
+        services.Configure<CookiePolicyOptions>(options =>
+        {
+            options.MinimumSameSitePolicy = SameSiteMode.Unspecified;
+            options.OnAppendCookie = cookieContext => CheckSameSite(cookieContext.Context, cookieContext.CookieOptions);
+            options.OnDeleteCookie = cookieContext => CheckSameSite(cookieContext.Context, cookieContext.CookieOptions);
+        });
+
+    private static void CheckSameSite(HttpContext httpContext, CookieOptions options)
+    {
+        if (options.SameSite == SameSiteMode.None)
+        {
+            bool isSecure = httpContext.Request.IsHttps;
+
+            if (!isSecure && httpContext.Request.Headers.TryGetValue("X-Forwarded-Proto", out var proto))
+                isSecure = string.Equals(proto, "https", StringComparison.OrdinalIgnoreCase);
+
+            if (!isSecure && httpContext.Request.Headers.TryGetValue("Forwarded", out var forwarded))
+                isSecure = forwarded.ToString().Contains("proto=https", StringComparison.OrdinalIgnoreCase);
+                        
+            if (!isSecure) options.SameSite = SameSiteMode.Unspecified;
+        }
+    }
+
     public static IServiceCollection AddLiteCharmsApiSecurity(this IServiceCollection services, IConfiguration configuration)
     {
         var configSection = configuration.GetSection(nameof(LiteCharmsSettings));