49 KiB
Gateway TLS Auto-Certificate + Lenient Client Trust — Implementation Plan
For Claude: REQUIRED SUB-SKILL: Use superpowers-extended-cc:executing-plans to implement this plan task-by-task.
Goal: Make the gateway auto-generate and persist a long-lived self-signed certificate for any HTTPS Kestrel endpoint that has no certificate configured, and make all five language clients accept any server certificate by default when using TLS without a pinned CA.
Architecture: Gateway gains a SelfSignedCertificateProvider + KestrelTlsInspector under Security/Tls/, wired in GatewayApplication.CreateBuilder via ConfigureKestrel(o => o.ConfigureHttpsDefaults(...)) so it only fills a missing default cert. A new optional MxGateway:Tls config block tunes path/validity. Each client gets a RequireCertificateValidation opt-out flag; lenient-by-default skip-verify is added at the existing TLS-construction site. Plaintext deployments are untouched.
Tech Stack: .NET 10 (ASP.NET Core Kestrel, System.Security.Cryptography.X509Certificates), Go (crypto/tls, grpc-go), Java (grpc-netty-shaded 1.76, Netty InsecureTrustManagerFactory), Python (grpc.aio, ssl), Rust (tonic 0.13.1 + rustls tls-ring).
Branch: feat/tls-cert-autogen
Environment notes (read first)
- Where to build/test the gateway: the gateway server is
net10.0. If the local macOS .NET 10 SDK can buildsrc/ZB.MOM.WW.MxGateway.Server+src/ZB.MOM.WW.MxGateway.Tests, run there. Otherwise build/test on the Windows dev host (ssh windev/dohertj2@10.100.0.48, passwordless) per the project deploy memory. The cert provider's X509 generation/load tests are cross-platform; the ACL-hardening assertions are Windows-only and must be guarded withOperatingSystem.IsWindows()(skip the ACL assertion off-Windows). - Clients build/test on macOS directly:
dotnet,go,gradle,pytest,cargo. Toolchain paths are indocs/ToolchainLinks.md. - Style:
docs/style-guides/CSharpStyleGuide.md— file-scoped namespaces,sealed,Asyncsuffix, nullable enabled,TreatWarningsAsErrors=true(a new analyzer warning breaks the build). Platform-specific code needs[SupportedOSPlatform("windows")]on the helper + anOperatingSystem.IsWindows()guard at the call site, or CA1416 fails the build. - Never log secrets: thumbprint/SAN/notAfter are fine to log; PFX bytes, private keys, and any client value/password are not.
Task 1: Add TlsOptions config class + bind into GatewayOptions
Classification: small Estimated implement time: ~3 min Parallelizable with: Task 7, Task 8, Task 9, Task 10, Task 11 (client tasks)
Files:
- Create:
src/ZB.MOM.WW.MxGateway.Server/Configuration/TlsOptions.cs - Modify:
src/ZB.MOM.WW.MxGateway.Server/Configuration/GatewayOptions.cs - Test:
src/ZB.MOM.WW.MxGateway.Tests/Configuration/TlsOptionsBindingTests.cs
Step 1: Write the failing test (TlsOptionsBindingTests.cs)
using Microsoft.Extensions.Configuration;
using ZB.MOM.WW.MxGateway.Server.Configuration;
using Xunit;
namespace ZB.MOM.WW.MxGateway.Tests.Configuration;
public sealed class TlsOptionsBindingTests
{
[Fact]
public void Defaults_AreApplied_WhenSectionAbsent()
{
TlsOptions options = new();
Assert.Equal(10, options.ValidityYears);
Assert.True(options.RegenerateIfExpired);
Assert.Empty(options.AdditionalDnsNames);
Assert.False(string.IsNullOrWhiteSpace(options.SelfSignedCertPath));
}
[Fact]
public void Binds_FromMxGatewayTlsSection()
{
IConfiguration config = new ConfigurationBuilder()
.AddInMemoryCollection(new Dictionary<string, string?>
{
["MxGateway:Tls:ValidityYears"] = "5",
["MxGateway:Tls:SelfSignedCertPath"] = @"C:\tmp\gw.pfx",
["MxGateway:Tls:RegenerateIfExpired"] = "false",
["MxGateway:Tls:AdditionalDnsNames:0"] = "gw.internal",
})
.Build();
GatewayOptions options = config.GetSection(GatewayOptions.SectionName).Get<GatewayOptions>()!;
Assert.Equal(5, options.Tls.ValidityYears);
Assert.Equal(@"C:\tmp\gw.pfx", options.Tls.SelfSignedCertPath);
Assert.False(options.Tls.RegenerateIfExpired);
Assert.Equal("gw.internal", Assert.Single(options.Tls.AdditionalDnsNames));
}
}
Step 2: Run, expect FAIL (no TlsOptions / no GatewayOptions.Tls)
Run: dotnet test src/ZB.MOM.WW.MxGateway.Tests/ZB.MOM.WW.MxGateway.Tests.csproj --filter FullyQualifiedName~TlsOptionsBindingTests
Expected: compile error / FAIL.
Step 3: Create TlsOptions.cs
namespace ZB.MOM.WW.MxGateway.Server.Configuration;
/// <summary>
/// Options controlling the gateway's self-signed certificate auto-generation.
/// Only consulted when a Kestrel HTTPS endpoint is configured without its own
/// certificate; plaintext deployments never trigger generation.
/// </summary>
public sealed class TlsOptions
{
/// <summary>Path to the persisted self-signed PFX. Reused across restarts.</summary>
public string SelfSignedCertPath { get; init; } =
@"C:\ProgramData\MxGateway\certs\gateway-selfsigned.pfx";
/// <summary>Lifetime in years of a freshly generated certificate.</summary>
public int ValidityYears { get; init; } = 10;
/// <summary>Extra DNS SANs to embed (e.g. a load-balancer name).</summary>
public IReadOnlyList<string> AdditionalDnsNames { get; init; } = [];
/// <summary>Regenerate the persisted certificate when it has expired.</summary>
public bool RegenerateIfExpired { get; init; } = true;
}
Add to GatewayOptions.cs (after the Alarms property):
/// <summary>Gets self-signed TLS certificate auto-generation options.</summary>
public TlsOptions Tls { get; init; } = new();
Step 4: Run, expect PASS (same command as Step 2).
Step 5: Commit
git add src/ZB.MOM.WW.MxGateway.Server/Configuration/TlsOptions.cs \
src/ZB.MOM.WW.MxGateway.Server/Configuration/GatewayOptions.cs \
src/ZB.MOM.WW.MxGateway.Tests/Configuration/TlsOptionsBindingTests.cs
git commit -m "feat(gateway): add MxGateway:Tls options block"
Task 2: Validate MxGateway:Tls in GatewayOptionsValidator
Classification: small Estimated implement time: ~3 min Parallelizable with: Task 7–11
Files:
- Modify:
src/ZB.MOM.WW.MxGateway.Server/Configuration/GatewayOptionsValidator.cs - Test:
src/ZB.MOM.WW.MxGateway.Tests/Configuration/GatewayOptionsValidatorTests.cs(add cases; create file if absent — check first)
Step 1: Write failing tests (add to the validator test class; mirror existing style)
[Fact]
public void Validate_Fails_WhenTlsValidityYearsOutOfRange()
{
GatewayOptions options = ValidOptions() with { }; // use existing helper; set Tls below
GatewayOptions withBadTls = CloneWithTls(options, new TlsOptions { ValidityYears = 0 });
ValidateOptionsResult result = new GatewayOptionsValidator().Validate(null, withBadTls);
Assert.True(result.Failed);
Assert.Contains(result.Failures!, f => f.Contains("MxGateway:Tls:ValidityYears"));
}
[Fact]
public void Validate_Fails_WhenAdditionalDnsNameBlank()
{
GatewayOptions options = CloneWithTls(ValidOptions(), new TlsOptions { AdditionalDnsNames = [" "] });
ValidateOptionsResult result = new GatewayOptionsValidator().Validate(null, options);
Assert.True(result.Failed);
Assert.Contains(result.Failures!, f => f.Contains("MxGateway:Tls:AdditionalDnsNames"));
}
If the test class has no
ValidOptions()/CloneWithTlshelper, construct a minimal validGatewayOptionsinline (copy the pattern already used by neighbouring validator tests). The assertions on failure messages are what matter.
Step 2: Run, expect FAIL
Run: dotnet test src/ZB.MOM.WW.MxGateway.Tests/ZB.MOM.WW.MxGateway.Tests.csproj --filter FullyQualifiedName~GatewayOptionsValidatorTests
Step 3: Implement — in GatewayOptionsValidator.Validate, add ValidateTls(options.Tls, failures); after ValidateAlarms(...), then add:
private const int MinimumCertValidityYears = 1;
private const int MaximumCertValidityYears = 100;
private static void ValidateTls(TlsOptions options, List<string> failures)
{
if (options.ValidityYears is < MinimumCertValidityYears or > MaximumCertValidityYears)
{
failures.Add(
$"MxGateway:Tls:ValidityYears must be between {MinimumCertValidityYears} and {MaximumCertValidityYears}.");
}
AddIfInvalidPath(
options.SelfSignedCertPath,
"MxGateway:Tls:SelfSignedCertPath must be a valid filesystem path.",
failures);
foreach (string dns in options.AdditionalDnsNames)
{
if (string.IsNullOrWhiteSpace(dns))
{
failures.Add("MxGateway:Tls:AdditionalDnsNames entries must be non-blank.");
}
}
}
Step 4: Run, expect PASS.
Step 5: Commit
git add src/ZB.MOM.WW.MxGateway.Server/Configuration/GatewayOptionsValidator.cs \
src/ZB.MOM.WW.MxGateway.Tests/Configuration/GatewayOptionsValidatorTests.cs
git commit -m "feat(gateway): validate MxGateway:Tls options"
Task 3: SelfSignedCertificateProvider.GenerateCertificate
Classification: standard Estimated implement time: ~5 min Parallelizable with: Task 7–11 (NOT with Task 4/6 — same file)
Files:
- Create:
src/ZB.MOM.WW.MxGateway.Server/Security/Tls/SelfSignedCertificateProvider.cs - Test:
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/SelfSignedCertificateProviderTests.cs
Step 1: Write failing tests
using System.Security.Cryptography.X509Certificates;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Time.Testing;
using ZB.MOM.WW.MxGateway.Server.Configuration;
using ZB.MOM.WW.MxGateway.Server.Security.Tls;
using Xunit;
namespace ZB.MOM.WW.MxGateway.Tests.Security.Tls;
public sealed class SelfSignedCertificateProviderTests
{
private static SelfSignedCertificateProvider CreateProvider(TlsOptions options, FakeTimeProvider time)
=> new(options, NullLogger<SelfSignedCertificateProvider>.Instance, time);
[Fact]
public void GenerateCertificate_HasExpectedSansEkuAndValidity()
{
FakeTimeProvider time = new(new DateTimeOffset(2026, 1, 1, 0, 0, 0, TimeSpan.Zero));
TlsOptions options = new() { ValidityYears = 7, AdditionalDnsNames = ["gw.internal"] };
using X509Certificate2 cert = CreateProvider(options, time).GenerateCertificate();
Assert.Equal(time.GetUtcNow().AddYears(7).UtcDateTime.Date, cert.NotAfter.ToUniversalTime().Date);
Assert.True(cert.NotBefore.ToUniversalTime() < time.GetUtcNow().UtcDateTime);
Assert.True(cert.HasPrivateKey);
string sans = ReadSubjectAltNames(cert);
Assert.Contains("localhost", sans);
Assert.Contains("gw.internal", sans);
X509EnhancedKeyUsageExtension eku = cert.Extensions.OfType<X509EnhancedKeyUsageExtension>().Single();
Assert.Contains(eku.EnhancedKeyUsages.Cast<System.Security.Cryptography.Oid>(),
o => o.Value == "1.3.6.1.5.5.7.3.1"); // serverAuth
}
private static string ReadSubjectAltNames(X509Certificate2 cert)
=> cert.Extensions
.First(e => e.Oid?.Value == "2.5.29.17")
.Format(false);
}
Uses
Microsoft.Extensions.TimeProvider.Testing(FakeTimeProvider). If the test project lacks the package, add<PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" />(version via the repo's central package management if present — checkDirectory.Packages.props).
Step 2: Run, expect FAIL.
Run: dotnet test src/ZB.MOM.WW.MxGateway.Tests/ZB.MOM.WW.MxGateway.Tests.csproj --filter FullyQualifiedName~SelfSignedCertificateProviderTests
Step 3: Implement (SelfSignedCertificateProvider.cs)
using System.Net;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using Microsoft.Extensions.Logging;
using ZB.MOM.WW.MxGateway.Server.Configuration;
namespace ZB.MOM.WW.MxGateway.Server.Security.Tls;
/// <summary>
/// Generates and persists a long-lived self-signed certificate used as the
/// Kestrel HTTPS default when no operator certificate is configured.
/// </summary>
public sealed class SelfSignedCertificateProvider
{
private const string ServerAuthOid = "1.3.6.1.5.5.7.3.1";
private readonly TlsOptions _options;
private readonly ILogger<SelfSignedCertificateProvider> _logger;
private readonly TimeProvider _timeProvider;
public SelfSignedCertificateProvider(
TlsOptions options,
ILogger<SelfSignedCertificateProvider> logger,
TimeProvider timeProvider)
{
_options = options;
_logger = logger;
_timeProvider = timeProvider;
}
/// <summary>Creates a fresh in-memory ECDSA P-256 self-signed certificate.</summary>
public X509Certificate2 GenerateCertificate()
{
using ECDsa key = ECDsa.Create(ECCurve.NamedCurves.nistP256);
CertificateRequest request = new(
new X500DistinguishedName("CN=MxAccessGateway Self-Signed"),
key,
HashAlgorithmName.SHA256);
request.CertificateExtensions.Add(new X509BasicConstraintsExtension(false, false, 0, true));
request.CertificateExtensions.Add(new X509KeyUsageExtension(
X509KeyUsageFlags.DigitalSignature | X509KeyUsageFlags.KeyEncipherment,
critical: true));
request.CertificateExtensions.Add(new X509EnhancedKeyUsageExtension(
[new Oid(ServerAuthOid, "Server Authentication")],
critical: false));
SubjectAlternativeNameBuilder san = new();
san.AddDnsName("localhost");
string machine = Environment.MachineName;
if (!string.IsNullOrWhiteSpace(machine))
{
san.AddDnsName(machine);
}
foreach (string extra in _options.AdditionalDnsNames)
{
if (!string.IsNullOrWhiteSpace(extra))
{
san.AddDnsName(extra);
}
}
san.AddIpAddress(IPAddress.Loopback);
san.AddIpAddress(IPAddress.IPv6Loopback);
request.CertificateExtensions.Add(san.Build());
DateTimeOffset now = _timeProvider.GetUtcNow();
return request.CreateSelfSigned(now.AddDays(-1), now.AddYears(_options.ValidityYears));
}
}
Step 4: Run, expect PASS.
Step 5: Commit
git add src/ZB.MOM.WW.MxGateway.Server/Security/Tls/SelfSignedCertificateProvider.cs \
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/SelfSignedCertificateProviderTests.cs
git commit -m "feat(gateway): generate self-signed ECDSA cert with SANs"
Task 4: SelfSignedCertificateProvider.LoadOrCreate (persist, reuse, regenerate, ACL)
Classification: high-risk Estimated implement time: ~5 min Parallelizable with: Task 7–11 (NOT Task 3/6 — same file) Depends on: Task 3
Files:
- Modify:
src/ZB.MOM.WW.MxGateway.Server/Security/Tls/SelfSignedCertificateProvider.cs - Test:
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/SelfSignedCertificateProviderTests.cs
Step 1: Write failing tests (add to existing class; write under a temp dir)
[Fact]
public void LoadOrCreate_GeneratesPersistsAndReuses_SameThumbprint()
{
string dir = Directory.CreateTempSubdirectory().FullName;
try
{
string path = Path.Combine(dir, "gw.pfx");
FakeTimeProvider time = new(new DateTimeOffset(2026, 1, 1, 0, 0, 0, TimeSpan.Zero));
TlsOptions options = new() { SelfSignedCertPath = path };
using X509Certificate2 first = CreateProvider(options, time).LoadOrCreate();
Assert.True(File.Exists(path));
using X509Certificate2 second = CreateProvider(options, time).LoadOrCreate();
Assert.Equal(first.Thumbprint, second.Thumbprint); // reused, not regenerated
}
finally { Directory.Delete(dir, recursive: true); }
}
[Fact]
public void LoadOrCreate_Regenerates_WhenPersistedCertExpired()
{
string dir = Directory.CreateTempSubdirectory().FullName;
try
{
string path = Path.Combine(dir, "gw.pfx");
FakeTimeProvider time = new(new DateTimeOffset(2026, 1, 1, 0, 0, 0, TimeSpan.Zero));
TlsOptions options = new() { SelfSignedCertPath = path, ValidityYears = 1 };
using X509Certificate2 first = CreateProvider(options, time).LoadOrCreate();
time.Advance(TimeSpan.FromDays(800)); // past 1-year validity
using X509Certificate2 second = CreateProvider(options, time).LoadOrCreate();
Assert.NotEqual(first.Thumbprint, second.Thumbprint);
}
finally { Directory.Delete(dir, recursive: true); }
}
[Fact]
public void LoadOrCreate_Regenerates_WhenPersistedFileCorrupt()
{
string dir = Directory.CreateTempSubdirectory().FullName;
try
{
string path = Path.Combine(dir, "gw.pfx");
File.WriteAllText(path, "not a pfx");
TlsOptions options = new() { SelfSignedCertPath = path };
using X509Certificate2 cert = CreateProvider(options, new FakeTimeProvider()).LoadOrCreate();
Assert.True(cert.HasPrivateKey);
}
finally { Directory.Delete(dir, recursive: true); }
}
[Fact]
public void LoadOrCreate_Throws_WhenExpiredAndRegenerateDisabled()
{
string dir = Directory.CreateTempSubdirectory().FullName;
try
{
string path = Path.Combine(dir, "gw.pfx");
FakeTimeProvider time = new(new DateTimeOffset(2026, 1, 1, 0, 0, 0, TimeSpan.Zero));
TlsOptions options = new() { SelfSignedCertPath = path, ValidityYears = 1, RegenerateIfExpired = false };
using (CreateProvider(options, time).LoadOrCreate()) { }
time.Advance(TimeSpan.FromDays(800));
Assert.Throws<InvalidOperationException>(() => CreateProvider(options, time).LoadOrCreate());
}
finally { Directory.Delete(dir, recursive: true); }
}
Step 2: Run, expect FAIL.
Step 3: Implement — add to SelfSignedCertificateProvider:
/// <summary>Loads the persisted certificate, regenerating when missing,
/// expired (and allowed), or unreadable.</summary>
public X509Certificate2 LoadOrCreate()
{
string path = _options.SelfSignedCertPath;
if (string.IsNullOrWhiteSpace(path))
{
throw new InvalidOperationException(
"MxGateway:Tls:SelfSignedCertPath must be set when an HTTPS endpoint has no certificate.");
}
if (File.Exists(path))
{
try
{
X509Certificate2 existing = X509CertificateLoader.LoadPkcs12FromFile(path, password: null, KeyStorageFlags());
if (existing.NotAfter.ToUniversalTime() > _timeProvider.GetUtcNow().UtcDateTime)
{
Log("Loaded", existing);
return existing;
}
if (!_options.RegenerateIfExpired)
{
string notAfter = existing.NotAfter.ToUniversalTime().ToString("u");
existing.Dispose();
throw new InvalidOperationException(
$"Persisted gateway certificate at '{path}' expired on {notAfter} " +
"and MxGateway:Tls:RegenerateIfExpired is false.");
}
_logger.LogWarning(
"Persisted gateway certificate at {Path} expired on {NotAfter:u}; regenerating.",
path, existing.NotAfter.ToUniversalTime());
existing.Dispose();
}
catch (CryptographicException ex)
{
_logger.LogWarning(ex,
"Persisted gateway certificate at {Path} is unreadable; regenerating.", path);
}
}
return GenerateAndPersist(path);
}
private X509Certificate2 GenerateAndPersist(string path)
{
using X509Certificate2 generated = GenerateCertificate();
byte[] pfx = generated.Export(X509ContentType.Pkcs12);
string? directory = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(directory))
{
Directory.CreateDirectory(directory);
}
string temp = path + ".tmp";
File.WriteAllBytes(temp, pfx);
File.Move(temp, path, overwrite: true);
HardenPermissions(path);
X509Certificate2 loaded = X509CertificateLoader.LoadPkcs12FromFile(path, password: null, KeyStorageFlags());
Log("Generated", loaded);
return loaded;
}
private static X509KeyStorageFlags KeyStorageFlags()
=> OperatingSystem.IsWindows()
? X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.Exportable
: X509KeyStorageFlags.Exportable;
private void HardenPermissions(string path)
{
if (OperatingSystem.IsWindows())
{
HardenWindowsAcl(path);
}
else
{
File.SetUnixFileMode(path, UnixFileMode.UserRead | UnixFileMode.UserWrite);
}
}
[System.Runtime.Versioning.SupportedOSPlatform("windows")]
private static void HardenWindowsAcl(string path)
{
FileInfo file = new(path);
System.Security.AccessControl.FileSecurity security = new();
security.SetAccessRuleProtection(isProtected: true, preserveInheritance: false);
foreach (System.Security.Principal.WellKnownSidType sid in new[]
{
System.Security.Principal.WellKnownSidType.LocalSystemSid,
System.Security.Principal.WellKnownSidType.BuiltinAdministratorsSid,
})
{
System.Security.Principal.SecurityIdentifier identifier = new(sid, null);
security.AddAccessRule(new System.Security.AccessControl.FileSystemAccessRule(
identifier,
System.Security.AccessControl.FileSystemRights.FullControl,
System.Security.AccessControl.AccessControlType.Allow));
}
file.SetAccessControl(security);
}
private void Log(string action, X509Certificate2 cert)
{
string sans = cert.Extensions
.FirstOrDefault(e => e.Oid?.Value == "2.5.29.17")?
.Format(false) ?? "(none)";
_logger.LogInformation(
"{Action} gateway self-signed certificate: thumbprint={Thumbprint}, notAfter={NotAfter:u}, sans={Sans}",
action, cert.Thumbprint, cert.NotAfter.ToUniversalTime(), sans);
}
Note: persisted PFX uses no password (reuse requires a reproducible secret; a random in-memory password could not be reloaded). The private key is protected by the file ACL (
0600on non-Windows).System.Security.AccessControlis in the framework onnet10.0; theHardenWindowsAclmethod is platform-guarded so CA1416 passes.
Step 4: Run, expect PASS. (On macOS the ACL branch is skipped; tests assert behavior, not ACL.)
Step 5: Commit
git add src/ZB.MOM.WW.MxGateway.Server/Security/Tls/SelfSignedCertificateProvider.cs \
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/SelfSignedCertificateProviderTests.cs
git commit -m "feat(gateway): persist/reuse self-signed cert with hardened permissions"
Task 5: KestrelTlsInspector — detect HTTPS-without-cert
Classification: standard Estimated implement time: ~4 min Parallelizable with: Task 7–11
Files:
- Create:
src/ZB.MOM.WW.MxGateway.Server/Security/Tls/KestrelTlsInspector.cs - Test:
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/KestrelTlsInspectorTests.cs
Step 1: Write failing tests
using Microsoft.Extensions.Configuration;
using ZB.MOM.WW.MxGateway.Server.Security.Tls;
using Xunit;
namespace ZB.MOM.WW.MxGateway.Tests.Security.Tls;
public sealed class KestrelTlsInspectorTests
{
private static IConfiguration Config(params (string Key, string Value)[] entries)
=> new ConfigurationBuilder()
.AddInMemoryCollection(entries.ToDictionary(e => e.Key, e => (string?)e.Value))
.Build();
[Fact]
public void RequiresGeneratedCertificate_True_WhenHttpsEndpointHasNoCertificate()
=> Assert.True(KestrelTlsInspector.RequiresGeneratedCertificate(
Config(("Kestrel:Endpoints:Http:Url", "https://0.0.0.0:5120"))));
[Fact]
public void RequiresGeneratedCertificate_False_WhenAllEndpointsPlaintext()
=> Assert.False(KestrelTlsInspector.RequiresGeneratedCertificate(
Config(("Kestrel:Endpoints:Http:Url", "http://0.0.0.0:5120"))));
[Fact]
public void RequiresGeneratedCertificate_False_WhenHttpsEndpointHasOwnCertificate()
=> Assert.False(KestrelTlsInspector.RequiresGeneratedCertificate(
Config(
("Kestrel:Endpoints:Http:Url", "https://0.0.0.0:5120"),
("Kestrel:Endpoints:Http:Certificate:Path", @"C:\certs\real.pfx"))));
[Fact]
public void RequiresGeneratedCertificate_False_WhenNoEndpointsConfigured()
=> Assert.False(KestrelTlsInspector.RequiresGeneratedCertificate(Config()));
}
Step 2: Run, expect FAIL.
Step 3: Implement
using Microsoft.Extensions.Configuration;
namespace ZB.MOM.WW.MxGateway.Server.Security.Tls;
/// <summary>
/// Inspects the Kestrel configuration to decide whether the gateway must supply
/// a generated default certificate (an HTTPS endpoint exists with no certificate
/// of its own).
/// </summary>
public static class KestrelTlsInspector
{
public static bool RequiresGeneratedCertificate(IConfiguration configuration)
{
IConfigurationSection endpoints = configuration.GetSection("Kestrel:Endpoints");
foreach (IConfigurationSection endpoint in endpoints.GetChildren())
{
string? url = endpoint["Url"];
if (string.IsNullOrWhiteSpace(url) ||
!url.StartsWith("https://", StringComparison.OrdinalIgnoreCase))
{
continue;
}
IConfigurationSection certificate = endpoint.GetSection("Certificate");
bool hasOwnCertificate =
!string.IsNullOrWhiteSpace(certificate["Path"]) ||
!string.IsNullOrWhiteSpace(certificate["Subject"]);
if (!hasOwnCertificate)
{
return true;
}
}
return false;
}
}
Step 4: Run, expect PASS.
Step 5: Commit
git add src/ZB.MOM.WW.MxGateway.Server/Security/Tls/KestrelTlsInspector.cs \
src/ZB.MOM.WW.MxGateway.Tests/Security/Tls/KestrelTlsInspectorTests.cs
git commit -m "feat(gateway): detect HTTPS endpoints missing a certificate"
Task 6: Wire auto-cert into GatewayApplication.CreateBuilder
Classification: high-risk Estimated implement time: ~5 min Parallelizable with: Task 7–11 Depends on: Task 1, Task 4, Task 5
Files:
- Modify:
src/ZB.MOM.WW.MxGateway.Server/GatewayApplication.cs:49-73 - Test:
src/ZB.MOM.WW.MxGateway.Tests/Gateway/GatewayTlsBootstrapTests.cs
Step 1: Write failing test — build the host with an in-memory HTTPS endpoint on an ephemeral port and assert it starts (today this throws "No server certificate was specified").
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;
using Xunit;
namespace ZB.MOM.WW.MxGateway.Tests.Gateway;
public sealed class GatewayTlsBootstrapTests
{
[Fact]
public async Task Host_StartsAndBinds_WhenHttpsEndpointHasNoCertificate()
{
string certDir = Directory.CreateTempSubdirectory().FullName;
try
{
Environment.SetEnvironmentVariable("Kestrel__Endpoints__Test__Url", "https://127.0.0.1:0");
Environment.SetEnvironmentVariable(
"MxGateway__Tls__SelfSignedCertPath", Path.Combine(certDir, "gw.pfx"));
WebApplication app = GatewayApplication.Build([]);
await app.StartAsync();
await app.StopAsync();
await app.DisposeAsync();
}
finally
{
Environment.SetEnvironmentVariable("Kestrel__Endpoints__Test__Url", null);
Environment.SetEnvironmentVariable("MxGateway__Tls__SelfSignedCertPath", null);
Directory.Delete(certDir, recursive: true);
}
}
}
If
GatewayApplication.Buildneeds more env (auth pepper, worker path) to start, mirror whatever the existingGatewayEndToEndFakeWorkerSmokeTests/host tests set up. The assertion is simply thatStartAsyncdoes not throw. Keep this test in the same opt-in tier as other host-level tests if the suite gates them.
Step 2: Run, expect FAIL (Kestrel throws on the cert-less HTTPS endpoint).
Step 3: Implement — in CreateBuilder, after StaticWebAssetsLoader.UseStaticWebAssets(...) and before builder.Services.AddGatewayConfiguration();:
ConfigureSelfSignedTls(builder);
Add the private method to GatewayApplication:
private static void ConfigureSelfSignedTls(WebApplicationBuilder builder)
{
if (!Security.Tls.KestrelTlsInspector.RequiresGeneratedCertificate(builder.Configuration))
{
return;
}
Configuration.TlsOptions tlsOptions =
builder.Configuration.GetSection("MxGateway:Tls").Get<Configuration.TlsOptions>()
?? new Configuration.TlsOptions();
using ILoggerFactory loggerFactory = LoggerFactory.Create(logging => logging.AddConsole());
Security.Tls.SelfSignedCertificateProvider provider = new(
tlsOptions,
loggerFactory.CreateLogger<Security.Tls.SelfSignedCertificateProvider>(),
TimeProvider.System);
X509Certificate2 certificate = provider.LoadOrCreate();
builder.WebHost.ConfigureKestrel(options =>
options.ConfigureHttpsDefaults(https => https.ServerCertificate = certificate));
}
Add using System.Security.Cryptography.X509Certificates; and using Microsoft.Extensions.Logging; to the file.
Step 4: Run, expect PASS.
Step 5: Build the full server + run gateway tests
Run:
dotnet build src/ZB.MOM.WW.MxGateway.Server/ZB.MOM.WW.MxGateway.Server.csproj
dotnet test src/ZB.MOM.WW.MxGateway.Tests/ZB.MOM.WW.MxGateway.Tests.csproj
Expected: build clean (no CA1416 / nullable / warning-as-error breaks), tests PASS.
Step 6: Commit
git add src/ZB.MOM.WW.MxGateway.Server/GatewayApplication.cs \
src/ZB.MOM.WW.MxGateway.Tests/Gateway/GatewayTlsBootstrapTests.cs
git commit -m "feat(gateway): supply generated cert as Kestrel HTTPS default"
Task 7: .NET client — lenient TLS by default
Classification: small Estimated implement time: ~3 min Parallelizable with: Task 1–6, 8, 9, 10, 11
Files:
- Modify:
clients/dotnet/ZB.MOM.WW.MxGateway.Client/MxGatewayClientOptions.cs(add option + no new validation failure) - Modify:
clients/dotnet/ZB.MOM.WW.MxGateway.Client/MxGatewayClient.cs:325-353 - Test:
clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/(add a handler-construction or loopback-TLS test; follow existing test patterns)
Step 1: Write failing test — assert that with UseTls=true and no CaCertificatePath, the built SocketsHttpHandler.SslOptions.RemoteCertificateValidationCallback is non-null (accept-all), and that setting RequireCertificateValidation=true leaves it null (OS default). If CreateHttpHandler is private, expose an internal static test seam (and InternalsVisibleTo the test project — check whether it already exists) or test via a loopback TLS server.
[Fact]
public void Handler_SkipsVerification_WhenTlsAndNoCaPinned()
{
MxGatewayClientOptions options = new()
{
Endpoint = new Uri("https://localhost:5120"),
ApiKey = "k",
UseTls = true,
};
using SocketsHttpHandler handler = MxGatewayClient.CreateHttpHandlerForTests(options);
Assert.NotNull(handler.SslOptions.RemoteCertificateValidationCallback);
}
[Fact]
public void Handler_KeepsDefaultVerification_WhenRequireCertificateValidation()
{
MxGatewayClientOptions options = new()
{
Endpoint = new Uri("https://localhost:5120"),
ApiKey = "k",
UseTls = true,
RequireCertificateValidation = true,
};
using SocketsHttpHandler handler = MxGatewayClient.CreateHttpHandlerForTests(options);
Assert.Null(handler.SslOptions.RemoteCertificateValidationCallback);
}
Step 2: Run, expect FAIL.
Run: dotnet test clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/ZB.MOM.WW.MxGateway.Client.Tests.csproj --filter FullyQualifiedName~Handler
Step 3: Implement
In MxGatewayClientOptions.cs, add after CaCertificatePath:
/// <summary>
/// When true, TLS connections without a pinned <see cref="CaCertificatePath"/>
/// use the OS trust store. When false (default), the gateway certificate is
/// accepted without verification — appropriate for this internal tool's
/// auto-generated self-signed certificate. Pinning a CA always verifies.
/// </summary>
public bool RequireCertificateValidation { get; init; }
In MxGatewayClient.cs, change the else after the CaCertificatePath block (line ~352) so the no-CA path installs an accept-all callback unless strict:
if (!string.IsNullOrWhiteSpace(options.CaCertificatePath))
{
// ... existing custom-root validation, unchanged ...
}
else if (!options.RequireCertificateValidation)
{
handler.SslOptions.RemoteCertificateValidationCallback = (_, _, _, _) => true;
}
Rename CreateHttpHandler to internal static SocketsHttpHandler CreateHttpHandlerForTests OR add an internal wrapper; ensure the client's .csproj has InternalsVisibleTo for the test assembly (add if missing).
Step 4: Run, expect PASS.
Step 5: Build + test
Run: dotnet build clients/dotnet/MxGateway.Client.sln && dotnet test clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/ZB.MOM.WW.MxGateway.Client.Tests.csproj
Step 6: Commit
git add clients/dotnet/ZB.MOM.WW.MxGateway.Client/ clients/dotnet/ZB.MOM.WW.MxGateway.Client.Tests/
git commit -m "feat(client-dotnet): accept gateway cert by default over TLS"
Task 8: Go client — lenient TLS by default
Classification: small Estimated implement time: ~3 min Parallelizable with: Task 1–7, 9, 10, 11
Files:
- Modify:
clients/go/mxgateway/options.go(addRequireCertificateValidation bool) - Modify:
clients/go/mxgateway/client.go:214-229(buildCredentialsfinal TLS branch) - Test:
clients/go/mxgateway/(addclient_tls_test.go)
Step 1: Write failing test — start an in-process TLS gRPC server with a self-signed cert, dial with default options (TLS, no CA), assert the RPC succeeds; then dial with RequireCertificateValidation: true and assert it fails with a cert error. (If a full server is heavy, at minimum unit-test buildCredentials returns credentials whose tls.Config.InsecureSkipVerify is true by default and false when RequireCertificateValidation — by exposing an internal helper that returns the *tls.Config.)
Step 2: Run, expect FAIL.
Run: cd clients/go && go test ./... -run TLS
Step 3: Implement
options.go — add field with doc:
// RequireCertificateValidation forces TLS certificate verification even when
// no CACertFile is pinned. Default false: the gateway's self-signed cert is
// accepted without verification (internal-tool posture).
RequireCertificateValidation bool
client.go — final TLS branch:
return credentials.NewTLS(&tls.Config{
MinVersion: tls.VersionTLS12,
ServerName: opts.ServerNameOverride,
InsecureSkipVerify: !opts.RequireCertificateValidation, //nolint:gosec // internal tool; opt-in strict via RequireCertificateValidation
}), nil
Step 4: Run, expect PASS.
Step 5: Verify — cd clients/go && gofmt -l . && go build ./... && go test ./... (gofmt prints nothing, build/tests pass).
Step 6: Commit
git add clients/go/mxgateway/options.go clients/go/mxgateway/client.go clients/go/mxgateway/client_tls_test.go
git commit -m "feat(client-go): accept gateway cert by default over TLS"
Task 9: Java client — lenient TLS by default
Classification: small Estimated implement time: ~4 min Parallelizable with: Task 1–8, 10, 11
Files:
- Modify:
clients/java/zb-mom-ww-mxgateway-client/src/main/java/com/zb/mom/ww/mxgateway/client/MxGatewayClientOptions.java(addrequireCertificateValidationfield + builder setter + accessor) - Modify:
clients/java/zb-mom-ww-mxgateway-client/src/main/java/com/zb/mom/ww/mxgateway/client/MxGatewayClient.java:387-389(theelseTLS branch) - Test:
clients/java/zb-mom-ww-mxgateway-client/src/test/java/com/zb/mom/ww/mxgateway/client/(add a TLS fixture test)
Step 1: Write failing test — using grpc-inprocess is not TLS-capable, so spin a Netty server on localhost:0 with a self-signed cert (SelfSignedCertificate from shaded Netty: io.grpc.netty.shaded.io.netty.handler.ssl.util.SelfSignedCertificate). Assert default options (TLS, no CA) connect, and requireCertificateValidation(true) fails. Follow MxGatewayFixtureTests patterns.
Step 2: Run, expect FAIL.
Run: cd clients/java && gradle test --tests '*Tls*'
Step 3: Implement
Options: add private final boolean requireCertificateValidation; (default false), builder requireCertificateValidation(boolean), accessor requireCertificateValidation().
MxGatewayClient.createChannel — replace the final else:
} else if (!options.requireCertificateValidation()) {
try {
builder.sslContext(GrpcSslContexts.forClient()
.trustManager(io.grpc.netty.shaded.io.netty.handler.ssl.util
.InsecureTrustManagerFactory.INSTANCE)
.build());
} catch (SSLException error) {
throw new MxGatewayException("failed to configure lenient gateway TLS", error);
}
} else {
builder.useTransportSecurity();
}
Step 4: Run, expect PASS.
Step 5: Verify — cd clients/java && gradle test.
Step 6: Commit
git add clients/java/zb-mom-ww-mxgateway-client/
git commit -m "feat(client-java): accept gateway cert by default over TLS"
Task 10: Python client — lenient TLS via TOFU pre-fetch
Classification: standard Estimated implement time: ~5 min Parallelizable with: Task 1–9, 11
Files:
- Modify:
clients/python/src/zb_mom_ww_mxgateway/options.py(addrequire_certificate_validation: bool = False; update__repr__andcreate_channel) - Test:
clients/python/tests/test_tls.py
Step 1: Write failing test — start a local TLS gRPC server (grpc.aio with a self-signed cert via server_credentials), connect with default options (TLS, no CA) and assert a healthcheck/OpenSession-style RPC succeeds. Mark @pytest.mark.tls and allow opt-in/skip if loopback timing is flaky on CI (mirror how the suite gates network tests).
Step 2: Run, expect FAIL.
Run: cd clients/python && python -m pytest tests/test_tls.py -q
Step 3: Implement — in options.py:
Add the dataclass field:
require_certificate_validation: bool = False
Rework the TLS branch of create_channel:
if options.plaintext:
return grpc.aio.insecure_channel(options.endpoint, options=channel_options)
if options.ca_file:
root_certificates = Path(options.ca_file).read_bytes()
credentials = grpc.ssl_channel_credentials(root_certificates=root_certificates)
elif options.require_certificate_validation:
credentials = grpc.ssl_channel_credentials()
else:
# Lenient default: grpc-python has no per-channel skip-verify, so fetch the
# server's certificate (unverified) and pin it for this channel (TOFU).
host, port = _split_authority(options.endpoint)
presented = ssl.get_server_certificate((host, port))
credentials = grpc.ssl_channel_credentials(root_certificates=presented.encode("ascii"))
# The gateway self-signed cert always carries a "localhost" SAN, so default
# the SNI/target-name override to it when none was supplied, tolerating
# dial-by-IP or hostname mismatch.
if not options.server_name_override:
channel_options.append(("grpc.ssl_target_name_override", "localhost"))
return grpc.aio.secure_channel(options.endpoint, credentials, options=channel_options)
Add at top: import ssl. Add a helper:
def _split_authority(endpoint: str) -> tuple[str, int]:
"""Split a gRPC target (optionally scheme-prefixed) into (host, port)."""
target = endpoint.split("://", 1)[-1]
host, _, port = target.rpartition(":")
return (host or "localhost", int(port) if port else 443)
Wrap the ssl.get_server_certificate call so a connection failure raises the client's existing connect-error type with the endpoint in the message (match how create_channel/connect already surface failures — check the client module).
Step 4: Run, expect PASS.
Step 5: Verify — cd clients/python && python -m pytest -q (and ruff/mypy if the repo runs them — check pyproject.toml).
Step 6: Commit
git add clients/python/src/zb_mom_ww_mxgateway/options.py clients/python/tests/test_tls.py
git commit -m "feat(client-python): accept gateway cert by default via TOFU pre-fetch"
Task 11: Rust client — lenient TLS via custom rustls verifier (with spike + fallback)
Classification: high-risk Estimated implement time: ~5 min (spike may push to a second task — split if so) Parallelizable with: Task 1–10
Files:
- Modify:
clients/rust/src/options.rs(addrequire_certificate_validation: bool, default false; builder method) - Modify:
clients/rust/src/client.rs:81-94(TLS construction) - Possibly Modify:
clients/rust/Cargo.toml(addrustlsif a direct dep is needed for the verifier types) - Test:
clients/rust/tests/client_behavior.rsor a newtests/tls.rs
Step 0 (SPIKE, ~2 min, no commit): Determine the tonic 0.13.1 wiring for a custom rustls verifier. Check whether tonic::transport::ClientTlsConfig exposes a way to supply a raw rustls::ClientConfig (e.g. a with_* method) in 0.13. Run cargo doc --open -p tonic or inspect ~/.cargo source. Two outcomes:
- (a) tonic accepts a rustls config / custom verifier: implement below.
- (b) it does not without a custom connector: implement the documented fallback — when TLS is requested with no CA and
!require_certificate_validation, return a clearError::InvalidEndpoint-style error instructing the user to pass a CA file for Rust TLS, and document Rust as the pin-only exception in the design/README. Do NOT sink hours into a bespoke hyper-rustls connector.
Step 1: Write failing test — start a local tonic TLS server (or rustls-backed) with a self-signed cert; connect with default options (TLS, no CA) and assert success. For the fallback path instead assert that connecting TLS-without-CA returns the documented "CA required" error and that pinning the test CA succeeds.
Step 2: Run, expect FAIL.
Run: cd clients/rust && cargo test --workspace tls
Step 3: Implement
options.rs:
/// Require TLS certificate verification even without a pinned CA. Default
/// false: the gateway's self-signed certificate is accepted (internal-tool
/// posture). Setting a CA file always verifies.
pub fn with_require_certificate_validation(mut self, require: bool) -> Self {
self.require_certificate_validation = require;
self
}
(add the require_certificate_validation: bool struct field, defaulting to false in the constructor, and a require_certificate_validation(&self) -> bool accessor.)
client.rs TLS block (outcome a):
if !options.plaintext() {
let mut tls = ClientTlsConfig::new();
if let Some(server_name) = options.server_name_override() {
tls = tls.domain_name(server_name.to_owned());
}
if let Some(ca_file) = options.ca_file() {
let certificate = fs::read(ca_file).map_err(/* unchanged */)?;
tls = tls.ca_certificate(Certificate::from_pem(certificate));
} else if !options.require_certificate_validation() {
// Accept any server certificate (lenient internal-tool default).
tls = tls /* apply custom rustls verifier per spike outcome (a) */;
}
endpoint = endpoint.tls_config(tls)?;
}
If a custom verifier struct is needed, add to client.rs:
#[derive(Debug)]
struct AcceptAnyServerCert(std::sync::Arc<rustls::crypto::CryptoProvider>);
impl rustls::client::danger::ServerCertVerifier for AcceptAnyServerCert {
fn verify_server_cert(
&self,
_end_entity: &rustls::pki_types::CertificateDer<'_>,
_intermediates: &[rustls::pki_types::CertificateDer<'_>],
_server_name: &rustls::pki_types::ServerName<'_>,
_ocsp: &[u8],
_now: rustls::pki_types::UnixTime,
) -> Result<rustls::client::danger::ServerCertVerified, rustls::Error> {
Ok(rustls::client::danger::ServerCertVerified::assertion())
}
fn verify_tls12_signature(/* delegate to self.0 default verifier */) { /* ... */ }
fn verify_tls13_signature(/* delegate to self.0 default verifier */) { /* ... */ }
fn supported_verify_schemes(&self) -> Vec<rustls::SignatureScheme> {
self.0.signature_verification_algorithms.supported_schemes()
}
}
(Built into a rustls::ClientConfig via .dangerous().with_custom_certificate_verifier(Arc::new(...)), then handed to tonic per the spike's confirmed API.)
Step 4: Run, expect PASS.
Step 5: Verify — cd clients/rust && cargo fmt && cargo check --workspace && cargo test --workspace && cargo clippy --workspace --all-targets -- -D warnings. (Clippy will warn on the dangerous verifier; scope an #[allow(...)] with a justification comment if needed.)
Step 6: Commit
git add clients/rust/
git commit -m "feat(client-rust): accept gateway cert by default over TLS (or documented pin-only fallback)"
Task 12: Documentation
Classification: small (doc-only, but spans several files) Estimated implement time: ~5 min Parallelizable with: none Depends on: Task 6, 7, 8, 9, 10, 11
Files:
- Modify:
docs/GatewayConfiguration.md(extend the "Host Endpoints and Transport Security (Kestrel)" section) - Modify:
docs/DesignDecisions.md(record both posture choices + why) - Modify: each client README + design doc:
clients/dotnet/README.md,clients/rust/README.md+clients/rust/RustClientDesign.md,clients/python/README.md+clients/python/PythonClientDesign.md,clients/java/README.md+clients/java/JavaClientDesign.md,clients/go/README.md+clients/go/GoClientDesign.md
- Modify:
docs/CrossLanguageSmokeMatrix.md(TLS variant note; matrix-over-TLS stays manual/opt-in)
Step 1: In docs/GatewayConfiguration.md, under the existing TLS section, add an "Automatic self-signed certificate" subsection documenting: trigger (HTTPS endpoint with no Certificate), the MxGateway:Tls:* table (path / ValidityYears=10 / AdditionalDnsNames / RegenerateIfExpired), persistence path + empty-password-protected-by-ACL, thumbprint/SAN/notAfter logging, and operator override (drop a real cert into Kestrel:Endpoints:*:Certificate).
Step 2: In each client README + design doc, add a short "TLS is lenient by default" note: TLS without a pinned CA accepts any cert; pin a CA (CaCertificatePath/ca_file/caCertificatePath) to verify; set RequireCertificateValidation/require_certificate_validation/require_certificate_validation to force verification. Note the Python TOFU behavior (pre-fetches + pins the presented cert; defaults SNI override to localhost) and any Rust pin-only fallback if Task 11 took outcome (b).
Step 3: In docs/DesignDecisions.md, add an entry: gateway auto-self-signs for cert-less HTTPS endpoints (internal tool, no PKI), persisted & reused; clients accept by default — and why, so it is not mistaken for an oversight.
Step 4: In docs/CrossLanguageSmokeMatrix.md, note a TLS variant exists and stays a manual/opt-in run (needs the gateway started with an HTTPS endpoint).
Step 5: Commit
git add docs/ clients/*/README.md clients/*/*Design.md
git commit -m "docs: gateway auto-cert and lenient client TLS"
Final verification (after all tasks)
Per CLAUDE.md source-update table, run for each touched component:
- Gateway:
dotnet build src/ZB.MOM.WW.MxGateway.Server/...+dotnet test src/ZB.MOM.WW.MxGateway.Tests/...(on Windows host if local SDK can't). - .NET client:
dotnet build clients/dotnet/MxGateway.Client.sln+ its tests. - Go:
gofmt -l clients/go && (cd clients/go && go build ./... && go test ./...). - Rust:
(cd clients/rust && cargo fmt && cargo check --workspace && cargo test --workspace && cargo clippy --workspace --all-targets -- -D warnings). - Python:
(cd clients/python && python -m pytest). - Java:
(cd clients/java && gradle test).
Then use superpowers-extended-cc:finishing-a-development-branch to decide merge/PR for feat/tls-cert-autogen.