Add managed TLS interoperability and persisted credentials

dotnet/tests/VoiceCat.Tests/IdentityTests.cs

@@ -0,0 +1,68 @@
+using System.Security.Cryptography;
+using System.Security.Cryptography.X509Certificates;
+using System.Formats.Asn1;
+using VoiceCat.Crypto;
+
+namespace VoiceCat.Tests;
+
+public class IdentityTests
+{
+    [Fact]
+    public void CredentialsSurviveRestartAndBindIdentityIntoCertificate()
+    {
+        string directory = Path.Combine(Path.GetTempPath(), "voicecat-credentials-" + Guid.NewGuid());
+        try
+        {
+            string identityFingerprint, certificateFingerprint;
+            using (var credentials = ServerCredentials.LoadOrCreate(directory, "Server, with punctuation"))
+            {
+                identityFingerprint = credentials.Identity.Fingerprint;
+                certificateFingerprint = credentials.CertificateFingerprint;
+                using var tls = credentials.CreateTlsSession();
+                Assert.False(tls.IsReady);
+                byte[] identity = File.ReadAllBytes(Path.Combine(directory, "identity.key"));
+                Assert.Equal(96, identity.Length);
+                Assert.Equal(identity[..32], identity[64..]);
+                using var certificate = X509Certificate2.CreateFromPem(File.ReadAllText(Path.Combine(directory, "server.crt")));
+                var san = new AsnReader(certificate.Extensions["2.5.29.17"]!.RawData, AsnEncodingRules.DER).ReadSequence();
+                Assert.Equal("urn:voicecat:identity:ed25519:" + Convert.ToHexString(credentials.Identity.PublicKey).ToLowerInvariant(),
+                    san.ReadCharacterString(UniversalTagNumber.IA5String, new Asn1Tag(TagClass.ContextSpecific, 6)));
+                Assert.False(san.HasData);
+            }
+            using var restored = ServerCredentials.LoadOrCreate(directory, "ignored after creation");
+            Assert.Equal(identityFingerprint, restored.Identity.Fingerprint);
+            Assert.Equal(certificateFingerprint, restored.CertificateFingerprint);
+            File.Delete(Path.Combine(directory, "server.key"));
+            Assert.Throws<InvalidDataException>(() => ServerCredentials.LoadOrCreate(directory, "unchanged"));
+            using var stillPresent = ServerIdentity.Load(Path.Combine(directory, "identity.key"));
+            Assert.Equal(identityFingerprint, stillPresent.Fingerprint);
+        }
+        finally { if (Directory.Exists(directory)) Directory.Delete(directory, true); }
+    }
+
+    [Fact]
+    public void TofuRequiresExplicitPinAndPreservesCppFileFormat()
+    {
+        string directory = Path.Combine(Path.GetTempPath(), "voicecat-pins-" + Guid.NewGuid());
+        Directory.CreateDirectory(directory);
+        string path = Path.Combine(directory, "pins.txt");
+        string fingerprint = Convert.ToHexString(RandomNumberGenerator.GetBytes(32));
+        try
+        {
+            var store = new TofuStore(path);
+            Assert.Equal(TofuStatus.FirstConnect, store.Check("localhost", 9987, fingerprint));
+            Assert.False(File.Exists(path));
+            store.Pin("localhost", 9987, fingerprint);
+            Assert.Equal($"localhost:9987 {fingerprint.ToLowerInvariant()}\n", File.ReadAllText(path));
+            store = new(path);
+            Assert.Equal(TofuStatus.Matched, store.Check("localhost", 9987, fingerprint));
+            Assert.Equal(TofuStatus.Mismatch, store.Check("localhost", 9987, new string('0', 64)));
+            Assert.Equal(TofuStatus.Matched, new TofuStore(path).Check("localhost", 9987, fingerprint));
+            store.Remove("localhost", 9987);
+            Assert.Equal(TofuStatus.FirstConnect, new TofuStore(path).Check("localhost", 9987, fingerprint));
+            File.WriteAllText(path, "localhost:9987 " + new string('g', 64));
+            Assert.Throws<InvalidDataException>(() => new TofuStore(path));
+        }
+        finally { Directory.Delete(directory, true); }
+    }
+}