From 6975119b7d21cafdd0620d35b9542fb5d47ef392 Mon Sep 17 00:00:00 2001
From: Rory& <root@rory.gay>
Date: Fri, 20 Jun 2025 04:50:00 +0200
Subject: Basic federation, move some response classes to the right namespace

---
 LibMatrix.Federation/Utilities/JsonSigning.cs | 108 ++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 LibMatrix.Federation/Utilities/JsonSigning.cs

(limited to 'LibMatrix.Federation/Utilities/JsonSigning.cs')

diff --git a/LibMatrix.Federation/Utilities/JsonSigning.cs b/LibMatrix.Federation/Utilities/JsonSigning.cs
new file mode 100644
index 0000000..c727cde
--- /dev/null
+++ b/LibMatrix.Federation/Utilities/JsonSigning.cs
@@ -0,0 +1,108 @@
+using System.Globalization;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+using ArcaneLibs.Extensions;
+using LibMatrix.Extensions;
+using LibMatrix.FederationTest.Utilities;
+using LibMatrix.Homeservers;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math.EC.Rfc8032;
+
+namespace LibMatrix.Federation.Utilities;
+
+public static class JsonSigning { }
+
+[JsonConverter(typeof(SignedObjectConverterFactory))]
+public class SignedObject<T> {
+    [JsonPropertyName("signatures")]
+    public Dictionary<string, Dictionary<string, string>> Signatures { get; set; } = new();
+
+    [JsonIgnore]
+    public Dictionary<string, Dictionary<ServerKeysResponse.VersionedKeyId, string>> VerifyKeysById {
+        get => Signatures.ToDictionary(server => server.Key, server => server.Value.ToDictionary(key => (ServerKeysResponse.VersionedKeyId)key.Key, key => key.Value));
+        set => Signatures = value.ToDictionary(server => server.Key, server => server.Value.ToDictionary(key => (string)key.Key, key => key.Value));
+    }
+
+    [JsonExtensionData]
+    public required JsonObject Content { get; set; }
+
+    [JsonIgnore]
+    public T TypedContent {
+        get => Content.Deserialize<T>() ?? throw new JsonException("Failed to deserialize TypedContent from Content.");
+        set => Content = JsonSerializer.Deserialize<JsonObject>(JsonSerializer.Serialize(value)) ?? new JsonObject();
+    }
+}
+
+// Content needs to be merged at toplevel
+public class SignedObjectConverter<T> : JsonConverter<SignedObject<T>> {
+    public override SignedObject<T> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+        var jsonObject = JsonSerializer.Deserialize<JsonObject>(ref reader, options);
+        if (jsonObject == null) {
+            throw new JsonException("Failed to deserialize SignedObject, JSON object is null.");
+        }
+
+        var signatures = jsonObject["signatures"] ?? throw new JsonException("Failed to find 'signatures' property in JSON object.");
+        jsonObject.Remove("signatures");
+
+        var signedObject = new SignedObject<T> {
+            Content = jsonObject,
+            Signatures = signatures.Deserialize<Dictionary<string, Dictionary<string, string>>>()
+                         ?? throw new JsonException("Failed to deserialize 'signatures' property into Dictionary<string, Dictionary<string, string>>.")
+        };
+
+        return signedObject;
+    }
+
+    public override void Write(Utf8JsonWriter writer, SignedObject<T> value, JsonSerializerOptions options) {
+        var targetObj = value.Content.DeepClone();
+        targetObj["signatures"] = value.Signatures.ToJsonNode();
+        JsonSerializer.Serialize(writer, targetObj, options);
+    }
+}
+
+internal class SignedObjectConverterFactory : JsonConverterFactory {
+    public override bool CanConvert(Type typeToConvert) {
+        if (!typeToConvert.IsGenericType) return false;
+        return typeToConvert.GetGenericTypeDefinition() == typeof(SignedObject<>);
+    }
+
+    public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options) {
+        var wrappedType = typeToConvert.GetGenericArguments()[0];
+        var converter = (JsonConverter)Activator.CreateInstance(typeof(SignedObjectConverter<>).MakeGenericType(wrappedType))!;
+        return converter;
+    }
+}
+
+public static class ObjectExtensions {
+    public static SignedObject<T> Sign<T>(this SignedObject<T> content, string serverName, string keyName, Ed25519PrivateKeyParameters key) {
+        var signResult = Sign(content.Content, serverName, keyName, key);
+        var signedObject = new SignedObject<T> {
+            Signatures = content.Signatures,
+            Content = signResult.Content
+        };
+        
+        if (!signedObject.Signatures.ContainsKey(serverName))
+            signedObject.Signatures[serverName] = new Dictionary<string, string>();
+        
+        signedObject.Signatures[serverName][keyName] = signResult.Signatures[serverName][keyName];
+        return signedObject;
+    }
+
+    public static SignedObject<T> Sign<T>(this T content, string serverName, string keyName, Ed25519PrivateKeyParameters key) {
+        SignedObject<T> signedObject = new() {
+            Signatures = [],
+            Content = JsonSerializer.Deserialize<JsonObject>(JsonSerializer.Serialize(content)) ?? new JsonObject(),
+        };
+
+        var contentBytes = CanonicalJsonSerializer.SerializeToUtf8Bytes(signedObject.Content);
+        var signature = new byte[Ed25519.SignatureSize];
+        key.Sign(Ed25519.Algorithm.Ed25519, null, contentBytes, 0, contentBytes.Length, signature, 0);
+
+        if (!signedObject.Signatures.ContainsKey(serverName))
+            signedObject.Signatures[serverName] = new Dictionary<string, string>();
+
+        signedObject.Signatures[serverName][keyName] = UnpaddedBase64.Encode(signature);
+        return signedObject;
+    }
+}
\ No newline at end of file
-- 
cgit 1.5.1