AUS-1004: Add JsonRpcLimits with document and batch bounds

AustinHarris.JsonRpcTestN/AspNetCoreTests.cs

@@ -72,6 +72,7 @@ public async Task StartHost()
 
             _app = builder.Build();
             _app.MapJsonRpc("/rpc");
+            _app.MapJsonRpc("/raised-limit", new JsonRpcOptions { MaxRequestBytes = 6 * 1024 * 1024 });
             await _app.StartAsync();
 
             var addresses = _app.Services.GetRequiredService<IServer>().Features.Get<IServerAddressesFeature>().Addresses;
@@ -157,11 +158,28 @@ public async Task Http_DiService_IsBoundAndSeesHttpContext()
         [Test]
         public async Task Http_LargeBody_Is413()
         {
-            var big = "{\"jsonrpc\":\"2.0\",\"method\":\"internal.echo\",\"params\":[\"" + new string('x', 5 * 1024 * 1024) + "\"],\"id\":1}";
+            var big = SizedDocument(4 * 1024 * 1024 + 1);
             var response = await PostAsync(big);
             Assert.AreEqual(HttpStatusCode.RequestEntityTooLarge, response.StatusCode);
         }
 
+        [Test]
+        public async Task Http_RaisedTransportLimit_UsesCoreDocumentLimit()
+        {
+            var response = await _http.PostAsync("/raised-limit",
+                new StringContent(SizedDocument(4 * 1024 * 1024 + 1), Encoding.UTF8, "application/json"));
+            Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
+            Assert.AreEqual("{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":{\"limit\":\"maxDocumentBytes\",\"maximum\":4194304}},\"id\":null}",
+                await response.Content.ReadAsStringAsync());
+        }
+
+        private static string SizedDocument(int bytes)
+        {
+            const string prefix = "{\"method\":\"IntToInt\",\"params\":[\"";
+            const string suffix = "\"],\"id\":1}";
+            return prefix + new string('x', bytes - prefix.Length - suffix.Length) + suffix;
+        }
+
         [Test]
         public async Task Tcp_TwoDocumentsInOneWrite_AreAnsweredInOrder()
         {

AustinHarris.JsonRpcTestN/LimitsTests.cs

@@ -0,0 +1,287 @@
+using System;
+using System.Buffers;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using AustinHarris.JsonRpc;
+using AustinHarris.JsonRpc.Serialization;
+using NUnit.Framework;
+
+namespace AustinHarris.JsonRpcTestN
+{
+    [TestFixture]
+    [NonParallelizable]
+    public class LimitsTests
+    {
+        private const string Call = "{\"jsonrpc\":\"2.0\",\"method\":\"limits.hit\",\"id\":1}";
+        private const string Notification = "{\"jsonrpc\":\"2.0\",\"method\":\"limits.hit\"}";
+        private const string Result = "{\"jsonrpc\":\"2.0\",\"result\":7,\"id\":1}";
+        private string _session;
+        private Service _service;
+
+        public sealed class Service
+        {
+            public int Calls;
+            [JsonRpcMethod("limits.hit")]
+            public int Hit() { Interlocked.Increment(ref Calls); return 7; }
+        }
+
+        private sealed class Segment : ReadOnlySequenceSegment<byte>
+        {
+            internal Segment(ReadOnlyMemory<byte> memory) { Memory = memory; }
+            internal Segment Append(ReadOnlyMemory<byte> memory)
+            {
+                var next = new Segment(memory) { RunningIndex = RunningIndex + Memory.Length };
+                Next = next;
+                return next;
+            }
+
+            internal Segment AppendAt(long index, ReadOnlyMemory<byte> memory)
+            {
+                var next = new Segment(memory) { RunningIndex = index };
+                Next = next;
+                return next;
+            }
+        }
+
+        [SetUp]
+        public void SetUp()
+        {
+            _session = "limits-" + Guid.NewGuid().ToString("N");
+            _service = new Service();
+            ServiceBinder.BindService(_session, _service);
+            Config.SetLimits(JsonRpcLimits.Default);
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            Config.SetLimits(JsonRpcLimits.Default);
+            Handler.DestroySession(_session);
+        }
+
+        private static ReadOnlySequence<byte> Split(byte[] bytes)
+        {
+            int middle = bytes.Length / 2;
+            var first = new Segment(bytes.AsMemory(0, middle));
+            var last = first.Append(bytes.AsMemory(middle));
+            return new ReadOnlySequence<byte>(first, 0, last, last.Memory.Length);
+        }
+
+        private static string Text(ArrayBufferWriter<byte> output) => Encoding.UTF8.GetString(output.WrittenSpan);
+
+        private static string LimitError(string name, long maximum) =>
+            "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":{\"limit\":\"" +
+            name + "\",\"maximum\":" + maximum + "}},\"id\":null}";
+
+        [TestCase("jsmn")]
+        [TestCase("newtonsoft")]
+        [TestCase("stj")]
+        public async Task DocumentBytes_AllPublicEntriesRejectBeforeDispatch(string serializerName)
+        {
+            var serializer = SerializerCatalog.Create(serializerName);
+            byte[] bytes = Encoding.UTF8.GetBytes(Call);
+            long maximum = bytes.Length - 1;
+            string expected = LimitError("maxDocumentBytes", maximum);
+            Config.SetLimits(new JsonRpcLimits(maximum, 0));
+
+            var output = new ArrayBufferWriter<byte>();
+            var single = new ReadOnlySequence<byte>(bytes);
+            JsonRpcProcessor.Process(_session, in single, output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "sync single-segment sequence");
+            output.Clear();
+            var multi = Split(bytes);
+            JsonRpcProcessor.Process(_session, in multi, output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "sync multi-segment sequence");
+            output.Clear();
+            JsonRpcProcessor.Process(_session, bytes.AsMemory(), output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "sync memory");
+            output.Clear();
+            JsonRpcProcessor.Process(_session, bytes.AsSpan(), output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "sync span");
+            Assert.AreEqual(expected, Encoding.UTF8.GetString(JsonRpcProcessor.ProcessBytes(_session, bytes.AsSpan(), serializer: serializer)));
+            Assert.AreEqual(expected, JsonRpcProcessor.ProcessSync(_session, Call, null, serializer));
+            Assert.AreEqual(expected, await JsonRpcProcessor.Process(_session, Call, null, serializer));
+
+            output.Clear();
+            await JsonRpcProcessor.ProcessAsync(_session, single, output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "async single-segment sequence");
+            output.Clear();
+            await JsonRpcProcessor.ProcessAsync(_session, multi, output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "async multi-segment sequence");
+            output.Clear();
+            await JsonRpcProcessor.ProcessAsync(_session, bytes.AsMemory(), output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "async memory");
+            output.Clear();
+            await JsonRpcProcessor.ProcessAsync(_session, bytes.AsSpan(), output, serializer: serializer);
+            Assert.AreEqual(expected, Text(output), "async span");
+            Assert.AreEqual(expected, await JsonRpcProcessor.ProcessAsync(_session, Call, serializer: serializer));
+            Assert.AreEqual(0, _service.Calls);
+        }
+
+        [Test]
+        public async Task DefaultSessionAndStateWrappersInheritByteCheck()
+        {
+            Config.SetLimits(new JsonRpcLimits(1, 0));
+            string expected = LimitError("maxDocumentBytes", 1);
+            Assert.AreEqual(expected, JsonRpcProcessor.ProcessSync(Call));
+            Assert.AreEqual(expected, JsonRpcProcessor.ProcessSync(SerializerCatalog.Create("jsmn"), Call));
+            Assert.AreEqual(expected, await JsonRpcProcessor.Process(Call));
+            Assert.AreEqual(expected, await JsonRpcProcessor.Process(SerializerCatalog.Create("jsmn"), Call));
+            Assert.AreEqual(expected, await JsonRpcProcessor.ProcessAsync(Call));
+
+            async Task<string> StateResult(bool defaultSession)
+            {
+                var completion = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
+                var state = new JsonRpcStateAsync(ar => completion.SetResult(((JsonRpcStateAsync)ar).Result), null) { JsonRpc = Call };
+                if (defaultSession) JsonRpcProcessor.Process(state);
+                else JsonRpcProcessor.Process(_session, state);
+                return await completion.Task.WaitAsync(TimeSpan.FromSeconds(5));
+            }
+
+            Assert.AreEqual(expected, await StateResult(false));
+            Assert.AreEqual(expected, await StateResult(true));
+            Assert.AreEqual(0, _service.Calls);
+        }
+
+        [Test]
+        public async Task SequenceLengthIsCheckedBeforeIntConversionOrFlattening()
+        {
+            Config.SetLimits(_session, new JsonRpcLimits(1, 0));
+            var first = new Segment(ReadOnlyMemory<byte>.Empty);
+            var last = first.AppendAt((long)int.MaxValue + 1, ReadOnlyMemory<byte>.Empty);
+            var sequence = new ReadOnlySequence<byte>(first, 0, last, 0);
+            var output = new ArrayBufferWriter<byte>();
+            JsonRpcProcessor.Process(_session, in sequence, output);
+            Assert.AreEqual(LimitError("maxDocumentBytes", 1), Text(output));
+            output.Clear();
+            await JsonRpcProcessor.ProcessAsync(_session, sequence, output);
+            Assert.AreEqual(LimitError("maxDocumentBytes", 1), Text(output));
+        }
+
+        [Test]
+        public void AsyncPreCancellationWinsOverDocumentLimit()
+        {
+            Config.SetLimits(_session, new JsonRpcLimits(1, 0));
+            using var cts = new CancellationTokenSource();
+            cts.Cancel();
+            var bytes = Encoding.UTF8.GetBytes(Call);
+            var output = new ArrayBufferWriter<byte>();
+            var sequence = new ReadOnlySequence<byte>(bytes);
+            Assert.IsTrue(JsonRpcProcessor.ProcessAsync(_session, sequence, output, cancellationToken: cts.Token).IsCanceled);
+            Assert.IsTrue(JsonRpcProcessor.ProcessAsync(_session, bytes.AsMemory(), output, cancellationToken: cts.Token).IsCanceled);
+            Assert.IsTrue(JsonRpcProcessor.ProcessAsync(_session, bytes.AsSpan(), output, cancellationToken: cts.Token).IsCanceled);
+            Assert.IsTrue(JsonRpcProcessor.ProcessAsync(_session, Call, cancellationToken: cts.Token).IsCanceled);
+            Assert.AreEqual(0, output.WrittenCount);
+        }
+
+        [TestCase("jsmn")]
+        [TestCase("newtonsoft")]
+        [TestCase("stj")]
+        public async Task BatchCountRejectsWholeMixedAndNotificationOnlyBatches(string serializerName)
+        {
+            var serializer = SerializerCatalog.Create(serializerName);
+            Config.SetLimits(_session, new JsonRpcLimits(0, 2));
+            string expected = LimitError("maxBatchCount", 2);
+            string mixed = "[" + Call + "," + Notification + ",42]";
+            string notifications = "[" + Notification + "," + Notification + "," + Notification + "]";
+            foreach (string batch in new[] { mixed, notifications })
+            {
+                Assert.AreEqual(expected, JsonRpcProcessor.ProcessSync(_session, batch, null, serializer));
+                Assert.AreEqual(expected, await JsonRpcProcessor.ProcessAsync(_session, batch, serializer: serializer));
+            }
+            Assert.AreEqual(0, _service.Calls);
+        }
+
+        [TestCase("jsmn")]
+        [TestCase("newtonsoft")]
+        [TestCase("stj")]
+        public async Task StringLimitUsesUtf8ByteCount(string serializerName)
+        {
+            var serializer = SerializerCatalog.Create(serializerName);
+            string ascii = "{\"method\":\"limits.hit\",\"id\":1,\"note\":\"aa\"}";
+            string multibyte = "{\"method\":\"limits.hit\",\"id\":1,\"note\":\"€€\"}";
+            int maximum = Encoding.UTF8.GetByteCount(ascii);
+            Config.SetLimits(_session, new JsonRpcLimits(maximum, 0));
+            Assert.AreEqual(Result, JsonRpcProcessor.ProcessSync(_session, ascii, null, serializer));
+            Assert.AreEqual(LimitError("maxDocumentBytes", maximum), JsonRpcProcessor.ProcessSync(_session, multibyte, null, serializer));
+            Assert.AreEqual(LimitError("maxDocumentBytes", maximum), await JsonRpcProcessor.ProcessAsync(_session, multibyte, serializer: serializer));
+            Assert.AreEqual(1, _service.Calls);
+        }
+
+        [Test]
+        public void ConfigurationRejectsNegativesAndNullGlobal_AndSessionCanInherit()
+        {
+            Assert.AreEqual(4 * 1024 * 1024, JsonRpcLimits.Default.MaxDocumentBytes);
+            Assert.AreEqual(1024, JsonRpcLimits.Default.MaxBatchCount);
+            Assert.AreEqual(0, JsonRpcLimits.Unlimited.MaxDocumentBytes);
+            Assert.AreEqual(0, JsonRpcLimits.Unlimited.MaxBatchCount);
+            Assert.AreEqual("maxDocumentBytes", Assert.Throws<ArgumentOutOfRangeException>(() => new JsonRpcLimits(-1, 1)).ParamName);
+            Assert.AreEqual("maxBatchCount", Assert.Throws<ArgumentOutOfRangeException>(() => new JsonRpcLimits(1, -1)).ParamName);
+            Assert.Throws<ArgumentNullException>(() => Config.SetLimits(null));
+
+            var global = new JsonRpcLimits(1, 0);
+            Config.SetLimits(global);
+            Config.SetLimits(_session, null);
+            Assert.AreSame(global, Config.Limits);
+            Assert.AreEqual(LimitError("maxDocumentBytes", 1), JsonRpcProcessor.ProcessSync(_session, Call, null));
+            Config.SetLimits(_session, new JsonRpcLimits(0, 0));
+            Assert.AreEqual(Result, JsonRpcProcessor.ProcessSync(_session, Call, null));
+            Assert.AreEqual(1, _service.Calls);
+            Config.SetLimits(_session, null);
+            Assert.AreEqual(LimitError("maxDocumentBytes", 1), JsonRpcProcessor.ProcessSync(_session, Call, null));
+
+            string created = "limits-created-" + Guid.NewGuid().ToString("N");
+            try
+            {
+                Config.SetLimits(created, null);
+                Assert.IsTrue(Handler.TryGetSessionHandler(created, out var handler));
+                Assert.IsNull(handler.Limits);
+            }
+            finally { Handler.DestroySession(created); }
+        }
+
+        [Test]
+        public void ZeroDisablesEachField_AndUnlimitedAcceptsFiveMiB()
+        {
+            Config.SetLimits(_session, new JsonRpcLimits(0, 1));
+            string large = "{\"method\":\"limits.hit\",\"id\":1,\"note\":\"" + new string('x', 5 * 1024 * 1024) + "\"}";
+            Assert.AreEqual(Result, JsonRpcProcessor.ProcessSync(_session, large, null));
+            Config.SetLimits(_session, new JsonRpcLimits(0, 0));
+            Assert.AreEqual("[" + Result + "," + Result + "]", JsonRpcProcessor.ProcessSync(_session, "[" + Call + "," + Call + "]", null));
+            Config.SetLimits(_session, JsonRpcLimits.Unlimited);
+            Assert.AreEqual(Result, JsonRpcProcessor.ProcessSync(_session, large, null));
+            Assert.AreEqual(4, _service.Calls);
+        }
+
+        [Test]
+        public async Task LimitErrorsReachParseHandler_ButNotPreProcessHandler()
+        {
+            int parsed = 0, pre = 0;
+            Config.SetLimits(_session, new JsonRpcLimits(1, 1));
+            Config.SetParseErrorHandler(_session, (raw, error) =>
+            {
+                Assert.IsNotNull(raw);
+                Assert.AreEqual(-32600, error.code);
+                Assert.IsInstanceOf<LimitExceededInfo>(error.data);
+                parsed++;
+                return error;
+            });
+            Config.SetPreProcessHandler(_session, (request, context) => { pre++; return null; });
+            try
+            {
+                Assert.AreEqual(LimitError("maxDocumentBytes", 1), JsonRpcProcessor.ProcessSync(_session, Call, null));
+                Config.SetLimits(_session, new JsonRpcLimits(0, 1));
+                Assert.AreEqual(LimitError("maxBatchCount", 1), await JsonRpcProcessor.ProcessAsync(_session, "[" + Call + "," + Call + "]"));
+                Assert.AreEqual(2, parsed);
+                Assert.AreEqual(0, pre);
+                Assert.AreEqual(0, _service.Calls);
+            }
+            finally
+            {
+                Config.SetParseErrorHandler(_session, null);
+                Config.SetPreProcessHandler(_session, null);
+            }
+        }
+    }
+}

CHANGELOG.md

@@ -12,6 +12,7 @@ behaviour: a breaking change to either means a new major version.
 
 ### Added
 
+- `JsonRpcLimits` and `Config.SetLimits`: the core rejects documents over 4 MiB and batches over 1024 entries with `-32600` and a `data` object naming the limit; `JsonRpcLimits.Unlimited` restores the 1.x behaviour.
 - `ServiceBinder.BindInterface` registers interface trees atomically, with contract naming, filtering, defaults and ownership-aware disposal (`RpcBinding`).
 - `ServiceBinder.BindMethod` registers any delegate as a method without attributes or a service class.
 - `JsonRpcProcessor.ProcessAsync` awaits `Task` and `ValueTask` methods with typed result writing, sequential batches and cooperative cancellation; `[JsonRpcCancellation]` injects the processor's token.
@@ -61,6 +62,7 @@ behaviour: a breaking change to either means a new major version.
 
 ### Security
 
+- Documents and batches are bounded in the core by default (`JsonRpcLimits`), independent of the transport.
 - With `Config.IncludeExceptionDetails` off (the default), an unhandled exception is answered as `-32603` with `data: null`: the exception's type name and message are no longer sent. Error handlers still receive the exception itself and can author what the client sees. The same applies to an exception thrown while writing a result. `ExceptionInfo.ForResponse` returns null when details are off.
 - The session registry no longer grows from untrusted session ids on the request path (see Changed).
 

Json-Rpc/Config.cs

@@ -67,6 +67,23 @@ public static JsonRpcVersionPolicy VersionPolicy
             set { _versionPolicy = value; }
         }
 
+        private static volatile JsonRpcLimits _limits = JsonRpcLimits.Default;
+
+        /// <summary>The process-wide document and batch limits, used when a session has no override.</summary>
+        public static JsonRpcLimits Limits => _limits;
+
+        /// <summary>Sets the process-wide document and batch limits. Null is not allowed.</summary>
+        public static void SetLimits(JsonRpcLimits limits)
+        {
+            _limits = limits ?? throw new ArgumentNullException(nameof(limits));
+        }
+
+        /// <summary>Sets one session's limits; null makes it inherit <see cref="Limits"/>. Creates the session if needed.</summary>
+        public static void SetLimits(string sessionId, JsonRpcLimits limits)
+        {
+            Handler.GetSessionHandler(sessionId).Limits = limits;
+        }
+
         /// <summary>Sets the version policy for one session; null makes the session follow <see cref="VersionPolicy"/>.</summary>
         public static void SetVersionPolicy(string sessionId, JsonRpcVersionPolicy? policy)
         {