From 343ce0f01bd26055af174e3eab88ef609ddecf95 Mon Sep 17 00:00:00 2001
From: Cesar Blum Silveira <cesars@microsoft.com>
Date: Thu, 21 Sep 2017 10:05:56 -0700
Subject: [PATCH] HTTP/2: close connection with PROTOCOL_ERROR when a stream
 depends on itself.

---
 .../Internal/Http2/Http2Connection.cs         | 12 ++++++++--
 .../Http2ConnectionTests.cs                   | 24 +++++++++++++++++--
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/Kestrel.Core/Internal/Http2/Http2Connection.cs b/src/Kestrel.Core/Internal/Http2/Http2Connection.cs
index 70ca7a28c4..3622686dfd 100644
--- a/src/Kestrel.Core/Internal/Http2/Http2Connection.cs
+++ b/src/Kestrel.Core/Internal/Http2/Http2Connection.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.IO.Pipelines;
 using System.Text;
 using System.Threading.Tasks;
@@ -13,7 +12,6 @@ using Microsoft.AspNetCore.Protocols;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
-using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions.Internal;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
@@ -275,6 +273,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 throw new Http2ConnectionErrorException(Http2ErrorCode.PROTOCOL_ERROR);
             }
 
+            if (_incomingFrame.HeadersHasPriority && _incomingFrame.HeadersStreamDependency == _incomingFrame.StreamId)
+            {
+                throw new Http2ConnectionErrorException(Http2ErrorCode.PROTOCOL_ERROR);
+            }
+
             _currentHeadersStream = new Http2Stream<TContext>(application, new Http2StreamContext
             {
                 ConnectionId = ConnectionId,
@@ -316,6 +319,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 throw new Http2ConnectionErrorException(Http2ErrorCode.PROTOCOL_ERROR);
             }
 
+            if (_incomingFrame.PriorityStreamDependency == _incomingFrame.StreamId)
+            {
+                throw new Http2ConnectionErrorException(Http2ErrorCode.PROTOCOL_ERROR);
+            }
+
             if (_incomingFrame.Length != 5)
             {
                 throw new Http2ConnectionErrorException(Http2ErrorCode.FRAME_SIZE_ERROR);
diff --git a/test/Kestrel.Core.Tests/Http2ConnectionTests.cs b/test/Kestrel.Core.Tests/Http2ConnectionTests.cs
index 93515b1267..7b3a96221a 100644
--- a/test/Kestrel.Core.Tests/Http2ConnectionTests.cs
+++ b/test/Kestrel.Core.Tests/Http2ConnectionTests.cs
@@ -692,6 +692,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await WaitForConnectionErrorAsync(expectedLastStreamId: 0, expectedErrorCode: Http2ErrorCode.PROTOCOL_ERROR, ignoreNonGoAwayFrames: false);
         }
 
+        [Fact]
+        public async Task HEADERS_Received_WithPriority_StreamDependencyOnSelf_ConnectionError()
+        {
+            await InitializeConnectionAsync(_readHeadersApplication);
+
+            await SendHeadersWithPriorityAsync(1, _browserRequestHeaders, priority: 42, streamDependency: 1, endStream: true);
+
+            await WaitForConnectionErrorAsync(expectedLastStreamId: 0, expectedErrorCode: Http2ErrorCode.PROTOCOL_ERROR, ignoreNonGoAwayFrames: false);
+        }
+
         [Fact]
         public async Task PRIORITY_Received_StreamIdZero_ConnectionError()
         {
@@ -735,6 +745,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await WaitForConnectionErrorAsync(expectedLastStreamId: 0, expectedErrorCode: Http2ErrorCode.PROTOCOL_ERROR, ignoreNonGoAwayFrames: false);
         }
 
+        [Fact]
+        public async Task PRIORITY_Received_StreamDependencyOnSelf_ConnectionError()
+        {
+            await InitializeConnectionAsync(_readHeadersApplication);
+
+            await SendPriorityAsync(1, streamDependency: 1);
+
+            await WaitForConnectionErrorAsync(expectedLastStreamId: 0, expectedErrorCode: Http2ErrorCode.PROTOCOL_ERROR, ignoreNonGoAwayFrames: false);
+        }
+
         [Fact]
         public async Task RST_STREAM_Received_AbortsStream()
         {
@@ -1507,10 +1527,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             return SendAsync(pingFrame.Raw);
         }
 
-        private Task SendPriorityAsync(int streamId)
+        private Task SendPriorityAsync(int streamId, int streamDependency = 0)
         {
             var priorityFrame = new Http2Frame();
-            priorityFrame.PreparePriority(streamId, streamDependency: 0, exclusive: false, weight: 0);
+            priorityFrame.PreparePriority(streamId, streamDependency: streamDependency, exclusive: false, weight: 0);
             return SendAsync(priorityFrame.Raw);
         }