Fix Kestrel psuedo header reuse

src/Servers/Kestrel/Core/src/Internal/Http/HttpHeaders.Generated.cs

@@ -7102,6 +7102,11 @@ protected override bool CopyToFast(KeyValuePair<string, StringValues>[] array, i
             return true;
         }
 
+        internal void ClearPseudoRequestHeaders()
+        {
+            _pseudoBits = _bits & 240;
+            _bits &= ~240;
+        }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static unsafe ushort ReadUnalignedLittleEndian_ushort(ref byte source)
@@ -17014,4 +17019,4 @@ public bool MoveNext()
             }
         }
     }
-}
+}

src/Servers/Kestrel/Core/src/Internal/Http/HttpRequestHeaders.cs

@@ -19,6 +19,7 @@ internal sealed partial class HttpRequestHeaders : HttpHeaders
 {
     private EnumeratorCache? _enumeratorCache;
     private long _previousBits;
+    private long _pseudoBits;
 
     public bool ReuseHeaderValues { get; set; }
     public Func<string, Encoding?> EncodingSelector { get; set; }
@@ -54,16 +55,19 @@ protected override void ClearFast()
         if (!ReuseHeaderValues)
         {
             // If we aren't reusing headers clear them all
-            Clear(_bits);
+            Clear(_bits | _pseudoBits);
         }
         else
         {
             // If we are reusing headers, store the currently set headers for comparison later
-            _previousBits = _bits;
+            // Pseudo header bits were cleared at the start of a request to hide from the user.
+            // Keep those values for reuse.
+            _previousBits = _bits | _pseudoBits;
         }
 
         // Mark no headers as currently in use
         _bits = 0;
+        _pseudoBits = 0;
         // Clear ContentLength and any unknown headers as we will never reuse them
         _contentLength = null;
         MaybeUnknown?.Clear();

src/Servers/Kestrel/Core/src/Internal/Http2/Http2Stream.cs

@@ -208,6 +208,10 @@ protected override bool TryParseRequest(ReadResult result, out bool endConnectio
         // We don't need any of the parameters because we don't implement BeginRead to actually
         // do the reading from a pipeline, nor do we use endConnection to report connection-level errors.
         endConnection = !TryValidatePseudoHeaders();
+
+        // Suppress pseudo headers from the public headers collection.
+        HttpRequestHeaders.ClearPseudoRequestHeaders();
+
         return true;
     }
 
@@ -249,7 +253,6 @@ private bool TryValidatePseudoHeaders()
         // enabling the use of HTTP to interact with non - HTTP services.
         // A common example is TLS termination.
         var headerScheme = HttpRequestHeaders.HeaderScheme.ToString();
-        HttpRequestHeaders.HeaderScheme = default; // Suppress pseduo headers from the public headers collection.
         if (!ReferenceEquals(headerScheme, Scheme) &&
             !string.Equals(headerScheme, Scheme, StringComparison.OrdinalIgnoreCase))
         {
@@ -266,7 +269,6 @@ private bool TryValidatePseudoHeaders()
         // :path (and query) - Required
         // Must start with / except may be * for OPTIONS
         var path = HttpRequestHeaders.HeaderPath.ToString();
-        HttpRequestHeaders.HeaderPath = default; // Suppress pseduo headers from the public headers collection.
         RawTarget = path;
 
         // OPTIONS - https://tools.ietf.org/html/rfc7540#section-8.1.2.3
@@ -304,7 +306,6 @@ private bool TryValidateMethod()
     {
         // :method
         _methodText = HttpRequestHeaders.HeaderMethod.ToString();
-        HttpRequestHeaders.HeaderMethod = default; // Suppress pseduo headers from the public headers collection.
         Method = HttpUtilities.GetKnownMethod(_methodText);
 
         if (Method == HttpMethod.None)
@@ -331,7 +332,6 @@ private bool TryValidateAuthorityAndHost(out string hostText)
         // Prefer this over Host
 
         var authority = HttpRequestHeaders.HeaderAuthority;
-        HttpRequestHeaders.HeaderAuthority = default; // Suppress pseduo headers from the public headers collection.
         var host = HttpRequestHeaders.HeaderHost;
         if (!StringValues.IsNullOrEmpty(authority))
         {

src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

@@ -755,6 +755,10 @@ protected override MessageBody CreateMessageBody()
     protected override bool TryParseRequest(ReadResult result, out bool endConnection)
     {
         endConnection = !TryValidatePseudoHeaders();
+
+        // Suppress pseudo headers from the public headers collection.
+        HttpRequestHeaders.ClearPseudoRequestHeaders();
+
         return true;
     }
 
@@ -791,7 +795,6 @@ private bool TryValidatePseudoHeaders()
         // proxy or gateway can translate requests for non - HTTP schemes,
         // enabling the use of HTTP to interact with non - HTTP services.
         var headerScheme = HttpRequestHeaders.HeaderScheme.ToString();
-        HttpRequestHeaders.HeaderScheme = default; // Suppress pseduo headers from the public headers collection.
         if (!ReferenceEquals(headerScheme, Scheme) &&
             !string.Equals(headerScheme, Scheme, StringComparison.OrdinalIgnoreCase))
         {
@@ -808,7 +811,6 @@ private bool TryValidatePseudoHeaders()
         // :path (and query) - Required
         // Must start with / except may be * for OPTIONS
         var path = HttpRequestHeaders.HeaderPath.ToString();
-        HttpRequestHeaders.HeaderPath = default; // Suppress pseduo headers from the public headers collection.
         RawTarget = path;
 
         // OPTIONS - https://tools.ietf.org/html/rfc7540#section-8.1.2.3
@@ -847,7 +849,6 @@ private bool TryValidateMethod()
     {
         // :method
         _methodText = HttpRequestHeaders.HeaderMethod.ToString();
-        HttpRequestHeaders.HeaderMethod = default; // Suppress pseduo headers from the public headers collection.
         Method = HttpUtilities.GetKnownMethod(_methodText);
 
         if (Method == Http.HttpMethod.None)
@@ -874,7 +875,6 @@ private bool TryValidateAuthorityAndHost(out string hostText)
         // Prefer this over Host
 
         var authority = HttpRequestHeaders.HeaderAuthority;
-        HttpRequestHeaders.HeaderAuthority = default; // Suppress pseduo headers from the public headers collection.
         var host = HttpRequestHeaders.HeaderHost;
         if (!StringValues.IsNullOrEmpty(authority))
         {

src/Servers/Kestrel/Core/test/HttpRequestHeadersTests.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Text;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
@@ -112,6 +113,23 @@ public void EntriesCanBeEnumeratedAfterResets()
         EnumerateEntries((IDictionary<string, StringValues>)headers);
     }
 
+    [Fact]
+    public void ClearPseudoRequestHeadersPlusResetClearsHeaderReferenceValue()
+    {
+        const BindingFlags privateFlags = BindingFlags.NonPublic | BindingFlags.Instance;
+
+        HttpRequestHeaders headers = new HttpRequestHeaders(reuseHeaderValues: false);
+        headers.HeaderMethod = "GET";
+        headers.ClearPseudoRequestHeaders();
+        headers.Reset();
+
+        // Hacky but required because header references is private.
+        var headerReferences = typeof(HttpRequestHeaders).GetField("_headers", privateFlags).GetValue(headers);
+        var methodValue = (StringValues)headerReferences.GetType().GetField("_Method").GetValue(headerReferences);
+
+        Assert.Equal(StringValues.Empty, methodValue);
+    }
+
     [Fact]
     public void EnumeratorNotReusedBeforeReset()
     {

src/Servers/Kestrel/shared/KnownHeaders.cs

@@ -39,7 +39,7 @@ public class KnownHeaders
             HeaderNames.DNT,
         };
 
-    public static readonly string[] PsuedoHeaderNames = new[]
+    public static readonly string[] PseudoHeaderNames = new[]
     {
             "Authority", // :authority
             "Method", // :method
@@ -50,7 +50,7 @@ public class KnownHeaders
 
     public static readonly string[] NonApiHeaders =
         ObsoleteHeaderNames
-        .Concat(PsuedoHeaderNames)
+        .Concat(PseudoHeaderNames)
         .ToArray();
 
     public static readonly string[] ApiHeaderNames =
@@ -59,6 +59,7 @@ public class KnownHeaders
         .ToArray();
 
     public static readonly long InvalidH2H3ResponseHeadersBits;
+    public static readonly long PseudoRequestHeadersBits;
 
     static KnownHeaders()
     {
@@ -263,6 +264,11 @@ static KnownHeaders()
             .Where(header => invalidH2H3ResponseHeaders.Contains(header.Name))
             .Select(header => 1L << header.Index)
             .Aggregate((a, b) => a | b);
+
+        PseudoRequestHeadersBits = RequestHeaders
+            .Where(header => PseudoHeaderNames.Contains(header.Identifier))
+            .Select(header => 1L << header.Index)
+            .Aggregate((a, b) => a | b);
     }
 
     static string Each<T>(IEnumerable<T> values, Func<T, string> formatter)
@@ -1249,6 +1255,11 @@ internal unsafe void CopyToFast(ref BufferWriter<PipeWriter> output)
                 }}
             }} while (tempBits != 0);
         }}" : "")}{(loop.ClassName == "HttpRequestHeaders" ? $@"
+        internal void ClearPseudoRequestHeaders()
+        {{
+            _pseudoBits = _bits & {PseudoRequestHeadersBits};
+            _bits &= ~{PseudoRequestHeadersBits};
+        }}
         {Each(new string[] { "ushort", "uint", "ulong" }, type => $@"
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static unsafe {type} ReadUnalignedLittleEndian_{type}(ref byte source)

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2ConnectionTests.cs

@@ -179,6 +179,8 @@ await ExpectAsync(Http2FrameType.HEADERS,
             withStreamId: 1);
 
         var contentType1 = _receivedHeaders["Content-Type"];
+        var authority1 = _receivedRequestFields.Authority;
+        var path1 = _receivedRequestFields.Path;
 
         // TriggerTick will trigger the stream to be returned to the pool so we can assert it
         TriggerTick();
@@ -194,8 +196,12 @@ await ExpectAsync(Http2FrameType.HEADERS,
             withStreamId: 3);
 
         var contentType2 = _receivedHeaders["Content-Type"];
+        var authority2 = _receivedRequestFields.Authority;
+        var path2 = _receivedRequestFields.Path;
 
         Assert.Same(contentType1, contentType2);
+        Assert.Same(authority1, authority2);
+        Assert.Same(path1, path2);
 
         await StopConnectionAsync(expectedLastStreamId: 3, ignoreNonGoAwayFrames: false);
     }

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2TestBase.cs

@@ -182,6 +182,7 @@ public Http2TestBase()
             _receivedRequestFields.Scheme = context.Request.Scheme;
             _receivedRequestFields.Path = context.Request.Path.Value;
             _receivedRequestFields.RawTarget = context.Features.Get<IHttpRequestFeature>().RawTarget;
+            _receivedRequestFields.Authority = context.Request.Host.Value;
             foreach (var header in context.Request.Headers)
             {
                 _receivedHeaders[header.Key] = header.Value.ToString();
@@ -1413,5 +1414,6 @@ public class RequestFields
         public string Scheme { get; set; }
         public string Path { get; set; }
         public string RawTarget { get; set; }
+        public string Authority { get; set; }
     }
 }

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3ConnectionTests.cs

@@ -336,6 +336,42 @@ public async Task StreamPool_MultipleStreamsInSequence_PooledStreamReused()
         Assert.Same(streamContext1, streamContext2);
     }
 
+    [Fact]
+    public async Task StreamPool_MultipleStreamsInSequence_KnownHeaderReused()
+    {
+        var headers = new[]
+        {
+            new KeyValuePair<string, string>(HeaderNames.Method, "Custom"),
+            new KeyValuePair<string, string>(HeaderNames.Path, "/"),
+            new KeyValuePair<string, string>(HeaderNames.Scheme, "http"),
+            new KeyValuePair<string, string>(HeaderNames.Authority, "localhost:80"),
+            new KeyValuePair<string, string>(HeaderNames.ContentType, "application/json"),
+        };
+
+        string contentType = null;
+        string authority = null;
+        await Http3Api.InitializeConnectionAsync(async context =>
+        {
+            contentType = context.Request.ContentType;
+            authority = context.Request.Host.Value;
+            await _echoApplication(context);
+        });
+
+        var streamContext1 = await MakeRequestAsync(0, headers, sendData: true, waitForServerDispose: true);
+        var contentType1 = contentType;
+        var authority1 = authority;
+
+        var streamContext2 = await MakeRequestAsync(1, headers, sendData: true, waitForServerDispose: true);
+        var contentType2 = contentType;
+        var authority2 = authority;
+
+        Assert.NotNull(contentType1);
+        Assert.NotNull(authority1);
+
+        Assert.Same(contentType1, contentType2);
+        Assert.Same(authority1, authority2);
+    }
+
     [Theory]
     [InlineData(10)]
     [InlineData(100)]