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Respect SETTINGS_MAX_HEADER_LIST_SIZE on HTTP/2 and HTTP/3 (#79281)
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@MihaZupan
MihaZupan committed Dec 27, 2022
1 parent 89b2740 commit c84d95d
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Showing 9 changed files with 273 additions and 36 deletions.
6 changes: 3 additions & 3 deletions src/libraries/Common/tests/System/Net/Http/Http3LoopbackConnection.cs
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Expand Up @@ -14,7 +14,7 @@

namespace System.Net.Test.Common
{
internal sealed class Http3LoopbackConnection : GenericLoopbackConnection
public sealed class Http3LoopbackConnection : GenericLoopbackConnection
{
public const long H3_NO_ERROR = 0x100;
public const long H3_GENERAL_PROTOCOL_ERROR = 0x101;
Expand Down Expand Up @@ -188,11 +188,11 @@ public async Task<Http3LoopbackStream> AcceptRequestStreamAsync()
return (controlStream, requestStream);
}

public async Task EstablishControlStreamAsync()
public async Task EstablishControlStreamAsync(SettingsEntry[] settingsEntries)
{
_outboundControlStream = await OpenUnidirectionalStreamAsync();
await _outboundControlStream.SendUnidirectionalStreamTypeAsync(Http3LoopbackStream.ControlStream);
await _outboundControlStream.SendSettingsFrameAsync();
await _outboundControlStream.SendSettingsFrameAsync(settingsEntries);
}

public override async Task<byte[]> ReadRequestBodyAsync()
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9 changes: 7 additions & 2 deletions src/libraries/Common/tests/System/Net/Http/Http3LoopbackServer.cs
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Expand Up @@ -66,12 +66,12 @@ public override void Dispose()
_cert.Dispose();
}

private async Task<Http3LoopbackConnection> EstablishHttp3ConnectionAsync()
private async Task<Http3LoopbackConnection> EstablishHttp3ConnectionAsync(params SettingsEntry[] settingsEntries)
{
QuicConnection con = await _listener.AcceptConnectionAsync().ConfigureAwait(false);
Http3LoopbackConnection connection = new Http3LoopbackConnection(con);

await connection.EstablishControlStreamAsync();
await connection.EstablishControlStreamAsync(settingsEntries);
return connection;
}

Expand All @@ -80,6 +80,11 @@ public override async Task<GenericLoopbackConnection> EstablishGenericConnection
return await EstablishHttp3ConnectionAsync();
}

public Task<Http3LoopbackConnection> EstablishConnectionAsync(params SettingsEntry[] settingsEntries)
{
return EstablishHttp3ConnectionAsync(settingsEntries);
}

public override async Task AcceptConnectionAsync(Func<GenericLoopbackConnection, Task> funcAsync)
{
await using Http3LoopbackConnection con = await EstablishHttp3ConnectionAsync().ConfigureAwait(false);
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15 changes: 6 additions & 9 deletions src/libraries/Common/tests/System/Net/Http/Http3LoopbackStream.cs
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Expand Up @@ -14,8 +14,7 @@

namespace System.Net.Test.Common
{

internal sealed class Http3LoopbackStream : IAsyncDisposable
public sealed class Http3LoopbackStream : IAsyncDisposable
{
private const int MaximumVarIntBytes = 8;
private const long VarIntMax = (1L << 62) - 1;
Expand Down Expand Up @@ -58,18 +57,16 @@ public async Task SendUnidirectionalStreamTypeAsync(long streamType)
await _stream.WriteAsync(buffer.AsMemory(0, bytesWritten)).ConfigureAwait(false);
}

public async Task SendSettingsFrameAsync(ICollection<(long settingId, long settingValue)> settings = null)
public async Task SendSettingsFrameAsync(SettingsEntry[] settingsEntries)
{
settings ??= Array.Empty<(long settingId, long settingValue)>();

var buffer = new byte[settings.Count * MaximumVarIntBytes * 2];
var buffer = new byte[settingsEntries.Length * MaximumVarIntBytes * 2];

int bytesWritten = 0;

foreach ((long settingId, long settingValue) in settings)
foreach (SettingsEntry setting in settingsEntries)
{
bytesWritten += EncodeHttpInteger(settingId, buffer.AsSpan(bytesWritten));
bytesWritten += EncodeHttpInteger(settingValue, buffer.AsSpan(bytesWritten));
bytesWritten += EncodeHttpInteger((int)setting.SettingId, buffer.AsSpan(bytesWritten));
bytesWritten += EncodeHttpInteger(setting.Value, buffer.AsSpan(bytesWritten));
}

await SendFrameAsync(SettingsFrame, buffer.AsMemory(0, bytesWritten)).ConfigureAwait(false);
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3 changes: 3 additions & 0 deletions src/libraries/System.Net.Http/src/Resources/Strings.resx
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Expand Up @@ -357,6 +357,9 @@
<data name="net_http_buffer_insufficient_length" xml:space="preserve">
<value>The buffer was not long enough.</value>
</data>
<data name="net_http_request_headers_exceeded_length" xml:space="preserve">
<value>The HTTP request headers length exceeded the server limit of {0} bytes.</value>
</data>
<data name="net_http_response_headers_exceeded_length" xml:space="preserve">
<value>The HTTP response headers length exceeded the set limit of {0} bytes.</value>
</data>
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63 changes: 54 additions & 9 deletions src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http2Connection.cs
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Expand Up @@ -56,6 +56,10 @@ internal sealed partial class Http2Connection : HttpConnectionBase
private readonly Channel<WriteQueueEntry> _writeChannel;
private bool _lastPendingWriterShouldFlush;

// Server-advertised SETTINGS_MAX_HEADER_LIST_SIZE
// https://www.rfc-editor.org/rfc/rfc9113.html#section-6.5.2-2.12.1
private uint _maxHeaderListSize = uint.MaxValue; // Defaults to infinite

// This flag indicates that the connection is shutting down and cannot accept new requests, because of one of the following conditions:
// (1) We received a GOAWAY frame from the server
// (2) We have exhaustead StreamIds (i.e. _nextStream == MaxStreamId)
Expand Down Expand Up @@ -162,6 +166,14 @@ public Http2Connection(HttpConnectionPool pool, Stream stream)
_nextPingRequestTimestamp = Environment.TickCount64 + _keepAlivePingDelay;
_keepAlivePingPolicy = _pool.Settings._keepAlivePingPolicy;

uint maxHeaderListSize = _pool._lastSeenHttp2MaxHeaderListSize;
if (maxHeaderListSize > 0)
{
// Previous connections to the same host advertised a limit.
// Use this as an initial value before we receive the SETTINGS frame.
_maxHeaderListSize = maxHeaderListSize;
}

if (HttpTelemetry.Log.IsEnabled())
{
HttpTelemetry.Log.Http20ConnectionEstablished();
Expand Down Expand Up @@ -822,6 +834,8 @@ private void ProcessSettingsFrame(FrameHeader frameHeader, bool initialFrame = f
uint settingValue = BinaryPrimitives.ReadUInt32BigEndian(settings);
settings = settings.Slice(4);

if (NetEventSource.Log.IsEnabled()) Trace($"Applying setting {(SettingId)settingId}={settingValue}");

switch ((SettingId)settingId)
{
case SettingId.MaxConcurrentStreams:
Expand Down Expand Up @@ -861,6 +875,11 @@ private void ProcessSettingsFrame(FrameHeader frameHeader, bool initialFrame = f
}
break;

case SettingId.MaxHeaderListSize:
_maxHeaderListSize = settingValue;
_pool._lastSeenHttp2MaxHeaderListSize = _maxHeaderListSize;
break;

default:
// All others are ignored because we don't care about them.
// Note, per RFC, unknown settings IDs should be ignored.
Expand Down Expand Up @@ -1379,14 +1398,18 @@ private void WriteBytes(ReadOnlySpan<byte> bytes, ref ArrayBuffer headerBuffer)
headerBuffer.Commit(bytes.Length);
}

private void WriteHeaderCollection(HttpRequestMessage request, HttpHeaders headers, ref ArrayBuffer headerBuffer)
private int WriteHeaderCollection(HttpRequestMessage request, HttpHeaders headers, ref ArrayBuffer headerBuffer)
{
if (NetEventSource.Log.IsEnabled()) Trace("");

HeaderEncodingSelector<HttpRequestMessage>? encodingSelector = _pool.Settings._requestHeaderEncodingSelector;

ref string[]? tmpHeaderValuesArray = ref t_headerValues;
foreach (HeaderEntry header in headers.GetEntries())

ReadOnlySpan<HeaderEntry> entries = headers.GetEntries();
int headerListSize = entries.Length * HeaderField.RfcOverhead;

foreach (HeaderEntry header in entries)
{
int headerValuesCount = HttpHeaders.GetStoreValuesIntoStringArray(header.Key, header.Value, ref tmpHeaderValuesArray);
Debug.Assert(headerValuesCount > 0, "No values for header??");
Expand All @@ -1402,6 +1425,10 @@ private void WriteHeaderCollection(HttpRequestMessage request, HttpHeaders heade
// The Connection, Upgrade and ProxyConnection headers are also not supported in HTTP2.
if (knownHeader != KnownHeaders.Host && knownHeader != KnownHeaders.Connection && knownHeader != KnownHeaders.Upgrade && knownHeader != KnownHeaders.ProxyConnection)
{
// The length of the encoded name may be shorter than the actual name.
// Ensure that headerListSize is always >= of the actual size.
headerListSize += knownHeader.Name.Length;

if (knownHeader == KnownHeaders.TE)
{
// HTTP/2 allows only 'trailers' TE header. rfc7540 8.1.2.2
Expand Down Expand Up @@ -1442,6 +1469,8 @@ private void WriteHeaderCollection(HttpRequestMessage request, HttpHeaders heade
WriteLiteralHeader(header.Key.Name, headerValues, valueEncoding, ref headerBuffer);
}
}

return headerListSize;
}

private void WriteHeaders(HttpRequestMessage request, ref ArrayBuffer headerBuffer)
Expand Down Expand Up @@ -1472,9 +1501,9 @@ private void WriteHeaders(HttpRequestMessage request, ref ArrayBuffer headerBuff

WriteIndexedHeader(_pool.IsSecure ? H2StaticTable.SchemeHttps : H2StaticTable.SchemeHttp, ref headerBuffer);

if (request.HasHeaders && request.Headers.Host != null)
if (request.HasHeaders && request.Headers.Host is string host)
{
WriteIndexedHeader(H2StaticTable.Authority, request.Headers.Host, ref headerBuffer);
WriteIndexedHeader(H2StaticTable.Authority, host, ref headerBuffer);
}
else
{
Expand All @@ -1492,16 +1521,19 @@ private void WriteHeaders(HttpRequestMessage request, ref ArrayBuffer headerBuff
WriteIndexedHeader(H2StaticTable.PathSlash, pathAndQuery, ref headerBuffer);
}

int headerListSize = 3 * HeaderField.RfcOverhead; // Method, Authority, Path

if (request.HasHeaders)
{
if (request.Headers.Protocol != null)
{
WriteBytes(ProtocolLiteralHeaderBytes, ref headerBuffer);
Encoding? protocolEncoding = _pool.Settings._requestHeaderEncodingSelector?.Invoke(":protocol", request);
WriteLiteralHeaderValue(request.Headers.Protocol, protocolEncoding, ref headerBuffer);
headerListSize += HeaderField.RfcOverhead;
}

WriteHeaderCollection(request, request.Headers, ref headerBuffer);
headerListSize += WriteHeaderCollection(request, request.Headers, ref headerBuffer);
}

// Determine cookies to send.
Expand All @@ -1511,9 +1543,9 @@ private void WriteHeaders(HttpRequestMessage request, ref ArrayBuffer headerBuff
if (cookiesFromContainer != string.Empty)
{
WriteBytes(KnownHeaders.Cookie.Http2EncodedName, ref headerBuffer);

Encoding? cookieEncoding = _pool.Settings._requestHeaderEncodingSelector?.Invoke(KnownHeaders.Cookie.Name, request);
WriteLiteralHeaderValue(cookiesFromContainer, cookieEncoding, ref headerBuffer);
headerListSize += HttpKnownHeaderNames.Cookie.Length + HeaderField.RfcOverhead;
}
}

Expand All @@ -1525,11 +1557,24 @@ private void WriteHeaders(HttpRequestMessage request, ref ArrayBuffer headerBuff
{
WriteBytes(KnownHeaders.ContentLength.Http2EncodedName, ref headerBuffer);
WriteLiteralHeaderValue("0", valueEncoding: null, ref headerBuffer);
headerListSize += HttpKnownHeaderNames.ContentLength.Length + HeaderField.RfcOverhead;
}
}
else
{
WriteHeaderCollection(request, request.Content.Headers, ref headerBuffer);
headerListSize += WriteHeaderCollection(request, request.Content.Headers, ref headerBuffer);
}

// The headerListSize is an approximation of the total header length.
// This is acceptable as long as the value is always >= the actual length.
// We must avoid ever sending more than the server allowed.
// This approach must be revisted if we ever support the dynamic table or compression when sending requests.
headerListSize += headerBuffer.ActiveLength;

uint maxHeaderListSize = _maxHeaderListSize;
if ((uint)headerListSize > maxHeaderListSize)
{
throw new HttpRequestException(SR.Format(SR.net_http_request_headers_exceeded_length, maxHeaderListSize));
}
}

Expand Down Expand Up @@ -1602,10 +1647,10 @@ private async ValueTask<Http2Stream> SendHeadersAsync(HttpRequestMessage request
// streams are created and started in order.
await PerformWriteAsync(totalSize, (thisRef: this, http2Stream, headerBytes, endStream: (request.Content == null && !request.IsExtendedConnectRequest), mustFlush), static (s, writeBuffer) =>
{
if (NetEventSource.Log.IsEnabled()) s.thisRef.Trace(s.http2Stream.StreamId, $"Started writing. Total header bytes={s.headerBytes.Length}");
s.thisRef.AddStream(s.http2Stream);
if (NetEventSource.Log.IsEnabled()) s.thisRef.Trace(s.http2Stream.StreamId, $"Started writing. Total header bytes={s.headerBytes.Length}");
Span<byte> span = writeBuffer.Span;
// Copy the HEADERS frame.
Expand Down
19 changes: 15 additions & 4 deletions src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/Http3Connection.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,9 @@ internal sealed class Http3Connection : HttpConnectionBase
// Our control stream.
private QuicStream? _clientControl;

// Current SETTINGS from the server.
private int _maximumHeadersLength = int.MaxValue; // TODO: this is not yet observed by Http3Stream when buffering headers.
// Server-advertised SETTINGS_MAX_FIELD_SECTION_SIZE
// https://www.rfc-editor.org/rfc/rfc9114.html#section-7.2.4.1-2.2.1
private uint _maxHeaderListSize = uint.MaxValue; // Defaults to infinite

// Once the server's streams are received, these are set to 1. Further receipt of these streams results in a connection error.
private int _haveServerControlStream;
Expand All @@ -53,7 +54,7 @@ internal sealed class Http3Connection : HttpConnectionBase

public HttpAuthority Authority => _authority;
public HttpConnectionPool Pool => _pool;
public int MaximumRequestHeadersLength => _maximumHeadersLength;
public uint MaxHeaderListSize => _maxHeaderListSize;
public byte[]? AltUsedEncodedHeaderBytes => _altUsedEncodedHeader;
public Exception? AbortException => Volatile.Read(ref _abortException);
private object SyncObj => _activeRequests;
Expand Down Expand Up @@ -84,6 +85,13 @@ public Http3Connection(HttpConnectionPool pool, HttpAuthority? origin, HttpAutho
_altUsedEncodedHeader = QPack.QPackEncoder.EncodeLiteralHeaderFieldWithoutNameReferenceToArray(KnownHeaders.AltUsed.Name, altUsedValue);
}

uint maxHeaderListSize = _pool._lastSeenHttp3MaxHeaderListSize;
if (maxHeaderListSize > 0)
{
// Previous connections to the same host advertised a limit.
// Use this as an initial value before we receive the SETTINGS frame.
_maxHeaderListSize = maxHeaderListSize;
}

if (HttpTelemetry.Log.IsEnabled())
{
Expand Down Expand Up @@ -725,10 +733,13 @@ async ValueTask ProcessSettingsFrameAsync(long settingsPayloadLength)

buffer.Discard(bytesRead);

if (NetEventSource.Log.IsEnabled()) Trace($"Applying setting {(Http3SettingType)settingId}={settingValue}");

switch ((Http3SettingType)settingId)
{
case Http3SettingType.MaxHeaderListSize:
_maximumHeadersLength = (int)Math.Min(settingValue, int.MaxValue);
_maxHeaderListSize = (uint)Math.Min((ulong)settingValue, uint.MaxValue);
_pool._lastSeenHttp3MaxHeaderListSize = _maxHeaderListSize;
break;
case Http3SettingType.ReservedHttp2EnablePush:
case Http3SettingType.ReservedHttp2MaxConcurrentStreams:
Expand Down
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