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[release/6.0] Fix HTTTP/2 header decoder buffer allocation #85976

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merged 1 commit into from
May 15, 2023
Merged

[release/6.0] Fix HTTTP/2 header decoder buffer allocation #85976

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11 changes: 6 additions & 5 deletions src/libraries/Common/src/System/Net/Http/aspnetcore/Http2/Hpack/HPackDecoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -187,12 +187,11 @@ private void DecodeInternal(ReadOnlySpan<byte> data, IHttpHeadersHandler handler
// will no longer be valid.
if (_headerNameRange != null)
{
EnsureStringCapacity(ref _headerNameOctets);
EnsureStringCapacity(ref _headerNameOctets, _headerNameLength);
_headerName = _headerNameOctets;

ReadOnlySpan<byte> headerBytes = data.Slice(_headerNameRange.GetValueOrDefault().start, _headerNameRange.GetValueOrDefault().length);
headerBytes.CopyTo(_headerName);
_headerNameLength = headerBytes.Length;
_headerNameRange = null;
}
}
Expand Down Expand Up @@ -427,6 +426,7 @@ private void ParseHeaderName(ReadOnlySpan<byte> data, ref int currentIndex, IHtt
{
// Fast path. Store the range rather than copying.
_headerNameRange = (start: currentIndex, count);
_headerNameLength = _stringLength;
currentIndex += count;

_state = State.HeaderValueLength;
Expand Down Expand Up @@ -616,11 +616,12 @@ int Decode(ref byte[] dst)
_state = nextState;
}

private void EnsureStringCapacity(ref byte[] dst)
private void EnsureStringCapacity(ref byte[] dst, int stringLength = -1)
{
if (dst.Length < _stringLength)
stringLength = stringLength >= 0 ? stringLength : _stringLength;
if (dst.Length < stringLength)
{
dst = new byte[Math.Max(_stringLength, dst.Length * 2)];
dst = new byte[Math.Max(stringLength, dst.Length * 2)];
}
}

Expand Down
106 changes: 106 additions & 0 deletions src/libraries/Common/tests/Tests/System/Net/aspnetcore/Http2/HPackDecoderTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,13 @@ public class HPackDecoderTests

private const string _headerNameString = "new-header";

// On purpose longer than 4096 (DefaultStringOctetsSize from HPackDecoder) to trigger https://github.com/dotnet/runtime/issues/78516
private static readonly string _literalHeaderNameString = string.Concat(Enumerable.Range(0, 4100).Select(c => (char)('a' + (c % 26))));

private static readonly byte[] _headerNameBytes = Encoding.ASCII.GetBytes(_headerNameString);

private static readonly byte[] _literalHeaderNameBytes = Encoding.ASCII.GetBytes(_literalHeaderNameString);

// n e w - h e a d e r *
// 10101000 10111110 00010110 10011100 10100011 10010000 10110110 01111111
private static readonly byte[] _headerNameHuffmanBytes = new byte[] { 0xa8, 0xbe, 0x16, 0x9c, 0xa3, 0x90, 0xb6, 0x7f };
Expand All @@ -64,6 +69,12 @@ public class HPackDecoderTests
.Concat(_headerNameBytes)
.ToArray();

// size = 4096 ==> 0x7f, 0x81, 0x1f (7+) prefixed integer
// size = 4100 ==> 0x7f, 0x85, 0x1f (7+) prefixed integer
private static readonly byte[] _literalHeaderName = new byte[] { 0x7f, 0x85, 0x1f } // 4100
.Concat(_literalHeaderNameBytes)
.ToArray();

private static readonly byte[] _headerNameHuffman = new byte[] { (byte)(0x80 | _headerNameHuffmanBytes.Length) }
.Concat(_headerNameHuffmanBytes)
.ToArray();
Expand Down Expand Up @@ -392,6 +403,101 @@ public void DecodesLiteralHeaderFieldNeverIndexed_IndexedName_OutOfRange_Error()
Assert.Empty(_handler.DecodedHeaders);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_SingleBuffer()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded, endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_NameLengthBrokenIntoSeparateBuffers()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded[..1], endHeaders: false, handler: _handler);
_decoder.Decode(encoded[1..], endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_NameBrokenIntoSeparateBuffers()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded[..(_literalHeaderNameString.Length / 2)], endHeaders: false, handler: _handler);
_decoder.Decode(encoded[(_literalHeaderNameString.Length / 2)..], endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_NameAndValueBrokenIntoSeparateBuffers()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded[..^_headerValue.Length], endHeaders: false, handler: _handler);
_decoder.Decode(encoded[^_headerValue.Length..], endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_ValueLengthBrokenIntoSeparateBuffers()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded[..^(_headerValue.Length - 1)], endHeaders: false, handler: _handler);
_decoder.Decode(encoded[^(_headerValue.Length - 1)..], endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesLiteralHeaderFieldNeverIndexed_NewName_ValueBrokenIntoSeparateBuffers()
{
byte[] encoded = _literalHeaderFieldWithoutIndexingNewName
.Concat(_literalHeaderName)
.Concat(_headerValue)
.ToArray();

_decoder.Decode(encoded[..^(_headerValueString.Length / 2)], endHeaders: false, handler: _handler);
_decoder.Decode(encoded[^(_headerValueString.Length / 2)..], endHeaders: true, handler: _handler);

Assert.Equal(1, _handler.DecodedHeaders.Count);
Assert.True(_handler.DecodedHeaders.ContainsKey(_literalHeaderNameString));
Assert.Equal(_headerValueString, _handler.DecodedHeaders[_literalHeaderNameString]);
}

[Fact]
public void DecodesDynamicTableSizeUpdate()
{
Expand Down