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Port long Huffman encoding bug fix 

https://github.com/dotnet/corefx/pull/32043
This commit is contained in:
John Luo 2018-09-13 16:37:34 -07:00
parent a1ffc5345b
commit 025aca52df
3 changed files with 33 additions and 17 deletions
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2
src/Kestrel.Core/Internal/Http2/HPack/HPackDecoder.cs
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@ -360,7 +360,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack
{
if (_huffman)
{
return Huffman.Decode(_stringOctets, 0, _stringLength, dst);
return Huffman.Decode(new ReadOnlySpan<byte>(_stringOctets, 0, _stringLength), dst);
}
else
{

20
src/Kestrel.Core/Internal/Http2/HPack/Huffman.cs
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@ -303,24 +303,26 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack
/// Decodes a Huffman encoded string from a byte array.
/// </summary>
/// <param name="src">The source byte array containing the encoded data.</param>
/// <param name="offset">The offset in the byte array where the coded data starts.</param>
/// <param name="count">The number of bytes to decode.</param>
/// <param name="dst">The destination byte array to store the decoded data.</param>
/// <returns>The number of decoded symbols.</returns>
public static int Decode(byte[] src, int offset, int count, byte[] dst)
public static int Decode(ReadOnlySpan<byte> src, Span<byte> dst)
{
var i = offset;
var i = 0;
var j = 0;
var lastDecodedBits = 0;
while (i < count)
while (i < src.Length)
{
// Note that if lastDecodeBits is 3 or more, then we will only get 5 bits (or less)
// from src[i]. Thus we need to read 5 bytes here to ensure that we always have
// at least 30 bits available for decoding.
var next = (uint)(src[i] << 24 + lastDecodedBits);
next |= (i + 1 < src.Length ? (uint)(src[i + 1] << 16 + lastDecodedBits) : 0);
next |= (i + 2 < src.Length ? (uint)(src[i + 2] << 8 + lastDecodedBits) : 0);
next |= (i + 3 < src.Length ? (uint)(src[i + 3] << lastDecodedBits) : 0);
next |= (i + 4 < src.Length ? (uint)(src[i + 4] >> (8 - lastDecodedBits)) : 0);
var ones = (uint)(int.MinValue >> (8 - lastDecodedBits - 1));
if (i == count - 1 && lastDecodedBits > 0 && (next & ones) == ones)
if (i == src.Length - 1 && lastDecodedBits > 0 && (next & ones) == ones)
{
// The remaining 7 or less bits are all 1, which is padding.
// We specifically check that lastDecodedBits > 0 because padding
@ -332,8 +334,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack
// The longest possible symbol size is 30 bits. If we're at the last 4 bytes
// of the input, we need to make sure we pass the correct number of valid bits
// left, otherwise the trailing 0s in next may form a valid symbol.
var validBits = Math.Min(30, (8 - lastDecodedBits) + (count - i - 1) * 8);
var ch = Decode(next, validBits, out var decodedBits);
var validBits = Math.Min(30, (8 - lastDecodedBits) + (src.Length - i - 1) * 8);
var ch = DecodeValue(next, validBits, out var decodedBits);
if (ch == -1)
{
@ -377,7 +379,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack
/// </param>
/// <param name="decodedBits">The number of bits decoded from <paramref name="data"/>.</param>
/// <returns>The decoded symbol.</returns>
public static int Decode(uint data, int validBits, out int decodedBits)
internal static int DecodeValue(uint data, int validBits, out int decodedBits)
{
// The code below implements the decoding logic for a canonical Huffman code.
//

28
test/Kestrel.Core.Tests/HuffmanTests.cs
View File

@ -1,6 +1,7 @@
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Text;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.HPack;
using Xunit;
@ -67,7 +68,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
public void HuffmanDecodeArray(byte[] encoded, byte[] expected)
{
var dst = new byte[expected.Length];
Assert.Equal(expected.Length, Huffman.Decode(encoded, 0, encoded.Length, dst));
Assert.Equal(expected.Length, Huffman.Decode(new ReadOnlySpan<byte>(encoded), dst));
Assert.Equal(expected, dst);
}
@ -87,7 +88,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
[MemberData(nameof(_longPaddingData))]
public void ThrowsOnPaddingLongerThanSevenBits(byte[] encoded)
{
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(encoded, 0, encoded.Length, new byte[encoded.Length * 2]));
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(new ReadOnlySpan<byte>(encoded), new byte[encoded.Length * 2]));
Assert.Equal(CoreStrings.HPackHuffmanErrorIncomplete, exception.Message);
}
@ -103,7 +104,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
[MemberData(nameof(_eosData))]
public void ThrowsOnEOS(byte[] encoded)
{
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(encoded, 0, encoded.Length, new byte[encoded.Length * 2]));
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(new ReadOnlySpan<byte>(encoded), new byte[encoded.Length * 2]));
Assert.Equal(CoreStrings.HPackHuffmanErrorEOS, exception.Message);
}
@ -112,7 +113,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
{
// h e l l o *
var encoded = new byte[] { 0b100111_00, 0b101_10100, 0b0_101000_0, 0b0111_1111 };
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(encoded, 0, encoded.Length, new byte[encoded.Length]));
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(new ReadOnlySpan<byte>(encoded), new byte[encoded.Length]));
Assert.Equal(CoreStrings.HPackHuffmanErrorDestinationTooSmall, exception.Message);
}
@ -144,10 +145,23 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
[MemberData(nameof(_incompleteSymbolData))]
public void ThrowsOnIncompleteSymbol(byte[] encoded)
{
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(encoded, 0, encoded.Length, new byte[encoded.Length * 2]));
var exception = Assert.Throws<HuffmanDecodingException>(() => Huffman.Decode(new ReadOnlySpan<byte>(encoded), new byte[encoded.Length * 2]));
Assert.Equal(CoreStrings.HPackHuffmanErrorIncomplete, exception.Message);
}
[Fact]
public void DecodeCharactersThatSpans5Octets()
{
var expectedLength = 2;
var decodedBytes = new byte[expectedLength];
// B LF EOS
var encoded = new byte[] { 0b1011101_1, 0b11111111, 0b11111111, 0b11111111, 0b11100_111 };
var decodedLength = Huffman.Decode(new ReadOnlySpan<byte>(encoded, 0, encoded.Length), decodedBytes);
Assert.Equal(expectedLength, decodedLength);
Assert.Equal(new byte [] { (byte)'B', (byte)'\n' }, decodedBytes);
}
[Theory]
[MemberData(nameof(HuffmanData))]
public void HuffmanEncode(int code, uint expectedEncoded, int expectedBitLength)
@ -161,7 +175,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
[MemberData(nameof(HuffmanData))]
public void HuffmanDecode(int code, uint encoded, int bitLength)
{
Assert.Equal(code, Huffman.Decode(encoded, bitLength, out var decodedBits));
Assert.Equal(code, Huffman.DecodeValue(encoded, bitLength, out var decodedBits));
Assert.Equal(bitLength, decodedBits);
}
@ -176,7 +190,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
#pragma warning restore xUnit1026
int bitLength)
{
Assert.Equal(code, Huffman.Decode(Huffman.Encode(code).encoded, bitLength, out var decodedBits));
Assert.Equal(code, Huffman.DecodeValue(Huffman.Encode(code).encoded, bitLength, out var decodedBits));
Assert.Equal(bitLength, decodedBits);
}