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Fix Utf8JsonReader invalid-literal errors: unbounded message, dropped bytes, IndexOutOfRangeException #134448

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Fix Utf8JsonReader invalid-literal errors: unbounded message, dropped bytes, IndexOutOfRangeException #134448

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48 changes: 24 additions & 24 deletions src/libraries/System.Text.Json/src/System/Text/Json/Reader/Utf8JsonReader.MultiSegment.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -539,31 +539,38 @@ private unsafe bool CheckLiteralMultiSegment(ReadOnlySpan<byte> span, ReadOnlySp
{
Debug.Assert(span.Length > 0 && span[0] == literal[0] && literal.Length <= JsonConstants.MaximumLiteralLength);

// The exception message quotes the literal's bytes up to and including the first mismatch,
// or all of them if the data ends first, so at most literal.Length bytes are ever written.
Span<byte> readSoFar = stackalloc byte[JsonConstants.MaximumLiteralLength];
int written = 0;
int written;

long prevTotalConsumed = _totalConsumed;
int prevConsumed = _consumed;
SequencePosition copy = _currentPosition;
if (span.Length >= literal.Length || IsLastSpan)
{
_bytePositionInLine += FindMismatch(span, literal);
int indexOfFirstMismatch = FindMismatch(span, literal);
_bytePositionInLine += indexOfFirstMismatch;

int amountToWrite = AmountToWrite(span, _bytePositionInLine, readSoFar, written);
span.Slice(0, amountToWrite).CopyTo(readSoFar);
written += amountToWrite;
written = Math.Min(span.Length, indexOfFirstMismatch + 1);
span.Slice(0, written).CopyTo(readSoFar);
goto Throw;
}
else
{
if (!literal.StartsWith(span))
{
_bytePositionInLine += FindMismatch(span, literal);
int amountToWrite = AmountToWrite(span, _bytePositionInLine, readSoFar, written);
span.Slice(0, amountToWrite).CopyTo(readSoFar);
written += amountToWrite;
int indexOfFirstMismatch = FindMismatch(span, literal);
_bytePositionInLine += indexOfFirstMismatch;

written = indexOfFirstMismatch + 1;
span.Slice(0, written).CopyTo(readSoFar);
goto Throw;
}

span.CopyTo(readSoFar);
written = span.Length;

ReadOnlySpan<byte> leftToMatch = literal.Slice(span.Length);

SequencePosition startPosition = _currentPosition;
Expand All @@ -585,10 +592,6 @@ private unsafe bool CheckLiteralMultiSegment(ReadOnlySpan<byte> span, ReadOnlySp
return false;
}

int amountToWrite = Math.Min(span.Length, readSoFar.Length - written);
span.Slice(0, amountToWrite).CopyTo(readSoFar.Slice(written));
written += amountToWrite;

span = _buffer;

if (span.StartsWith(leftToMatch))
Expand All @@ -603,28 +606,25 @@ private unsafe bool CheckLiteralMultiSegment(ReadOnlySpan<byte> span, ReadOnlySp

if (!leftToMatch.StartsWith(span))
{
_bytePositionInLine += FindMismatch(span, leftToMatch);

amountToWrite = AmountToWrite(span, _bytePositionInLine, readSoFar, written);
span.Slice(0, amountToWrite).CopyTo(readSoFar.Slice(written));
written += amountToWrite;
int indexOfFirstMismatch = FindMismatch(span, leftToMatch);
_bytePositionInLine += indexOfFirstMismatch;

span.Slice(0, indexOfFirstMismatch + 1).CopyTo(readSoFar.Slice(written));
written += indexOfFirstMismatch + 1;
goto Throw;
}

span.CopyTo(readSoFar.Slice(written));
written += span.Length;

leftToMatch = leftToMatch.Slice(span.Length);
alreadyMatched = span.Length;
}
}

static int AmountToWrite(ReadOnlySpan<byte> span, long bytePositionInLine, ReadOnlySpan<byte> readSoFar, int written)
{
return Math.Min(
readSoFar.Length - written,
Math.Min(span.Length, (int)bytePositionInLine + 1));
}
Throw:
_totalConsumed = prevTotalConsumed;
_consumed = prevConsumed;
consumed = default;
_currentPosition = copy;
throw GetInvalidLiteralMultiSegment(readSoFar.Slice(0, written).ToArray());
Expand Down
2 changes: 1 addition & 1 deletion src/libraries/System.Text.Json/src/System/Text/Json/Reader/Utf8JsonReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1195,7 +1195,7 @@ private bool CheckLiteral(ReadOnlySpan<byte> span, ReadOnlySpan<byte> literal)
if (span[i] != literal[i])
{
_bytePositionInLine += i;
ThrowInvalidLiteral(span);
ThrowInvalidLiteral(span.Slice(0, i + 1));
}
}
else
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67 changes: 67 additions & 0 deletions ...braries/System.Text.Json/tests/System.Text.Json.Tests/Utf8JsonReaderTests.MultiSegment.cs
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Expand Up @@ -1914,6 +1914,73 @@ public static void MultiSegmentInvalidLiteralInObject()
});
}

[Theory]
[InlineData("t", 1, 0, "t")]
[InlineData("nul", 3, 0, "nul")]
[InlineData("fals", 4, 0, "fals")]
[InlineData("[tru", 4, 1, "tru")]
[InlineData("tb:", 1, 0, "tb")]
[InlineData("f-2.2e-2,-", 1, 0, "f-")]
[InlineData("[nulL]", 4, 1, "nulL")]
[InlineData("[falsX]", 5, 1, "falsX")]
[InlineData("[[n{\"a\":", 3, 2, "n{")]
[InlineData("{\"\":tr", 6, 4, "tr")]
[InlineData("[ trux]", 10, 7, "trux")]
public static void InvalidLiteralVariousSegmentSizes(string input, int expectedBytePositionInLine, int expectedConsumed, string expectedLiteral)
{
byte[] utf8 = Encoding.UTF8.GetBytes(input);

var jsonReader = new Utf8JsonReader(utf8);
InvalidReadLiteralHelper(ref jsonReader, sequence: null, expectedBytePositionInLine, expectedConsumed, expectedLiteral);

var sequence = new ReadOnlySequence<byte>(utf8);
jsonReader = new Utf8JsonReader(sequence);
InvalidReadLiteralHelper(ref jsonReader, sequence, expectedBytePositionInLine, expectedConsumed, expectedLiteral);

sequence = JsonTestHelper.GetSequence(utf8, 1);
jsonReader = new Utf8JsonReader(sequence);
InvalidReadLiteralHelper(ref jsonReader, sequence, expectedBytePositionInLine, expectedConsumed, expectedLiteral);

for (int splitLocation = 0; splitLocation <= utf8.Length; splitLocation++)
{
sequence = JsonTestHelper.CreateSegments(utf8, splitLocation);
jsonReader = new Utf8JsonReader(sequence);
InvalidReadLiteralHelper(ref jsonReader, sequence, expectedBytePositionInLine, expectedConsumed, expectedLiteral);
}

for (int firstSplit = 0; firstSplit <= utf8.Length; firstSplit++)
{
for (int secondSplit = firstSplit; secondSplit <= utf8.Length; secondSplit++)
{
sequence = JsonTestHelper.CreateSegments(utf8, firstSplit, secondSplit);
jsonReader = new Utf8JsonReader(sequence);
InvalidReadLiteralHelper(ref jsonReader, sequence, expectedBytePositionInLine, expectedConsumed, expectedLiteral);
}
}
}

private static void InvalidReadLiteralHelper(ref Utf8JsonReader jsonReader, ReadOnlySequence<byte>? sequence, int expectedBytePositionInLine, int expectedConsumed, string expectedLiteral)
{
JsonException ex = JsonTestHelper.AssertThrows<JsonException>(ref jsonReader, (ref jsonReader) =>
{
while (jsonReader.Read())
;
});

Assert.Equal(0, ex.LineNumber);
Assert.Equal(expectedBytePositionInLine, ex.BytePositionInLine);
Assert.Equal(expectedConsumed, jsonReader.BytesConsumed);
if (sequence is ReadOnlySequence<byte> input)
{
Assert.Equal(expectedConsumed, input.Slice(0, jsonReader.Position).Length);
}
else
{
Assert.Equal(default, jsonReader.Position);
}
Assert.Contains($"'{expectedLiteral}' ", ex.Message);
}

[Theory]
[MemberData(nameof(JsonTokenWithExtraValueAndComments))]
public static void ReadJsonTokenWithExtraValueAndCommentsMultiSegment(string jsonString)
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