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Added sanity check for every jpeg marker #2084

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merged 2 commits into from
Apr 14, 2022
Merged

Added sanity check for every jpeg marker #2084

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8cdcda3
Added sanity check for every jpeg marker
Apr 13, 2022
64d9146
Added malformed image
Apr 13, 2022
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40 changes: 24 additions & 16 deletions src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -315,14 +315,22 @@ internal void ParseStream(BufferedReadStream stream, HuffmanScanDecoder scanDeco
if (!fileMarker.Invalid)
{
// Get the marker length.
int remaining = this.ReadUint16(stream) - 2;
int markerContentByteSize = this.ReadUint16(stream) - 2;

// Check whether stream actually has enought bytes to read
// markerContentByteSize is always positive so we cast
// to uint to avoid sign extension
if (stream.RemainingBytes < (uint)markerContentByteSize)
{
JpegThrowHelper.ThrowNotEnoughBytesForMarker(fileMarker.Marker);
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Note: this error message would contain hex value of the marker. While we can map byte to ITU spec name I don't think it's worth the effort.

}

switch (fileMarker.Marker)
{
case JpegConstants.Markers.SOF0:
case JpegConstants.Markers.SOF1:
case JpegConstants.Markers.SOF2:
this.ProcessStartOfFrameMarker(stream, remaining, fileMarker, metadataOnly);
this.ProcessStartOfFrameMarker(stream, markerContentByteSize, fileMarker, metadataOnly);
break;

case JpegConstants.Markers.SOF5:
Expand Down Expand Up @@ -350,7 +358,7 @@ internal void ParseStream(BufferedReadStream stream, HuffmanScanDecoder scanDeco
case JpegConstants.Markers.SOS:
if (!metadataOnly)
{
this.ProcessStartOfScanMarker(stream, remaining);
this.ProcessStartOfScanMarker(stream, markerContentByteSize);
break;
}
else
Expand All @@ -364,41 +372,41 @@ internal void ParseStream(BufferedReadStream stream, HuffmanScanDecoder scanDeco

if (metadataOnly)
{
stream.Skip(remaining);
stream.Skip(markerContentByteSize);
}
else
{
this.ProcessDefineHuffmanTablesMarker(stream, remaining);
this.ProcessDefineHuffmanTablesMarker(stream, markerContentByteSize);
}

break;

case JpegConstants.Markers.DQT:
this.ProcessDefineQuantizationTablesMarker(stream, remaining);
this.ProcessDefineQuantizationTablesMarker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.DRI:
if (metadataOnly)
{
stream.Skip(remaining);
stream.Skip(markerContentByteSize);
}
else
{
this.ProcessDefineRestartIntervalMarker(stream, remaining);
this.ProcessDefineRestartIntervalMarker(stream, markerContentByteSize);
}

break;

case JpegConstants.Markers.APP0:
this.ProcessApplicationHeaderMarker(stream, remaining);
this.ProcessApplicationHeaderMarker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.APP1:
this.ProcessApp1Marker(stream, remaining);
this.ProcessApp1Marker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.APP2:
this.ProcessApp2Marker(stream, remaining);
this.ProcessApp2Marker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.APP3:
Expand All @@ -411,20 +419,20 @@ internal void ParseStream(BufferedReadStream stream, HuffmanScanDecoder scanDeco
case JpegConstants.Markers.APP10:
case JpegConstants.Markers.APP11:
case JpegConstants.Markers.APP12:
stream.Skip(remaining);
stream.Skip(markerContentByteSize);
break;

case JpegConstants.Markers.APP13:
this.ProcessApp13Marker(stream, remaining);
this.ProcessApp13Marker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.APP14:
this.ProcessApp14Marker(stream, remaining);
this.ProcessApp14Marker(stream, markerContentByteSize);
break;

case JpegConstants.Markers.APP15:
case JpegConstants.Markers.COM:
stream.Skip(remaining);
stream.Skip(markerContentByteSize);
break;

case JpegConstants.Markers.DAC:
Expand Down Expand Up @@ -1260,7 +1268,7 @@ private void ProcessStartOfScanMarker(BufferedReadStream stream, int remaining)
int selectorsBytes = selectorsCount * 2;
if (remaining != 4 + selectorsBytes)
{
JpegThrowHelper.ThrowBadMarker("SOS", remaining);
JpegThrowHelper.ThrowBadMarker(nameof(JpegConstants.Markers.SOS), remaining);
}

// selectorsCount*2 bytes: component index + huffman tables indices
Expand Down
3 changes: 3 additions & 0 deletions src/ImageSharp/Formats/Jpeg/JpegThrowHelper.cs
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Expand Up @@ -25,6 +25,9 @@ internal static class JpegThrowHelper
[MethodImpl(InliningOptions.ColdPath)]
public static void ThrowBadMarker(string marker, int length) => throw new InvalidImageContentException($"Marker {marker} has bad length {length}.");

[MethodImpl(InliningOptions.ColdPath)]
public static void ThrowNotEnoughBytesForMarker(byte marker) => throw new InvalidImageContentException($"Input stream does not have enough bytes to parse declared contents of the {marker:X2} marker.");

[MethodImpl(InliningOptions.ColdPath)]
public static void ThrowBadQuantizationTableIndex(int index) => throw new InvalidImageContentException($"Bad Quantization Table index {index}.");

Expand Down
9 changes: 9 additions & 0 deletions src/ImageSharp/IO/BufferedReadStream.cs
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Expand Up @@ -114,6 +114,15 @@ public override long Position
/// <inheritdoc/>
public override bool CanWrite { get; } = false;

/// <summary>
/// Gets remaining byte count available to read.
/// </summary>
public long RemainingBytes
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get => this.Length - this.Position;
}

/// <summary>
/// Gets the underlying stream.
/// </summary>
Expand Down