diff --git a/src/ImageSharp/Formats/Png/PngDecoderCore.cs b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
index 179bf38ba8..a96c53c104 100644
--- a/src/ImageSharp/Formats/Png/PngDecoderCore.cs
+++ b/src/ImageSharp/Formats/Png/PngDecoderCore.cs
@@ -120,6 +120,11 @@ internal sealed class PngDecoderCore : IImageDecoderInternals
///
private readonly PngCrcChunkHandling pngCrcChunkHandling;
+ ///
+ /// The maximum memory in bytes that a zTXt, sPLT, iTXt, iCCP, or unknown chunk can occupy when decompressed.
+ ///
+ private readonly int maxUncompressedLength;
+
///
/// Initializes a new instance of the class.
///
@@ -132,6 +137,7 @@ public PngDecoderCore(PngDecoderOptions options)
this.skipMetadata = options.GeneralOptions.SkipMetadata;
this.memoryAllocator = this.configuration.MemoryAllocator;
this.pngCrcChunkHandling = options.PngCrcChunkHandling;
+ this.maxUncompressedLength = options.MaxUncompressedAncillaryChunkSizeBytes;
}
internal PngDecoderCore(PngDecoderOptions options, bool colorMetadataOnly)
@@ -143,6 +149,7 @@ internal PngDecoderCore(PngDecoderOptions options, bool colorMetadataOnly)
this.configuration = options.GeneralOptions.Configuration;
this.memoryAllocator = this.configuration.MemoryAllocator;
this.pngCrcChunkHandling = options.PngCrcChunkHandling;
+ this.maxUncompressedLength = options.MaxUncompressedAncillaryChunkSizeBytes;
}
///
@@ -596,23 +603,7 @@ private static void ReadGammaChunk(PngMetadata pngMetadata, ReadOnlySpan d
private void InitializeImage(ImageMetadata metadata, FrameControl frameControl, out Image image)
where TPixel : unmanaged, IPixel
{
- // When ignoring data CRCs, we can't use the image constructor that leaves the buffer uncleared.
- if (this.pngCrcChunkHandling is PngCrcChunkHandling.IgnoreData or PngCrcChunkHandling.IgnoreAll)
- {
- image = new Image(
- this.configuration,
- this.header.Width,
- this.header.Height,
- metadata);
- }
- else
- {
- image = Image.CreateUninitialized(
- this.configuration,
- this.header.Width,
- this.header.Height,
- metadata);
- }
+ image = new Image(this.configuration, this.header.Width, this.header.Height, metadata);
PngFrameMetadata frameMetadata = image.Frames.RootFrame.Metadata.GetPngMetadata();
frameMetadata.FromChunk(in frameControl);
@@ -1572,7 +1563,7 @@ private void ReadColorProfileChunk(ImageMetadata metadata, ReadOnlySpan da
ReadOnlySpan compressedData = data[(zeroIndex + 2)..];
- if (this.TryDecompressZlibData(compressedData, out byte[] iccpProfileBytes))
+ if (this.TryDecompressZlibData(compressedData, this.maxUncompressedLength, out byte[] iccpProfileBytes))
{
metadata.IccProfile = new IccProfile(iccpProfileBytes);
}
@@ -1582,9 +1573,10 @@ private void ReadColorProfileChunk(ImageMetadata metadata, ReadOnlySpan da
/// Tries to decompress zlib compressed data.
///
/// The compressed data.
+ /// The maximum uncompressed length.
/// The uncompressed bytes array.
/// True, if de-compressing was successful.
- private unsafe bool TryDecompressZlibData(ReadOnlySpan compressedData, out byte[] uncompressedBytesArray)
+ private unsafe bool TryDecompressZlibData(ReadOnlySpan compressedData, int maxLength, out byte[] uncompressedBytesArray)
{
fixed (byte* compressedDataBase = compressedData)
{
@@ -1604,6 +1596,12 @@ private unsafe bool TryDecompressZlibData(ReadOnlySpan compressedData, out
int bytesRead = inflateStream.CompressedStream.Read(destUncompressedData, 0, destUncompressedData.Length);
while (bytesRead != 0)
{
+ if (memoryStreamOutput.Length > maxLength)
+ {
+ uncompressedBytesArray = Array.Empty();
+ return false;
+ }
+
memoryStreamOutput.Write(destUncompressedData[..bytesRead]);
bytesRead = inflateStream.CompressedStream.Read(destUncompressedData, 0, destUncompressedData.Length);
}
@@ -1746,7 +1744,7 @@ private void ReadInternationalTextChunk(ImageMetadata metadata, ReadOnlySpanThe .
private bool TryDecompressTextData(ReadOnlySpan compressedData, Encoding encoding, [NotNullWhen(true)] out string? value)
{
- if (this.TryDecompressZlibData(compressedData, out byte[] uncompressedData))
+ if (this.TryDecompressZlibData(compressedData, this.maxUncompressedLength, out byte[] uncompressedData))
{
value = encoding.GetString(uncompressedData);
return true;
diff --git a/src/ImageSharp/Formats/Png/PngDecoderOptions.cs b/src/ImageSharp/Formats/Png/PngDecoderOptions.cs
index ab6ba4770e..abfa4b1da8 100644
--- a/src/ImageSharp/Formats/Png/PngDecoderOptions.cs
+++ b/src/ImageSharp/Formats/Png/PngDecoderOptions.cs
@@ -15,4 +15,10 @@ public sealed class PngDecoderOptions : ISpecializedDecoderOptions
/// Gets a value indicating how to handle validation of any CRC (Cyclic Redundancy Check) data within the encoded PNG.
///
public PngCrcChunkHandling PngCrcChunkHandling { get; init; } = PngCrcChunkHandling.IgnoreNonCritical;
+
+ ///
+ /// Gets the maximum memory in bytes that a zTXt, sPLT, iTXt, iCCP, or unknown chunk can occupy when decompressed.
+ /// Defaults to 8MB
+ ///
+ public int MaxUncompressedAncillaryChunkSizeBytes { get; init; } = 8 * 1024 * 1024; // 8MB
}
diff --git a/tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs b/tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs
index b9f6075fb8..9b165526eb 100644
--- a/tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs
@@ -672,4 +672,23 @@ public void Decode_Issue2666()
string path = Path.GetFullPath(Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, TestImages.Png.Issue2666));
using Image image = Image.Load(path);
}
+
+ [Theory]
+
+ [InlineData(TestImages.Png.Bad.BadZTXT)]
+ [InlineData(TestImages.Png.Bad.BadZTXT2)]
+ public void Decode_BadZTXT(string file)
+ {
+ string path = Path.GetFullPath(Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, file));
+ using Image image = Image.Load(path);
+ }
+
+ [Theory]
+ [InlineData(TestImages.Png.Bad.BadZTXT)]
+ [InlineData(TestImages.Png.Bad.BadZTXT2)]
+ public void Info_BadZTXT(string file)
+ {
+ string path = Path.GetFullPath(Path.Combine(TestEnvironment.InputImagesDirectoryFullPath, file));
+ _ = Image.Identify(path);
+ }
}
diff --git a/tests/ImageSharp.Tests/TestImages.cs b/tests/ImageSharp.Tests/TestImages.cs
index e72f6fad8d..00f7370f31 100644
--- a/tests/ImageSharp.Tests/TestImages.cs
+++ b/tests/ImageSharp.Tests/TestImages.cs
@@ -186,8 +186,10 @@ public static class Bad
// Invalid color type.
public const string ColorTypeOne = "Png/xc1n0g08.png";
public const string ColorTypeNine = "Png/xc9n2c08.png";
-
public const string FlagOfGermany0000016446 = "Png/issues/flag_of_germany-0000016446.png";
+
+ public const string BadZTXT = "Png/issues/bad-ztxt.png";
+ public const string BadZTXT2 = "Png/issues/bad-ztxt2.png";
}
}
diff --git a/tests/Images/Input/Png/issues/bad-ztxt.png b/tests/Images/Input/Png/issues/bad-ztxt.png
new file mode 100644
index 0000000000..710f888d0b
--- /dev/null
+++ b/tests/Images/Input/Png/issues/bad-ztxt.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:132a70cf0ac458a55cf4a44f4c6c025587491d304595835959955de6682fa472
+size 3913750
diff --git a/tests/Images/Input/Png/issues/bad-ztxt2.png b/tests/Images/Input/Png/issues/bad-ztxt2.png
new file mode 100644
index 0000000000..958c00e3f0
--- /dev/null
+++ b/tests/Images/Input/Png/issues/bad-ztxt2.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:778a5fc8e915d79e9f55e58c6e4f646ae55dd7e866e65960754cb67a2b445987
+size 93