diff --git a/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs b/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs index 3ac7e803ea..b223bda4f5 100644 --- a/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs +++ b/src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs @@ -1445,6 +1445,12 @@ private int ReadImageHeaders(BufferedReadStream stream, out bool inverted, out b switch (this.fileMarkerType) { case BmpFileMarkerType.Bitmap: + if (this.fileHeader.Offset > stream.Length) + { + BmpThrowHelper.ThrowInvalidImageContentException( + $"Pixel data offset {this.fileHeader.Offset} exceeds file size {stream.Length}."); + } + colorMapSizeBytes = this.fileHeader.Offset - BmpFileHeader.Size - this.infoHeader.HeaderSize; int colorCountForBitDepth = ColorNumerics.GetColorCountForBitDepth(this.infoHeader.BitsPerPixel); bytesPerColorMapEntry = colorMapSizeBytes / colorCountForBitDepth; diff --git a/tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs b/tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs index 80e3061205..1b4a43129b 100644 --- a/tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs +++ b/tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs @@ -571,6 +571,34 @@ public void BmpDecoder_ThrowsException_Issue2696(TestImageProvider(ex.InnerException); } + // https://github.com/SixLabors/ImageSharp/issues/3074 + [Fact] + public void BmpDecoder_ThrowsException_Issue3074() + { + // Crafted BMP: pixel data offset = 0x7FFFFFFF, actual file = 35 bytes + byte[] data = + [ + 0x42, 0x4D, // "BM" signature + 0x3A, 0x00, 0x00, 0x00, // file size: 58 + 0x00, 0x00, 0x00, 0x00, // reserved + 0xFF, 0xFF, 0xFF, 0x7F, // pixel offset: 0x7FFFFFFF (2,147,483,647) + 0x28, 0x00, 0x00, 0x00, // DIB header size: 40 + 0x01, 0x00, 0x00, 0x00, // width: 1 + 0x01, 0xFF, 0x00, 0x00, // height: 65281 + 0x01, 0x00, // color planes: 1 + 0x08, 0x00, // bits per pixel: 8 + 0x00, 0x00, 0x00, 0x00, // compression: RGB + 0x00, 0x00, 0x00 // (truncated) + ]; + + using MemoryStream stream = new(data); + + Assert.Throws(() => + { + using Image image = Image.Load(stream); + }); + } + [Fact] public void BmpDecoder_ThrowsException_Issue3067() {