Merge pull request #3069 from SixLabors/js/v4-fix-3067

Throw explicit InvalidImageContentException when BMP BPP is invalid.

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -131,6 +131,7 @@ internal sealed class BmpDecoderCore : ImageDecoderCore
         try
         {
             int bytesPerColorMapEntry = this.ReadImageHeaders(stream, out bool inverted, out byte[] palette);
+            ushort bitsPerPixel = this.infoHeader.BitsPerPixel;
 
             image = new Image<TPixel>(this.configuration, this.infoHeader.Width, this.infoHeader.Height, this.metadata);
 
@@ -138,23 +139,27 @@ internal sealed class BmpDecoderCore : ImageDecoderCore
 
             switch (this.infoHeader.Compression)
             {
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is 32 && this.bmpMetadata.InfoHeaderType is BmpInfoHeaderType.WinVersion3:
+                case BmpCompression.RGB when bitsPerPixel is 32 && this.bmpMetadata.InfoHeaderType is BmpInfoHeaderType.WinVersion3:
                     this.ReadRgb32Slow(stream, pixels, this.infoHeader.Width, this.infoHeader.Height, inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is 32:
+
+                case BmpCompression.RGB when bitsPerPixel is 32:
                     this.ReadRgb32Fast(stream, pixels, this.infoHeader.Width, this.infoHeader.Height, inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is 24:
+
+                case BmpCompression.RGB when bitsPerPixel is 24:
                     this.ReadRgb24(stream, pixels, this.infoHeader.Width, this.infoHeader.Height, inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is 16:
+
+                case BmpCompression.RGB when bitsPerPixel is 16:
                     this.ReadRgb16(stream, pixels, this.infoHeader.Width, this.infoHeader.Height, inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is <= 8 && this.processedAlphaMask:
+
+                case BmpCompression.RGB when bitsPerPixel is > 0 and <= 8 && this.processedAlphaMask:
                     this.ReadRgbPaletteWithAlphaMask(
                         stream,
                         pixels,
@@ -166,7 +171,8 @@ internal sealed class BmpDecoderCore : ImageDecoderCore
                         inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is <= 8:
+
+                case BmpCompression.RGB when bitsPerPixel is > 0 and <= 8:
                     this.ReadRgbPalette(
                         stream,
                         pixels,
@@ -179,6 +185,10 @@ internal sealed class BmpDecoderCore : ImageDecoderCore
 
                     break;
 
+                case BmpCompression.RGB when bitsPerPixel is <= 0 or > 32:
+                    BmpThrowHelper.ThrowInvalidImageContentException($"Invalid bits per pixel: {bitsPerPixel}");
+                    break;
+
                 case BmpCompression.RLE24:
                     this.ReadRle24(stream, pixels, this.infoHeader.Width, this.infoHeader.Height, inverted);
 

tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs

@@ -571,4 +571,27 @@ public class BmpDecoderTests
             });
         Assert.IsType<InvalidMemoryOperationException>(ex.InnerException);
     }
+
+    [Fact]
+    public void BmpDecoder_ThrowsException_Issue3067()
+    {
+        // Construct minimal BMP with bitsPerPixel = 0
+        byte[] bmp = new byte[54];
+        bmp[0] = (byte)'B';
+        bmp[1] = (byte)'M';
+        BitConverter.GetBytes(54).CopyTo(bmp, 2);
+        BitConverter.GetBytes(54).CopyTo(bmp, 10);
+        BitConverter.GetBytes(40).CopyTo(bmp, 14);
+        BitConverter.GetBytes(1).CopyTo(bmp, 18);
+        BitConverter.GetBytes(1).CopyTo(bmp, 22);
+        BitConverter.GetBytes((short)1).CopyTo(bmp, 26);
+        BitConverter.GetBytes((short)0).CopyTo(bmp, 28);  // bitsPerPixel = 0
+
+        using MemoryStream stream = new(bmp);
+
+        Assert.Throws<InvalidImageContentException>(() =>
+        {
+            using Image image = BmpDecoder.Instance.Decode(DecoderOptions.Default, stream);
+        });
+    }
 }

tests/ImageSharp.Tests/Formats/Icon/Ico/IcoDecoderTests.cs

@@ -204,12 +204,19 @@ public class IcoDecoderTests
     }
 
     [Theory]
-    [WithFile(InvalidAll, PixelTypes.Rgba32)]
     [WithFile(InvalidBpp, PixelTypes.Rgba32)]
+    public void InvalidThrows_InvalidImageContentException(TestImageProvider<Rgba32> provider)
+        => Assert.Throws<InvalidImageContentException>(() =>
+        {
+            using Image<Rgba32> image = provider.GetImage(IcoDecoder.Instance);
+        });
+
+    [Theory]
+    [WithFile(InvalidAll, PixelTypes.Rgba32)]
     [WithFile(InvalidCompression, PixelTypes.Rgba32)]
     [WithFile(InvalidRLE4, PixelTypes.Rgba32)]
     [WithFile(InvalidRLE8, PixelTypes.Rgba32)]
-    public void InvalidTest(TestImageProvider<Rgba32> provider)
+    public void InvalidThows_NotSupportedException(TestImageProvider<Rgba32> provider)
         => Assert.Throws<NotSupportedException>(() =>
         {
             using Image<Rgba32> image = provider.GetImage(IcoDecoder.Instance);