Fix #3067

Author: JimBobSquarePants

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -130,6 +130,13 @@ protected override Image<TPixel> Decode<TPixel>(BufferedReadStream stream, Cance
         Image<TPixel>? image = null;
         try
         {
+            ushort bitsPerPixel = this.infoHeader.BitsPerPixel;
+
+            if (bitsPerPixel is not (1 or 2 or 4 or 8 or 16 or 24 or 32))
+            {
+                BmpThrowHelper.ThrowInvalidImageContentException($"Invalid bits per pixel: {bitsPerPixel}");
+            }
+
             int bytesPerColorMapEntry = this.ReadImageHeaders(stream, out bool inverted, out byte[] palette);
 
             image = new Image<TPixel>(this.configuration, this.infoHeader.Width, this.infoHeader.Height, this.metadata);
@@ -138,23 +145,23 @@ protected override Image<TPixel> Decode<TPixel>(BufferedReadStream stream, Cance
 
             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 <= 8 && this.processedAlphaMask:
                     this.ReadRgbPaletteWithAlphaMask(
                         stream,
                         pixels,
@@ -166,7 +173,7 @@ protected override Image<TPixel> Decode<TPixel>(BufferedReadStream stream, Cance
                         inverted);
 
                     break;
-                case BmpCompression.RGB when this.infoHeader.BitsPerPixel is <= 8:
+                case BmpCompression.RGB when bitsPerPixel is <= 8:
                     this.ReadRgbPalette(
                         stream,
                         pixels,

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

@@ -571,4 +571,27 @@ public void BmpDecoder_ThrowsException_Issue2696<TPixel>(TestImageProvider<TPixe
             });
         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);
+
+        InvalidImageContentException ex = Assert.Throws<InvalidImageContentException>(() =>
+        {
+            using Image image = BmpDecoder.Instance.Decode(DecoderOptions.Default, stream);
+        });
+    }
 }