Explicitly handle missing SOS marker. Fix #2948

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -71,6 +71,11 @@ internal sealed class JpegDecoderCore : ImageDecoderCore, IRawJpegData
     /// </summary>
     private bool hasAdobeMarker;
 
+    /// <summary>
+    /// Whether the image has a SOS marker.
+    /// </summary>
+    private bool hasSOSMarker;
+
     /// <summary>
     /// Contains information about the JFIF marker.
     /// </summary>
@@ -197,6 +202,12 @@ internal sealed class JpegDecoderCore : ImageDecoderCore, IRawJpegData
     {
         using SpectralConverter<TPixel> spectralConverter = new(this.configuration, this.resizeMode == JpegDecoderResizeMode.ScaleOnly ? null : this.Options.TargetSize);
         this.ParseStream(stream, spectralConverter, cancellationToken);
+
+        if (!this.hasSOSMarker)
+        {
+            JpegThrowHelper.ThrowInvalidImageContentException("Missing SOS marker.");
+        }
+
         this.InitExifProfile();
         this.InitIccProfile();
         this.InitIptcProfile();
@@ -215,6 +226,12 @@ internal sealed class JpegDecoderCore : ImageDecoderCore, IRawJpegData
     protected override ImageInfo Identify(BufferedReadStream stream, CancellationToken cancellationToken)
     {
         this.ParseStream(stream, spectralConverter: null, cancellationToken);
+
+        if (!this.hasSOSMarker)
+        {
+            JpegThrowHelper.ThrowInvalidImageContentException("Missing SOS marker.");
+        }
+
         this.InitExifProfile();
         this.InitIccProfile();
         this.InitIptcProfile();
@@ -403,6 +420,8 @@ internal sealed class JpegDecoderCore : ImageDecoderCore, IRawJpegData
                         break;
 
                     case JpegConstants.Markers.SOS:
+
+                        this.hasSOSMarker = true;
                         if (!metadataOnly)
                         {
                             this.ProcessStartOfScanMarker(stream, markerContentByteSize);

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs

@@ -417,4 +417,24 @@ public partial class JpegDecoderTests
         image.DebugSave(provider);
         image.CompareToReferenceOutput(provider);
     }
+
+    // https://github.com/SixLabors/ImageSharp/issues/2948
+    [Theory]
+    [WithFile(TestImages.Jpeg.Issues.Issue2948, PixelTypes.Rgb24)]
+    public void Issue2948_No_SOS_Decode_Throws_InvalidImageContentException<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+        => Assert.Throws<InvalidImageContentException>(() =>
+        {
+            using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance);
+        });
+
+    // https://github.com/SixLabors/ImageSharp/issues/2948
+    [Theory]
+    [InlineData(TestImages.Jpeg.Issues.Issue2948)]
+    public void Issue2948_No_SOS_Identify_Throws_InvalidImageContentException(string imagePath)
+        => Assert.Throws<InvalidImageContentException>(() =>
+        {
+            TestFile testFile = TestFile.Create(imagePath);
+            ImageInfo imageInfo = Image.Identify(testFile.Bytes);
+        });
 }

tests/ImageSharp.Tests/TestImages.cs

@@ -348,6 +348,7 @@ public static class TestImages
             public const string Issue2638 = "Jpg/issues/Issue2638.jpg";
             public const string Issue2758 = "Jpg/issues/issue-2758.jpg";
             public const string Issue2857 = "Jpg/issues/issue-2857-subsub-ifds.jpg";
+            public const string Issue2948 = "Jpg/issues/issue-2948-sos.jpg";
 
             public static class Fuzz
             {

tests/Images/Input/Jpg/issues/issue-2948-sos.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:ad9c3a6babb41c5aa2a46fbfe74ed5482028c73f48531cf144e1e324ca7988b3
+size 103789