Merge branch 'release/2.1.x' into af/backport-2759-2.1.x

Author: antonfirsov

tests/ImageSharp.Tests/Formats/Gif/GifDecoderTests.cs

@@ -306,5 +306,16 @@ public void IssueDeferredClearCode<TPixel>(TestImageProvider<TPixel> provider)
             image.DebugSave(provider);
             image.CompareFirstFrameToReferenceOutput(ImageComparer.Exact, provider);
         }
+
+        // https://github.com/SixLabors/ImageSharp/issues/2743
+        [Theory]
+        [WithFile(TestImages.Gif.Issues.BadMaxLzwBits, PixelTypes.Rgba32)]
+        public void IssueTooLargeLzwBits<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            using Image<TPixel> image = provider.GetImage();
+            image.DebugSaveMultiFrame(provider);
+            image.CompareToReferenceOutputMultiFrame(provider, ImageComparer.Exact);
+        }
     }
 }

tests/ImageSharp.Tests/Formats/Gif/GifMetadataTests.cs

@@ -190,5 +190,20 @@ public void Decode_VerifyRepeatCount(string imagePath, uint repeatCount)
                 }
             }
         }
+
+        [Theory]
+        [InlineData(TestImages.Gif.Issues.BadMaxLzwBits, 8)]
+        [InlineData(TestImages.Gif.Issues.Issue2012BadMinCode, 1)]
+        public void Identify_Frames_Bad_Lzw(string imagePath, int framesCount)
+        {
+            TestFile testFile = TestFile.Create(imagePath);
+            using MemoryStream stream = new(testFile.Bytes, false);
+
+            IImageInfo imageInfo = Image.Identify(stream);
+
+            Assert.NotNull(imageInfo);
+            GifMetadata gifMetadata = imageInfo.Metadata.GetGifMetadata();
+            Assert.NotNull(gifMetadata);
+        }
     }
 }

tests/ImageSharp.Tests/TestImages.cs

@@ -456,6 +456,7 @@ public static class Issues
                 public const string BadAppExtLength = "Gif/issues/issue405_badappextlength252.gif";
                 public const string BadAppExtLength_2 = "Gif/issues/issue405_badappextlength252-2.gif";
                 public const string BadDescriptorWidth = "Gif/issues/issue403_baddescriptorwidth.gif";
+                public const string BadMaxLzwBits = "Gif/issues/issue_2743.gif";
                 public const string DeferredClearCode = "Gif/issues/bugzilla-55918.gif";
                 public const string Issue1505 = "Gif/issues/issue1505_argumentoutofrange.png";
                 public const string Issue1530 = "Gif/issues/issue1530.gif";