Backport #2501

SixLabors · Aug 10, 2023 · e0d14b1 · e0d14b1
1 parent 71d5316
commit e0d14b1
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs b/src/ImageSharp/Formats/Pbm/BufferedReadStreamExtensions.cs
@@ -29,7 +29,7 @@ public static void SkipWhitespaceAndComments(this BufferedReadStream stream)
                     {
                         innerValue = stream.ReadByte();
                     }
-                    while (innerValue != 0x0a);
+                    while (innerValue is not 0x0a and not -0x1);
 
                     // Continue searching for whitespace.
                     val = innerValue;

diff --git a/tests/ImageSharp.Tests/Formats/Pbm/PbmMetadataTests.cs b/tests/ImageSharp.Tests/Formats/Pbm/PbmMetadataTests.cs
@@ -1,7 +1,9 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using System.IO;
+using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Formats.Pbm;
 
 using Xunit;
@@ -82,5 +84,15 @@ public void Identify_DetectsCorrectComponentType(string imagePath, PbmComponentT
             Assert.NotNull(bitmapMetadata);
             Assert.Equal(expectedComponentType, bitmapMetadata.ComponentType);
         }
+
+        [Fact]
+        public void Identify_HandlesCraftedDenialOfServiceString()
+        {
+            byte[] bytes = Convert.FromBase64String("UDEjWAAACQAAAAA=");
+            IImageInfo info = Image.Identify(bytes);
+            Assert.Equal(default, info.Size());
+            IImageFormat format = Configuration.Default.ImageFormatsManager.FindFormatByFileExtension("pbm");
+            Assert.Equal("PBM", format.Name);
+        }
     }
 }