Add fix and tests (#5664)

DataDog · Jun 14, 2024 · a489d7b · a489d7b
1 parent 92cc9eb
commit a489d7b
Show file tree

Hide file tree

Showing 2 changed files with 34 additions and 3 deletions.
diff --git a/tracer/src/Datadog.Trace/AppSec/ObjectExtractor.cs b/tracer/src/Datadog.Trace/AppSec/ObjectExtractor.cs
@@ -9,6 +9,7 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Reflection;
 using System.Reflection.Emit;
 using Datadog.Trace.AppSec.Waf;
@@ -56,13 +57,22 @@ internal static class ObjectExtractor
 
         private static IReadOnlyDictionary<string, object?> ExtractProperties(object body, int depth, HashSet<object> visited)
         {
-            if (visited.Contains(body))
+            try
             {
+                if (visited.Contains(body))
+                {
+                    return EmptyDictionary;
+                }
+
+                visited.Add(body);
+            }
+            catch
+            {
+                // Contains and Add call GetHashCode which can throw an exception if has a custom implementation
+                // If visited is empty, we could potentially get the exception only when calling Add
                 return EmptyDictionary;
             }
 
-            visited.Add(body);
-
             if (Log.IsEnabled(LogEventLevel.Debug))
             {
                 Log.Debug("ExtractProperties - body: {Body}", body);

diff --git a/tracer/test/Datadog.Trace.Security.Unit.Tests/ObjectExtractorTests.cs b/tracer/test/Datadog.Trace.Security.Unit.Tests/ObjectExtractorTests.cs
@@ -391,6 +391,15 @@ public void TestCyclicDictionary()
             Assert.Empty(result);
         }
 
+        [Fact]
+        public void TestNullValues()
+        {
+            TestObject testObject = new TestObject();
+            testObject.Test = new();
+            var result = ObjectExtractor.Extract(testObject);
+            result.Should().NotBeNull();
+        }
+
         private static void PopulateNestedTarget(TestNestedPropertiesPoco target, int count)
         {
             var current = target;
@@ -534,4 +543,16 @@ public class TestNestedDictionaryPoco
     {
         public Dictionary<string, TestNestedDictionaryPoco> TestDictionary { get; set; } = new Dictionary<string, TestNestedDictionaryPoco>();
     }
+
+    public class TestObject
+    {
+        public TestObject Test { get; set; }
+
+        public object Prop { get; set; }
+
+        public override int GetHashCode()
+        {
+            return Test.GetHashCode() + Prop.GetHashCode();
+        }
+    }
 }