tests:

added test for tlvobject

Author: DennisDyallo

Yubico.Core/src/Yubico/Core/Tlv/TlvObject.cs

@@ -16,19 +16,20 @@
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
+using System.Security.Cryptography;
 
 namespace Yubico.Core.Tlv
 {
     /// <summary>
     /// Tag, length, Value structure that helps to parse APDU response data.
     /// This class handles BER-TLV encoded data with determinate length.
     /// </summary>
-    public class TlvObject
+    public sealed class TlvObject : IDisposable
     {
         /// <summary>
         /// Returns the tag.
         /// </summary>
-        public int Tag { get; }
+        public int Tag { get; private set; }
 
         /// <summary>
         /// Returns a copy of the value.
@@ -38,10 +39,11 @@ public class TlvObject
         /// <summary>
         /// Returns the length of the value.
         /// </summary>
-        public int Length { get; }
+        public int Length { get; private set; }
 
         private readonly byte[] _bytes;
         private readonly int _offset;
+        private bool _disposed;
 
         /// <summary>
         /// Creates a new TLV (Tag-Length-Value) object with the specified tag and value.
@@ -64,6 +66,7 @@ public TlvObject(int tag, ReadOnlySpan<byte> value)
             }
 
             Tag = tag;
+            
             // Create a copy of the input value
             byte[] valueBuffer = value.ToArray();
             using var ms = new MemoryStream();
@@ -216,5 +219,20 @@ public override string ToString()
             return $"Tlv(0x{Tag:X}, {Length}, {BitConverter.ToString(Value.ToArray()).Replace("-", "")})";
 #endif
         }
+
+        /// <summary>
+        /// Dispose the object and clears its buffers
+        /// </summary>
+        public void Dispose()
+        {
+            if (_disposed)
+            {
+                return;
+            }
+            CryptographicOperations.ZeroMemory(_bytes);
+            Length = 0;
+            Tag = 0;
+            _disposed = true;
+        }
     }
 }

Yubico.Core/tests/Yubico/Core/Tlv/TlvObjectTests.cs

@@ -21,6 +21,30 @@ namespace Yubico.Core.Tlv.UnitTests
 {
     public class TlvObjectTests
     {
+        [Fact]
+        public void Value_Property_Returns_Only_Value_Portion()
+        {
+            // Arrange
+            int tag = 0x7F49;
+            byte[] originalValue = [0x01, 0x02, 0x03, 0x04];
+            TlvObject tlv = new TlvObject(tag, originalValue);
+
+            // Get the full encoded bytes for reference
+            byte[] fullEncodedTlv = tlv.GetBytes().ToArray();
+
+            // Act
+            byte[] extractedValue = tlv.Value.ToArray();
+
+            // Assert
+
+            Assert.Equal(originalValue, extractedValue);
+            Assert.Equal(originalValue.Length, tlv.Length);
+            Assert.NotEqual(fullEncodedTlv, extractedValue);
+            Assert.True(fullEncodedTlv.Length > extractedValue.Length);
+            Assert.Equal(0x7F, fullEncodedTlv[0]);
+            Assert.Equal(0x49, fullEncodedTlv[1]);
+        }
+
         [Fact]
         public void TestDoubleByteTags()
         {
@@ -74,7 +98,8 @@ public void TestUnwrap()
         [Fact]
         public void TestUnwrapThrowsException()
         {
-            Assert.Throws<InvalidOperationException>(() => TlvObjects.UnpackValue(0x7F48, new byte[] { 0x7F, 0x49, 0 }));
+            Assert.Throws<InvalidOperationException>(() =>
+                TlvObjects.UnpackValue(0x7F48, new byte[] { 0x7F, 0x49, 0 }));
         }
 
         [Fact]