Align X509EnhancedKeyUsageExtension.EnhancedKeyUsages behaviour with NetFX

2 files changed, 18 insertions, 1 deletions

diff --git a/src/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/X509EnhancedKeyUsageExtension.cs b/src/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/X509EnhancedKeyUsageExtension.cs
index 82ab80636d..d986f50807 100644
--- a/src/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/X509EnhancedKeyUsageExtension.cs
+++ b/src/System.Security.Cryptography.X509Certificates/src/System/Security/Cryptography/X509Certificates/X509EnhancedKeyUsageExtension.cs
@@ -42,7 +42,10 @@ namespace System.Security.Cryptography.X509Certificates
                     X509Pal.Instance.DecodeX509EnhancedKeyUsageExtension(RawData, out _enhancedKeyUsages);
                     _decoded = true;
                 }
-                return _enhancedKeyUsages;
+                OidCollection oids = new OidCollection();
+                foreach (Oid oid in _enhancedKeyUsages)
+                    oids.Add(oid);
+                return oids;
             }
         }
 
diff --git a/src/System.Security.Cryptography.X509Certificates/tests/ExtensionsTests.cs b/src/System.Security.Cryptography.X509Certificates/tests/ExtensionsTests.cs
index 32cba5be20..2db1267d4d 100644
--- a/src/System.Security.Cryptography.X509Certificates/tests/ExtensionsTests.cs
+++ b/src/System.Security.Cryptography.X509Certificates/tests/ExtensionsTests.cs
@@ -299,6 +299,20 @@ namespace System.Security.Cryptography.X509Certificates.Tests
         }
 
         [Fact]
+        public static void EnhancedKeyUsageExtension_ImmutableOids()
+        {
+            Oid oid1 = new Oid("1.3.6.1.5.5.7.3.1");
+            OidCollection usages = new OidCollection();
+            X509EnhancedKeyUsageExtension e = new X509EnhancedKeyUsageExtension(usages, false);
+            Assert.Equal(0, e.EnhancedKeyUsages.Count);
+            usages.Add(oid1);
+            Assert.Equal(0, e.EnhancedKeyUsages.Count);
+            e.EnhancedKeyUsages.Add(oid1);
+            Assert.Equal(0, e.EnhancedKeyUsages.Count);
+            Assert.NotSame(e.EnhancedKeyUsages, e.EnhancedKeyUsages);
+        }
+
+        [Fact]
         public static void SubjectKeyIdentifierExtensionDefault()
         {
             X509SubjectKeyIdentifierExtension e = new X509SubjectKeyIdentifierExtension();