Fix ForceUTF8Encoding to only apply to certain AttributeTypes

src/libraries/Common/src/System/Security/Cryptography/Oids.cs

@@ -105,11 +105,17 @@ internal static partial class Oids
 
         // X500 Names
         internal const string CommonName = "2.5.4.3";
+        internal const string Surname = "2.5.4.4";
         internal const string CountryOrRegionName = "2.5.4.6";
         internal const string LocalityName = "2.5.4.7";
         internal const string StateOrProvinceName = "2.5.4.8";
+        internal const string Street = "2.5.4.9";
         internal const string Organization = "2.5.4.10";
         internal const string OrganizationalUnit = "2.5.4.11";
+        internal const string Title = "2.5.4.12";
+        internal const string GivenName = "2.5.4.42";
+        internal const string Initials = "2.5.4.43";
+
         internal const string EmailAddress = "1.2.840.113549.1.9.1";
 
         // Cert Extensions

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/X500NameEncoder.cs

@@ -522,7 +522,7 @@ private static byte[] ParseRdn(ReadOnlySpan<char> tagOid, ReadOnlySpan<char> cha
                         throw new CryptographicException(SR.Cryptography_Invalid_IA5String);
                     }
                 }
-                else if (forceUtf8Encoding)
+                else if (forceUtf8Encoding && IsForceUtf8Eligible(tagOid))
                 {
                     writer.WriteCharacterString(UniversalTagNumber.UTF8String, data);
                 }
@@ -542,6 +542,26 @@ private static byte[] ParseRdn(ReadOnlySpan<char> tagOid, ReadOnlySpan<char> cha
             return writer.Encode();
         }
 
+        private static bool IsForceUtf8Eligible(ReadOnlySpan<char> oid)
+        {
+            switch (oid)
+            {
+                case Oids.CommonName:
+                case Oids.GivenName:
+                case Oids.LocalityName:
+                case Oids.Organization:
+                case Oids.OrganizationalUnit:
+                case Oids.StateOrProvinceName:
+                case Oids.Surname:
+                case Oids.Street:
+                case Oids.Title:
+                case Oids.Initials:
+                    return true;
+                default:
+                    return false;
+            }
+        }
+
         private static int ExtractValue(ReadOnlySpan<char> chars, Span<char> destination)
         {
             Debug.Assert(destination.Length >= chars.Length);

src/libraries/System.Security.Cryptography/tests/X509Certificates/NameTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Formats.Asn1;
 using Test.Cryptography;
 using Xunit;
 
@@ -82,22 +83,55 @@ public static void ForceUtf8EncodingWithFlagWhenEncoding()
                 "CN=potato, O=jicama",
                 X500DistinguishedNameFlags.ForceUTF8Encoding);
 
-            ReadOnlySpan<byte> expectedDer = new byte[]
-            {
+            ReadOnlySpan<byte> expectedDer =
+            [
                 0x30, 0x22,
                 0x31, 0x0F,
                 0x30, 0x0D,
                     0x06, 0x03, 0x55, 0x04, 0x03, // id-at-commonName OID
                     0x0C, 0x06, 0x70, 0x6F, 0x74, 0x61, 0x74, 0x6F, // 0x0C is UTF8String
                 0x31, 0x0F,
                 0x30, 0x0D,
-                    0x06, 0x03, 0x55, 0x04, 0x0A,  // id-at-organizatioName OID
+                    0x06, 0x03, 0x55, 0x04, 0x0A,  // id-at-organizationName OID
                     0x0C, 0x06, 0x6A, 0x69, 0x63, 0x61, 0x6D, 0x61, // 0x0C is UTF8String
-            };
+            ];
 
             AssertExtensions.SequenceEqual(expectedDer, name.RawData);
         }
 
+        [Theory]
+        [InlineData("G=DotNet", UniversalTagNumber.UTF8String)]
+        [InlineData("L=Alexandria", UniversalTagNumber.UTF8String)]
+        [InlineData("O=GitHub", UniversalTagNumber.UTF8String)]
+        [InlineData("OU=ProdSec", UniversalTagNumber.UTF8String)]
+        [InlineData("S=Virginia", UniversalTagNumber.UTF8String)]
+        [InlineData("SN=Doe", UniversalTagNumber.UTF8String)]
+        [InlineData("ST=Main", UniversalTagNumber.UTF8String)]
+        [InlineData("T=Pancake", UniversalTagNumber.UTF8String)]
+        [InlineData("CN=Foo", UniversalTagNumber.UTF8String)]
+        [InlineData("I=DD", UniversalTagNumber.UTF8String)]
+        [InlineData("[email protected]", UniversalTagNumber.IA5String)]
+        [InlineData("OID.2.5.4.11=ProdSec", UniversalTagNumber.UTF8String)]
+        [InlineData("OID.2.5.4.43=DD", UniversalTagNumber.UTF8String)]
+        [InlineData("OID.1.2.3.4=sample", UniversalTagNumber.PrintableString)]
+        [InlineData("C=US", UniversalTagNumber.PrintableString)]
+        public static void ForceUtf8EncodingForEligibleComponents(string distinguishedName, UniversalTagNumber tagNumber)
+        {
+            X500DistinguishedName name = new(distinguishedName, X500DistinguishedNameFlags.ForceUTF8Encoding);
+            byte[] encoded = name.RawData;
+
+            AsnValueReader reader = new(encoded, AsnEncodingRules.DER);
+            AsnValueReader component = reader.ReadSequence();
+            reader.ThrowIfNotEmpty();
+            AsnValueReader rdn = component.ReadSetOf();
+            component.ThrowIfNotEmpty();
+            AsnValueReader value = rdn.ReadSequence();
+            rdn.ThrowIfNotEmpty();
+
+            value.ReadObjectIdentifier();
+            Assert.Equal(new Asn1Tag(tagNumber), value.PeekTag());
+        }
+
         [Theory]
         [InlineData(false)]
         [InlineData(true)]