Final batch: Replace Marshal calls in Interop.Errors, Crypto, ASN1, and OpenSsl files

Co-authored-by: jkotas <6668460+jkotas@users.noreply.github.com>

Author: Copilot

src/libraries/Common/src/Interop/Unix/Interop.Errors.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Marshalling;
 
 internal static partial class Interop
 {
@@ -179,7 +180,7 @@ internal static unsafe string StrError(int platformErrno)
                 message = buffer;
             }
 
-            return Marshal.PtrToStringUTF8((IntPtr)message)!;
+            return Utf8StringMarshaller.ConvertToManaged(message)!;
         }
 
 #if SERIAL_PORTS

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.ASN1.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Marshalling;
 using System.Security.Cryptography;
 
 using Microsoft.Win32.SafeHandles;
@@ -67,7 +68,7 @@ internal static unsafe string GetOidValue(IntPtr asn1ObjectPtr)
 
             if (bytesNeeded < StackCapacity)
             {
-                return Marshal.PtrToStringUTF8((IntPtr)bufStack, bytesNeeded);
+                return Utf8StringMarshaller.ConvertToManaged(bufStack, bytesNeeded);
             }
 
             // bytesNeeded does not count the \0 which will be written on the end (based on OpenSSL 1.0.1f),
@@ -93,7 +94,7 @@ internal static unsafe string GetOidValue(IntPtr asn1ObjectPtr)
                     throw new CryptographicException();
                 }
 
-                return Marshal.PtrToStringUTF8((IntPtr)buf, bytesNeeded);
+                return Utf8StringMarshaller.ConvertToManaged(buf, bytesNeeded);
             }
         }
     }

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.Crypto.cs

@@ -5,6 +5,7 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Marshalling;
 using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
 using Microsoft.Win32.SafeHandles;
@@ -71,13 +72,13 @@ internal static int BioTell(SafeBioHandle bio)
             byte usedDefault;
             IntPtr ptr = GetX509RootStorePath_private(&usedDefault);
             defaultPath = (usedDefault != 0);
-            return Marshal.PtrToStringUTF8(ptr);
+            return Utf8StringMarshaller.ConvertToManaged(ptr);
         }
 
         internal static unsafe string? GetX509RootStoreFile()
         {
             byte unused;
-            return Marshal.PtrToStringUTF8(GetX509RootStoreFile_private(&unused));
+            return Utf8StringMarshaller.ConvertToManaged(GetX509RootStoreFile_private(&unused));
         }
 
         [LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_GetX509RootStorePath")]

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OpenSsl.cs

@@ -12,6 +12,7 @@
 using System.Net;
 using System.Net.Security;
 using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Marshalling;
 using System.Security.Authentication;
 using System.Security.Authentication.ExtendedProtection;
 using System.Security.Cryptography;
@@ -1077,7 +1078,7 @@ internal static SslException CreateSslException(string message)
             // Capture last error to be consistent with CreateOpenSslCryptographicException
             ulong errorVal = Crypto.ErrPeekLastError();
             Crypto.ErrClearError();
-            string msg = SR.Format(message, Marshal.PtrToStringUTF8(Crypto.ErrReasonErrorString(errorVal)));
+            string msg = SR.Format(message, Utf8StringMarshaller.ConvertToManaged(Crypto.ErrReasonErrorString(errorVal)));
             return new SslException(msg, (int)errorVal);
         }