PSSodium

0.2.0

SecureStringExtensions.cs

using System;
using System.Runtime.InteropServices;
using System.Security;

namespace PSSodium
{
    internal static class SecureStringExtensions
    {
        public static T Process<T>(this SecureString src, Func<byte[], T> func)
        {
            IntPtr bstr = IntPtr.Zero;
            byte[] workArray = null;
            GCHandle handle = GCHandle.Alloc(workArray, GCHandleType.Pinned);
            try
            {
                /*** PLAINTEXT EXPOSURE BEGINS HERE ***/
                bstr = Marshal.SecureStringToBSTR(src);
                unsafe
                {
                    byte* bstrBytes = (byte*)bstr;
                    workArray = new byte[src.Length * 2];

                    for (int i = 0; i < workArray.Length; i++)
                        workArray[i] = *bstrBytes++;
                }

                return func(workArray);
            }
            finally
            {
                if (workArray != null)
                    for (int i = 0; i < workArray.Length; i++)
                        workArray[i] = 0;
                handle.Free();
                if (bstr != IntPtr.Zero)
                    Marshal.ZeroFreeBSTR(bstr);
                /*** PLAINTEXT EXPOSURE ENDS HERE ***/
            }
        }
    }
}