Access Violation on call to DsAddressToSiteNames

Describe the bug and how to reproduce

When passing an array of SOCKET_ADDRESS to DsAddressToSiteNames either an access violation or win32 (1783) error (The stub received bad data) is throw.

What code is involved

The header for SOCKET_ADDRESS is as follows

[StructLayout(LayoutKind.Sequential,
#if x64
	Size = 16)]
#else
	Size = 8)]
#endif
	public struct SOCKET_ADDRESS

However, there appears to be no compiler definition for x64 and therefore, the layout size is always set to 8. If you compile your app to run 32-bit it succeeds. If you compile as AnyCPU or x64, it fails.

https://github.com/dahall/Vanara/blob/d1d0ff51ca959a1e0f60c34382260d8d353b5f6a/PInvoke/Ws2_32/ws2def.cs#L1716

Changing this struct value manually works.

Expected behavior

The call should succeed on both x86 an x64 builds.

Repo sample

Modify the dcname variable below with the name of a domain controller to reproduce the issue. Running as x64 fails, running as x86 succeeds

using System.Net;
using System.Runtime.InteropServices;
using Vanara.Extensions;
using Vanara.PInvoke;
using static Vanara.PInvoke.NetApi32;
using static Vanara.PInvoke.Ws2_32;

internal class Program
{
    private static void Main(string[] args)
    {
        string dcname = "dc1";

        Ws2_32.WSAStartup(2, out _);
        List<IPAddress> ipAddresses;

        try
        {
            // fails
            ipAddresses = new List<IPAddress>() { IPAddress.Parse("127.0.0.1"), IPAddress.Parse("::1") };
            GetSites(ipAddresses, dcname);
        }

        catch (Exception ex)
        {
            Console.WriteLine("lookup failed\r\n{0}", ex);
        }

        Console.WriteLine("=======================================================\r\n");

        try
        {
            // works
            ipAddresses = new List<IPAddress>() { IPAddress.Parse("127.0.0.1") };
            GetSites(ipAddresses, dcname);
        }
        catch (Exception ex)
        {
            Console.WriteLine("lookup failed\r\n{0}", ex);
        }

        Console.WriteLine("=======================================================\r\n");

        try
        {
            // works
            ipAddresses = new List<IPAddress>() { IPAddress.Parse("::1") };
            GetSites(ipAddresses, dcname);
        }
        catch (Exception ex)
        {
            Console.WriteLine("lookup failed\r\n{0}", ex);
        }

        Console.WriteLine("=======================================================\r\n");


        Console.WriteLine("press any key to exit");
        Console.ReadLine();
    }

    private static void GetSites(List<IPAddress> ipAddresses, string dcname)
    {
        List<Ws2_32.SOCKADDR> resolvedAddresses = new List<Ws2_32.SOCKADDR>();

        foreach (IPAddress ipAddress in ipAddresses.OrderBy(t => (int)t.AddressFamily))
        {
            Ws2_32.SOCKADDR socketAddress;

            if (ipAddress.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
            {
                socketAddress = new Ws2_32.SOCKADDR_IN();
            }
            else if (ipAddress.AddressFamily == System.Net.Sockets.AddressFamily.InterNetworkV6)
            {
                socketAddress = new Ws2_32.SOCKADDR_IN6();
            }
            else
            {
                Console.WriteLine("Ignoring unknown address type {0}", ipAddress.AddressFamily.ToString());
                continue;
            }

            int length = socketAddress.Size;
            string addr = ipAddress.ToString();

            var wsresult = Ws2_32.WSAStringToAddress(addr, (Ws2_32.ADDRESS_FAMILY)ipAddress.AddressFamily, IntPtr.Zero, socketAddress, ref length);

            if (wsresult.Failed)
            {
                Console.WriteLine("WSAStringToAddress failed\r\n{0}", wsresult.GetException());
            }

            resolvedAddresses.Add(socketAddress);
        }

        if (resolvedAddresses.Count == 0)
        {
            Console.WriteLine("No addresses found");
            return;
        }

        var socketAddresses = new SOCKET_ADDRESS[resolvedAddresses.Count];
        for (int i = 0; i < resolvedAddresses.Count; i++)
        {
            socketAddresses[i].iSockaddrLength = resolvedAddresses[i].Size;
            socketAddresses[i].lpSockaddr = resolvedAddresses[i].DangerousGetHandle();
        }

        NetApi32.SafeNetApiBuffer siteNames = null;

        var dsresult = DsAddressToSiteNames(dcname, (uint)socketAddresses.Length, socketAddresses, out siteNames);

        dsresult.ThrowIfFailed();

        if (siteNames == null || siteNames.IsInvalid)
        {
            Console.WriteLine("Sites were not found");
            return;
        }

        List<string> sites = siteNames.ToStringEnum(resolvedAddresses.Count).ToList();

        Console.WriteLine("Found sites {0} for addresses {1}", string.Join(", ", sites), string.Join(", ", ipAddresses));
    }
}

[dahall]

Thank you for submitting such a thorough bug report! I’ll have this resolved shortly.

[dahall]

This is fixed with the latest commit. I’ll publish soon.