Develop Reference

Setting PIN prompt in Smart Card Crypto Provider's dialog box

I want to change the text that shows when invoking CryptoApi operation that requires smart card PIN. Current prompt is pretty generic (and in system's language), "Please enter your authentication PIN":
This dialog shows when calling CryptSignMessage in COM object, but the call is made from C# WPF desktop app (.NET 4.5). How can I customize the dialog? I've found PP_PIN_PROMPT_STRING parameter for CryptSetProvParam function, but the function requires HCRYPTPROV and I don't have that handle. All I have is reader's name and signing certificate. Just can't wrap my head around it.
Is it possible to customize PIN dialog from either C++ or C# (preferably C#)?

I believe the following should work. As I don't have anything setup to test collecting the information I can't verify.
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CryptAcquireContext(out IntPtr phProv, string pszContainer, string pszProvider, uint dwProvType, uint dwFlags);
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool CryptSetProvParam(IntPtr hProv, uint dwParam, [In] byte[] pbData, uint dwFlags);
[DllImport("advapi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CryptReleaseContext(IntPtr hProv, uint dwFlags);
const string MS_DEF_PROV = "Microsoft Base Cryptographic Provider v1.0";
const uint NTE_BAD_KEYSET = 0x80090016;
const uint PROV_RSA_FULL = 1;
const uint CRYPT_VERIFYCONTEXT = 0xF0000000;
const uint CRYPT_NEWKEYSET = 0x00000008;
const uint PP_PIN_PROMPT_STRING = 0x2C;
public void SetPinText(string text)
{
byte[] data = Encoding.UTF8.GetBytes(text);
IntPtr hCryptProv = IntPtr.Zero;
try
{
if (!CryptAcquireContext(out hCryptProv, null, MS_DEF_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
{
if (Convert.ToUInt32(Marshal.GetLastWin32Error()) == NTE_BAD_KEYSET)
{
if (!CryptAcquireContext(out hCryptProv, null, null, PROV_RSA_FULL, CRYPT_NEWKEYSET))
throw new Exception("Unable to acquire crypt context.");
}
else
{
throw new Exception("Unable to acquire crypt context.");
}
}
if (!CryptSetProvParam(hCryptProv, PP_PIN_PROMPT_STRING, data, 0))
throw new Exception("Unable to set prompt string.");
}
finally
{
if (hCryptProv != IntPtr.Zero)
{
CryptReleaseContext(hCryptProv, 0);
}
}
}

How to marshal the multi byte character set C#

I need to call a function (c/c++) that uses the multi-byte character set from C#. But I don't know how to marshall it as multi-byte. Does anyone know how to convert the result to a string?
C#:
[DllImport("essentials.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
public static extern System.IntPtr GetFiles(string filedir, string path);
[STAThread]
static void Main()
{
string filedir = #"C:\Users\Ruben\Documents\School\*";
string path = #"C:\Users\Ruben\Documents\School\";
System.IntPtr pointer = GetFiles(filedir, path);
string files = Marshal.PtrToStringAnsi(pointer); // nothing
}
C++
extern "C"
{
__declspec(dllexport) char* GetFiles(char* filedir, char* path)
{
string filedir2 = filedir;
string path2 = path;
string files = GetFiles2(filedir2, path2);
char* Rfiles = new char[files.length() + 1];
strcpy_s(Rfiles, files.length() + 1, files.c_str());
return Rfiles;
}
}

Information on MSDN : Default Marshaling for Strings

You need the marshal the C# string first, try this:
[DllImport("essentials.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
public static extern System.IntPtr GetFiles
([MarshalAs(UnmanagedType.AnsiBStr)]string filedir,
[MarshalAs(UnmanagedType.AnsiBStr)]string path);

Why IEGetProtectedModeCookie() always return 0x80070057?

According the function description in "http://msdn.microsoft.com/en-us/library/cc196998%28v=VS.85%29.aspx", I wrote the following code to try to get IE protected cookies:
public static string GetProtectedModeCookie(string lpszURL, string lpszCookieName, uint dwFlags)
{
var size = 255;
var sb = new System.Text.StringBuilder(size);
var acturalSize = sb.Capacity;
var code = IEGetProtectedModeCookie(lpszURL, lpszCookieName, sb, ref acturalSize, dwFlags);
if ((code & 0x80000000) > 0) return string.Empty;
if (acturalSize > size)
{
sb.EnsureCapacity(acturalSize);
IEGetProtectedModeCookie(lpszURL, lpszCookieName, sb, ref acturalSize, dwFlags);
}
return sb.ToString();
}
[DllImport("ieframe.dll", SetLastError = true)]
public static extern uint IEGetProtectedModeCookie(string lpszURL, string lpszCookieName, System.Text.StringBuilder pszCookieData, ref int pcchCookieData, int dwFlags);
to test this function:
var cookies = GetProtectedModeCookie("http://bbs.pcbeta.com/", null, 0);
But the api IEGetProtectedModeCookie always return 0x80070057 which indicates that one or more arguments are invalid.
I was confused, after a lot of try finally failed, only get this result. Can anybody help me?

IEGetProtectedModeCookie will return E_INVALIDARG if it thinks that the URL isn't meant to open in Protected Mode. It determines this using the IEIsProtectedModeURL API. So if you've put that URL in the Trusted Zone or whatnot, then you'll hit this error. The underlying InternetGetCookie API will return E_INVALIDARG if you fail to pass a URL or fail to pass a pointer to an integer for the size of the buffer.
Also note that the IEGetProtectedModeCookie API will not work from a high integrity (e.g. Admin) process; it will return ERROR_INVALID_ACCESS (0x8000000C).
Here's the code I use:
[DllImport("ieframe.dll", CharSet = CharSet.Unicode, EntryPoint = "IEGetProtectedModeCookie", SetLastError = true)]
public static extern int IEGetProtectedModeCookie(String url, String cookieName, StringBuilder cookieData, ref int size, uint flag);
private void GetCookie_Click(object sender, EventArgs e)
{
int iSize = 4096;
StringBuilder sbValue = new StringBuilder(iSize);
int hResult = IEAPI.IEGetProtectedModeCookie("http://www.google.com", "PREF", sbValue, ref iSize, 0);
if (hResult == 0)
{
MessageBox.Show(sbValue.ToString());
}
else
{
MessageBox.Show("Failed to get cookie. HRESULT=0x" + hResult.ToString("x") + "\nLast Win32Error=" + Marshal.GetLastWin32Error().ToString(), "Failed");
}
}

Charset parameter must be exist in DllImport attribute. Change the API declartion to follow will works well:
[DllImport("ieframe.dll", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern uint IEGetProtectedModeCookie(string lpszURL, string lpszCookieName, System.Text.StringBuilder pszCookieData, ref int pcchCookieData, uint dwFlags);
If Charset parameter missed, this API will always return 0x80070057 which indicates one or more arguments are invalid.

Trying to upgrade to .NET Framework 4

I am trying to upgrade to the MS .NET Framework 4 and I am encountering an error with a dllimport function (see below). When the code reaches the dllimport, the program just exits with error code 0x80000003. I have tried changing it so the input and output are StringBuilder and I also tried setting the charset by both changing the charset (to either unicode or ansi) and setting a EntryPoint (either PathGetArgsA or PathGetArgsW). This code works fine in v3.5 but not in v4.
[DllImport("Shlwapi.dll", SetLastError = true, CharSet = CharSet.Auto)] public static extern string PathGetArgs([In] string path);
[DllImport("Shlwapi.dll", SetLastError = true, CharSet = CharSet.Auto)] public static extern void PathRemoveArgs([In, Out] StringBuilder path);
public static bool ExtractArguments(string cmdLine, out string filePath, out string fileArgs)
{
StringBuilder strCmdLine = new StringBuilder(cmdLine.ToLower().Trim());
filePath = fileArgs = "";
if (strCmdLine.Length <= 0)
throw new ArgumentNullException("cmdLine");
fileArgs = string.Copy(PathGetArgs(strCmdLine.ToString())); // Error occurs here
PathRemoveArgs(strCmdLine);
filePath = string.Copy(strCmdLine.ToString());
if (!string.IsNullOrEmpty(filePath))
if (Utils.FileExists(filePath))
return true;
return false;
}
Thanks!

I'm not sure what the native dll retuns in the PathGetArgs however, the Marshal Class could help.
[DllImport("Shlwapi.dll")]
public static extern IntPtr PathGetArgs([In] string path);
fileArgs = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(PathGetArgs(strCmdLine.ToString()));

How can I determine if a remote drive has enough space to write a file using C#?

How can I determine if a remote drive has enough space for me to upload a given file using C# in .Net?

There are two possible solutions.
Call the Win32 function GetDiskFreeSpaceEx. Here is a sample program:
internal static class Win32
{
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern bool GetDiskFreeSpaceEx(string drive, out long freeBytesForUser, out long totalBytes, out long freeBytes);
}
class Program
{
static void Main(string[] args)
{
long freeBytesForUser;
long totalBytes;
long freeBytes;
if (Win32.GetDiskFreeSpaceEx(#"\\prime\cargohold", out freeBytesForUser, out totalBytes, out freeBytes)) {
Console.WriteLine(freeBytesForUser);
Console.WriteLine(totalBytes);
Console.WriteLine(freeBytes);
}
}
}
Use the system management interface. There is another answer in this post which describes this. This method is really designed for use in scripting languages such as PowerShell. It performs a lot of fluff just to get the right object. Ultimately, I suspect, this method boils down to calling GetDiskFreeSpaceEx.
Anybody doing any serious Windows development in C# will probably end up calling many Win32 functions. The .NET framework just doesn't cover 100% of the Win32 API. Any large program will quickly uncover gaps in the .NET libraries that are only available through the Win32 API. I would get hold of one of the Win32 wrappers for .NET and include this in your project. This will give you instant access to just about every Win32 API.

Use WMI
using System.Management;
// Get all the network drives (drivetype=4)
SelectQuery query = new SelectQuery("select Name, VolumeName, FreeSpace from win32_logicaldisk where drivetype=4");
ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);
foreach (ManagementObject drive in searcher.Get())
{
string Name = (string)drive["Name"];
string VolumeName = (string)drive["VolumeName"];
UInt64 freeSpace = (UInt64)drive["FreeSpace"];
}
based on (stolen from) http://www.dreamincode.net/code/snippet1576.htm

Are you talking about mapping a network share to a logical drive on you computer?
If so you can use DriveInfo.
DriveInfo info = new DriveInfo("X:");
info.AvailableFreeSpace;
DriveInfo only works with logical drives so if you are just using the full share (UNC) name I don't think the above code will work.

I'm not sure if GetDiskFreeSpaceEx works on UNC shares, but if it does use that, otherwise here is how to mount a UNC share to a logal drive:
EDIT GetDiskFreeSpaceEx does work on UNC shares, use that...however, this code was too much effort to just delete, and is handy if you ever want to mount a UNC share as a local drive in your code.
public class DriveWrapper
{
[StructLayout(LayoutKind.Sequential)]
public struct NETRESOURCEA
{
public int dwScope;
public int dwType;
public int dwDisplayType;
public int dwUsage;
[MarshalAs(UnmanagedType.LPStr)]
public string lpLocalName;
[MarshalAs(UnmanagedType.LPStr)]
public string lpRemoteName;
[MarshalAs(UnmanagedType.LPStr)]
public string lpComment;
[MarshalAs(UnmanagedType.LPStr)]
public string lpProvider;
public override String ToString()
{
String str = "LocalName: " + lpLocalName + " RemoteName: " + lpRemoteName
+ " Comment: " + lpComment + " lpProvider: " + lpProvider;
return (str);
}
}
[DllImport("mpr.dll")]
public static extern int WNetAddConnection2A(
[MarshalAs(UnmanagedType.LPArray)] NETRESOURCEA[] lpNetResource,
[MarshalAs(UnmanagedType.LPStr)] string lpPassword,
[MarshalAs(UnmanagedType.LPStr)] string UserName,
int dwFlags);
[DllImport("mpr.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto)]
private static extern int WNetCancelConnection2A(
[MarshalAs(UnmanagedType.LPStr)]
string lpName,
int dwFlags,
int fForce
);
public int GetDriveSpace(string shareName, string userName, string password)
{
NETRESOURCEA[] n = new NETRESOURCEA[1];
n[0] = new NETRESOURCEA();
n[0].dwScope = 0;
n[0].dwType = 0;
n[0].dwDisplayType = 0;
n[0].dwUsage = 0;
n[0].dwType = 1;
n[0].lpLocalName = "x:";
n[0].lpRemoteName = shareName;
n[0].lpProvider = null;
int res = WNetAddConnection2A(n, userName, password, 1);
DriveInfo info = new DriveInfo("x:");
int space = info.AvailableFreeSpace;
int err = 0;
err = WNetCancelConnection2A("x:", 0, 1);
return space;
}
}