external authentication login script using c#

Submitted by fcipriani on Tue, 2007-07-03 16:57

I don't know if anybody has already done it, but this is a small script which allows external authentication using C# under windows.

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace ExternalAuthenticationCSharpScript
{
	class Program
	{
		static void Main(string[] args)
		{
			const int maxbuflen = 1000;		// maximum buffer len
			int read;				// number of bytes read
			char[] charray = new char[maxbuflen];	// buffer
			
			String opcode;				// operation code
			String username;			// username
			String password = "";			// password

			// Read data from stdin
			read = Console.In.Read(charray, 0, 2);
			if (read != 2)
			{
				return;
			}

			// Perform big endian conversion
			int len = charray[1] + (charray[0] * 256);
			// Check for buffer overrun
			if (len > maxbuflen)
			{
				return;
			}

			// Read opcode, username and password
			read = Console.In.ReadBlock(charray, 0, len);
			
			// Splits the data
			string data = new string(charray);
			string[] elements = data.Split(':');

			opcode = elements[0];
			username = elements[1];
			if (elements.Length > 2)
				password = elements[2];

			/*
			 * PERFORM AUTHENTICATION HERE
			 */
			
			// Prepare return value, first short is always 2
			charray[0] = (char)0;
			charray[1] = (char)2;
			
			// Second short is 1 for success, 0 for failure
			charray[2] = (char)0;
			charray[3] = (char)1; // or 0 for failure

			// Send return value
			Console.Out.Write(charray, 0, 4);

			return;
		}
	}
}

sizeof(char) in .NET is 2.

Submitted by ooo27 on Fri, 2012-03-30 22:46.

sizeof(char) in .NET is 2. This code will break if the incoming data is sufficiently large. Use a binary reader to read the correct number of bytes from stdin.

// (this should be outside your while(true) loop)
var stdinStream = Console.OpenStandardInput();
var binReader = new BinaryReader(stdinStream);
// Read data from stdin
var b1 = binReader.ReadByte();
var b2 = binReader.ReadByte();
// Perform big endian conversion
int len = b2 + (b1 * 256);
// Check for buffer overrun
if (len > maxbuflen)
    throw new InternalBufferOverflowException(string.Format("{0} > {1}", len, maxbuflen));
                    
// Read opcode, username and password
var bytes = binReader.ReadBytes(len);
var data = ASCIIEncoding.ASCII.GetString(bytes);
string[] elements = data.Split(':');
// etc etc ...