Authentication.cs

/**
 *  Copyright (C) 2006 Alex Pedenko
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
using System;
using System.Collections;
using System.IO;
using System.Text;

namespace NetSync
{
	class Authentication
	{
		public static string password_file = "";

		public static string base64_encode(string message)
		{
			Encoding asciiEncoding = Encoding.ASCII;
			byte[] byteArray = new byte[asciiEncoding.GetByteCount(message)];
			byteArray = asciiEncoding.GetBytes(message);			
			return Convert.ToBase64String(byteArray);
		}

		public static string gen_challenge(string addr, Options opt)
		{			
			string challenge = "";
			byte[] input = new byte[32];			
			DateTime tv = DateTime.Now;			
			
			for(int i=0; i < addr.Length; i++)
				input[i] = Convert.ToByte(addr[i]);
						
			CheckSum.SIVAL(ref input, 16, (UInt32)tv.Second);
			CheckSum.SIVAL(ref input, 20, (UInt32)tv.Hour);
			CheckSum.SIVAL(ref input, 24, (UInt32)tv.Day);

			Sum sum = new Sum(opt);
			sum.Init(0);
			sum.Update(input,0,input.Length);
			challenge = Encoding.ASCII.GetString(sum.End());
			return challenge;
		}

		public static string generate_hash(string indata, string challenge, Options options)
		{
			Sum sum = new Sum(options);

			sum.Init(0);
			sum.Update(Encoding.ASCII.GetBytes(indata), 0, indata.Length);
			sum.Update(Encoding.ASCII.GetBytes(challenge), 0, challenge.Length);
			byte[] buf = sum.End();
			string hash = Convert.ToBase64String(buf);
			return hash.Substring(0, (buf.Length * 8 + 5)/6);
		}

		public static string auth_client( string user, string pass, string challenge, Options options)
		{			
			if(String.Compare(user, "") == 0)
				user = "nobody";
			if(pass == null || String.Compare(pass, "") == 0)
				pass = getpassf(password_file);
			if(String.Compare(pass, "") == 0)
				pass = System.Environment.GetEnvironmentVariable("RSYNC_PASSWORD");			
			if(pass == null || String.Compare(pass, "") == 0)
				pass = getpass();
			string pass2 = generate_hash(pass, challenge, options);
			Log.WriteLine(user + " " + pass2);

			return pass2;
		}

		public static string getpass()
		{
			Console.Write("Password: ");
			return Console.ReadLine();
		}

		public static string getpassf(string filename)
		{
			return "";
		}

		public static bool AuthServer(ClientInfo cInfo, int moduleNumber, string addr, string leader)
		{
			string users = Daemon.config.GetAuthUsers(moduleNumber).Trim();
			string challenge;
			string b64_challenge;
			IOStream f = cInfo.IoStream;
			string line;

			string user = "";
			string secret = "";
			string pass = "";
			string pass2 = "";
			string[] listUsers;
			string tok = "";
			

			/* if no auth list then allow anyone in! */
			if (users == null || users.CompareTo("") == 0)
			return true;

			challenge = gen_challenge(addr, cInfo.Options);

			b64_challenge = base64_encode(challenge);
			
			f.IOPrintf(leader + b64_challenge + "\n");

			line = f.ReadLine();			

			if(line.IndexOf(' ') > 0)
			{
				user = line.Substring(0,line.IndexOf(' '));
				pass = line.Substring(line.IndexOf(' ')).Trim('\n').Trim();
			} else 			
				return false;
			listUsers = users.Split(',');
						
			for (int i = 0; i < listUsers.Length; i++) 
			{
				tok = listUsers[i];
				if (user.CompareTo(tok) == 0)
					break;
				tok = null;
			}			

			if (tok == null || tok.CompareTo("") == 0)
				return false;
			
			if ((secret = GetSecret(moduleNumber, user)) == null) 
			{				
				return false;
			}

			pass2 = generate_hash(secret, b64_challenge, cInfo.Options);			

			if (pass.CompareTo(pass2) == 0)
				return true;
			return false;
		}

		static string GetSecret(int moduleNumber, string user)
		{
			string fname = Path.Combine(Environment.SystemDirectory,Daemon.config.GetSecretsFile(moduleNumber));			
			string secret = null;
			TextReader fd;			

			if (fname == null || fname.CompareTo("") == 0)
				return null;
			try{
				fd = new System.IO.StreamReader(fname);
			} catch(Exception) {
				return null;
			}						

			while(true)
			{
				string line = fd.ReadLine();
				if(line == null)
					break;
				line.Trim();
				if(line.CompareTo("") != 0 && (line[0] != ';' && line[0] != '#'))
				{
					string[] userp = line.Split(':');
					if(userp[0].Trim().CompareTo(user) == 0)
					{
						secret = userp[1].Trim();
						break;
					}
				}					
			}
			fd.Close();
			return secret; 
		}

	}

}