ssh using exec() - Perl Programming

Posted by wei (wei), 19 June 2007

hi

i was trying to use ssh using exec() and execute a command from a browser using cgi
$ssh = "sudo ssh ip-address -l root ls /";
$exec = exec("$ssh");

and the result was

Permission denied, please try again.
Permission denied, please try again.
Permission denied (publickey,gssapi-with-mic,password).

i have no idea on how to input the password for the authentication. any helps ?

thanks

Posted by admin (Graham Ellis), 20 June 2007

Typically, passwords are read from /dev/tty and not from STDIN in programs like ssh to avoid them being used as automated breakin tools - which means you have to program around that issue to do it legitimately. I would use expect

See http://www.infocopter.com/perl/expect.htm

Posted by wei (wei), 20 June 2007

hi

i just tried Expect using ssh at cmd and it work (thanks), but there is an error which said that IO::Stty is not installed and i can find it in CPAN website.

I come across Net::SSH and i tried it in command line which it works, but when i use it from a browser the page can't be load.

#!/usr/bin/perl -w

use Net::SSH:

erl;

$destination = "my-IP-addr";
$user = "root";
$password = "my password";
$command = "ls";

my $ssh = Net::SSH:

erl->new($destination);
$ssh->login($user,$password);
my ($stdout,$stderr,$exit) = $ssh->cmd($command);

print "Content-type: text/html

<head>
<title>Example</title>
</head>

<body>
<pre>\n";
print "$stdout";
print "</pre>
</body>";

any idea?

thanks

Posted by admin (Graham Ellis), 21 June 2007

Almost ceratinly an issue with the setup or environment. Hard to be more precise without fuller details of how you tested it and what actually happened.

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