How do i provide password for su command while using net/telnet in ruby

Question

Hi all ,

I am using Net/TELNET to connect to remote host trying to run su command in order to get root privilage. This is how I am doing it

require 'net/telnet'

localhost = Net::Telnet::new("Host" => "192.147.217.27",
                             "Timeout" => 50,
                             "Prompt" => /[$%#>] \z/n)
localhost.login("dvsdkrp", "dvsdkvrp") { |c| print c }
localhost.cmd("cd /home/dvsdkrp/workdir/smruti") { |c| print c }
localhost.cmd("su") { |c| print c }
localhost.puts("passwd"){ |c| print c }

I am able to login and able to do smruti directory but when I use su command it takes me to the password prompt but then I get this error, even after I changed the Timeout parameter to 150

Password: C:/Ruby/lib/ruby/1.8/net/telnet.rb:552:in `waitfor': timed out
while waiting for more data (Timeout::Error)
        from C:/Ruby/lib/ruby/1.8/net/telnet.rb:679:in `cmd'
        from tel.rb:7

What should I do?

Answer 1

The prompt you specify when you create the Telnet object is the one its going to look for before it runs its next command. If you are timing out then I think its because its not seeing the prompt it expects. If you use the Match option when you send the 'su' command, you can specify a prompt specifically for this command.

su_prompt = "Password: "
localhost.cmd("String" => "su", "Match" => /#{su_prompt}/) { |c| print c }
localhost.cmd("passwd")

This new prompt is only used for the current command. The originally specified prompt is still in affect for the rest of the session.