How to pass the password to su/sudo/ssh without overriding the TTY?

Question

I'm writing a C Shell program that will be doing su or sudo or ssh. They all want their passwords in console input (the TTY) rather than stdin or the command line.

Does anybody know a solution?

Setting up password-less sudo is not an option.

expect could be an option, but it's not present on my stripped-down system.

Answer 1

For sudo there is a -S option for accepting the password from standard input. Here is the man entry:

    -S          The -S (stdin) option causes sudo to read the password from
                the standard input instead of the terminal device.

This will allow you to run a command like:

echo myPassword | sudo -S ls /tmp

As for ssh, I have made many attempts to automate/script it's usage with no success. There doesn't seem to be any build-in way to pass the password into the command without prompting. As others have mentioned, the "expect" utility seems like it is aimed at addressing this dilemma but ultimately, setting up the correct private-key authorization is the correct way to go when attempting to automate this.

Answer 2

I wrote some Applescript which prompts for a password via a dialog box and then builds a custom bash command, like this:

echo <password> | sudo -S <command>

I'm not sure if this helps.

It'd be nice if sudo accepted a pre-encrypted password, so I could encrypt it within my script and not worry about echoing clear text passwords around. However this works for me and my situation.

Answer 3

For ssh you can use sshpass: sshpass -p yourpassphrase ssh user@host.

You just need to download sshpass first :)

$ apt-get install sshpass
$ sshpass -p 'password' ssh username@server

Answer 4

For sudo you can do this too:

sudo -S <<< "password" command

Answer 5

I've got:

ssh user@host bash -c "echo mypass | sudo -S mycommand"

Works for me.

Answer 6

The usual solution to this problem is setuiding a helper app that performs the task requiring superuser access: http://en.wikipedia.org/wiki/Setuid

Sudo is not meant to be used offline.

Later edit: SSH can be used with private-public key authentication. If the private key does not have a passphrase, ssh can be used without prompting for a password.

Answer 7

This can be done by setting up public/private keys on the target hosts you will be connecting to. The first step would be to generate an ssh key for the user running the script on the local host, by executing:

ssh-keygen
Enter file in which to save the key (/home/myuser/.ssh/id_rsa): <Hit enter for default>
Overwrite (y/n)? y

Then enter a blank password. After that, copy your ssh key onto the target host which you will be connecting to.

ssh-copy-id <remote_user>@<other_host>
remote_user@other_host's password: <Enter remote user's password here>

After registering the ssh keys, you would be able to perform a silent ssh remote_user@other_host from you local host.

Answer 8

Maybe you can use an expect command?:

expect -c 'spawn ssh root@your-domain.com;expect password;send "your-password\n";interact

That command gives the password automatically.

Answer 9

Take a look at expect linux utility.

It allows you to send output to stdio based on simple pattern matching on stdin.

Answer 10

When there's no better choice (as suggested by others), then man socat can help:

   (sleep 5; echo PASSWORD; sleep 5; echo ls; sleep 1) |
   socat - EXEC:'ssh -l user server',pty,setsid,ctty

          EXEC’utes an ssh session to server. Uses a pty for communication
          between socat and ssh, makes it ssh’s  controlling  tty  (ctty),
          and makes this pty the owner of a new process group (setsid), so
          ssh accepts the password from socat.

All of the pty,setsid,ctty complexity is necessary and, while you might not need to sleep as long, you will need to sleep. The echo=0 option is worth a look too, as is passing the remote command on ssh's command line.

Answer 11

Set SSH up for Public Key Authentication, with no pasphrase on the Key. Loads of guides on the net. You won't need a password to login then. You can then limit connections for a key based on client hostname. Provides reasonable security and is great for automated logins.

Answer 12

ssh -t -t me@myserver.io << EOF
echo SOMEPASSWORD | sudo -S do something
sudo do something else
exit
EOF

Answer 13

a better sshpass alternative is: passh https://github.com/clarkwang/passh

Login to a remote server

 $ passh -p password ssh user@host

Run a command on remote server

 $ passh -p password ssh user@host date

other methods to pass the password

-p The password (Default: `password')

-p env: Read password from env var

-p file: Read password from file

here I explained why it is better than sshpass, and other solutions.

Answer 14

echo <password> | su -c <command> <user> 

This is working.

Answer 15

I had the same problem. dialog script to create directory on remote pc. dialog with ssh is easy. I use sshpass (previously installed).

   dialog --inputbox "Enter IP" 8 78 2> /tmp/ip

   IP=$(cat /tmp/ip)


   dialog --inputbox "Please enter username" 8 78 2> /tmp/user

   US=$(cat /tmp/user)


   dialog --passwordbox "enter password for \"$US\" 8 78 2> /tmp/pass

   PASSWORD = $(cat /tmp/pass)


   sshpass -p "$PASSWORD" ssh $US@$IP mkdir -p /home/$US/TARGET-FOLDER


   rm /tmp/ip

   rm /tmp/user

   rm /tmp/pass

greetings from germany

titus

Answer 16

Building on @Jahid's answer, this worked for me on macOS 10.13:

ssh <remote_username>@<remote_server> sudo -S <<< <remote_password> cat /etc/sudoers

Answer 17

One way would be to use read -s option .. this way the password characters are not echoed back to the screen. I wrote a small script for some use cases and you can see it in my blog: http://www.datauniv.com/blogs/2013/02/21/a-quick-little-expect-script/

Answer 18

USE:

echo password | sudo command

Example:

echo password | sudo apt-get update; whoami

Hope It Helps..

Answer 19

You can provide password as parameter to expect script.

Answer 20

su -c "Command" < "Password"

Hope it is helpful.