Home / ubuntu / Questions / 281742
Accepted
Drew Noakes
Asked: 2013-04-16 06:32:56 +0800 CST

sudo: no tty present and no askpass program specified

  • 772

When attempting to run a remote binary using sudo on the remote box:

ssh remotehost "sudo ./binary"

I see this error:

sudo: no tty present and no askpass program specified

How can I work around this?

ssh

6 Answers

  1. Best Answer

    A simple way is to specify -t:

    ssh -t remotehost "sudo ./binary"

    From the man page:

    Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine, which can be very useful, e.g. when implementing menu services. Multiple -t options force tty allocation, even if ssh has no local tty.

    I cannot explain exactly why this works, and there may be a better way. I'd like to hear about it if so :)

    @psusi explains why this works in a comment below.

    • 102

  2. Question:

    How can I work around this?

    sudo: no tty present and no askpass program specified

    Alternate Answer

    As an alternative, try:

    sudo -S ./[yourExecutable]

    This directs sudo to read the password from the standard input, stdin.

    Scenarios where this Helps

    In chroot environments, these other answers may not work correctly ... perhaps because:

    1. /etc/shadow vs /etc/passwd conflict not allowing the user to enter a password.
    2. In a chroot-ed environment, access to tty1 can be a bit glitchy, and ctrl-alt f2 -- to tty2 is unfeasible, because it is a tty of the non-chroot-ed environment.

    For example: Manually installing / repairing linux or the bootloader, using a chroot environment, (such as Archlinux and arch-chroot).

    • 38

  3. It fails, because sudo is trying to prompt on root password and there is no pseudo-tty allocated.

    You've to either log-in as root or set-up the following rules in your /etc/sudoers (or: sudo visudo):

    # Members of the admin group may gain root privileges
%admin  ALL=(ALL) NOPASSWD:ALL

    Then make sure that your user belongs to admin group (or wheel).

    • 6

  4. You need to define terminal/application that will read the password. There are two variants:

    1. export SUDO_ASKPASS=/usr/libexec/openssh/ssh-askpass
    2. vim /etc/sudoers (Defaults visiblepw)
    • 4

  5. In my case I've received this error because I wasn't specifying a command that I would like to use as root in the sudoers

    Something like

    /etc/sudoers.d/myuser:

    myuser ALL=(root) NOPASSWD: \
    /bin/ls -la

    worked for me

    • 4

  6. You can also create a file like "sudo_shutdown" in /etc/sudoers.d, with content:

    # Allow admins to shutdown without pass
%adm ALL=(ALL) NOPASSWD: /sbin/shutdown

    This allows users which are in the adm group to shutdown without a password.

    • 3