java gksudo persist elevation

Question

I have a java application that has a timer that executes a separate application that requires elevated privileges. I have been doing this:

String command = "gksudo /home/bob/sensor";
Process child = Runtime.getRuntime().exec(command);

The problem is that every time the timer kicks off, it requests the password, so I get it every two seconds. Is there a way to only request the password once and then stay elevated so that as long as the java application is running it won't ask again?

I tried using gconf-editor to change the apps/gksu/save-to-keyring option, but that didn't change anything, and I think it might be a nuclear option anyway.

score 0 · Answer 1 · edited May 23 '17 at 11:55

I don't think this actually possible, because gksudo does not allow you to pass a password. However su and sudo do allow this (see How to pass the password to su/sudo/ssh without overriding the TTY?).

You can use gksudo -p to use a graphical auth-window and retrieve the password. Then the next time you don't need gksudo, since you don't want to ask for a password anyway.

Might look something like this

String sessionPassword = null;
String command = "/my/elevated/app";

void executeStuff() {
    // Get the password in case it does not exist yet
    if( sessionPassword == null )
      sessionPassword = exec("gksudo -p -m 'Please enter you password once.'");

    // Construct the command
    String elevatedCommand = "echo '"+ sessionPassword +"' | sudo -S " + command;

    // Launch elevated
    Process child = Runtime.getRuntime().exec(elevatedCommand);
}

I suspect security experts to hate me for suggesting this (storing a password), so use with care.

java gksudo persist elevation

1 Answers1