Running a program as another user without typing a password

Solution 1:

According to sudo manual:

    By default, sudo does not modify HOME

It means that when your run sudo -u <dummy user> <command>, HOME is unchanged and point to the invoking user home directory. More precisely, the entire environment remains unchanged, and the command is executed, therefore, in the environment of the user who invoked sudo. Only uid is changed and when command try to write in $HOME it has not right permission.

In order to run command as <dummy user> without being prompt for the password and have the right environment, you should create a simple file:

    sudo visudo -f /etc/sudoers.d/myOverrides 

with this directive:

    <user> ALL= NOPASSWD:/bin/su

That allow <user> to run su command as root without being prompt for password (<user> password) and running su as root doesn't require to enter the target user's password (<dummy user> in this case).

   sudo su - <dummy user> -c /path/to/chromium-browser

Another better approach, change /etc/sudoers.d/myOverrides with:

   <user> ALL= (<dummy user>) NOPASSWD:/path/to/chromium-browser

this allow <user> to run /path/to/chromium-browser as <dummy user> without being prompt for password.

   sudo -u <dummy user> -i /path/to/chromium-browser

where -i option, according to sudo manual:

The -i (simulate initial login) option runs the shell specified in the passwd(5) entry of the target user as a login shell. This means that login-specific resource files such as .profile or .login will be read by the shell. If a command is specified, it is passed to the shell for execution. Otherwise, an interactive shell is executed. sudo attempts to change to that user’s home directory before running the shell. It also initializes the environment, leaving DISPLAY and TERM unchanged, setting HOME, SHELL, USER, LOGNAME, and PATH, as well as the contents of /etc/environment on Linux and AIX systems. All other environment variables are removed.