Validated `su` password in python accepted by user

Question

I want to validate root password which is entered by user script which is used to install the driver which requires root. if I try to run that installer as a sudo or superuser privilege it gives below Error:

ERROR: installer must be run as root

I am accepting the password with the help of getpass() method at the beginning of a script and will use that password in between the execution of it so don't want to make a user wait for such long time.

I found what-is-the-best-way-for-checking-if-the-user-of-a-script-has-root-like-privileg and how-to-verify-a-users-password-for-root-privledges-in-python but this will check validation of sudo password not the root. I want to check password is valid for root login.

How Should I validate that user entered the password is correct for root using python?

As well as My knowledge is a concern I have to check the validity of root password by performing so su operation

we can not run the whole script as a root as after installation script is going to run some test as a normal user.

Possibly helpful or related: [How to verify a users password for root privledges in python](https://stackoverflow.com/questions/20928103/how-to-verify-a-users-password-for-root-privledges-in-python) — chickity china chinese chicken, Oct 19 '18 at 19:52
yes, you are correct, but because you don't want run the script as a normal user (not `root` user) you will want to give that normal user `sudo` privileges and run the script using the user's "sudo" password, not `root` user with `root` password. Is that right? — chickity china chinese chicken, Oct 19 '18 at 20:03
giving root privileges to some user will not work, installer requires root to install — Aman Jaiswal, Oct 19 '18 at 20:04
a user running as `sudo` is same as running as `root`. See: [Sudo vs root; any actual differences?](https://superuser.com/questions/771500/sudo-vs-root-any-actual-differences) — chickity china chinese chicken, Oct 19 '18 at 20:05
@AmanJaiswal they are - or, you cannot gain more capabilities to an existing process — Antti Haapala -- Слава Україні, Oct 19 '18 at 20:11
As soon as you accept the password perform a `sudo ls &>/dev/null`. The command will fail if the password is incorrect. — jww, Oct 19 '18 at 23:18

score 1 · Accepted Answer · answered Oct 24 '18 at 17:13

After reading multiple stuff somehow I figure out that we can authenticate root password via a Python script. Below is My approach to Authenticate the Same.

import subprocess
import getpass
FAIL = 'Password: \r\nsu: Authentication failure'

def validate_pass(passwd):
    ret = 0
    try:
        cmd = '{ sleep 1; echo "%s"; } | script -q -c "su -l root -c ls /root" /dev/null' % passwd
        ret = subprocess.check_output(cmd, shell=True)
        return ret
    except:
        return 1



passwd = getpass.getpass(prompt='Password: ', stream=None)
res = validate_pass(passwd).strip()
if FAIL == res:
    print(res)
    print ("Invalid paasword")
else:
    print(res)
    print ("Valid paasword")

Validated `su` password in python accepted by user

1 Answers1