CODEWITHSUNDEEP
pythonlinux
PLNewbie
PLNewbie

Reputation: 69

invoke os.system as a non-root user in a root-user launched python program

I want to run a python program using sudo (e.g. sudo python test.py) but within the python program when I use os.system(<some command>) to invoke other processes, I want to run them as a non-root user.

Is this doable?

Thanks!

Upvotes: 0

Views: 1195

Answers (2)

PLNewbie
PLNewbie

Reputation: 69

Another way to do this is to add a prefix sudo -u username in front of the command one wants to run to execute as that specific user. For example, one can use os.system('sudo -u user_a python test.py') to run test.py inside a python script as user_a.

Upvotes: 0

alani
alani

Reputation: 13079

Example:

import os
import pwd

username = "nobody"

pwent = pwd.getpwnam(username)
uid = pwent.pw_uid
gid = pwent.pw_gid

pid = os.fork()
if pid == 0:
    # child

    # relinquish any privileged groups before we call setuid
    # (not bothering to load the target user's supplementary groups here)
    os.setgid(gid)
    os.setgroups([])

    # now relinquish root privs
    os.setuid(uid)

    # os.setuid should probably raise an exception if it fails,
    # but I'm paranoid so...
    if os.getuid() != uid:
        print("setuid failed - bailing")
        os._exit(1)

    return_value = os.system("id") // 256  # or whatever
    os._exit(return_value)

# parent
os.waitpid(pid, 0)

print("parent continues (still root here)")

os.system("id")

Gives:

uid=65534(nobody) gid=65534(nogroup) groups=65534(nogroup)
parent continues (still root here)
uid=0(root) gid=0(root) groups=0(root)

Upvotes: 1

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