[systemd-devel] logind, su - sessions and initscripts compatibility

[Michael Biebl]

2014-12-18 13:19 GMT+01:00 Simon McVittie <simon.mcvittie at collabora.co.uk>:
> On 18/12/14 08:05, Andrei Borzenkov wrote:
>> Any initscript that is using "su -" would [cause badness]
>
> Don't do that then? Init scripts are fairly clearly not login sessions.
> Which init scripts do that?
>
> In Debian, our init scripts would typically use "start-stop-daemon
> --chuid whateveruser  --start whateverd" instead of su. Does your
> distribution have an equivalent?
>
> I'm gradually forming the opinion that su should be considered
> deprecated for both its roles (interactive privilege
> escalation/privilege-dropping for one-off commands or interactive
> shells, and automated uid swapping), because it doesn't do either of
> them particularly well; in particular, it doesn't sanitize environment
> variables by default (you have to remember the "-" which has other
> side-effects), and the need for the command to be a shell command-line
> rather than an argument vector makes it hard to use securely.

I remember that util-linux added a "runuser" utility [1] which is
supposed to be more suitable to run processes under certain gid/uids
from within scripts.


[1] http://linux.die.net/man/1/runuser

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