[hahainternet]

> Except it's less than clear that this is an "invalid username"

Indeed, and once that was pointed out his response was equally polite and accurate, offering a workaround which keeps everyone happy.

Literally, what more do people expect?

[detaro]

The thing not being closed as "not a bug" before the situation is figured out (e.g. the opener had a user account starting with a 0, so it could be expected input) or clearer context is given (e.g. if systemd had an established policy on what a username is allowed to be, a reference to that)?

While understandable (maintainers are busy people and likely have to deal with a lot of reports that have clear cut answers), it sadly fits into the image people have of them.

I personally think "thumbs down" (since you referenced those) is a completely valid response to that – but to be clear, posting insults or other attacks is not!

[viraptor]

Strict validation. If some option is not valid, fail loudly. And he still fails to acknowledge this is a security issue. Here's a scenario for you:

You're running a SaaS which spawns restricted demons/containers per customer, separating the users by assigning them local user accounts. One day, user "0zero" registers and their account has access to your whole environment. Would you expect this? Would you not classify this as a security issue?

[JdeBP]

I am going with ...

    root # chpst -u 0zero id
    uid=1462(0zero) gid=1481(0zero) groups=1481(0zero)
    root # setuidgid 0zero id
    uid=1462(0zero) gid=1481(0zero) groups=1481(0zero)
    root #

... I would not; I would. Both of these use the getpwnam() library function of course. Their behaviours are ...

    root # chpst -u 0day id
    chpst: fatal: unable to get password/group file entry: file does not exist
    root # setuidgid 0day id
    setuidgid: FATAL: 0day: No such user.
    root #

... to abend when the account name is not found rather than continue on as the superuser without dropping privileges ...

* http://jdebp.eu./Softwares/nosh/guide/setuidgid.html

* http://cr.yp.to/daemontools/setuidgid.html

* http://untroubled.org/daemontools-encore/setuidgid.8.html

... as is documented in their user manuals, resulting in ...

    root # system-control convert-systemd-units ./0day.service
    root # install -d /home/0day
    root # ln -s /etc/service-bundles/services/sysinit-log 0day/log
    root # system-control start 0day 
    root # system-control status 0day
    /var/local/sv/0day: 
            State   : failed since 2017-07-02 11:14:17 +0100; 0s ago
            Main PID: 80083
             Started: exit 0 at 2017-07-02 11:13:35 +0100; 42s ago
                 Ran: exit 111 at 2017-07-02 11:14:17 +0100; 0s ago
            Config  : enabled
    2017-07-02 11:14:17.130870725 setuidgid: FATAL: 0day: No such user.
    2017-07-02 11:14:17.247334398 setuidgid: FATAL: 0day: No such user.
    2017-07-02 11:14:17.363857132 setuidgid: FATAL: 0day: No such user.
    2017-07-02 11:14:17.481175128 setuidgid: FATAL: 0day: No such user.
    2017-07-02 11:14:17.598958702 setuidgid: FATAL: 0day: No such user.
    root #

... the 0day service from the headlined bug report failing to start.

[ArneBab]

Or maybe 0pointer → http://0pointer.net/imprint

[digi_owl]

He seems to prefer various alcoholic drinks when posting not posting under his own name though...