adduser race conditions

Christian Ehrhardt christian.ehrhardt at
Mon Feb 22 08:04:57 UTC 2021

On Fri, Feb 19, 2021 at 6:19 PM Brent W. Baccala <cosine at> wrote:
> Hi -
> I've found at least one race condition in the adduser script on Ubuntu 18.
> The program searches for an available UID (and GID), then adds the new user with the selected UID/GID numbers without any synchronization, so two near-simultaneous invocations of the program can produce two users with identical GIDs (what I saw), or, presumably, identical UIDs.
> Is there a bug/issue tracker somewhere for this program?

Hi Brent,
the upstream for this program is Debian [1][2] for general bugs and/or
feature requests you'd use those.
While the Ubuntu bug tracker [3] would mostly be for issues due to the
Ubuntu Delta or to ask for backports of fixes into active Ubuntu
Releases as part of the SRU process [4].

Do these pointers help enough to enable you to take the next step
reporting [5][6] this?


>     agape
>     brent
> --
> Ubuntu-devel-discuss mailing list
> Ubuntu-devel-discuss at
> Modify settings or unsubscribe at:

Christian Ehrhardt
Staff Engineer, Ubuntu Server
Canonical Ltd

More information about the Ubuntu-devel-discuss mailing list