Re: [gentoo-dev] GLEP81 and /home

[Rich Freeman <rich0@gentoo.org>]

On Sun, Jan 19, 2020 at 2:27 PM Michael Orlitzky <mjo@gentoo.org> wrote:
>
> On 1/19/20 2:02 PM, Rich Freeman wrote:
> >
> >> If you're sharing /home, you also have to be sharing user accounts,
> >> unless you want everyone to be assigned a random set of files.
> >
> > I imagine that most people setting up something like this would only
> > be sharing high-value UIDs (>1000 in our case).  There is no need for
> > postfix on your Gentoo box and postfix on your Debian box to have the
> > same UID.  You wouldn't be sshing from postfix on the one to postfix
> > on the other and expecting to have the same home directory contents.
> >
>
> You can't do that. If you're going to mount files from one system onto
> another system, using only an integer <--> username mapping as your
> access control mechanism, then you'd better be damn sure that those
> integers and usernames match on all systems. Otherwise I might wind up
> sharing /home/mjo to rich0 because the "mjo" and "rich0" groups both
> have gid 1000 locally.

Obviously the UIDs associated with the shared /home need to be
identical.  Simplest solution is to sync anything > 1000 in
/etc/passwd, and then not allow UIDs below 1000 in /home.  A cron job
could easily handle both, and of course regular users can't go
creating stuff with the wrong UID anyway.

> We've talked this to death. Barring any new evidence, /home still seems
> like the best place for these, and I don't want to put them in the wrong
> spot (forcing users to migrate) just to appease a QA warning from before
> GLEP81 was a thing.

Well, great, then by all means ask QA for a policy exception.  Not my
place to yell at you if you don't, but don't be surprised if somebody
else does...

-- 
Rich