[18307] in bugtraq
Re: where user temp files should go, env var names
daemon@ATHENA.MIT.EDU (Doug Wyatt)
Thu Dec 21 21:14:37 2000
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Date: Thu, 21 Dec 2000 15:36:30 -0600
Reply-To: dwyatt@sunflower.com
From: Doug Wyatt <dwyatt@SUNFLOWER.COM>
To: BUGTRAQ@SECURITYFOCUS.COM
In-Reply-To: <20001221113019.A1217@wsr.ac.at>
Just my $0.02 - DomainOS was actually the HP/Apollo Aegis O/S and
BSD4 or SYS5 'ran' on top of it based primarily on environment variable
selection. Appropriate pathnames were managed by embedding ENV
variable references in symlinks, something like;
/usr/bin --> /usr/$(OS)/bin
Our last Apollo DN3500 is temporarily offline, so I can't be more specific,
sorry.
Regards,
Doug Wyatt
> On 2000-12-19 00:55:34 -0500, Mike A. Harris wrote:
> > On Tue, 19 Dec 2000, Aaron Drew wrote:
> >
> > >I wouldn't envisage a kernel patch to give each tty or user its own
> > >virtual /tmp being be THAT hard to do.
> >
> > The kernel doesn't differentiate between directories in the
> > filesystem. For all the kernel cares /tmp is where user directories
> > are stored. The kernel doesn't ever know or treat differently any
> > names of dirs in the filesystem.
>
> It shouldn't treat directories differently based on the *name*.
>
> Some unixes have/had a "hidden directories" feature. If a flag is set
> on a directory, any attempt to access the directory would instead
> access one of its subdirectories, depending on some other factor.
> DomainOS and some versions of Minix used this to keep different binaries
> in the "same" place. So, for example, on DomainOS, you would have
> /usr/bin/sysv/ps and /usr/bin/bsd/ps, and depending on whether you
> were running it in SysV or BSD mode, you would get one or the other
> executable when executing /usr/bin/ps. HP-UX inherited the feature from
> Domain-OS, but I can't recall whether it was used for anything useful.
> HP-UX 11 doesn't seem to have it anymore, anyway.
>
> Similarly, instead of a "OS mode", the subdirectory could be based
> on the user-id, so if /tmp has the "hidden-subdirs-are-userids"
> bit set, an access to /tmp/mutt.12345.msg would in fact access
> /tmp/1010/mutt.12345.msg, if my uid is 1010.
>
> > This definitely has nothing at all to do with the kernel whatsoever.
> > It is a userland programming issue.
> >
> > The kernel does not impose policy decisions upon systems, that is what
> > a sysadmin is for. Fix the programmer.
>
> "mechanism, not policy", right. However, the kernel can provide a
> mechanism. Whether it is the right one (personally, I found those hidden
> directories rather confusing) is debatable. Especially since there is
> another mechanism in userland (the TMPDIR environment variable) which
> has almost the same effect, if it is used.
>
> hp
>
> --
> _ | Peter J. Holzer | Any setuid root program that does an
> |_|_) | Sysadmin WSR / LUGA | exec() somewhere is just a less
> | | | hjp@wsr.ac.at | user friendly version of su.
> __/ | http://www.hjp.at/ | -- Olaf Kirch on bugtraq 2000-08-07
>
