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SubjectRe: [PATCH][RFC] Make /proc/<pid> chmod'able
On Mon, 14 Mar 2005, Albert Cahalan wrote:
> On Mon, 2005-03-14 at 10:42 +0100, Rene Scharfe wrote:
> > Albert Cahalan wrote:

> > Why do you think users should not be allowed to chmod their processes'
> > /proc directories? Isn't it similar to being able to chmod their home
> > directories? They own both objects, after all (both conceptually and as
> > attributed in the filesystem).
>
> This is, to use your own word, "cloaking". This would let
> a bad user or even an unauthorized user hide from the admin.

NACK, the admin (and with the new inherited capabilities all users with
cap_???_override) can see all processes. Only users who don't need to know
won't see the other user's processes.

> Note that the admin hopefully does not normally run as root.

su1 and sudo exist.

> Even if the admin were not running as a normal user, it is
> expected that normal users can keep tabs on each other.
> The admin may be sleeping. Social pressure is important to
> prevent one user from sucking up all the memory and CPU time.

Privacy is important, too. Imagine each user can see the CEO (or the
admin) executing "ee nakedgirl.jpg".

> > > Note: I'm the procps (ps, top, w, etc.) maintainer.
> > >
> > > Probably I'd have to make /bin/ps run setuid root
> > > to deal with this. (minor changes needed) The same
> > > goes for /usr/bin/top, which I know is currently
> > > unsafe and difficult to fix.

I used unpatched procps 3.1.11, and it worked for me, except pstree.

> > Why do ps and top need to be setuid root to deal with a resticted /proc?
> > What information in /proc/<pid> needs to be available to any and all
> > users?
>
> Anything provided by traditional UNIX and BSD systems
> should be available.

e.g. the buffer overflow in sendmail? Or all the open relays? :)

The demands to security and privacy have increased. Linux should be able
to provide the requested privacy.

> Users who want privacy can get their
> own computer. So, these need to work:
>
> ps -ef
> ps -el
> ps -ej
> ps axu
> ps axl
> ps axj
> ps axv
> w
> top

Works as intended. Only pstree breaks, if init isn't visible.

> > > If you restricted this new ability to root, then I'd
> > > have much less of an objection. (not that I'd like it)
> >
> > How about a boot parameter or sysctl to enable the chmod'ability of
> > /proc/<pid>, defaulting to off? But I'd like to resolve your more
> > general objections above first, if possible. :)

I'd prefer a minimum and a maximum mask. If the admin wants to enforce
privacy, he can do it, and if he wants the users to spy on each other, so
be it.
--
Top 100 things you don't want the sysadmin to say:
23. What do mean by "fired"?

Friß, Spammer: kRT8@[211.158.7.114] hire@wjkwwi.info
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