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SubjectRe: High UID support for Linux

On Fri, 27 Nov 1998, Matti Aarnio wrote:

> (Peter Benie) wrote:
> > Matti Aarnio writes ("Re: High UID support for Linux"):
> > > > That's why I want 16 bit uid to 32 bit uids to be a planned change,
> > > > rather than for it to be flag day for Linux where everyone has to
> > > > throw away all their existing code.
> > >
> > > If your runtime environment has only 16-bit UIDs, use of
> > > old binaries via old syscalls will continue as before
> > > *without any changes*.
> >
> > I don't see why I should have to recompile code for programs that
> > aren't interested in uids, but happen to use them purely because
> > braindamaged Unix APIs.
> There are two issues:
> - the way how KERNEL represents the values (e.g. 16-bit uids)
> - the way how LIBRARY represents the values (e.g. 32-bit uids)
> The glibc-2.0.7-19 at i386 has 32-bit unsigned integers as uids.
> It hides the __kernel_uid_t from the user.
> This means:
> We can *any day* change kernel to support 32-bit uids
> at i386 (with new kernel syscalls) as long as we do
> remember to write matching interface routines for the
> glibc so that it can take full advantage of the result.

Hi gang, here are my 0.02 euros to this topic:

So why don't we note to move this 32-bits <-> 16-bits transaltion into the
kernel as one of the first 2.3.x issues? I don't think that it would be
that hard to do this - it's just to late for such a change before 2.2.0.

After this is done we could write function to translate 32-bit-uids to
16-bit-uids. This function could check for uids higher than 32767 (or
65535?) and converts them to 'nobody' and prints a kernel warning (could
this behavor result in security problem?).

As soon as this framework is done we could migrate step-by-step to
32-bit-uids without breaking any user-level interface anymore.

The only hard thing (tm) will be the filesystems ....

keep hacking,

-- -- -- -- -- -- -- -- -- -- -- -- --
Clifford Wolf (CEO and CTO)
The ROCK Projects Workgoup IRC: IRCnet / clifford
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