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    SubjectRe: High UID support for Linux

    On Fri, 27 Nov 1998, Matti Aarnio wrote:

    > pjb1008@cam.ac.uk (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

    -- -- -- -- -- -- -- -- -- -- -- -- --
    Clifford Wolf (CEO and CTO)
    The ROCK Projects Workgoup IRC: IRCnet / clifford
    http://www.rock-projects.com/ http://www.clifford.at/
    e-mail: c.wolf@rock-projects.com email: god@clifford.at


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