Re: Possible security hole? [was: verify_area(...) possible problem]

Pavel Machek (pavel@atrey.karlin.mff.cuni.cz)
Mon, 19 Apr 1999 17:08:50 +0200


Hi!

[Linus stripped from Cc:, he is probably not interested in our 386
discussion]

> > This is old news. I even did a patch: [hopefully noone uses 386's for
> > multiuser shell servers :-)] . But still it is a bug. I think it
> > should be fixed.
>
> Oh, I was hoping the patch would actually fix the behaviour, rather than
> turning off clone :-)

Noone uses clone, anyway ;-).

> > I do have 386. If you post me nice .c program, I'll happily test it
> > for you. [What about duplicating it by forcing kernel to think it has
> > old 386. That should work - 486+ all backward compatible after all.]
>
> Unfortunately 486s are not backward compatible in this regard.

I do think they are. You need to enable special bit 'write protect even
in supervisor mode' to get non-386 (==good) behaviour.

Pavel

-- 
The best software in life is free (not shareware)!		Pavel
GCM d? s-: !g p?:+ au- a--@ w+ v- C++@ UL+++ L++ N++ E++ W--- M- Y- R+

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