RE: [char-misc-next 2/8] mei: hbm: validate client index is notexceeding allocated array size

From: Winkler, Tomas
Date: Thu Nov 07 2013 - 07:22:10 EST


> >
> > This somehow should guard buffer overflow allocated of size dev-
> >me_clients_num
> > In theory this can happen only if something go wrong in hardware
> > initialization or there is some other security hole that can change
> > client_num.
>
> What _kind_ of "security hole" could ever change that number? Where
> does it come from? Who can modify it? If you don't know that now then
> we have worse problems...

The allocation of me_clients arrays of mei_clients_num is happening on ME enumeration message,
While the filling out the array is looping over get properties message which is bounded by MEI_CLIENTS_MAX,
so the overflow is indeed possible, of course only on some faulty HW. We had such errors only on new
HW bring ups.

Thanks
Tomas
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