Re: [PATCH v6 8/8] x86/microcode/AMD: Don't scan past the CPU equivalence table data
From: Borislav Petkov
Date: Tue Jun 05 2018 - 04:55:13 EST
On Sun, May 20, 2018 at 12:07:22AM +0200, Maciej S. Szmigiero wrote:
> Currently, the code scanning a CPU equivalence table read from a microcode
> container file assumes that it actually contains a terminating zero entry,
> but if does not then the code will continue the scan past its valid data.
>
> For the late loader this can be improved by always appending a terminating
> zero entry to such table when loading it.
> This way we don't need an extra global variable for holding the table size
> and we don't have to reject such incomplete tables (for backward
> compatibility with the existing code which didn't do so).
>
> For the early loader, since we can't allocate memory and have to work
> in-place, let's pass an explicit size of this table to its scanning
> functions so they will know when to stop.
I don't like the difference between early and late here. Just pass
explicit size to the late loader too.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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