Re: [x86] copy_from{to}_user question

From: Borislav Petkov
Date: Fri Aug 21 2015 - 00:36:11 EST


On Thu, Aug 20, 2015 at 11:22:43AM -0700, H. Peter Anvin wrote:
> There is a valid reason to do this, which is that currently
> copy_{to,from}_user() effectively bypass SMAP as they don't verify that
> the kernel pointer is actually a kernel pointer.

Well, we do STAC before we copy but SMAP is checking for supervisor
access to *user* data. But you say "kernel pointers" which is supervisor
data. What am I missing?

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Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.

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