linux-kernel - Re: [patch V3 61/66] x86/fpu/signal: Sanitize the xstate check on sigframe

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Date:   Tue, 22 Jun 2021 21:10:52 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [patch V3 61/66] x86/fpu/signal: Sanitize the xstate check on
 sigframe

On Fri, Jun 18, 2021 at 04:19:24PM +0200, Thomas Gleixner wrote:
> Utilize the check for the extended state magic in the FX software reserved
> bytes and set the parameters for restoring fx_only in the relevant members
> of fw_sw_user.
> 
> This allows further cleanups on top because the data is consistent.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/kernel/fpu/signal.c |   69 +++++++++++++++++++------------------------
>  1 file changed, 32 insertions(+), 37 deletions(-)

Modulo Andy's catch, I can't find anything out of the ordinary here and
all this does makes sense to me. Still a tentative

Reviewed-by: Borislav Petkov <bp@...e.de>

because this is all nasty magic to me. (yah, magic1 and magic2 :-))

-- 
Regards/Gruss,
    Boris.

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