linux-kernel - Re: [patch 09/31] x86/fpu: Do not inherit FPU context for CLONE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 12 Oct 2021 18:10:40 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [patch 09/31] x86/fpu: Do not inherit FPU context for
 CLONE_THREAD

On Tue, Oct 12, 2021 at 02:00:11AM +0200, Thomas Gleixner wrote:
> CLONE_THREAD does not have the guarantee of a true fork to inherit all
> state. Especially the FPU state is meaningless for CLONE_THREAD.
> 
> Just wipe out the minimal required state so restore on return to user space
> let's the thread start with a clean FPU.

This sentence reads weird, needs massaging.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette