linux-kernel - Re: [RFCv2 00/10] Linear Address Masking enabling

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]

Message-ID: <875ym9u98w.ffs@tglx>
Date:   Fri, 13 May 2022 10:28:31 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Dave Hansen <dave.hansen@...el.com>,
        "H.J. Lu" <hjl.tools@...il.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Linux-MM <linux-mm@...ck.org>,
        Catalin Marinas <catalin.marinas@....com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFCv2 00/10] Linear Address Masking enabling

On Thu, May 12 2022 at 20:05, Dave Hansen wrote:

> On 5/12/22 18:27, Thomas Gleixner wrote:
>> On Thu, May 12 2022 at 17:46, Dave Hansen wrote:
>>> On 5/12/22 17:08, H.J. Lu wrote:
>>> If I had to take a shot at this today, I think I'd opt for:
>>>
>>> 	mask = sys_enable_masking(bits=6, flags=FUZZY_NR_BITS);
>>>
>>> although I'm not super confident about the "fuzzy" flag.  I also don't
>>> think I'd totally hate the "blind" interface where the kernel just gets
>>> to pick unilaterally and takes zero input from userspace.
>> That's the only sane choice and you can make it simple for userspace:
>> 
>>        ret = prctl(GET_XXX_MASK, &mask);
>> 
>> and then let it decide based on @ret and @mask whether to use it or not.
>> 
>> But of course nobody thought about this as a generic feature and so we
>> have the ARM64 TBI muck as a precedence.
>
> Well, not quite *nobody*:
>
>  https://lore.kernel.org/linux-arm-kernel/7a34470c-73f0-26ac-e63d-161191d4b1e4@intel.com/

Sigh....