linux-kernel - Re: [PATCH v8 32/43] arm64: mte: Switch GCR

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: <20201105174239.GI30030@gaia>
Date:   Thu, 5 Nov 2020 17:42:39 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     Andrey Konovalov <andreyknvl@...gle.com>
Cc:     Will Deacon <will.deacon@....com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Evgenii Stepanov <eugenis@...gle.com>,
        Branislav Rankov <Branislav.Rankov@....com>,
        Kevin Brodsky <kevin.brodsky@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        kasan-dev@...glegroups.com, linux-arm-kernel@...ts.infradead.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 32/43] arm64: mte: Switch GCR_EL1 in kernel entry and
 exit

On Thu, Nov 05, 2020 at 12:18:47AM +0100, Andrey Konovalov wrote:
> From: Vincenzo Frascino <vincenzo.frascino@....com>
> 
> When MTE is present, the GCR_EL1 register contains the tags mask that
> allows to exclude tags from the random generation via the IRG instruction.
> 
> With the introduction of the new Tag-Based KASAN API that provides a
> mechanism to reserve tags for special reasons, the MTE implementation
> has to make sure that the GCR_EL1 setting for the kernel does not affect
> the userspace processes and viceversa.
> 
> Save and restore the kernel/user mask in GCR_EL1 in kernel entry and exit.
> 
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@....com>
> Co-developed-by: Andrey Konovalov <andreyknvl@...gle.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>

Reviewed-by: Catalin Marinas <catalin.marinas@....com>