linux-kernel - Re: [PATCH] kasan, slub: fix HW_TAGS zeroing with slub

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] [day] [month] [year] [list]

Date:   Mon, 10 Jul 2023 11:53:40 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     andrey.konovalov@...ux.dev, Marco Elver <elver@...gle.com>,
        Mark Rutland <mark.rutland@....com>
Cc:     Andrey Konovalov <andreyknvl@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        kasan-dev@...glegroups.com,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        Catalin Marinas <catalin.marinas@....com>,
        Peter Collingbourne <pcc@...gle.com>,
        Feng Tang <feng.tang@...el.com>, stable@...r.kernel.org,
        Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Hyeonggon Yoo <42.hyeyoo@...il.com>,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: Re: [PATCH] kasan, slub: fix HW_TAGS zeroing with slub_debug

On 7/5/23 14:44, andrey.konovalov@...ux.dev wrote:
> From: Andrey Konovalov <andreyknvl@...gle.com>
> 
> Commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated
> kmalloc space than requested") added precise kmalloc redzone poisoning
> to the slub_debug functionality.
> 
> However, this commit didn't account for HW_TAGS KASAN fully initializing
> the object via its built-in memory initialization feature. Even though
> HW_TAGS KASAN memory initialization contains special memory initialization
> handling for when slub_debug is enabled, it does not account for in-object
> slub_debug redzones. As a result, HW_TAGS KASAN can overwrite these
> redzones and cause false-positive slub_debug reports.
> 
> To fix the issue, avoid HW_TAGS KASAN memory initialization when slub_debug
> is enabled altogether. Implement this by moving the __slub_debug_enabled
> check to slab_post_alloc_hook. Common slab code seems like a more
> appropriate place for a slub_debug check anyway.
> 
> Fixes: 946fa0dbf2d8 ("mm/slub: extend redzone check to extra allocated kmalloc space than requested")
> Cc: <stable@...r.kernel.org>
> Reported-by: Mark Rutland <mark.rutland@....com>
> Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>

Acked-by: Vlastimil Babka <vbabka@...e.cz>

Thanks!