[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <YbibPyHQXjU2A/jg@arm.com>
Date: Tue, 14 Dec 2021 13:25:19 +0000
From: Catalin Marinas <catalin.marinas@....com>
To: andrey.konovalov@...ux.dev
Cc: Marco Elver <elver@...gle.com>,
Alexander Potapenko <glider@...gle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Andrey Konovalov <andreyknvl@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
kasan-dev@...glegroups.com, linux-mm@...ck.org,
Vincenzo Frascino <vincenzo.frascino@....com>,
Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
linux-arm-kernel@...ts.infradead.org,
Peter Collingbourne <pcc@...gle.com>,
Evgenii Stepanov <eugenis@...gle.com>,
linux-kernel@...r.kernel.org,
Andrey Konovalov <andreyknvl@...gle.com>
Subject: Re: [PATCH mm v3 23/38] kasan, arm64: reset pointer tags of vmapped
stacks
On Mon, Dec 13, 2021 at 10:54:19PM +0100, andrey.konovalov@...ux.dev wrote:
> From: Andrey Konovalov <andreyknvl@...gle.com>
>
> Once tag-based KASAN modes start tagging vmalloc() allocations,
> kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled.
>
> Reset the tag of kernel stack pointers after allocation in
> arch_alloc_vmap_stack().
>
> For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the
> instrumentation can't handle the SP register being tagged.
>
> For HW_TAGS KASAN, there's no instrumentation-related issues. However,
> the impact of having a tagged SP register needs to be properly evaluated,
> so keep it non-tagged for now.
>
> Note, that the memory for the stack allocation still gets tagged to
> catch vmalloc-into-stack out-of-bounds accesses.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Powered by blists - more mailing lists