From: Andrey Konovalov <andreyknvl@gmail.com>
To: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Uladzislau Rezki <urezki@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
linux-kernel@vger.kernel.org,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
kasan-dev@googlegroups.com
Subject: Re: [PATCH] fork, vmalloc: KASAN-poison backing pages of vmapped stacks
Date: Mon, 23 Jan 2023 17:45:55 +0100 [thread overview]
Message-ID: <CA+fCnZfTrxvmQqVd5zo8jo3JY5YqpvQJGx=PSuUvzb8J+KNG3Q@mail.gmail.com> (raw)
In-Reply-To: <20230117163543.1049025-1-jannh@google.com>
On Tue, Jan 17, 2023 at 5:35 PM Jann Horn <jannh@google.com> wrote:
>
> KASAN (except in HW_TAGS mode) tracks memory state based on virtual
> addresses. The mappings of kernel stack pages in the linear mapping are
> currently marked as fully accessible.
> Since stack corruption issues can cause some very gnarly errors, let's be
> extra careful and tell KASAN to forbid accesses to stack memory through the
> linear mapping.
>
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
> I wrote this after seeing
> https://lore.kernel.org/all/Y8W5rjKdZ9erIF14@casper.infradead.org/
> and wondering about possible ways that this kind of stack corruption
> could be sneaking past KASAN.
> That's proooobably not the explanation, but still...
Hi Jann,
if you decide to keep KASAN poisoning after addressing Dmitry's
comments, please add a KASAN KUnit test for this.
Thank you!
next prev parent reply other threads:[~2023-01-23 16:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-17 16:35 Jann Horn
2023-01-18 7:36 ` Dmitry Vyukov
2023-01-25 9:27 ` Jann Horn
2023-01-25 9:30 ` Jann Horn
2023-01-23 16:45 ` Andrey Konovalov [this message]
2023-01-25 9:49 ` Jann Horn
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