From: Kees Cook <keescook@chromium.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Uladzislau Rezki <urezki@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Yu Zhao <yuzhao@google.com>,
dev@der-flo.net, linux-mm@kvack.org,
linux-hardening@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH 3/3] usercopy: Add find_vmap_area_try() to avoid deadlocks
Date: Fri, 16 Sep 2022 08:09:16 -0700 [thread overview]
Message-ID: <202209160805.CA47B2D673@keescook> (raw)
In-Reply-To: <YySML2HfqaE/wXBU@casper.infradead.org>
On Fri, Sep 16, 2022 at 03:46:07PM +0100, Matthew Wilcox wrote:
> On Fri, Sep 16, 2022 at 06:59:57AM -0700, Kees Cook wrote:
> > The check_object_size() checks under CONFIG_HARDENED_USERCOPY need to be
> > more defensive against running from interrupt context. Use a best-effort
> > check for VMAP areas when running in interrupt context
>
> I had something more like this in mind:
Yeah, I like -EAGAIN. I'd like to keep the interrupt test to choose lock
vs trylock, otherwise it's trivial to bypass the hardening test by having
all the other CPUs beating on the spinlock.
Thanks!
-Kees
--
Kees Cook
next prev parent reply other threads:[~2022-09-16 15:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 13:59 [PATCH 0/3] x86/dumpstack: Inline copy_from_user_nmi() Kees Cook
2022-09-16 13:59 ` [PATCH 1/3] x86/uaccess: Move nmi_uaccess_okay() into uaccess.h Kees Cook
2022-09-16 13:59 ` [PATCH 2/3] x86/dumpstack: Inline copy_from_user_nmi() Kees Cook
2022-09-16 13:59 ` [PATCH 3/3] usercopy: Add find_vmap_area_try() to avoid deadlocks Kees Cook
2022-09-16 14:46 ` Matthew Wilcox
2022-09-16 15:09 ` Kees Cook [this message]
2022-09-16 19:15 ` Matthew Wilcox
2022-09-19 8:29 ` Uladzislau Rezki
2022-09-16 17:29 ` Uladzislau Rezki
2022-09-16 19:57 ` [PATCH 0/3] x86/dumpstack: Inline copy_from_user_nmi() Andrew Morton
2022-09-19 14:46 ` Peter Zijlstra
2022-09-19 19:26 ` Kees Cook
2022-09-17 2:20 ` Yu Zhao
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