From: Kees Cook <kees@kernel.org>
To: Matthew Wilcox <willy@infradead.org>,
Uladzislau Rezki <urezki@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>,
zuoze <zuoze1@huawei.com>,
gustavoars@kernel.org, akpm@linux-foundation.org,
linux-hardening@vger.kernel.org, linux-mm@kvack.org,
keescook@chromium.org
Subject: Re: [PATCH -next] mm: usercopy: add a debugfs interface to bypass the vmalloc check.
Date: Wed, 04 Dec 2024 14:43:54 +1000 [thread overview]
Message-ID: <D99B0795-152B-4D63-94C4-5953192A5E53@kernel.org> (raw)
In-Reply-To: <Z09icnP7QuaLg4Qv@casper.infradead.org>
On December 4, 2024 5:56:34 AM GMT+10:00, Matthew Wilcox <willy@infradead.org> wrote:
>On Tue, Dec 03, 2024 at 08:02:26PM +0100, Uladzislau Rezki wrote:
>
>I think there are a few other things we can try here.
>
>First, if the copy is small (and I still don't have an answer to that
>...), we can skip the vmalloc lookup if the copy doesn't cross a page
>boundary.
Yeah, this seems a reasonable optimization.
>Anyway, NACK to the original patch; that's just a horrible idea.
Right, please no debugfs knob. The point is to make sure the check cannot be disabled at runtime and to make the check a no-op. Please use the boot param to disable this check.
-Kees
--
Kees Cook
next prev parent reply other threads:[~2024-12-04 4:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-03 2:31 Ze Zuo
2024-12-03 4:11 ` Matthew Wilcox
2024-12-03 11:23 ` zuoze
2024-12-03 12:39 ` Uladzislau Rezki
2024-12-03 13:10 ` zuoze
2024-12-03 13:25 ` Uladzislau Rezki
2024-12-03 13:30 ` Kefeng Wang
2024-12-03 13:39 ` Uladzislau Rezki
2024-12-03 13:45 ` Kefeng Wang
2024-12-03 13:51 ` Uladzislau Rezki
2024-12-03 14:10 ` Kefeng Wang
2024-12-03 14:20 ` Uladzislau Rezki
2024-12-03 19:02 ` Uladzislau Rezki
2024-12-03 19:56 ` Matthew Wilcox
2024-12-04 1:38 ` zuoze
2024-12-04 4:43 ` Kees Cook [this message]
2024-12-04 7:55 ` Uladzislau Rezki
2024-12-04 9:21 ` zuoze
2024-12-04 9:27 ` Uladzislau Rezki
2024-12-04 8:51 ` Uladzislau Rezki
2024-12-16 4:24 ` Matthew Wilcox
2024-12-16 19:18 ` Uladzislau Rezki
2024-12-04 1:21 ` zuoze
2024-12-03 6:12 ` Uladzislau Rezki
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