From: Kees Cook <keescook@chromium.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] usercopy: Skip HIGHMEM page checking
Date: Tue, 17 Sep 2019 10:39:50 -0700 [thread overview]
Message-ID: <201909171039.09E75C2@keescook> (raw)
In-Reply-To: <20190917163606.GU29434@bombadil.infradead.org>
On Tue, Sep 17, 2019 at 09:36:06AM -0700, Matthew Wilcox wrote:
> If the copy has the correct bounds, the 'wholly within one base page'
> check will pass and it'll return. If the copy does span a page,
> the virt_to_head_page(end) call will return something bogus, then the
> PageReserved and CMA test will cause the usercopy_abort() test to fail.
>
> So I think your first patch is the right patch.
Okay, good points. I'll respin...
--
Kees Cook
prev parent reply other threads:[~2019-09-17 17:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-16 21:32 [PATCH] usercopy: Skip HIGHMEM page checking Kees Cook
2019-09-17 0:32 ` Matthew Wilcox
2019-09-17 3:05 ` Kees Cook
2019-09-17 16:36 ` Matthew Wilcox
2019-09-17 17:39 ` Kees Cook [this message]
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