From: David Hildenbrand <david@redhat.com>
To: Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH] mm: Prevent mapping typed pages to userspace
Date: Wed, 30 Jan 2019 13:01:23 +0100 [thread overview]
Message-ID: <44ea1fd9-f0ae-f031-0232-05afbd7aa7e5@redhat.com> (raw)
In-Reply-To: <20190129053830.3749-1-willy@infradead.org>
On 29.01.19 06:38, Matthew Wilcox wrote:
> Pages which use page_type must never be mapped to userspace as it would
> destroy their page type. Add an explicit check for this instead of
> assuming that kernel drivers always get this right.
>
> Signed-off-by: Matthew Wilcox <willy@infradead.org>
> ---
> mm/memory.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index ce8c90b752be..db3534bbd652 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1451,7 +1451,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
> spinlock_t *ptl;
>
> retval = -EINVAL;
> - if (PageAnon(page) || PageSlab(page))
> + if (PageAnon(page) || PageSlab(page) || page_has_type(page))
> goto out;
> retval = -ENOMEM;
> flush_dcache_page(page);
>
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2019-01-30 12:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 5:38 Matthew Wilcox
2019-01-29 8:09 ` Kees Cook
2019-01-30 12:01 ` David Hildenbrand [this message]
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