From: Andrew Morton <akpm@linux-foundation.org>
To: Yuanzheng Song <songyuanzheng@huawei.com>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] mm: usercopy: move the virt_addr_valid() below the is_vmalloc_addr()
Date: Mon, 9 May 2022 20:37:32 -0700 [thread overview]
Message-ID: <20220509203732.951da2e00ddfa628decf24a2@linux-foundation.org> (raw)
In-Reply-To: <20220505071037.4121100-1-songyuanzheng@huawei.com>
Matthew & Kees,
On Thu, 5 May 2022 07:10:37 +0000 Yuanzheng Song <songyuanzheng@huawei.com> wrote:
> The is_kmap_addr() and the is_vmalloc_addr() in the check_heap_object()
> will not work, because the virt_addr_valid() will exclude the kmap and
> vmalloc regions. So let's move the virt_addr_valid() below
> the is_vmalloc_addr().
The author,
> Signed-off-by: Yuanzheng Song <songyuanzheng@huawei.com>
Tells me off-list that this fix:
> --- a/mm/usercopy.c
> +++ b/mm/usercopy.c
> @@ -163,9 +163,6 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
> {
> struct folio *folio;
>
> - if (!virt_addr_valid(ptr))
> - return;
> -
> if (is_kmap_addr(ptr)) {
> unsigned long page_end = (unsigned long)ptr | (PAGE_SIZE - 1);
>
> @@ -190,6 +187,9 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
> return;
> }
>
> + if (!virt_addr_valid(ptr))
> + return;
> +
> folio = virt_to_folio(ptr);
>
> if (folio_test_slab(folio)) {
is required to fix patches "mm/usercopy: Check kmap addresses properly"
and "mm/usercopy: Detect vmalloc overruns".
next prev parent reply other threads:[~2022-05-10 3:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-05 7:10 [PATCH] mm: usercopy: move the virt_addr_valid() below the is_vmalloc_addr() Yuanzheng Song
2022-05-10 3:37 ` Andrew Morton [this message]
2022-05-10 21:54 ` Kees Cook
2022-05-12 5:39 ` Kees Cook
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