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Subject: Re: [PATCH 1/9] mm: Hardened usercopy
From: Rik van Riel <riel@redhat.com>
To: Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org
Cc: Casey Schaufler <casey@schaufler-ca.com>, PaX Team <pageexec@freemail.hu>,
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Date: Thu, 07 Jul 2016 12:35:17 -0400
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On Wed, 2016-07-06 at 15:25 -0700, Kees Cook wrote:
>=C2=A0
> +	/* Allow kernel rodata region (if not marked as Reserved).
> */
> +	if (ptr >=3D (const void *)__start_rodata &&
> +	=C2=A0=C2=A0=C2=A0=C2=A0end <=3D (const void *)__end_rodata)
> +		return NULL;
>=20
One comment here.

__check_object_size gets "to_user" as an argument.

It may make sense to pass that to check_heap_object, and
only allow copy_to_user from rodata, never copy_from_user,
since that section should be read only.

> +void __check_object_size(const void *ptr, unsigned long n, bool
> to_user)
> +{
>=C2=A0

--=20

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