Date:   Fri, 17 Dec 2021 09:05:32 +0100
From:   Joerg Roedel <joro@8bytes.org>
To:     Kees Cook <keescook@chromium.org>
Cc:     Lu Baolu <baolu.lu@linux.intel.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Will Deacon <will@kernel.org>,
        Yury Norov <yury.norov@gmail.com>,
        linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] iommu: Use correctly sized arguments for bit field
Message-ID: <YbxEzHVdvzCiProP@8bytes.org>
References: <20211215232432.2069605-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211215232432.2069605-1-keescook@chromium.org>
Precedence: bulk

On Wed, Dec 15, 2021 at 03:24:32PM -0800, Kees Cook wrote:
> The find.h APIs are designed to be used only on unsigned long arguments.
> This can technically result in a over-read, but it is harmless in this
> case. Regardless, fix it to avoid the warning seen under -Warray-bounds,
> which we'd like to enable globally:
> 
> In file included from ./include/linux/bitmap.h:9,
>                  from drivers/iommu/intel/iommu.c:17:
> drivers/iommu/intel/iommu.c: In function 'domain_context_mapping_one':
> ./include/linux/find.h:119:37: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'int[1]' [-Warray-bounds]
>   119 |                 unsigned long val = *addr & GENMASK(size - 1, 0);
>       |                                     ^~~~~
> drivers/iommu/intel/iommu.c:2115:18: note: while referencing 'max_pde'
>  2115 |         int pds, max_pde;
>       |                  ^~~~~~~
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/iommu/intel/iommu.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied, thanks.