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R. Silva" , Kees Cook Cc: iommu@lists.linux.dev, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hardening@vger.kernel.org References: <20240211182250.12656-1-erick.archer@gmx.com> From: AngeloGioacchino Del Regno In-Reply-To: <20240211182250.12656-1-erick.archer@gmx.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Il 11/02/24 19:22, Erick Archer ha scritto: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1]. > > Here the multiplication is obviously safe because MTK_PROTECT_PA_ALIGN > is defined as a literal value of 256 or 128. > > For the "mtk_iommu.c" file: 256 > For the "mtk_iommu_v1.c" file: 128 > > However, using devm_kcalloc() is more appropriate [2] and improves > readability. This patch has no effect on runtime behavior. > > Link: https://github.com/KSPP/linux/issues/162 [1] > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2] > Signed-off-by: Erick Archer Reviewed-by: AngeloGioacchino Del Regno > --- > drivers/iommu/mtk_iommu.c | 2 +- > drivers/iommu/mtk_iommu_v1.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index 7abe9e85a570..9aae6eb604b1 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -1264,7 +1264,7 @@ static int mtk_iommu_probe(struct platform_device *pdev) > data->plat_data = of_device_get_match_data(dev); > > /* Protect memory. HW will access here while translation fault.*/ > - protect = devm_kzalloc(dev, MTK_PROTECT_PA_ALIGN * 2, GFP_KERNEL); > + protect = devm_kcalloc(dev, 2, MTK_PROTECT_PA_ALIGN, GFP_KERNEL); > if (!protect) > return -ENOMEM; > data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > index 25b41222abae..45cd845d153f 100644 > --- a/drivers/iommu/mtk_iommu_v1.c > +++ b/drivers/iommu/mtk_iommu_v1.c > @@ -621,8 +621,8 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev) > data->dev = dev; > > /* Protect memory. HW will access here while translation fault.*/ > - protect = devm_kzalloc(dev, MTK_PROTECT_PA_ALIGN * 2, > - GFP_KERNEL | GFP_DMA); > + protect = devm_kcalloc(dev, 2, MTK_PROTECT_PA_ALIGN, > + GFP_KERNEL | GFP_DMA); > if (!protect) > return -ENOMEM; > data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); > -- > 2.25.1 >