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Wed, 08 Oct 2025 05:19:32 -0700 (PDT) Received: from ziepe.ca ([140.209.225.78]) by smtp.gmail.com with ESMTPSA id af79cd13be357-87778650910sm1707535585a.40.2025.10.08.05.19.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Oct 2025 05:19:31 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1v6T8l-0000000FnKy-011C; Wed, 08 Oct 2025 09:19:31 -0300 Date: Wed, 8 Oct 2025 09:19:30 -0300 From: Jason Gunthorpe To: Alex Mastro Cc: Alex Williamson , Alejandro Jimenez , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] vfio/type1: sanitize for overflow using check_*_overflow Message-ID: <20251008121930.GA3734646@ziepe.ca> References: <20251007-fix-unmap-v2-0-759bceb9792e@fb.com> <20251007-fix-unmap-v2-1-759bceb9792e@fb.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251007-fix-unmap-v2-1-759bceb9792e@fb.com> On Tue, Oct 07, 2025 at 09:08:46PM -0700, Alex Mastro wrote: > Adopt check_*_overflow functions to clearly express overflow check > intent. > > Signed-off-by: Alex Mastro > --- > drivers/vfio/vfio_iommu_type1.c | 54 ++++++++++++++++++++++++++++++++--------- > 1 file changed, 43 insertions(+), 11 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index f8d68fe77b41..b510ef3f397b 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > #include "vfio.h" > > #define DRIVER_VERSION "0.2" > @@ -825,14 +826,25 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data, > unsigned long remote_vaddr; > struct vfio_dma *dma; > bool do_accounting; > + dma_addr_t iova_end; > + size_t iova_size; > > - if (!iommu || !pages) > + if (!iommu || !pages || npage < 0) > return -EINVAL; > > /* Supported for v2 version only */ > if (!iommu->v2) > return -EACCES; > > + if (npage == 0) > + return 0; > + > + if (check_mul_overflow(npage, PAGE_SIZE, &iova_size)) > + return -EINVAL; -EOVERFLOW and everywhere else > + > + if (check_add_overflow(user_iova, iova_size - 1, &iova_end)) > + return -EINVAL; Let's be consistent with iommufd/etc, 'end' is start+size 'last' is start+size-1 Otherwise it is super confusing :( Jason