[PATCH][next] vfio/iommu_type1: Use struct_size() for kzalloc()

From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
To: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-hardening@vger.kernel.org
Subject: [PATCH][next] vfio/iommu_type1: Use struct_size() for kzalloc()
Date: Thu, 13 May 2021 18:01:55 -0500	[thread overview]
Message-ID: <20210513230155.GA217517@embeddedor> (raw)

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows
that, in the worst scenario, could lead to heap overflows.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index a0747c35a778..a3e925a41b0d 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2795,7 +2795,7 @@ static int vfio_iommu_iova_build_caps(struct vfio_iommu *iommu,
 		return 0;
 	}
 
-	size = sizeof(*cap_iovas) + (iovas * sizeof(*cap_iovas->iova_ranges));
+	size = struct_size(cap_iovas, iova_ranges, iovas);
 
 	cap_iovas = kzalloc(size, GFP_KERNEL);
 	if (!cap_iovas)
-- 
2.27.0

