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From:   Stefano Garzarella <sgarzare@redhat.com>
To:     virtualization@lists.linux-foundation.org
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Parav Pandit <parav@nvidia.com>, Eli Cohen <elic@nvidia.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] vdpa/mlx5: fix param validation in mlx5_vdpa_get_config()
Date:   Mon,  8 Feb 2021 17:17:41 +0100
Message-Id: <20210208161741.104939-1-sgarzare@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It's legal to have 'offset + len' equal to
sizeof(struct virtio_net_config), since 'ndev->config' is a
'struct virtio_net_config', so we can safely copy its content under
this condition.

Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index dc88559a8d49..10e9b09932eb 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1820,7 +1820,7 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 
-	if (offset + len < sizeof(struct virtio_net_config))
+	if (offset + len <= sizeof(struct virtio_net_config))
 		memcpy(buf, (u8 *)&ndev->config + offset, len);
 }
 
-- 
2.29.2