From a7bea9f4fecce0afd37ee58a552eef71d8b4ab9f Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 18 Sep 2023 16:56:16 -0400 Subject: vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info The memory layout of struct vfio_device_gfx_plane_info is architecture-dependent due to a u64 field and a struct size that is not a multiple of 8 bytes: - On x86_64 the struct size is padded to a multiple of 8 bytes. - On x32 the struct size is only a multiple of 4 bytes, not 8. - Other architectures may vary. Use __aligned_u64 to make memory layout consistent. This reduces the chance of 32-bit userspace on a 64-bit kernel breakage. This patch increases the struct size on x32 but this is safe because of the struct's argsz field. The kernel may grow the struct as long as it still supports smaller argsz values from userspace (e.g. applications compiled against older kernel headers). Suggested-by: Jason Gunthorpe Reviewed-by: Kevin Tian Signed-off-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/20230918205617.1478722-3-stefanha@redhat.com Signed-off-by: Alex Williamson --- samples/vfio-mdev/mbochs.c | 2 +- samples/vfio-mdev/mdpy.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'samples/vfio-mdev') diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index 3764d1911b51..93405264ff23 100644 --- a/samples/vfio-mdev/mbochs.c +++ b/samples/vfio-mdev/mbochs.c @@ -1262,7 +1262,7 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd, case VFIO_DEVICE_QUERY_GFX_PLANE: { - struct vfio_device_gfx_plane_info plane; + struct vfio_device_gfx_plane_info plane = {}; minsz = offsetofend(struct vfio_device_gfx_plane_info, region_index); diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index 064e1c0a7aa8..72ea5832c927 100644 --- a/samples/vfio-mdev/mdpy.c +++ b/samples/vfio-mdev/mdpy.c @@ -591,7 +591,7 @@ static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd, case VFIO_DEVICE_QUERY_GFX_PLANE: { - struct vfio_device_gfx_plane_info plane; + struct vfio_device_gfx_plane_info plane = {}; minsz = offsetofend(struct vfio_device_gfx_plane_info, region_index); -- cgit v1.2.3