On Tue, Feb 15, 2022 at 5:15 PM Rob Clark <robdcl...@gmail.com> wrote:
> From: Rob Clark <robdcl...@chromium.org>
>
> The UABI was already defined for pointer to 64b value, and all the
> userspace users of this ioctl that I could find are already using a
> uint64_t (but zeroing it out to work around kernel only copying 32b).
> Unfortunately this ioctl doesn't have a length field, so out of paranoia
> I restricted the change to copy 64b to the single 64b param that can be
> queried.
>
> Fixes: 78aa20fa4381 ("drm/virtio: implement context init: advertise
> feature to userspace")
> Signed-off-by: Rob Clark <robdcl...@chromium.org>
>
Reviewed-by: Gurchetan Singh <gurchetansi...@chromium.org>
> ---
> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 0f2f3f54dbf9..0158d27d5645 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -269,7 +269,8 @@ static int virtio_gpu_getparam_ioctl(struct drm_device
> *dev, void *data,
> {
> struct virtio_gpu_device *vgdev = dev->dev_private;
> struct drm_virtgpu_getparam *param = data;
> - int value;
> + int value, ret, sz = sizeof(int);
> + uint64_t value64;
>
> switch (param->param) {
> case VIRTGPU_PARAM_3D_FEATURES:
> @@ -291,13 +292,20 @@ static int virtio_gpu_getparam_ioctl(struct
> drm_device *dev, void *data,
> value = vgdev->has_context_init ? 1 : 0;
> break;
> case VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs:
> - value = vgdev->capset_id_mask;
> + value64 = vgdev->capset_id_mask;
> + sz = sizeof(value64);
> break;
> default:
> return -EINVAL;
> }
> - if (copy_to_user(u64_to_user_ptr(param->value), &value,
> sizeof(int)))
> - return -EFAULT;
> +
> + if (sz == sizeof(int)) {
> + if (copy_to_user(u64_to_user_ptr(param->value), &value,
> sz))
> + return -EFAULT;
> + } else {
> + if (copy_to_user(u64_to_user_ptr(param->value), &value64,
> sz))
> + return -EFAULT;
> + }
>
> return 0;
> }
> --
> 2.34.1
>
>
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