On Mon, Nov 28, 2022 at 01:58:00PM +0300, Dan Carpenter wrote:
On Mon, Nov 28, 2022 at 11:53:12AM +0100, Stefano Garzarella wrote:
On Mon, Nov 28, 2022 at 12:36:26AM -0800, Harshit Mogalapalli wrote:
> Add a limit to 'config->vq_num' which is user controlled data which
> comes from an vduse_ioctl to prevent large memory allocations.
>
> This is found using static analysis with smatch.
>
> Suggested-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
> ---
> v1->v2: Change title of the commit and description, add a limit to
> vq_num.
>
> Note: I think here 0xffff is the max size of vring = no: of vqueues.
> Only compile and boot tested.
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 35dceee3ed56..31017ebc4d7c 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1440,6 +1440,9 @@ static bool vduse_validate_config(struct vduse_dev_config *config)
> if (config->config_size > PAGE_SIZE)
> return false;
>
> + if (config->vq_num > 0xffff)
What about using U16_MAX here?
Where is the ->vq_num stored in a u16? I looked for this but didn't
see it.
I thought vq_num referred to the number of elements in the vq (like
.get_vq_num_max), since this patch wants to limit to 0xffff.
But it actually refers to the number of virtqueue, so @Harshit why do we
limit it to 0xffff?
Maybe we should explain it in the commit message or in a comment.
Thanks,
Stefano
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
