Re: [PATCH v2] vduse: Fix off by one in vduse_dev_mmap()

[Stefan Hajnoczi]

On Wed, 28 Feb 2024 at 12:44, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> The dev->vqs[] array has "dev->vq_num" elements.  It's allocated in
> vduse_dev_init_vqs().  Thus, this > comparison needs to be >= to avoid
> reading one element beyond the end of the array.
>
> Add an array_index_nospec() as well to prevent speculation issues.
>
> Fixes: 316ecd1346b0 ("vduse: Add file operation for mmap")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> v2: add array_index_nospec().

Did you forget to update the patch, I don't see array_index_nospec()?

>
>  drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index b7a1fb88c506..eb914084c650 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1532,9 +1532,10 @@ static int vduse_dev_mmap(struct file *file, struct vm_area_struct *vma)
>         if ((vma->vm_flags & VM_SHARED) == 0)
>                 return -EINVAL;
>
> -       if (index > dev->vq_num)
> +       if (index >= dev->vq_num)
>                 return -EINVAL;
>
>         vq = dev->vqs[index];
>         vaddr = vq->vdpa_reconnect_vaddr;
>         if (vaddr == 0)
> --
> 2.43.0
>
>