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From: Cindy Lu <lulu@redhat.com>
Date: Thu, 29 Feb 2024 15:21:09 +0800
Message-ID: <CACLfguXksa4TEb5gk2bvoeGaQrR8s5TZMJGzR0r7Y9Wo9N82UQ@mail.gmail.com>
Subject: Re: [PATCH v3] vduse: Fix off by one in vduse_dev_mmap()
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>, "Michael S. Tsirkin" <mst@redhat.com>, 
	Jason Wang <jasowang@redhat.com>, Xuan Zhuo <xuanzhuo@linux.alibaba.com>, 
	Xie Yongji <xieyongji@bytedance.com>, Maxime Coquelin <maxime.coquelin@redhat.com>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Christian Brauner <brauner@kernel.org>, 
	virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, 
	kernel-janitors@vger.kernel.org
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On Thu, Feb 29, 2024 at 3:19=E2=80=AFAM Stefan Hajnoczi <stefanha@gmail.com=
> wrote:
>
> On Wed, 28 Feb 2024 at 13:24, Dan Carpenter <dan.carpenter@linaro.org> wr=
ote:
> >
> > The dev->vqs[] array has "dev->vq_num" elements.  It's allocated in
> > vduse_dev_init_vqs().  Thus, this > comparison needs to be >=3D to avoi=
d
> > 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@linaro.org>
> > ---
> > v2: add array_index_nospec()
> > v3: I accidentally corrupted v2.  Try again.
> >
Thanks for fix this
> >  drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by:  Cindy Lu <lulu@redhat.com>
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_use=
r/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, str=
uct vm_area_struct *vma)
> >         if ((vma->vm_flags & VM_SHARED) =3D=3D 0)
> >                 return -EINVAL;
> >
> > -       if (index > dev->vq_num)
> > +       if (index >=3D dev->vq_num)
> >                 return -EINVAL;
> >
> > +       index =3D array_index_nospec(index, dev->vq_num);
> >         vq =3D dev->vqs[index];
> >         vaddr =3D vq->vdpa_reconnect_vaddr;
> >         if (vaddr =3D=3D 0)
> > --
> > 2.43.0
> >
> >
>