From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] vhost_vdpa: Fix potential underflow in vhost_vdpa_mmap() Date: Wed, 10 Jun 2020 05:39:35 -0400 Message-ID: <20200610053926-mutt-send-email-mst@kernel.org> References: <20200610085852.GB5439@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200610085852.GB5439@mwanda> Sender: kernel-janitors-owner@vger.kernel.org To: Dan Carpenter Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, kernel-janitors@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org On Wed, Jun 10, 2020 at 11:58:52AM +0300, Dan Carpenter wrote: > The "vma->vm_pgoff" variable is an unsigned long so if it's larger than > INT_MAX then "index" can be negative leading to an underflow. Fix this > by changing the type of "index" to "unsigned long". > > Fixes: ddd89d0a059d ("vhost_vdpa: support doorbell mapping via mmap") > Signed-off-by: Dan Carpenter Applied, thanks! > --- > drivers/vhost/vdpa.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 7580e34f76c10..a54b60d6623f0 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -818,7 +818,7 @@ static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma) > struct vdpa_device *vdpa = v->vdpa; > const struct vdpa_config_ops *ops = vdpa->config; > struct vdpa_notification_area notify; > - int index = vma->vm_pgoff; > + unsigned long index = vma->vm_pgoff; > > if (vma->vm_end - vma->vm_start != PAGE_SIZE) > return -EINVAL; > -- > 2.26.2