From c09cc2c319863f620caf5e723db496eed55f7c7f Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 10 Jun 2020 11:58:52 +0300 Subject: [PATCH] vhost_vdpa: Fix potential underflow in vhost_vdpa_mmap() 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 Link: https://lore.kernel.org/r/20200610085852.GB5439@mwanda Signed-off-by: Michael S. Tsirkin --- 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 7580e34..a54b60d 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; -- 2.7.4