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: ddd89d0a05 ("vhost_vdpa: support doorbell mapping via mmap")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200610085852.GB5439@mwanda
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Dan Carpenter 2020-06-10 11:58:52 +03:00 committed by Michael S. Tsirkin
parent 24eae8ebfb
commit c09cc2c319

View file

@ -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;