KVM: make checks stricter in coalesced_mmio_in_range()
My testing version of Smatch complains that addr and len come from
the user and they can wrap. The path is:
-> kvm_vm_ioctl()
-> kvm_vm_ioctl_unregister_coalesced_mmio()
-> coalesced_mmio_in_range()
I don't know what the implications are of wrapping here, but we may
as well fix it, if only to silence the warning.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index a6ec206..88b2fe3 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -28,9 +28,15 @@
* (addr,len) is fully included in
* (zone->addr, zone->size)
*/
-
- return (dev->zone.addr <= addr &&
- addr + len <= dev->zone.addr + dev->zone.size);
+ if (len < 0)
+ return 0;
+ if (addr + len < addr)
+ return 0;
+ if (addr < dev->zone.addr)
+ return 0;
+ if (addr + len > dev->zone.addr + dev->zone.size)
+ return 0;
+ return 1;
}
static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev)