if_epair abused the ifr_data field to insert its second interface in
IFC_IFLIST. If userspace provides a value for ifr_data it would get
dereferenced by the kernel leading to a panic.
Reported by: Ilja Van Sprundel <ivansprundel@ioactive.com>
MFC after: 3 days
Set up two jails connected by an epair. Create VLAN interfaces in both
jails and check connectivity.
This is a very basic test, but exposed panics during the network stack
epoch work, so this is worth testing.
There was a problem destroying renamed tun interfaces in vnet jails. This was
fixed in r344794. Test the previously failing scenario.
PR: 235704
MFC after: 2 weeks
