tun: forbid iface creation with rtnl ops
authorNicolas Dichtel <nicolas.dichtel@6wind.com>
Thu, 29 Nov 2018 13:45:39 +0000 (14:45 +0100)
committerDavid S. Miller <davem@davemloft.net>
Sat, 1 Dec 2018 01:31:03 +0000 (17:31 -0800)
commit35b827b6d06199841a83839e8bb69c0cd13a28be
treec1f0b4a3bd4cb90103cecd23122d207cfea74c72
parent436c9453a1ac0944b82870ef2e0d9be956b396d9
tun: forbid iface creation with rtnl ops

It's not supported right now (the goal of the initial patch was to support
'ip link del' only).

Before the patch:
$ ip link add foo type tun
[  239.632660] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[snip]
[  239.636410] RIP: 0010:register_netdevice+0x8e/0x3a0

This panic occurs because dev->netdev_ops is not set by tun_setup(). But to
have something usable, it will require more than just setting
netdev_ops.

Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/tun.c