| Message ID | 20181129134539.24483-1-nicolas.dichtel@6wind.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] tun: forbid iface creation with rtnl ops | expand |
From: Nicolas Dichtel <nicolas.dichtel@6wind.com> Date: Thu, 29 Nov 2018 14:45:39 +0100 > 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> Super old bug, scary. Applied, thanks.
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e244f5d7512a..cf349e65a66b 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -2293,9 +2293,9 @@ static void tun_setup(struct net_device *dev) static int tun_validate(struct nlattr *tb[], struct nlattr *data[], struct netlink_ext_ack *extack) { - if (!data) - return 0; - return -EINVAL; + NL_SET_ERR_MSG(extack, + "tun/tap creation via rtnetlink is not supported."); + return -EOPNOTSUPP; } static size_t tun_get_size(const struct net_device *dev)
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> --- drivers/net/tun.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)