ieee802154: Fix oops during ieee802154_sock_ioctl

Trying to run izlisten (from lowpan-tools tests) on a device that does not
exists I got the oops below. The problem is that we are using get_dev_by_name
without checking if we really get a device back. We don't in this case and
writing to dev->type generates this oops.

[Oops code removed by Dmitry Eremin-Solenikov]

If possible this patch should be applied to the current -rc fixes branch.

Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ieee802154/af_ieee802154.c b/net/ieee802154/af_ieee802154.c
index c7da600750bb..93c91b633a56 100644
--- a/net/ieee802154/af_ieee802154.c
+++ b/net/ieee802154/af_ieee802154.c
@@ -151,6 +151,9 @@ static int ieee802154_dev_ioctl(struct sock *sk, struct ifreq __user *arg,
         dev_load(sock_net(sk), ifr.ifr_name);
         dev = dev_get_by_name(sock_net(sk), ifr.ifr_name);
 
+        if (!dev)
+                return -ENODEV;
+
         if (dev->type == ARPHRD_IEEE802154 && dev->netdev_ops->ndo_do_ioctl)
                 ret = dev->netdev_ops->ndo_do_ioctl(dev, &ifr, cmd);