ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event()

A tun device type can trivially be set to arbitrary value using
TUNSETLINK ioctl().

Therefore, lowpan_device_event() must really check that ieee802154_ptr
is not NULL.

Fixes: 2c88b5283f ("ieee802154: 6lowpan: remove check on null")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Alexander Aring <[email protected]>
Cc: Stefan Schmidt <[email protected]>
Reported-by: syzbot <[email protected]>
Acked-by: Stefan Schmidt <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
This commit is contained in:
Eric Dumazet authored and David S. Miller committed 2018-03-09 11:19:26 -05:00
1 parent 9f62c15f28
commit ca0edb131b
1 file changed
+8 -4
+8 -4
View File
@@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(void)
static int lowpan_device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *wdev = netdev_notifier_info_to_dev(ptr);
struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
struct wpan_dev *wpan_dev;
if (wdev->type != ARPHRD_IEEE802154)
if (ndev->type != ARPHRD_IEEE802154)
return NOTIFY_DONE;
wpan_dev = ndev->ieee802154_ptr;
if (!wpan_dev)
return NOTIFY_DONE;
switch (event) {
@@ -217,8 +221,8 @@ static int lowpan_device_event(struct notifier_block *unused,
* also delete possible lowpan interfaces which belongs
* to the wpan interface.
*/
if (wdev->ieee802154_ptr->lowpan_dev)
lowpan_dellink(wdev->ieee802154_ptr->lowpan_dev, NULL);
if (wpan_dev->lowpan_dev)
lowpan_dellink(wpan_dev->lowpan_dev, NULL);
break;
default:
return NOTIFY_DONE;