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Commit ca0edb13 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: 2c88b528 ("ieee802154: 6lowpan: remove check on null")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@osg.samsung.com>
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Acked-by: default avatarStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9f62c15f

net/ieee802154/6lowpan/core.c

+8 −4
Original line number Diff line number Diff line
@@ -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;