From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Alexander Aring , Stefan Schmidt , syzbot , "David S. Miller" Subject: [PATCH 4.15 23/47] ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event() Date: Thu, 29 Mar 2018 20:00:04 +0200 Message-Id: <20180329175730.973977320@linuxfoundation.org> In-Reply-To: <20180329175729.225211114@linuxfoundation.org> References: <20180329175729.225211114@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit ca0edb131bdf1e6beaeb2b8289fd6b374b74147d ] 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: 2c88b5283f60d ("ieee802154: 6lowpan: remove check on null") Signed-off-by: Eric Dumazet Cc: Alexander Aring Cc: Stefan Schmidt Reported-by: syzbot Acked-by: Stefan Schmidt Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ieee802154/6lowpan/core.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/net/ieee802154/6lowpan/core.c +++ b/net/ieee802154/6lowpan/core.c @@ -206,9 +206,13 @@ static inline void lowpan_netlink_fini(v 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 no * 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;