7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhiling Zou commit bf79662bc85e820ac3b846e2f347da29fbf6ac95 upstream. TUNSETLINK allows a TUN device to change its link-layer type to ARPHRD_IEEE802154 without initializing ieee802154_ptr. lowpan_newlink() checks only the device type before dereferencing the pointer, so an RTM_NEWLINK request can trigger a NULL pointer dereference. Reject devices without ieee802154_ptr along with devices of the wrong type. Fixes: 51e0e5d8124e ("ieee802154: 6lowpan: remove multiple lowpan per wpan support") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Link: https://lore.kernel.org/0b715da69bd15a86ddc47dad5cf12da648211050.1787997209.git.zhilinz@nebusec.ai Signed-off-by: Stefan Schmidt Signed-off-by: Greg Kroah-Hartman --- net/ieee802154/6lowpan/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ieee802154/6lowpan/core.c +++ b/net/ieee802154/6lowpan/core.c @@ -150,7 +150,7 @@ static int lowpan_newlink(struct net_dev wdev = dev_get_by_index(dev_net(ldev), nla_get_u32(tb[IFLA_LINK])); if (!wdev) return -ENODEV; - if (wdev->type != ARPHRD_IEEE802154) { + if (wdev->type != ARPHRD_IEEE802154 || !wdev->ieee802154_ptr) { dev_put(wdev); return -EINVAL; }