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: 51e0e5d812 ("ieee802154: 6lowpan: remove multiple lowpan per wpan support")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai>
Link: https://lore.kernel.org/0b715da69bd15a86ddc47dad5cf12da648211050.1787997209.git.zhilinz@nebusec.ai
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
bf79662bc8