From bf79662bc85e820ac3b846e2f347da29fbf6ac95 Mon Sep 17 00:00:00 2001 From: Zhiling Zou Date: Sat, 29 Aug 2026 18:07:23 +0800 Subject: [PATCH] ieee802154: 6lowpan: fix NULL dereference in lowpan_newlink 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 --- net/ieee802154/6lowpan/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ieee802154/6lowpan/core.c b/net/ieee802154/6lowpan/core.c index 018929563c6b..6a8d6852cb93 100644 --- a/net/ieee802154/6lowpan/core.c +++ b/net/ieee802154/6lowpan/core.c @@ -150,7 +150,7 @@ static int lowpan_newlink(struct net_device *ldev, 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; }