In ieee80211_setup_sdata(), there is an if statement on line 1410 to check whether sdata->dev is NULL: if (sdata->dev) When sdata->dev is NULL, it is used on lines 1458 and 1459: sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP; sdata->dev->netdev_ops = &ieee80211_monitorif_ops; Thus, possible null-pointer dereferences may occur. To fix these bugs, sdata->dev is checked before being used. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx> --- net/mac80211/iface.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 06aac0aaae64..e49264981a7b 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -1455,8 +1455,10 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata, ieee80211_mesh_init_sdata(sdata); break; case NL80211_IFTYPE_MONITOR: - sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP; - sdata->dev->netdev_ops = &ieee80211_monitorif_ops; + if (sdata->dev) { + sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP; + sdata->dev->netdev_ops = &ieee80211_monitorif_ops; + } sdata->u.mntr.flags = MONITOR_FLAG_CONTROL | MONITOR_FLAG_OTHER_BSS; break; -- 2.17.0