Re: [PATCH 1/2] net: mac80211: Fix possible null-pointer dereferences in ieee80211_setup_sdata()

[Johannes Berg]

On Wed, 2019-07-24 at 20:36 +0800, Jia-Ju Bai wrote:
> 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.

No, this cannot happen, monitor interfaces (NL80211_IFTYPE_MONITOR) must
have a valid ->dev, only P2P device and NAN might not.

johannes