| Message ID | 20190724123623.10093-1-baijiaju1990@gmail.com |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | David Miller |
| Headers | show |
| Series | [1/2] net: mac80211: Fix possible null-pointer dereferences in ieee80211_setup_sdata() | expand |
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
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;
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@gmail.com> --- net/mac80211/iface.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)