[PATCH] mac80211: fix issue with possible txq NULL pointer

[PATCH] mac80211: fix issue with possible txq NULL pointer

[Erik Stromdahl]

Drivers that do not have the BUFF_MMPDU_TXQ flag set will not have a
TXQ for the special TID = 16.

In this case, the last member in the *struct ieee80211_sta* txq array
will be NULL.

We must check this in order not to get a NULL pointer dereference when
iterating the txq array.

Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
---
 net/mac80211/util.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 36a3c2ada515..ef5d1f60a63b 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -264,6 +264,9 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
 		for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
 			struct ieee80211_txq *txq = sta->sta.txq[i];
 
+			if (!txq)
+				continue;
+
 			txqi = to_txq_info(txq);
 
 			if (ac != txq->ac)
-- 
2.18.0

Re: [PATCH] mac80211: fix issue with possible txq NULL pointer

[Johannes Berg]

On Fri, 2018-09-14 at 18:00 +0200, Erik Stromdahl wrote:
> Drivers that do not have the BUFF_MMPDU_TXQ flag set will not have a
> TXQ for the special TID = 16.
> 
> In this case, the last member in the *struct ieee80211_sta* txq array
> will be NULL.
> 
> We must check this in order not to get a NULL pointer dereference when
> iterating the txq array.

Uh, yes, thanks. This is my fault - I merged the overlapping patches
closely together.

johannes