2021-05-17 16:30:06

by Johannes Berg

[permalink] [raw]
Subject: [PATCH] mac80211_hwsim: drop pending frames on stop

From: Johannes Berg <[email protected]>

Syzbot reports that we may be able to get into a situation where
mac80211 has pending ACK frames on shutdown with hwsim. It appears
that the reason for this is that syzbot uses the wmediumd hooks to
intercept/injection frames, and may shut down hwsim, removing the
radio(s), while frames are pending in the air simulation.

Clean out the pending queue when the interface is stopped, after
this the frames can't be reported back to mac80211 properly anyway.

Reported-by: [email protected]
#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ master
Signed-off-by: Johannes Berg <[email protected]>
drivers/net/wireless/mac80211_hwsim.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 51ce767eaf88..7a6fd46d0c6e 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -1693,8 +1693,13 @@ static int mac80211_hwsim_start(struct ieee80211_hw *hw)
static void mac80211_hwsim_stop(struct ieee80211_hw *hw)
struct mac80211_hwsim_data *data = hw->priv;
data->started = false;
+ while (!skb_queue_empty(&data->pending))
+ ieee80211_free_txskb(hw, skb_dequeue(&data->pending));
wiphy_dbg(hw->wiphy, "%s\n", __func__);