[PATCH 4.14 64/77] mac80211: Fix kernel panic due to use of txq after free

Greg Kroah-Hartman
2019-05-23T19:13:09Z

[ Upstream commit f1267cf3c01b12e0f843fb6a7450a7f0b2efab8a ]

The txq of vif is added to active_txqs list for ATF TXQ scheduling
in the function ieee80211_queue_skb(), but it was not properly removed
before freeing the txq object. It was causing use after free of the txq
objects from the active_txqs list, result was kernel panic
due to invalid memory access.

Fix kernel invalid memory access by properly removing txq object
from active_txqs list before free the object.

Signed-off-by: Bhagavathi Perumal S <bperumal@codeaurora.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/mac80211/iface.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 222c063244f56..6ce13e976b7a2 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1924,6 +1924,9 @@ void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata)
list_del_rcu(&sdata->list);
mutex_unlock(&sdata->local->iflist_mtx);

+ if (sdata->vif.txq)
+ ieee80211_txq_purge(sdata->local, to_txq_info(sdata->vif.txq));
+
synchronize_rcu();

if (sdata->dev) {
--
2.20.1