[PATCH 4.9 73/92] mwifiex: Fix NULL pointer dereference in skb_dequeue()

Greg Kroah-Hartman
2018-11-29T14:23:18Z

From: Amitkumar Karwar <akarwar@marvell.com>

commit c44c040300d7afd79294710313a4989683e2afb1 upstream.

At couple of places in cleanup path, we are just going through the
skb queue and freeing them without unlinking. This leads to a crash
when other thread tries to do skb_dequeue() and use already freed node.

The problem is freed by unlinking skb before freeing it.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/marvell/mwifiex/cfg80211.c | 4 +++-
drivers/net/wireless/marvell/mwifiex/wmm.c | 12 +++++++++---
2 files changed, 12 insertions(+), 4 deletions(-)

--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -3079,8 +3079,10 @@ int mwifiex_del_virtual_intf(struct wiph

mwifiex_stop_net_dev_queue(priv->netdev, adapter);

- skb_queue_walk_safe(&priv->bypass_txq, skb, tmp)
+ skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) {
+ skb_unlink(skb, &priv->bypass_txq);
mwifiex_write_data_complete(priv->adapter, skb, 0, -1);
+ }

if (netif_carrier_ok(priv->netdev))
netif_carrier_off(priv->netdev);
--- a/drivers/net/wireless/marvell/mwifiex/wmm.c
+++ b/drivers/net/wireless/marvell/mwifiex/wmm.c
@@ -503,8 +503,10 @@ mwifiex_wmm_del_pkts_in_ralist_node(stru
struct mwifiex_adapter *adapter = priv->adapter;
struct sk_buff *skb, *tmp;

- skb_queue_walk_safe(&ra_list->skb_head, skb, tmp)
+ skb_queue_walk_safe(&ra_list->skb_head, skb, tmp) {
+ skb_unlink(skb, &ra_list->skb_head);
mwifiex_write_data_complete(adapter, skb, 0, -1);
+ }
}

/*
@@ -600,11 +602,15 @@ mwifiex_clean_txrx(struct mwifiex_privat
priv->adapter->if_ops.clean_pcie_ring(priv->adapter);
spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, flags);

- skb_queue_walk_safe(&priv->tdls_txq, skb, tmp)
+ skb_queue_walk_safe(&priv->tdls_txq, skb, tmp) {
+ skb_unlink(skb, &priv->tdls_txq);
mwifiex_write_data_complete(priv->adapter, skb, 0, -1);
+ }

- skb_queue_walk_safe(&priv->bypass_txq, skb, tmp)
+ skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) {
+ skb_unlink(skb, &priv->bypass_txq);
mwifiex_write_data_complete(priv->adapter, skb, 0, -1);
+ }
atomic_set(&priv->adapter->bypass_tx_pending, 0);

idr_for_each(&priv->ack_status_frames, mwifiex_free_ack_frame, NULL);