zd1211rw: fix potential use-after-free bug
zd_mac_tx_to_dev() could potentially free the skb, or hand it off
to mac80211 which might free it. Hence, this code needs to get the
usb pointer out of skb->cb before handing it off to that function.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index 5316074..12e24f0 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zd1211rw/zd_usb.c
@@ -889,9 +889,13 @@
}
free_urb:
skb = (struct sk_buff *)urb->context;
- zd_mac_tx_to_dev(skb, urb->status);
+ /*
+ * grab 'usb' pointer before handing off the skb (since
+ * it might be freed by zd_mac_tx_to_dev or mac80211)
+ */
cb = (struct zd_tx_skb_control_block *)skb->cb;
usb = &zd_hw_mac(cb->hw)->chip.usb;
+ zd_mac_tx_to_dev(skb, urb->status);
free_tx_urb(usb, urb);
tx_dec_submitted_urbs(usb);
return;