[PATCH AUTOSEL 4.19 076/106] rtlwifi: Fix a double free in _rtl_usb_tx_urb_setup()
From: Sasha Levin <sashal@kernel.org>
Date: 2020-06-08 23:30:17
Also in:
lkml, netdev, stable
Subsystem:
realtek wireless driver (rtlwifi family), the rest · Maintainers:
Ping-Ke Shih, Linus Torvalds
From: Dan Carpenter <redacted>
[ Upstream commit beb12813bc75d4a23de43b85ad1c7cb28d27631e ]
Seven years ago we tried to fix a leak but actually introduced a double
free instead. It was an understandable mistake because the code was a
bit confusing and the free was done in the wrong place. The "skb"
pointer is freed in both _rtl_usb_tx_urb_setup() and _rtl_usb_transmit().
The free belongs _rtl_usb_transmit() instead of _rtl_usb_tx_urb_setup()
and I've cleaned the code up a bit to hopefully make it more clear.
Fixes: 36ef0b473fbf ("rtlwifi: usb: add missing freeing of skbuff")
Signed-off-by: Dan Carpenter <redacted>
Signed-off-by: Kalle Valo <redacted>
Link: https://lore.kernel.org/r/20200513093951.GD347693@mwanda (local)
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/realtek/rtlwifi/usb.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/usb.c b/drivers/net/wireless/realtek/rtlwifi/usb.c
index 1181b725f503..1893640555c1 100644
--- a/drivers/net/wireless/realtek/rtlwifi/usb.c
+++ b/drivers/net/wireless/realtek/rtlwifi/usb.c@@ -910,10 +910,8 @@ static struct urb *_rtl_usb_tx_urb_setup(struct ieee80211_hw *hw, WARN_ON(NULL == skb); _urb = usb_alloc_urb(0, GFP_ATOMIC); - if (!_urb) { - kfree_skb(skb); + if (!_urb) return NULL; - } _rtl_install_trx_info(rtlusb, skb, ep_num); usb_fill_bulk_urb(_urb, rtlusb->udev, usb_sndbulkpipe(rtlusb->udev, ep_num), skb->data, skb->len, _rtl_tx_complete, skb);
@@ -927,7 +925,6 @@ static void _rtl_usb_transmit(struct ieee80211_hw *hw, struct sk_buff *skb, struct rtl_usb *rtlusb = rtl_usbdev(rtl_usbpriv(hw)); u32 ep_num; struct urb *_urb = NULL; - struct sk_buff *_skb = NULL; WARN_ON(NULL == rtlusb->usb_tx_aggregate_hdl); if (unlikely(IS_USB_STOP(rtlusb))) {
@@ -936,8 +933,7 @@ static void _rtl_usb_transmit(struct ieee80211_hw *hw, struct sk_buff *skb, return; } ep_num = rtlusb->ep_map.ep_mapping[qnum]; - _skb = skb; - _urb = _rtl_usb_tx_urb_setup(hw, _skb, ep_num); + _urb = _rtl_usb_tx_urb_setup(hw, skb, ep_num); if (unlikely(!_urb)) { pr_err("Can't allocate urb. Drop skb!\n"); kfree_skb(skb);
--
2.25.1