ath9k: Fix use-after-free Read in ath9k_wmi_ctrl_rx

Free wmi later after cmd urb has been killed, as urb cb will access wmi.

the case reported by syzbot:
https://lore.kernel.org/linux-usb/0000000000000002fc05a1d61a68@google.com
BUG: KASAN: use-after-free in ath9k_wmi_ctrl_rx+0x416/0x500
drivers/net/wireless/ath/ath9k/wmi.c:215
Read of size 1 at addr ffff8881cef1417c by task swapper/1/0

Call Trace:
<IRQ>
ath9k_wmi_ctrl_rx+0x416/0x500 drivers/net/wireless/ath/ath9k/wmi.c:215
ath9k_htc_rx_msg+0x2da/0xaf0
drivers/net/wireless/ath/ath9k/htc_hst.c:459
ath9k_hif_usb_reg_in_cb+0x1ba/0x630
drivers/net/wireless/ath/ath9k/hif_usb.c:718
__usb_hcd_giveback_urb+0x29a/0x550 drivers/usb/core/hcd.c:1650
usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1716
dummy_timer+0x1258/0x32ae drivers/usb/gadget/udc/dummy_hcd.c:1966
call_timer_fn+0x195/0x6f0 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0x5f9/0x1500 kernel/time/timer.c:1786

Reported-and-tested-by: syzbot+5d338854440137ea0fef@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200404041838.10426-3-hqjagain@gmail.com

drivers/net/wireless/ath/ath9k/hif_usb.c

@@ -973,7 +973,7 @@ static int ath9k_hif_usb_alloc_urbs(struct hif_device_usb *hif_dev)
 	return -ENOMEM;
 }
 
-static void ath9k_hif_usb_dealloc_urbs(struct hif_device_usb *hif_dev)
+void ath9k_hif_usb_dealloc_urbs(struct hif_device_usb *hif_dev)
 {
 	usb_kill_anchored_urbs(&hif_dev->regout_submitted);
 	ath9k_hif_usb_dealloc_reg_in_urbs(hif_dev);
@@ -1341,8 +1341,9 @@ static void ath9k_hif_usb_disconnect(struct usb_interface *interface)
 
 	if (hif_dev->flags & HIF_USB_READY) {
 		ath9k_htc_hw_deinit(hif_dev->htc_handle, unplugged);
-		ath9k_htc_hw_free(hif_dev->htc_handle);
 		ath9k_hif_usb_dev_deinit(hif_dev);
+		ath9k_destoy_wmi(hif_dev->htc_handle->drv_priv);
+		ath9k_htc_hw_free(hif_dev->htc_handle);
 	}
 
 	usb_set_intfdata(interface, NULL);

drivers/net/wireless/ath/ath9k/hif_usb.h

@@ -133,5 +133,6 @@ struct hif_device_usb {
 
 int ath9k_hif_usb_init(void);
 void ath9k_hif_usb_exit(void);
+void ath9k_hif_usb_dealloc_urbs(struct hif_device_usb *hif_dev);
 
 #endif /* HTC_USB_H */

drivers/net/wireless/ath/ath9k/htc_drv_init.c

@@ -931,8 +931,9 @@ static int ath9k_init_device(struct ath9k_htc_priv *priv,
 int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 			   u16 devid, char *product, u32 drv_info)
 {
-	struct ieee80211_hw *hw;
+	struct hif_device_usb *hif_dev;
 	struct ath9k_htc_priv *priv;
+	struct ieee80211_hw *hw;
 	int ret;
 
 	hw = ieee80211_alloc_hw(sizeof(struct ath9k_htc_priv), &ath9k_htc_ops);
@@ -967,7 +968,10 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	return 0;
 
 err_init:
-	ath9k_deinit_wmi(priv);
+	ath9k_stop_wmi(priv);
+	hif_dev = (struct hif_device_usb *)htc_handle->hif_dev;
+	ath9k_hif_usb_dealloc_urbs(hif_dev);
+	ath9k_destoy_wmi(priv);
 err_free:
 	ieee80211_free_hw(hw);
 	return ret;
@@ -982,7 +986,7 @@ void ath9k_htc_disconnect_device(struct htc_target *htc_handle, bool hotunplug)
 			htc_handle->drv_priv->ah->ah_flags |= AH_UNPLUGGED;
 
 		ath9k_deinit_device(htc_handle->drv_priv);
-		ath9k_deinit_wmi(htc_handle->drv_priv);
+		ath9k_stop_wmi(htc_handle->drv_priv);
 		ieee80211_free_hw(htc_handle->drv_priv->hw);
 	}
 }

drivers/net/wireless/ath/ath9k/wmi.c

@@ -112,14 +112,17 @@ struct wmi *ath9k_init_wmi(struct ath9k_htc_priv *priv)
 	return wmi;
 }
 
-void ath9k_deinit_wmi(struct ath9k_htc_priv *priv)
+void ath9k_stop_wmi(struct ath9k_htc_priv *priv)
 {
 	struct wmi *wmi = priv->wmi;
 
 	mutex_lock(&wmi->op_mutex);
 	wmi->stopped = true;
 	mutex_unlock(&wmi->op_mutex);
+}
 
+void ath9k_destoy_wmi(struct ath9k_htc_priv *priv)
+{
 	kfree(priv->wmi);
 }
 

drivers/net/wireless/ath/ath9k/wmi.h

@@ -179,7 +179,6 @@ struct wmi {
 };
 
 struct wmi *ath9k_init_wmi(struct ath9k_htc_priv *priv);
-void ath9k_deinit_wmi(struct ath9k_htc_priv *priv);
 int ath9k_wmi_connect(struct htc_target *htc, struct wmi *wmi,
 		      enum htc_endpoint_id *wmi_ctrl_epid);
 int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
@@ -189,6 +188,8 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 void ath9k_wmi_event_tasklet(unsigned long data);
 void ath9k_fatal_work(struct work_struct *work);
 void ath9k_wmi_event_drain(struct ath9k_htc_priv *priv);
+void ath9k_stop_wmi(struct ath9k_htc_priv *priv);
+void ath9k_destoy_wmi(struct ath9k_htc_priv *priv);
 
 #define WMI_CMD(_wmi_cmd)						\
 	do {								\