[PATCH AUTOSEL 4.4 18/33] ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()

* [PATCH AUTOSEL 4.4 18/33] ath9k: hif_usb: fix race condition between usb_get_urb() and usb_kill_anchored_urbs()
       [not found] <20201018192728.4056577-1-sashal@kernel.org>
@ 2020-10-18 19:27 ` Sasha Levin
  2020-10-18 19:27 ` [PATCH AUTOSEL 4.4 25/33] brcmsmac: fix memory leak in wlc_phy_attach_lcnphy Sasha Levin
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2020-10-18 19:27 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Brooke Basile, syzbot+89bd486af9427a9fc605, Kalle Valo,
	Sasha Levin, linux-wireless, netdev

From: Brooke Basile <brookebasile@gmail.com>

[ Upstream commit 03fb92a432ea5abe5909bca1455b7e44a9380480 ]

Calls to usb_kill_anchored_urbs() after usb_kill_urb() on multiprocessor
systems create a race condition in which usb_kill_anchored_urbs() deallocates
the URB before the completer callback is called in usb_kill_urb(), resulting
in a use-after-free.
To fix this, add proper lock protection to usb_kill_urb() calls that can
possibly run concurrently with usb_kill_anchored_urbs().

Reported-by: syzbot+89bd486af9427a9fc605@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=cabffad18eb74197f84871802fd2c5117b61febf
Signed-off-by: Brooke Basile <brookebasile@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200911071427.32354-1-brookebasile@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ath9k/hif_usb.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 76d91859cfde9..75072a8f8cf42 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -445,10 +445,19 @@ static void hif_usb_stop(void *hif_handle)
 	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 
 	/* The pending URBs have to be canceled. */
+	spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
 				 &hif_dev->tx.tx_pending, list) {
+		usb_get_urb(tx_buf->urb);
+		spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 		usb_kill_urb(tx_buf->urb);
+		list_del(&tx_buf->list);
+		usb_free_urb(tx_buf->urb);
+		kfree(tx_buf->buf);
+		kfree(tx_buf);
+		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	}
+	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 
 	usb_kill_anchored_urbs(&hif_dev->mgmt_submitted);
 }
@@ -758,27 +767,37 @@ static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
 	struct tx_buf *tx_buf = NULL, *tx_buf_tmp = NULL;
 	unsigned long flags;
 
+	spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
 				 &hif_dev->tx.tx_buf, list) {
+		usb_get_urb(tx_buf->urb);
+		spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 		usb_kill_urb(tx_buf->urb);
 		list_del(&tx_buf->list);
 		usb_free_urb(tx_buf->urb);
 		kfree(tx_buf->buf);
 		kfree(tx_buf);
+		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	}
+	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 
 	spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	hif_dev->tx.flags |= HIF_USB_TX_FLUSH;
 	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 
+	spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	list_for_each_entry_safe(tx_buf, tx_buf_tmp,
 				 &hif_dev->tx.tx_pending, list) {
+		usb_get_urb(tx_buf->urb);
+		spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 		usb_kill_urb(tx_buf->urb);
 		list_del(&tx_buf->list);
 		usb_free_urb(tx_buf->urb);
 		kfree(tx_buf->buf);
 		kfree(tx_buf);
+		spin_lock_irqsave(&hif_dev->tx.tx_lock, flags);
 	}
+	spin_unlock_irqrestore(&hif_dev->tx.tx_lock, flags);
 
 	usb_kill_anchored_urbs(&hif_dev->mgmt_submitted);
 }
-- 
2.25.1


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