From d49424dd21fc97bd8b5868f9635ef3d38335aa77 Mon Sep 17 00:00:00 2001
From: Lin Ma <linma@zju.edu.cn>
Date: Tue, 15 Jun 2021 01:56:17 +0000
Subject: [PATCH] Bluetooth: fix the erroneous flush_work() order

stable inclusion
from stable-5.10.43
commit 3795007c8dfc8bca176529bfeceb17c6f4ef7e44
bugzilla: 109284
CVE: NA

--------------------------------

commit 6a137caec23aeb9e036cdfd8a46dd8a366460e5d upstream.

In the cleanup routine for failed initialization of HCI device,
the flush_work(&hdev->rx_work) need to be finished before the
flush_work(&hdev->cmd_work). Otherwise, the hci_rx_work() can
possibly invoke new cmd_work and cause a bug, like double free,
in late processings.

This was assigned CVE-2021-3564.

This patch reorder the flush_work() to fix this bug.

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: Hao Xiong <mart1n@zju.edu.cn>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 net/bluetooth/hci_core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 0152bc6b6796..86ebfc6ae698 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1602,8 +1602,13 @@ static int hci_dev_do_open(struct hci_dev *hdev)
 	} else {
 		/* Init failed, cleanup */
 		flush_work(&hdev->tx_work);
-		flush_work(&hdev->cmd_work);
+
+		/* Since hci_rx_work() is possible to awake new cmd_work
+		 * it should be flushed first to avoid unexpected call of
+		 * hci_cmd_work()
+		 */
 		flush_work(&hdev->rx_work);
+		flush_work(&hdev->cmd_work);
 
 		skb_queue_purge(&hdev->cmd_q);
 		skb_queue_purge(&hdev->rx_q);
-- 
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