From: linma linma@zju.edu.cn

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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bluetooth/hci_core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

v2: use "network comment style" for block comment.

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index fd12f1652bdf..7d71d104fdfd 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -1610,8 +1610,13 @@ 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);