From 2449007d3f73b2842c9734f45f0aadb522daf592 Mon Sep 17 00:00:00 2001 From: Ying Hsu Date: Thu, 4 Jan 2024 11:56:32 +0000 Subject: Bluetooth: Avoid potential use-after-free in hci_error_reset While handling the HCI_EV_HARDWARE_ERROR event, if the underlying BT controller is not responding, the GPIO reset mechanism would free the hci_dev and lead to a use-after-free in hci_error_reset. Here's the call trace observed on a ChromeOS device with Intel AX201: queue_work_on+0x3e/0x6c __hci_cmd_sync_sk+0x2ee/0x4c0 [bluetooth ] ? init_wait_entry+0x31/0x31 __hci_cmd_sync+0x16/0x20 [bluetooth ] hci_error_reset+0x4f/0xa4 [bluetooth ] process_one_work+0x1d8/0x33f worker_thread+0x21b/0x373 kthread+0x13a/0x152 ? pr_cont_work+0x54/0x54 ? kthread_blkcg+0x31/0x31 ret_from_fork+0x1f/0x30 This patch holds the reference count on the hci_dev while processing a HCI_EV_HARDWARE_ERROR event to avoid potential crash. Fixes: c7741d16a57c ("Bluetooth: Perform a power cycle when receiving hardware error event") Signed-off-by: Ying Hsu Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 65601aa52e0d..2821a42cefdc 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -1049,6 +1049,7 @@ static void hci_error_reset(struct work_struct *work) { struct hci_dev *hdev = container_of(work, struct hci_dev, error_reset); + hci_dev_hold(hdev); BT_DBG("%s", hdev->name); if (hdev->hw_error) @@ -1056,10 +1057,10 @@ static void hci_error_reset(struct work_struct *work) else bt_dev_err(hdev, "hardware error 0x%2.2x", hdev->hw_error_code); - if (hci_dev_do_close(hdev)) - return; + if (!hci_dev_do_close(hdev)) + hci_dev_do_open(hdev); - hci_dev_do_open(hdev); + hci_dev_put(hdev); } void hci_uuids_clear(struct hci_dev *hdev) -- cgit v1.2.3