Le 04/01/2024 à 12:56, Ying Hsu a écrit :
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 <HASH:3b4a6>]
? init_wait_entry+0x31/0x31
__hci_cmd_sync+0x16/0x20 [bluetooth <HASH:3b4a 6>]
hci_error_reset+0x4f/0xa4 [bluetooth <HASH:3b4a 6>]
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.
Signed-off-by: Ying Hsu <yinghsu-F7+t8E8rja9g9hUCZPvPmw@xxxxxxxxxxxxxxxx>
---
Tested this commit on a chromebook with Intel BT controller.
net/bluetooth/hci_core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 65601aa52e0d..a42417926028 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)
@@ -1060,6 +1061,7 @@ static void hci_error_reset(struct work_struct *work)
return;
^^^^^
Should we also call hci_dev_put() if we hit this return?
CJ
hci_dev_do_open(hdev);
+ hci_dev_put(hdev);
}
void hci_uuids_clear(struct hci_dev *hdev)
