4.19-stable review patch. If anyone has any objections, please let me know.
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From: Ying Hsu yinghsu@chromium.org
[ Upstream commit 2449007d3f73b2842c9734f45f0aadb522daf592 ]
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.
Fixes: c7741d16a57c ("Bluetooth: Perform a power cycle when receiving hardware error event") Signed-off-by: Ying Hsu yinghsu@chromium.org Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/hci_core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 4d89e38dceec3..f455a503f5b04 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2217,6 +2217,7 @@ 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) @@ -2224,10 +2225,10 @@ 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)