Patch "Bluetooth: Avoid potential use-after-free in hci_error_reset" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    Bluetooth: Avoid potential use-after-free in hci_error_reset

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bluetooth-avoid-potential-use-after-free-in-hci_erro.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 0ed602cdc1253d8815dc6a90a819c1726b5ba1f9
Author: Ying Hsu <yinghsu@xxxxxxxxxxxx>
Date:   Thu Jan 4 11:56:32 2024 +0000

    Bluetooth: Avoid potential use-after-free in hci_error_reset
    
    [ 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@xxxxxxxxxxxx>
    Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 54c55c30db17b..289fb28529f8c 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2272,6 +2272,7 @@ 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)
@@ -2279,10 +2280,10 @@ 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)