Commit de6dfcef authored by Douglas Anderson's avatar Douglas Anderson Committed by Luiz Augusto von Dentz
Browse files

Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor() 



KASAN reports that there's a use-after-free in
hci_remove_adv_monitor(). Trawling through the disassembly, you can
see that the complaint is from the access in bt_dev_dbg() under the
HCI_ADV_MONITOR_EXT_MSFT case. The problem case happens because
msft_remove_monitor() can end up freeing the monitor
structure. Specifically:
  hci_remove_adv_monitor() ->
  msft_remove_monitor() ->
  msft_remove_monitor_sync() ->
  msft_le_cancel_monitor_advertisement_cb() ->
  hci_free_adv_monitor()

Let's fix the problem by just stashing the relevant data when it's
still valid.

Fixes: 7cf5c297 ("Bluetooth: hci_sync: Refactor remove Adv Monitor")
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 6910e2eb

net/bluetooth/hci_core.c

+3 −1
Original line number Diff line number Diff line
@@ -1972,6 +1972,7 @@ static int hci_remove_adv_monitor(struct hci_dev *hdev, 
				  struct adv_monitor *monitor)

{

	int status = 0;

	int handle;



	switch (hci_get_adv_monitor_offload_ext(hdev)) {

	case HCI_ADV_MONITOR_EXT_NONE: /* also goes here when powered off */
@@ -1980,9 +1981,10 @@ static int hci_remove_adv_monitor(struct hci_dev *hdev, 
		goto free_monitor;



	case HCI_ADV_MONITOR_EXT_MSFT:

		handle = monitor->handle;

		status = msft_remove_monitor(hdev, monitor);

		bt_dev_dbg(hdev, "%s remove monitor %d msft status %d",

			   hdev->name, monitor->handle, status);

			   hdev->name, handle, status);

		break;

	}