[PATCH v2] Bluetooth: hci_core: Fix poential Use-after-Free bug in hci_remove_adv_monitor

From: Zheng Wang
Date: Fri Feb 17 2023 - 05:05:03 EST


In hci_remove_adv_monitor, if it gets into HCI_ADV_MONITOR_EXT_MSFT case,
the function will free the monitor and print its handle after that.
Fix it by removing the logging into msft_le_cancel_monitor_advertisement_cb
before calling hci_free_adv_monitor.

Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
---
v2:
- move the logging inside msft_remove_monitor suggested by Luiz
---
net/bluetooth/hci_core.c | 2 --
net/bluetooth/msft.c | 2 ++
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index b65c3aabcd53..69b82c2907ff 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1981,8 +1981,6 @@ static int hci_remove_adv_monitor(struct hci_dev *hdev,

case HCI_ADV_MONITOR_EXT_MSFT:
status = msft_remove_monitor(hdev, monitor);
- bt_dev_dbg(hdev, "%s remove monitor %d msft status %d",
- hdev->name, monitor->handle, status);
break;
}

diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
index bee6a4c656be..4b35f0ed1360 100644
--- a/net/bluetooth/msft.c
+++ b/net/bluetooth/msft.c
@@ -286,6 +286,8 @@ static int msft_le_cancel_monitor_advertisement_cb(struct hci_dev *hdev,
* suspend. It will be re-monitored on resume.
*/
if (!msft->suspending) {
+ bt_dev_dbg(hdev, "%s remove monitor %d status %d", hdev->name,
+ monitor->handle, status);
hci_free_adv_monitor(hdev, monitor);

/* Clear any monitored devices by this Adv Monitor */
--
2.25.1