CVE-2023-54210

In the Linux kernel, the following vulnerability has been resolved:

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.

This bug is a use-after-free read in hci_remove_adv_monitor() where msft_remove_monitor() may free the adv_monitor object before a subsequent debug log reads monitor->handle. An attacker with high local privileges could potentially trigger a kernel crash (DoS), especially in debug/KASAN configurations. It does not provide a practical path to memory corruption, privilege escalation, or code execution because the post-free access is a read used only for debugging output.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.