CVE-2023-53046

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

Bluetooth: Fix race condition in hci_cmd_sync_clear

There is a potential race condition in hci_cmd_sync_work and hci_cmd_sync_clear, and could lead to use-after-free. For instance, hci_cmd_sync_work is added to the req_workqueue after cancel_work_sync The entry of cmd_sync_work_list may be freed in hci_cmd_sync_clear, and causing kernel panic when it is used in hci_cmd_sync_work.

Heres the call trace:

dump_stack_lvl+0x49/0x63 print_report.cold+0x5e/0x5d3 ? hci_cmd_sync_work+0x282/0x320 kasan_report+0xaa/0x120 ? hci_cmd_sync_work+0x282/0x320 __asan_report_load8_noabort+0x14/0x20 hci_cmd_sync_work+0x282/0x320 process_one_work+0x77b/0x11c0 ? _raw_spin_lock_irq+0x8e/0xf0 worker_thread+0x544/0x1180 ? poll_idle+0x1e0/0x1e0 kthread+0x285/0x320 ? process_one_work+0x11c0/0x11c0 ? kthread_complete_and_exit+0x30/0x30 ret_from_fork+0x22/0x30

Allocated by task 266: kasan_save_stack+0x26/0x50 __kasan_kmalloc+0xae/0xe0 kmem_cache_alloc_trace+0x191/0x350 hci_cmd_sync_queue+0x97/0x2b0 hci_update_passive_scan+0x176/0x1d0 le_conn_complete_evt+0x1b5/0x1a00 hci_le_conn_complete_evt+0x234/0x340 hci_le_meta_evt+0x231/0x4e0 hci_event_packet+0x4c5/0xf00 hci_rx_work+0x37d/0x880 process_one_work+0x77b/0x11c0 worker_thread+0x544/0x1180 kthread+0x285/0x320 ret_from_fork+0x22/0x30

Freed by task 269: kasan_save_stack+0x26/0x50 kasan_set_track+0x25/0x40 kasan_set_free_info+0x24/0x40 ____kasan_slab_free+0x176/0x1c0 __kasan_slab_free+0x12/0x20 slab_free_freelist_hook+0x95/0x1a0 kfree+0xba/0x2f0 hci_cmd_sync_clear+0x14c/0x210 hci_unregister_dev+0xff/0x440 vhci_release+0x7b/0xf0 __fput+0x1f3/0x970 ____fput+0xe/0x20 task_work_run+0xd4/0x160 do_exit+0x8b0/0x22a0 do_group_exit+0xba/0x2a0 get_signal+0x1e4a/0x25b0 arch_do_signal_or_restart+0x93/0x1f80 exit_to_user_mode_prepare+0xf5/0x1a0 syscall_exit_to_user_mode+0x26/0x50 ret_from_fork+0x15/0x30

Weakness

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Software

Extended Description

A race condition occurs within concurrent environments, and it is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:

A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the product; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable product.

Potential Mitigations

• Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring.
• Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://git.kernel.org/stable/c/1c66bee492a5fe00ae3fe890bb693bfc99f994c6
• https://git.kernel.org/stable/c/608901a77c945ac15dea23f6098c9882ef19d9f0
• https://git.kernel.org/stable/c/be586211a3ab40a4f4ca60450e0d31606afc55ec