Use-after-free occurs in hci_disconnect_all_sync if a connection is deleted by concurrent processing of a controller event. This can occur while waiting for controller events (big time window) or at other times (less likely). Fix the iteration in hci_disconnect_all_sync to allow hci_conn to be deleted at any time. UAF crash log: ================================================================== BUG: KASAN: slab-use-after-free in hci_set_powered_sync (net/bluetooth/hci_sync.c:5424) [bluetooth] Read of size 8 at addr ffff888009d9c000 by task kworker/u9:0/124 CPU: 0 PID: 124 Comm: kworker/u9:0 Tainted: G W 6.5.0-rc1+ #10 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hci_cmd_sync_work [bluetooth] Call Trace: <TASK> dump_stack_lvl+0x5b/0x90 print_report+0xcf/0x670 ? __virt_addr_valid+0xdd/0x160 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] kasan_report+0xa6/0xe0 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_hci_set_powered_sync+0x10/0x10 [bluetooth] ? __pfx_lock_release+0x10/0x10 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_cmd_sync_work+0x137/0x220 [bluetooth] process_one_work+0x526/0x9d0 ? __pfx_process_one_work+0x10/0x10 ? __pfx_do_raw_spin_lock+0x10/0x10 ? mark_held_locks+0x1a/0x90 worker_thread+0x92/0x630 ? __pfx_worker_thread+0x10/0x10 kthread+0x196/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 </TASK> Allocated by task 1782: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 __kasan_kmalloc+0x8f/0xa0 hci_conn_add+0xa5/0xa80 [bluetooth] hci_bind_cis+0x881/0x9b0 [bluetooth] iso_connect_cis+0x121/0x520 [bluetooth] iso_sock_connect+0x3f6/0x790 [bluetooth] __sys_connect+0x109/0x130 __x64_sys_connect+0x40/0x50 do_syscall_64+0x60/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Freed by task 695: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2b/0x50 __kasan_slab_free+0x10a/0x180 __kmem_cache_free+0x14d/0x2e0 device_release+0x5d/0xf0 kobject_put+0xdf/0x270 hci_disconn_complete_evt+0x274/0x3a0 [bluetooth] hci_event_packet+0x579/0x7e0 [bluetooth] hci_rx_work+0x287/0xaa0 [bluetooth] process_one_work+0x526/0x9d0 worker_thread+0x92/0x630 kthread+0x196/0x1e0 ret_from_fork+0x2c/0x50 ================================================================== Fixes: 182ee45da083 ("Bluetooth: hci_sync: Rework hci_suspend_notifier") Signed-off-by: Pauli Virtanen <pav@xxxxxx> --- net/bluetooth/hci_sync.c | 41 +++++++++++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 51ff682f66e0..be0f9527de2b 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -5415,16 +5415,43 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason) static int hci_disconnect_all_sync(struct hci_dev *hdev, u8 reason) { - struct hci_conn *conn, *tmp; - int err; + struct hci_conn *c, *conn; + int err = 0; + + rcu_read_lock(); + + /* Any conn may be gone while waiting for events, iterate safely. + * If conn is in conn_hash and we didn't abort it, it probably + * has not yet been aborted. + */ + list_for_each_entry_rcu(c, &hdev->conn_hash.list, list) + c->abort_reason = (reason == 0xff) ? 0xfe : 0xff; + + do { + conn = NULL; + list_for_each_entry_rcu(c, &hdev->conn_hash.list, list) { + if (c->abort_reason != reason) { + conn = c; + break; + } + } + if (!conn) + break; + + conn->abort_reason = reason; + hci_conn_get(conn); + + rcu_read_unlock(); - list_for_each_entry_safe(conn, tmp, &hdev->conn_hash.list, list) { err = hci_abort_conn_sync(hdev, conn, reason); - if (err) - return err; - } + hci_conn_put(conn); - return 0; + rcu_read_lock(); + } while (!err); + + rcu_read_unlock(); + + return err; } /* This function perform power off HCI command sequence as follows: -- 2.41.0