From: Pauli Virtanen Date: Fri, 10 Jul 2026 08:23:40 +0000 (+0300) Subject: Bluetooth: hci_sync: extend conn_hash lookup critical sections X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5efd6e4b8b0634af6843178fe1a7dd2b2178a3d;p=thirdparty%2Fkernel%2Flinux.git Bluetooth: hci_sync: extend conn_hash lookup critical sections Using RCU-protected pointers outside the critical sections without refcount is incorrect and may result to UAF. Extend critical section to cover both hci_conn_hash lookup and use of the returned conn. Add surrounding rcu_read_lock() also when return value is not used, in preparation for RCU lockdep requirement to hci_lookup_le_connect(). This avoids concurrent deletion of the conn before we are done dereferencing it. Also, make sure to hold hdev->lock when accessing hdev->accept_list. Fixes: 6d0417e4e1cf ("Bluetooth: hci_conn: Fix not setting conn_timeout for Broadcast Receiver") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz --- diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index c896d4edd013..7a60e34c91b6 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -1054,14 +1054,19 @@ static int hci_set_random_addr_sync(struct hci_dev *hdev, bdaddr_t *rpa) * In this kind of scenario skip the update and let the random * address be updated at the next cycle. */ + rcu_read_lock(); + if (bacmp(&hdev->random_addr, BDADDR_ANY) && (hci_dev_test_flag(hdev, HCI_LE_ADV) || hci_lookup_le_connect(hdev))) { bt_dev_dbg(hdev, "Deferring random address update"); hci_dev_set_flag(hdev, HCI_RPA_EXPIRED); + rcu_read_unlock(); return 0; } + rcu_read_unlock(); + return __hci_cmd_sync_status(hdev, HCI_OP_LE_SET_RANDOM_ADDR, 6, rpa, HCI_CMD_TIMEOUT); } @@ -2647,12 +2652,17 @@ static int hci_pause_addr_resolution(struct hci_dev *hdev) /* Cannot disable addr resolution if scanning is enabled or * when initiating an LE connection. */ + rcu_read_lock(); + if (hci_dev_test_flag(hdev, HCI_LE_SCAN) || hci_lookup_le_connect(hdev)) { + rcu_read_unlock(); bt_dev_err(hdev, "Command not allowed when scan/LE connect"); return -EPERM; } + rcu_read_unlock(); + /* Cannot disable addr resolution if advertising is enabled. */ err = hci_pause_advertising_sync(hdev); if (err) { @@ -2790,6 +2800,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) if (hci_dev_test_flag(hdev, HCI_PA_SYNC)) { struct hci_conn *conn; + rcu_read_lock(); + conn = hci_conn_hash_lookup_create_pa_sync(hdev); if (conn) { struct conn_params pa; @@ -2799,6 +2811,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) bacpy(&pa.addr, &conn->dst); pa.addr_type = conn->dst_type; + rcu_read_unlock(); + /* Clear first since there could be addresses left * behind. */ @@ -2808,6 +2822,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) err = hci_le_add_accept_list_sync(hdev, &pa, &num_entries); goto done; + } else { + rcu_read_unlock(); } } @@ -2818,10 +2834,13 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) * the controller. */ list_for_each_entry_safe(b, t, &hdev->le_accept_list, list) { - if (hci_conn_hash_lookup_le(hdev, &b->bdaddr, b->bdaddr_type)) + rcu_read_lock(); + + if (hci_conn_hash_lookup_le(hdev, &b->bdaddr, b->bdaddr_type)) { + rcu_read_unlock(); continue; + } - /* Pointers not dereferenced, no locks needed */ pend_conn = hci_pend_le_action_lookup(&hdev->pend_le_conns, &b->bdaddr, b->bdaddr_type); @@ -2829,6 +2848,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) &b->bdaddr, b->bdaddr_type); + rcu_read_unlock(); + /* If the device is not likely to connect or report, * remove it from the acceptlist. */ @@ -2955,6 +2976,8 @@ static int hci_le_set_ext_scan_param_sync(struct hci_dev *hdev, u8 type, if (sent) { struct hci_conn *conn; + rcu_read_lock(); + conn = hci_conn_hash_lookup_ba(hdev, PA_LINK, &sent->bdaddr); if (conn) { @@ -2979,8 +3002,12 @@ static int hci_le_set_ext_scan_param_sync(struct hci_dev *hdev, u8 type, phy++; } + rcu_read_unlock(); + if (num_phy) goto done; + } else { + rcu_read_unlock(); } } } @@ -3231,12 +3258,16 @@ int hci_update_passive_scan_sync(struct hci_dev *hdev) /* If there is at least one pending LE connection, we should * keep the background scan running. */ + bool exists; /* If controller is connecting, we should not start scanning * since some controllers are not able to scan and connect at * the same time. */ - if (hci_lookup_le_connect(hdev)) + rcu_read_lock(); + exists = hci_lookup_le_connect(hdev); + rcu_read_unlock(); + if (exists) return 0; bt_dev_dbg(hdev, "start background scanning"); @@ -3454,6 +3485,7 @@ int hci_write_fast_connectable_sync(struct hci_dev *hdev, bool enable) } static bool disconnected_accept_list_entries(struct hci_dev *hdev) + __must_hold(&hdev->lock) { struct bdaddr_list *b; @@ -3494,12 +3526,16 @@ int hci_update_scan_sync(struct hci_dev *hdev) if (hdev->scanning_paused) return 0; + hci_dev_lock(hdev); + if (hci_dev_test_flag(hdev, HCI_CONNECTABLE) || disconnected_accept_list_entries(hdev)) scan = SCAN_PAGE; else scan = SCAN_DISABLED; + hci_dev_unlock(hdev); + if (hci_dev_test_flag(hdev, HCI_DISCOVERABLE)) scan |= SCAN_INQUIRY;