From: Kefeng Wang wangkefeng.wang@huawei.com
commit 56897b217a1d0a91c9920cb418d6b3fe922f590a upstream.
task A: task B: hci_uart_set_proto flush_to_ldisc - p->open(hu) -> h5_open //alloc h5 - receive_buf - set_bit HCI_UART_PROTO_READY - tty_port_default_receive_buf - hci_uart_register_dev - tty_ldisc_receive_buf - hci_uart_tty_receive - test_bit HCI_UART_PROTO_READY - h5_recv - clear_bit HCI_UART_PROTO_READY while() { - p->open(hu) -> h5_close //free h5 - h5_rx_3wire_hdr - h5_reset() //use-after-free }
It could use ioctl to set hci uart proto, but there is a use-after-free issue when hci_uart_register_dev() fail in hci_uart_set_proto(), see stack above, fix this by setting HCI_UART_PROTO_READY bit only when hci_uart_register_dev() return success.
Reported-by: syzbot+899a33dc0fa0dbaf06a6@syzkaller.appspotmail.com Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Reviewed-by: Jeremy Cline jcline@redhat.com Signed-off-by: Marcel Holtmann marcel@holtmann.org Cc: Ralph Siemsen ralph.siemsen@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/bluetooth/hci_ldisc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -653,15 +653,14 @@ static int hci_uart_set_proto(struct hci return err;
hu->proto = p; - set_bit(HCI_UART_PROTO_READY, &hu->flags);
err = hci_uart_register_dev(hu); if (err) { - clear_bit(HCI_UART_PROTO_READY, &hu->flags); p->close(hu); return err; }
+ set_bit(HCI_UART_PROTO_READY, &hu->flags); return 0; }