| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 097/159] Bluetooth: hci_ldisc: Postpone HCI_UART_PROTO_READY bit set in hci_uart_set_proto() | Date | Fri, 22 Nov 2019 11:28:08 +0100 |
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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; }
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