Messages in this thread Patch in this message | | | From | Shuah Khan <> | Subject | [PATCH v4] bluetooth: Fix WARNING in tty_set_termios() | Date | Sun, 3 Feb 2019 12:38:48 -0700 |
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tty_set_termios() has the following WARN_ON which can be triggered with a syscall to invoke TIOCSETD __NR_ioctl.
WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER); Reference: https://syzkaller.appspot.com/bug?id=2410d22f1d8e5984217329dd0884b01d99e3e48d
"The problem started with commit 7721383f4199 ("Bluetooth: hci_uart: Support operational speed during setup") which introduced a new way for how tty_set_termios() could end up being called for a master pty."
Fix it by by preventing setting the HCI line discipline for PTYs in hci_uart_tty_open().
Reported-by: syzbot+a950165cbb86bdd023a4@syzkaller.appspotmail.com Cc: Johan Hovold <johan@kernel.org> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Shuah Khan <shuah@kernel.org> --- drivers/bluetooth/hci_ldisc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index fbf7b4df23ab..c8faa4759cb7 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -475,9 +475,9 @@ static int hci_uart_tty_open(struct tty_struct *tty) BT_DBG("tty %p", tty); /* Error if the tty has no write op instead of leaving an exploitable - * hole + * hole. In addition check if setting HCI line discipline is allowed. */ - if (tty->ops->write == NULL) + if (tty->ops->write == NULL || tty->ops->set_termios == NULL) return -EOPNOTSUPP; hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL); -- 2.17.1
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