This is a note to let you know that I've just added the patch titled
serdev: ttyport: fix NULL-deref on hangup
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 8bcd4e6a8decac251d55c4377e2e67f052777ce0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Fri, 3 Nov 2017 15:30:55 +0100
Subject: serdev: ttyport: fix NULL-deref on hangup
Make sure to use a properly refcounted tty_struct in write_wake up to
avoid dereferencing a NULL-pointer when a port is being hung up.
Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 4.11
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serdev/serdev-ttyport.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 09fbdd52a561..12cb9139073e 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -49,12 +49,19 @@ static void ttyport_write_wakeup(struct tty_port *port)
{
struct serdev_controller *ctrl = port->client_data;
struct serport *serport = serdev_controller_get_drvdata(ctrl);
+ struct tty_struct *tty;
+
+ tty = tty_port_tty_get(port);
+ if (!tty)
+ return;
- if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags) &&
+ if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
test_bit(SERPORT_ACTIVE, &serport->flags))
serdev_controller_write_wakeup(ctrl);
- wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT);
+ wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
+
+ tty_kref_put(tty);
}
static const struct tty_port_client_operations client_ops = {
--
2.15.0