Commit 4466d6d2 authored Nov 05, 2020 by Matthias Reichl Committed by Greg Kroah-Hartman Nov 06, 2020

tty: fix crash in release_tty if tty->port is not set



Commit 2ae0b31e ("tty: don't crash in tty_init_dev when missing
tty_port") didn't fully prevent the crash as the cleanup path in
tty_init_dev() calls release_tty() which dereferences tty->port
without checking it for non-null.

Add tty->port checks to release_tty to avoid the kernel crash.

Fixes: 2ae0b31e ("tty: don't crash in tty_init_dev when missing tty_port")
Signed-off-by: Matthias Reichl <hias@horus.com>
Link: https://lore.kernel.org/r/20201105123432.4448-1-hias@horus.com


Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0c5fc926

drivers/tty/tty_io.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1515,9 +1515,11 @@ static void release_tty(struct tty_struct *tty, int idx)
		tty->ops->shutdown(tty);
		tty_save_termios(tty);
		tty_driver_remove_tty(tty->driver, tty);
		if (tty->port)
		tty->port->itty = NULL;
		if (tty->link)
		tty->link->port->itty = NULL;
		if (tty->port)
		tty_buffer_cancel_work(tty->port);
		if (tty->link)
		tty_buffer_cancel_work(tty->link->port);

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