Commit 27cfb3a5 authored Jan 20, 2019 by Greg Kroah-Hartman

tty: Handle problem if line discipline does not have receive_buf



Some tty line disciplines do not have a receive buf callback, so
properly check for that before calling it.  If they do not have this
callback, just eat the character quietly, as we can't fail this call.

Reported-by: Jann Horn <jannh@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent bfd8d8fe

drivers/tty/tty_io.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2189,6 +2189,7 @@ static int tiocsti(struct tty_struct tty, char __user p)
		ld = tty_ldisc_ref_wait(tty);
		if (!ld)
		return -EIO;
		if (ld->ops->receive_buf)
		ld->ops->receive_buf(tty, &ch, &mbz, 1);
		tty_ldisc_deref(ld);
		return 0;