| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 25/68] tty: Handle problem if line discipline does not have receive_buf | Date | Tue, 29 Jan 2019 12:35:47 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 27cfb3a53be46a54ec5e0bd04e51995b74c90343 upstream.
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>
--- drivers/tty/tty_io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2180,7 +2180,8 @@ static int tiocsti(struct tty_struct *tt ld = tty_ldisc_ref_wait(tty); if (!ld) return -EIO; - ld->ops->receive_buf(tty, &ch, &mbz, 1); + if (ld->ops->receive_buf) + ld->ops->receive_buf(tty, &ch, &mbz, 1); tty_ldisc_deref(ld); return 0; }
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