[PATCH AUTOSEL 4.14 35/43] tty: fix NULL pointer issue when tty_port ops is not set

Sasha Levin
2019-04-22T19:57:43Z

From: Fabien Dessenne <fabien.dessenne@st.com>

[ Upstream commit f4e68d58cf2b20a581759bbc7228052534652673 ]

Unlike 'client_ops' which is initialized to 'default_client_ops', the
port operations 'ops' may be left to NULL.
Check the 'ops' value before checking the 'ops->x' value.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
---
drivers/tty/tty_port.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index c93a33701d32..17743175c633 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -326,7 +326,7 @@ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
if (tty && C_HUPCL(tty))
tty_port_lower_dtr_rts(port);

- if (port->ops->shutdown)
+ if (port->ops && port->ops->shutdown)
port->ops->shutdown(port);
}
out:
@@ -401,7 +401,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);

int tty_port_carrier_raised(struct tty_port *port)
{
- if (port->ops->carrier_raised == NULL)
+ if (!port->ops || !port->ops->carrier_raised)
return 1;
return port->ops->carrier_raised(port);
}
@@ -418,7 +418,7 @@ EXPORT_SYMBOL(tty_port_carrier_raised);

void tty_port_raise_dtr_rts(struct tty_port *port)
{
- if (port->ops->dtr_rts)
+ if (port->ops && port->ops->dtr_rts)
port->ops->dtr_rts(port, 1);
}
EXPORT_SYMBOL(tty_port_raise_dtr_rts);
@@ -434,7 +434,7 @@ EXPORT_SYMBOL(tty_port_raise_dtr_rts);

void tty_port_lower_dtr_rts(struct tty_port *port)
{
- if (port->ops->dtr_rts)
+ if (port->ops && port->ops->dtr_rts)
port->ops->dtr_rts(port, 0);
}
EXPORT_SYMBOL(tty_port_lower_dtr_rts);
@@ -690,7 +690,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,

if (!tty_port_initialized(port)) {
clear_bit(TTY_IO_ERROR, &tty->flags);
- if (port->ops->activate) {
+ if (port->ops && port->ops->activate) {
int retval = port->ops->activate(port, tty);
if (retval) {
mutex_unlock(&port->mutex);
--
2.19.1