Commit 08bd5b7c authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: synaptics - fix crash when enabling pass-through port 



When enabling a pass-through port an interrupt might come before psmouse
driver binds to the pass-through port. However synaptics sub-driver
tries to access psmouse instance presumably associated with the
pass-through port to figure out if only 1 byte of response or entire
protocol packet needs to be forwarded to the pass-through port and may
crash if psmouse instance has not been attached to the port yet.

Fix the crash by introducing open() and close() methods for the port and
check if the port is open before trying to access psmouse instance.
Because psmouse calls serio_open() only after attaching psmouse instance
to serio port instance this prevents the potential crash.

Reported-by: default avatarTakashi Iwai <tiwai@suse.de>
Fixes: 100e1695 ("Input: libps2 - attach ps2dev instances as serio port's drvdata")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1219522


Cc: stable@vger.kernel.org
Reviewed-by: default avatarTakashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/Z4qSHORvPn7EU2j1@google.com


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 907bc926

drivers/input/mouse/synaptics.c

+42 −14
Original line number Diff line number Diff line
@@ -665,23 +665,50 @@ static void synaptics_pt_stop(struct serio *serio) 
	priv->pt_port = NULL;

}



static int synaptics_pt_open(struct serio *serio)

{

	struct psmouse *parent = psmouse_from_serio(serio->parent);

	struct synaptics_data *priv = parent->private;



	guard(serio_pause_rx)(parent->ps2dev.serio);

	priv->pt_port_open = true;



	return 0;

}



static void synaptics_pt_close(struct serio *serio)

{

	struct psmouse *parent = psmouse_from_serio(serio->parent);

	struct synaptics_data *priv = parent->private;



	guard(serio_pause_rx)(parent->ps2dev.serio);

	priv->pt_port_open = false;

}



static int synaptics_is_pt_packet(u8 *buf)

{

	return (buf[0] & 0xFC) == 0x84 && (buf[3] & 0xCC) == 0xC4;

}



static void synaptics_pass_pt_packet(struct serio *ptport, u8 *packet)

static void synaptics_pass_pt_packet(struct synaptics_data *priv, u8 *packet)

{

	struct psmouse *child = psmouse_from_serio(ptport);

	struct serio *ptport;



	ptport = priv->pt_port;

	if (!ptport)

		return;



	if (child && child->state == PSMOUSE_ACTIVATED) {

	serio_interrupt(ptport, packet[1], 0);



	if (priv->pt_port_open) {

		struct psmouse *child = psmouse_from_serio(ptport);



		if (child->state == PSMOUSE_ACTIVATED) {

			serio_interrupt(ptport, packet[4], 0);

			serio_interrupt(ptport, packet[5], 0);

			if (child->pktsize == 4)

				serio_interrupt(ptport, packet[2], 0);

	} else {

		serio_interrupt(ptport, packet[1], 0);

		}

	}

}
@@ -720,6 +747,8 @@ static void synaptics_pt_create(struct psmouse *psmouse) 
	serio->write = synaptics_pt_write;

	serio->start = synaptics_pt_start;

	serio->stop = synaptics_pt_stop;

	serio->open = synaptics_pt_open;

	serio->close = synaptics_pt_close;

	serio->parent = psmouse->ps2dev.serio;



	psmouse->pt_activate = synaptics_pt_activate;
@@ -1216,11 +1245,10 @@ static psmouse_ret_t synaptics_process_byte(struct psmouse *psmouse) 


		if (SYN_CAP_PASS_THROUGH(priv->info.capabilities) &&

		    synaptics_is_pt_packet(psmouse->packet)) {

			if (priv->pt_port)

				synaptics_pass_pt_packet(priv->pt_port,

							 psmouse->packet);

		} else

			synaptics_pass_pt_packet(priv, psmouse->packet);

		} else {

			synaptics_process_packet(psmouse);

		}



		return PSMOUSE_FULL_PACKET;

	}

drivers/input/mouse/synaptics.h

+1 −0
Original line number Diff line number Diff line
@@ -188,6 +188,7 @@ struct synaptics_data { 
	bool disable_gesture;			/* disable gestures */



	struct serio *pt_port;			/* Pass-through serio port */

	bool pt_port_open;



	/*

	 * Last received Advanced Gesture Mode (AGM) packet. An AGM packet