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Subject[PATCH 4.19 10/14] Input: sunkbd - avoid use-after-free in teardown paths
Date
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

commit 77e70d351db7de07a46ac49b87a6c3c7a60fca7e upstream.

We need to make sure we cancel the reinit work before we tear down the
driver structures.

Reported-by: Bodong Zhao <nopitydays@gmail.com>
Tested-by: Bodong Zhao <nopitydays@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/input/keyboard/sunkbd.c | 41 ++++++++++++++++++++++++++++++++--------
1 file changed, 33 insertions(+), 8 deletions(-)

--- a/drivers/input/keyboard/sunkbd.c
+++ b/drivers/input/keyboard/sunkbd.c
@@ -111,7 +111,8 @@ static irqreturn_t sunkbd_interrupt(stru
switch (data) {

case SUNKBD_RET_RESET:
- schedule_work(&sunkbd->tq);
+ if (sunkbd->enabled)
+ schedule_work(&sunkbd->tq);
sunkbd->reset = -1;
break;

@@ -212,16 +213,12 @@ static int sunkbd_initialize(struct sunk
}

/*
- * sunkbd_reinit() sets leds and beeps to a state the computer remembers they
- * were in.
+ * sunkbd_set_leds_beeps() sets leds and beeps to a state the computer remembers
+ * they were in.
*/

-static void sunkbd_reinit(struct work_struct *work)
+static void sunkbd_set_leds_beeps(struct sunkbd *sunkbd)
{
- struct sunkbd *sunkbd = container_of(work, struct sunkbd, tq);
-
- wait_event_interruptible_timeout(sunkbd->wait, sunkbd->reset >= 0, HZ);
-
serio_write(sunkbd->serio, SUNKBD_CMD_SETLED);
serio_write(sunkbd->serio,
(!!test_bit(LED_CAPSL, sunkbd->dev->led) << 3) |
@@ -234,11 +231,39 @@ static void sunkbd_reinit(struct work_st
SUNKBD_CMD_BELLOFF - !!test_bit(SND_BELL, sunkbd->dev->snd));
}

+
+/*
+ * sunkbd_reinit() wait for the keyboard reset to complete and restores state
+ * of leds and beeps.
+ */
+
+static void sunkbd_reinit(struct work_struct *work)
+{
+ struct sunkbd *sunkbd = container_of(work, struct sunkbd, tq);
+
+ /*
+ * It is OK that we check sunkbd->enabled without pausing serio,
+ * as we only want to catch true->false transition that will
+ * happen once and we will be woken up for it.
+ */
+ wait_event_interruptible_timeout(sunkbd->wait,
+ sunkbd->reset >= 0 || !sunkbd->enabled,
+ HZ);
+
+ if (sunkbd->reset >= 0 && sunkbd->enabled)
+ sunkbd_set_leds_beeps(sunkbd);
+}
+
static void sunkbd_enable(struct sunkbd *sunkbd, bool enable)
{
serio_pause_rx(sunkbd->serio);
sunkbd->enabled = enable;
serio_continue_rx(sunkbd->serio);
+
+ if (!enable) {
+ wake_up_interruptible(&sunkbd->wait);
+ cancel_work_sync(&sunkbd->tq);
+ }
}

/*

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