Re: [PATCH] max17042_battery: fix potential use-after-free on device remove

From: Hans de Goede
Date: Fri Feb 15 2019 - 17:08:25 EST


Hi,

On 2/15/19 11:03 PM, Sven Van Asbroeck wrote:
The work which is scheduled on a POR boot is potentially left
pending or running until after the device module is removed,
which could result in a use-after-free.

Fix by registering a cancel/sync callback, which gets executed as
part of standard resource unwinding.

This issue was detected with the help of Coccinelle.

Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Sven Van Asbroeck <TheSven73@xxxxxxxxx>

Looks good to me:

Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Regards,

Hans


---
drivers/power/supply/max17042_battery.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index 2a8d75e5e930..581c6bd23388 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -995,6 +995,13 @@ static const struct power_supply_desc max17042_no_current_sense_psy_desc = {
.num_properties = ARRAY_SIZE(max17042_battery_props) - 2,
};
+static void max17042_stop_work(void *data)
+{
+ struct max17042_chip *chip = data;
+
+ cancel_work_sync(&chip->work);
+}
+
static int max17042_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -1101,6 +1108,9 @@ static int max17042_probe(struct i2c_client *client,
regmap_read(chip->regmap, MAX17042_STATUS, &val);
if (val & STATUS_POR_BIT) {
INIT_WORK(&chip->work, max17042_init_worker);
+ ret = devm_add_action(&client->dev, max17042_stop_work, chip);
+ if (ret)
+ return ret;
schedule_work(&chip->work);
} else {
chip->init_complete = 1;