[PATCH] iio: cm36651: Fix i2c client leak and possible NULL pointer dereference

From: Krzysztof Kozlowski
Date: Thu Mar 06 2014 - 04:33:38 EST


During probe the driver allocates dummy I2C devices (i2c_new_dummy())
but they aren't unregistered during driver remove or probe failure.

Additionally driver does not check the return value of i2c_new_dummy().
In case of error (i2c_new_device(): memory allocation failure or I2C
address cannot be used) this function returns NULL which is later
dereferenced by i2c_smbus_{read,write}_data() functions.

Fix issues by properly checking for i2c_new_dummy() return value and
unregistering I2C devices on driver remove or probe failure.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
---
drivers/iio/light/cm36651.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/iio/light/cm36651.c b/drivers/iio/light/cm36651.c
index a45e07492db3..e7e9a597159f 100644
--- a/drivers/iio/light/cm36651.c
+++ b/drivers/iio/light/cm36651.c
@@ -653,6 +653,11 @@ static int cm36651_probe(struct i2c_client *client,
cm36651->ps_client = i2c_new_dummy(client->adapter,
CM36651_I2C_ADDR_PS);
cm36651->ara_client = i2c_new_dummy(client->adapter, CM36651_ARA);
+ if (!cm36651->ps_client || !cm36651->ara_client) {
+ dev_err(&client->dev, "%s: new i2c device failed\n", __func__);
+ ret = -ENODEV;
+ goto error_i2c_unregister;
+ }
mutex_init(&cm36651->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->channels = cm36651_channels;
@@ -687,6 +692,11 @@ error_free_irq:
free_irq(client->irq, indio_dev);
error_disable_reg:
regulator_disable(cm36651->vled_reg);
+error_i2c_unregister:
+ if (cm36651->ps_client)
+ i2c_unregister_device(cm36651->ps_client);
+ if (cm36651->ara_client)
+ i2c_unregister_device(cm36651->ara_client);
return ret;
}

@@ -698,6 +708,8 @@ static int cm36651_remove(struct i2c_client *client)
iio_device_unregister(indio_dev);
regulator_disable(cm36651->vled_reg);
free_irq(client->irq, indio_dev);
+ i2c_unregister_device(cm36651->ps_client);
+ i2c_unregister_device(cm36651->ara_client);

return 0;
}
--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/