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Commit 1d1b564f authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Jiri Kosina
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hid: thingm: reorder calls in thingm_probe 



When reviewing another thingm patch Benjamin Tissoires pointed out
the following: "The problem here is that hid_hw_start() is called
before thingm_version() which allows user space to briefly introduce
races between thingm_version() and any hidraw requests.
The mutex will not help here as it is initialized after hid_hw_start()
and only used for protecting the concurrent access of the rgb."

Avoid this possible issue by calling hid_hw_start() later in the
probe function.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 43a4a04d

drivers/hid/hid-thingm.c

+13 −18
Original line number Diff line number Diff line
@@ -216,17 +216,13 @@ static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id) 


	err = hid_parse(hdev);

	if (err)

		goto error;



	err = hid_hw_start(hdev, HID_CONNECT_HIDRAW);

	if (err)

		goto error;

		return err;



	mutex_init(&tdev->lock);



	err = thingm_version(tdev);

	if (err)

		goto stop;

		return err;



	hid_dbg(hdev, "firmware version: %c.%c\n",

			tdev->version.major, tdev->version.minor);
@@ -237,17 +233,18 @@ static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id) 


	if (!tdev->fwinfo) {

		hid_err(hdev, "unsupported firmware %c\n", tdev->version.major);

		err = -ENODEV;

		goto stop;

		return -ENODEV;

	}



	tdev->rgb = devm_kzalloc(&hdev->dev,

			sizeof(struct thingm_rgb) * tdev->fwinfo->numrgb,

			GFP_KERNEL);

	if (!tdev->rgb) {

		err = -ENOMEM;

		goto stop;

	}

	if (!tdev->rgb)

		return -ENOMEM;



	err = hid_hw_start(hdev, HID_CONNECT_HIDRAW);

	if (err)

		return err;



	for (i = 0; i < tdev->fwinfo->numrgb; ++i) {

		struct thingm_rgb *rgb = tdev->rgb + i;
@@ -255,15 +252,13 @@ static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id) 
		rgb->tdev = tdev;

		rgb->num = tdev->fwinfo->first + i;

		err = thingm_init_rgb(rgb);

		if (err)

			goto stop;

		if (err) {

			hid_hw_stop(hdev);

			return err;

		}

	}



	return 0;

stop:

	hid_hw_stop(hdev);

error:

	return err;

}



static const struct hid_device_id thingm_table[] = {