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hid: thingm: reorder calls in thingm_probe

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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: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Heiner Kallweit 2016-03-10 20:52:21 +01:00 committed by Jiri Kosina
parent 43a4a04d4d
commit 1d1b564ff8
1 changed files with 13 additions and 18 deletions
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31
drivers/hid/hid-thingm.c
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@ -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[] = {