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@xxxxxxxxx>
---
v2:
- make commit message more verbose
---
drivers/hid/hid-thingm.c | 31 +++++++++++++------------------
1 file changed, 13 insertions(+), 18 deletions(-)
diff --git a/drivers/hid/hid-thingm.c b/drivers/hid/hid-thingm.c
index f4196ac..847a497 100644
--- a/drivers/hid/hid-thingm.c
+++ b/drivers/hid/hid-thingm.c
@@ -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[] = {
--
2.7.1
--
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