Re: [PATCH] HID: hid-lg4ff: Fix uninit-value set_autocenter_default
From: Benjamin Tissoires <hidden>
Date: 2019-11-18 09:43:41
Also in:
linux-kernel-mentees, lkml
On Tue, Nov 5, 2019 at 3:18 PM Phong Tran [off-list ref] wrote:
syzbot found a problem using of uinit pointer in lg4ff_set_autocenter_default(). Reported-by: syzbot+1234691fec1b8ceba8b1@syzkaller.appspotmail.com Tested by syzbot: https://groups.google.com/d/msg/syzkaller-bugs/ApnMLW6sfKE/Qq0bIHGEAQAJ
This seems weird to me: the syzbot link above is about `hid_get_drvdata(hid)`, and, as I read it, the possibility that hid might not have an initialized value. Here you are changing the initialized values of value, entry and drv_data, all 3 are never used before their first assignment. I have a feeling this particular syzbot check has already been fixed upstream by d9d4b1e46d95 "HID: Fix assumption that devices have inputs". Cheers, Benjamin
quoted hunk ↗ jump to hunk
Signed-off-by: Phong Tran <redacted> --- drivers/hid/hid-lg4ff.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c index 5e6a0cef2a06..44dfd08b0c32 100644 --- a/drivers/hid/hid-lg4ff.c +++ b/drivers/hid/hid-lg4ff.c@@ -468,10 +468,10 @@ static int lg4ff_play(struct input_dev *dev, void *data, struct ff_effect *effec static void lg4ff_set_autocenter_default(struct input_dev *dev, u16 magnitude) { struct hid_device *hid = input_get_drvdata(dev); - s32 *value; + s32 *value = NULL; u32 expand_a, expand_b; - struct lg4ff_device_entry *entry; - struct lg_drv_data *drv_data; + struct lg4ff_device_entry *entry = NULL; + struct lg_drv_data *drv_data = NULL; unsigned long flags; drv_data = hid_get_drvdata(hid); --2.20.1