From 28b06dc3e53970fe82ee1e5b8bbc74cb73f08909 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 6 Nov 2019 13:49:01 +0100 Subject: [PATCH] appledisplay: fix error handling in the scheduled work commit 91feb01596e5efc0cc922cc73f5583114dccf4d2 upstream. The work item can operate on 1. stale memory left over from the last transfer the actual length of the data transfered needs to be checked 2. memory already freed the error handling in appledisplay_probe() needs to cancel the work in that case Reported-and-tested-by: syzbot+495dab1f175edc9c2f13@syzkaller.appspotmail.com Signed-off-by: Oliver Neukum Cc: stable Link: https://lore.kernel.org/r/20191106124902.7765-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/appledisplay.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c index 140af77..32dc0d9 100644 --- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -182,7 +182,12 @@ static int appledisplay_bl_get_brightness(struct backlight_device *bd) 0, pdata->msgdata, 2, ACD_USB_TIMEOUT); - brightness = pdata->msgdata[1]; + if (retval < 2) { + if (retval >= 0) + retval = -EMSGSIZE; + } else { + brightness = pdata->msgdata[1]; + } mutex_unlock(&pdata->sysfslock); if (retval < 0) @@ -324,6 +329,7 @@ error: if (pdata) { if (pdata->urb) { usb_kill_urb(pdata->urb); + cancel_delayed_work_sync(&pdata->work); if (pdata->urbdata) usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN, pdata->urbdata, pdata->urb->transfer_dma); -- 2.7.4