From: Oliver Neukum oneukum@suse.com
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 oneukum@suse.com Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20191106124902.7765-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/misc/appledisplay.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -170,7 +170,12 @@ static int appledisplay_bl_get_brightnes 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) @@ -305,6 +310,7 @@ 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);