USB: Do not pass negative length to snoop_urb()

When `echo Y > /sys/module/usbcore/parameters/usbfs_snoop` and
usb_control_msg() returns error, a lot of kernel memory is dumped to dmesg
until unhandled kernel paging request occurs.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Michal Sojka 2011-03-15 16:41:47 +01:00 committed by Greg Kroah-Hartman
parent 4bbba111d9
commit 9d02b42614

View File

@ -802,7 +802,7 @@ static int proc_control(struct dev_state *ps, void __user *arg)
tbuf, ctrl.wLength, tmo);
usb_lock_device(dev);
snoop_urb(dev, NULL, pipe, max(i, 0), min(i, 0), COMPLETE,
tbuf, i);
tbuf, max(i, 0));
if ((i > 0) && ctrl.wLength) {
if (copy_to_user(ctrl.data, tbuf, i)) {
free_page((unsigned long)tbuf);