4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit fa1ed74eb1c233be6131ec92df21ab46499a15b6 upstream. The user buffer has "uurb->buffer_length" bytes. If the kernel has more information than that, we should truncate it instead of writing past the end of the user's buffer. I added a WARN_ONCE() to help the user debug the issue. Reported-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/core/devio.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1417,7 +1417,11 @@ static int proc_do_submiturb(struct usb_ totlen += isopkt[u].length; } u *= sizeof(struct usb_iso_packet_descriptor); - uurb->buffer_length = totlen; + if (totlen <= uurb->buffer_length) + uurb->buffer_length = totlen; + else + WARN_ONCE(1, "uurb->buffer_length is too short %d vs %d", + totlen, uurb->buffer_length); break; default: