[PATCH 4.18 17/34] cdc-acm: fix race between reset and control messaging

Greg Kroah-Hartman
2018-11-08T22:09:43Z

From: Oliver Neukum <oneukum@suse.com>

commit 9397940ed812b942c520e0c25ed4b2c64d57e8b9 upstream.

If a device splits up a control message and a reset() happens
between the parts, the message is lost and already recieved parts
must be dropped.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Fixes: 1aba579f3cf51 ("cdc-acm: handle read pipe errors")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/class/cdc-acm.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1641,6 +1641,7 @@ static int acm_pre_reset(struct usb_inte
struct acm *acm = usb_get_intfdata(intf);

clear_bit(EVENT_RX_STALL, &acm->flags);
+ acm->nb_index = 0; /* pending control transfers are lost */

return 0;
}