From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752169AbdKVCkY (ORCPT ); Tue, 21 Nov 2017 21:40:24 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:56685 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751804AbdKVCUW (ORCPT ); Tue, 21 Nov 2017 21:20:22 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "=?UTF-8?q?Bj=C3=B8rn=20Mork?=" , "Oliver Neukum" Date: Wed, 22 Nov 2017 01:58:13 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 125/133] net: cdc_ether: fix divide by 0 on bad descriptors In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.51-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Bjørn Mork commit 2cb80187ba065d7decad7c6614e35e07aec8a974 upstream. Setting dev->hard_mtu to 0 will cause a divide error in usbnet_probe. Protect against devices with bogus CDC Ethernet functional descriptors by ignoring a zero wMaxSegmentSize. Signed-off-by: Bjørn Mork Acked-by: Oliver Neukum Signed-off-by: David S. Miller [bwh: Backported to 3.16: parsing code is organised differently] Signed-off-by: Ben Hutchings --- --- a/drivers/net/usb/cdc_ether.c +++ b/drivers/net/usb/cdc_ether.c @@ -235,8 +235,9 @@ int usbnet_generic_cdc_bind(struct usbne info->ether->bLength); goto bad_desc; } - dev->hard_mtu = le16_to_cpu( - info->ether->wMaxSegmentSize); + if (info->ether->wMaxSegmentSize) + dev->hard_mtu = le16_to_cpu( + info->ether->wMaxSegmentSize); /* because of Zaurus, we may be ignoring the host * side link address we were given. */