From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932075AbbBSAnq (ORCPT ); Wed, 18 Feb 2015 19:43:46 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:35689 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754076AbbBSAec (ORCPT ); Wed, 18 Feb 2015 19:34:32 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Wolfgang Grandegger , Oliver Hartkopp , Marc Kleine-Budde , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 079/103] can: dev: fix crtlmode_supported check Date: Wed, 18 Feb 2015 16:32:46 -0800 Message-Id: <1424305990-17983-80-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1424305990-17983-1-git-send-email-kamal@canonical.com> References: <1424305990-17983-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt16 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Hartkopp commit 9b1087aa5e86448fe6ad40a58964e35f3ba423d5 upstream. When changing flags in the CAN drivers ctrlmode the provided new content has to be checked whether the bits are allowed to be changed. The bits that are to be changed are given as a bitfield in cm->mask. Therefore checking against cm->flags is wrong as the content can hold any kind of values. The iproute2 tool sets the bits in cm->mask and cm->flags depending on the detected command line options. To be robust against bogus user space applications additionally sanitize the provided flags with the provided mask. Cc: Wolfgang Grandegger Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde Signed-off-by: Kamal Mostafa --- drivers/net/can/dev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 98a3b2b..c8f55ae 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -665,10 +665,14 @@ static int can_changelink(struct net_device *dev, if (dev->flags & IFF_UP) return -EBUSY; cm = nla_data(data[IFLA_CAN_CTRLMODE]); - if (cm->flags & ~priv->ctrlmode_supported) + + /* check whether changed bits are allowed to be modified */ + if (cm->mask & ~priv->ctrlmode_supported) return -EOPNOTSUPP; + + /* clear bits to be modified and copy the flag values */ priv->ctrlmode &= ~cm->mask; - priv->ctrlmode |= cm->flags; + priv->ctrlmode |= (cm->flags & cm->mask); } if (data[IFLA_CAN_RESTART_MS]) { -- 1.9.1