From patchwork Wed Sep 12 05:36:35 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 968846 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=1wt.eu Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4299Wj5P5Jz9s3l for ; Wed, 12 Sep 2018 15:36:49 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726992AbeILKjb (ORCPT ); Wed, 12 Sep 2018 06:39:31 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:33516 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726082AbeILKjb (ORCPT ); Wed, 12 Sep 2018 06:39:31 -0400 Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id w8C5aZ0N021173; Wed, 12 Sep 2018 07:36:35 +0200 Date: Wed, 12 Sep 2018 07:36:35 +0200 From: Willy Tarreau To: "David S. Miller" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jann Horn Subject: [PATCH] net/appletalk: fix minor pointer leak to userspace in SIOCFINDIPDDPRT Message-ID: <20180912053635.GA21168@1wt.eu> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.6.1 (2016-04-27) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fields ->dev and ->next of struct ipddp_route may be copied to userspace on the SIOCFINDIPDDPRT ioctl. This is only accessible to CAP_NET_ADMIN though. Let's manually copy the relevant fields instead of using memcpy(). BugLink: http://blog.infosectcbr.com.au/2018/09/linux-kernel-infoleaks.html Cc: Jann Horn Signed-off-by: Willy Tarreau --- drivers/net/appletalk/ipddp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/appletalk/ipddp.c b/drivers/net/appletalk/ipddp.c index 9375cef..3d27616 100644 --- a/drivers/net/appletalk/ipddp.c +++ b/drivers/net/appletalk/ipddp.c @@ -283,8 +283,12 @@ static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) case SIOCFINDIPDDPRT: spin_lock_bh(&ipddp_route_lock); rp = __ipddp_find_route(&rcp); - if (rp) - memcpy(&rcp2, rp, sizeof(rcp2)); + if (rp) { + memset(&rcp2, 0, sizeof(rcp2)); + rcp2.ip = rp->ip; + rcp2.at = rp->at; + rcp2.flags = rp->flags; + } spin_unlock_bh(&ipddp_route_lock); if (rp) {