From patchwork Thu May 9 03:20:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 1097319 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=fail (p=none dis=none) header.from=redhat.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44zzB31Frtz9s9y for ; Thu, 9 May 2019 13:20:27 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726753AbfEIDUX (ORCPT ); Wed, 8 May 2019 23:20:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43052 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726251AbfEIDUW (ORCPT ); Wed, 8 May 2019 23:20:22 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C8EC33092649; Thu, 9 May 2019 03:20:22 +0000 (UTC) Received: from hp-dl380pg8-02.lab.eng.pek2.redhat.com (hp-dl380pg8-02.lab.eng.pek2.redhat.com [10.73.8.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id B8E295C221; Thu, 9 May 2019 03:20:20 +0000 (UTC) From: Jason Wang To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: yuehaibing@huawei.com, xiyou.wangcong@gmail.com, weiyongjun1@huawei.com, eric.dumazet@gmail.com, Jason Wang Subject: [PATCH net V3 1/2] tuntap: fix dividing by zero in ebpf queue selection Date: Wed, 8 May 2019 23:20:17 -0400 Message-Id: <1557372018-18544-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Thu, 09 May 2019 03:20:22 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We need check if tun->numqueues is zero (e.g for the persist device) before trying to use it for modular arithmetic. Reported-by: Eric Dumazet Fixes: 96f84061620c6("tun: add eBPF based queue selection method") Signed-off-by: Jason Wang Reviewed-by: Eric Dumazet --- drivers/net/tun.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e9ca1c0..dc62fc3 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -596,13 +596,18 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb) { struct tun_prog *prog; + u32 numqueues; u16 ret = 0; + numqueues = READ_ONCE(tun->numqueues); + if (!numqueues) + return 0; + prog = rcu_dereference(tun->steering_prog); if (prog) ret = bpf_prog_run_clear_cb(prog->prog, skb); - return ret % tun->numqueues; + return ret % numqueues; } static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,