From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEA9EC43381 for ; Mon, 1 Apr 2019 17:52:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE77B20830 for ; Mon, 1 Apr 2019 17:52:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141151; bh=scHO8Hlt3p7MSGXsfkhENYV+d/8SBiW+x80bCdTfzeU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DSGQ67GmD2Wk7QWWE1zz7TyA578PCRSy3Uhe1j/Sa9ga1vP7y3N9XEx/E4RqhhnzN mL8oe+qe+wq8+FWo97pTtf5F+PhxfX9tsSzWUO5xjMz4MCXqn+mAO24DziqrH94Hfj zBlKn5dC3jceVkic+N3jOujEHBqwnq1zege5rLlI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732768AbfDARwa (ORCPT ); Mon, 1 Apr 2019 13:52:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:58884 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732377AbfDAR0i (ORCPT ); Mon, 1 Apr 2019 13:26:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 629F42063F; Mon, 1 Apr 2019 17:26:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139597; bh=scHO8Hlt3p7MSGXsfkhENYV+d/8SBiW+x80bCdTfzeU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hsWYhc7ICJrdLyRIIGOSJDCD7yF2TObagMgKw0Uv0XHiKMimortYxY2/fqecnCTp5 pwwgTFJeaFRy12n4/fweqYDqB0J6n0fcS8zPkZI3xp42olkFeSJVwmJDoTD/A7vYG1 duZ+Vj7Nzs2LywT/PsYAwNdIRl+VHZoXGFYG/H/M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" Subject: [PATCH 4.9 15/56] tun: properly test for IFF_UP Date: Mon, 1 Apr 2019 19:02:31 +0200 Message-Id: <20190401170104.716838996@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170103.398401360@linuxfoundation.org> References: <20190401170103.398401360@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 4477138fa0ae4e1b699786ef0600863ea6e6c61c ] Same reasons than the ones explained in commit 4179cb5a4c92 ("vxlan: test dev->flags & IFF_UP before calling netif_rx()") netif_rx_ni() or napi_gro_frags() must be called under a strict contract. At device dismantle phase, core networking clears IFF_UP and flush_all_backlogs() is called after rcu grace period to make sure no incoming packet might be in a cpu backlog and still referencing the device. A similar protocol is used for gro layer. Most drivers call netif_rx() from their interrupt handler, and since the interrupts are disabled at device dismantle, netif_rx() does not have to check dev->flags & IFF_UP Virtual drivers do not have this guarantee, and must therefore make the check themselves. Fixes: 1bd4978a88ac ("tun: honor IFF_UP in tun_get_user()") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tun.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1194,9 +1194,6 @@ static ssize_t tun_get_user(struct tun_s u32 rxhash; ssize_t n; - if (!(tun->dev->flags & IFF_UP)) - return -EIO; - if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; @@ -1273,9 +1270,11 @@ static ssize_t tun_get_user(struct tun_s err = skb_copy_datagram_from_iter(skb, 0, from, len); if (err) { + err = -EFAULT; +drop: this_cpu_inc(tun->pcpu_stats->rx_dropped); kfree_skb(skb); - return -EFAULT; + return err; } err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun)); @@ -1327,7 +1326,15 @@ static ssize_t tun_get_user(struct tun_s skb_probe_transport_header(skb, 0); rxhash = skb_get_hash(skb); + + rcu_read_lock(); + if (unlikely(!(tun->dev->flags & IFF_UP))) { + err = -EIO; + goto drop; + } + netif_rx_ni(skb); + rcu_read_unlock(); stats = get_cpu_ptr(tun->pcpu_stats); u64_stats_update_begin(&stats->syncp);