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=unavailable 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 2B905C43381 for ; Mon, 1 Apr 2019 17:56:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F04682084B for ; Mon, 1 Apr 2019 17:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141419; bh=oYflPXLztsa3jZ0io8ZwFcDBLU9GeoZxUi7LMyRtWrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Imw4HoESisl+Yh+ZmsZhhWxGVq1MNFN3aYE3RCg+7lKz3O/EFoM7jX/b5vw16vU7A w6Y+sIseONNmbk6MaKp995D32O1wIfZZS+rE2A07tnvUKPo3YYszCb4xAdGMsbGXYf 2RZyZw7+q41SG4w23ciyZu5q8B9xLUcwnCmYJ1ec= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731527AbfDARU4 (ORCPT ); Mon, 1 Apr 2019 13:20:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:49318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731518AbfDARU4 (ORCPT ); Mon, 1 Apr 2019 13:20:56 -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 1262620883; Mon, 1 Apr 2019 17:20:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139255; bh=oYflPXLztsa3jZ0io8ZwFcDBLU9GeoZxUi7LMyRtWrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JVoVqQe4VBOBzCNkPPtiOjJvnWGhSAUm7pt82QVFqt3l/InGtmDAYlKbSKt72UJsz ZtJVWl/TZ1M/p8iLTWYChnaBQ5S7aUWi63/hypnfY2kQG2KDOg7R0bnqH15Y4mewqP qXPEhTL09maqBJES/xi1ifO3oHDf5SHgMhRMLfxI= 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 4.14 022/107] tun: properly test for IFF_UP Date: Mon, 1 Apr 2019 19:01:37 +0200 Message-Id: <20190401170047.746995726@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170045.246405031@linuxfoundation.org> References: <20190401170045.246405031@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-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 @@ -1403,9 +1403,6 @@ static ssize_t tun_get_user(struct tun_s u32 rxhash; int skb_xdp = 1; - if (!(tun->dev->flags & IFF_UP)) - return -EIO; - if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; @@ -1493,9 +1490,11 @@ 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; } } @@ -1566,11 +1565,19 @@ static ssize_t tun_get_user(struct tun_s } rxhash = __skb_get_hash_symmetric(skb); + + rcu_read_lock(); + if (unlikely(!(tun->dev->flags & IFF_UP))) { + err = -EIO; + goto drop; + } + #ifndef CONFIG_4KSTACKS tun_rx_batched(tun, tfile, skb, more); #else netif_rx_ni(skb); #endif + rcu_read_unlock(); stats = get_cpu_ptr(tun->pcpu_stats); u64_stats_update_begin(&stats->syncp);