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 B1657C10F05 for ; Mon, 1 Apr 2019 17:05:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80D4321929 for ; Mon, 1 Apr 2019 17:05:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554138306; bh=pp7mW8KiaJh6Vc7/4sPgOBf8Wfjuy8rkr3VSZkUtwJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SCgo5VmKsXtCvYbYM2xx2oBdkkzKQ4YMkSpirVXZAYKxcFf9ou7Hp8zqZpak/hp/8 Flln/w9y2SGowoyTc0uaiPh5NuK/rV5ZCzbZPBmj9Rs9ma16w2DcN75yvM+FXa+fP9 nUYSJNReR+rLUmxkogJA+GyJnQPLB0ZjskRd57Z4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728678AbfDARFF (ORCPT ); Mon, 1 Apr 2019 13:05:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:49928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728019AbfDARFE (ORCPT ); Mon, 1 Apr 2019 13:05:04 -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 B119F21925; Mon, 1 Apr 2019 17:05:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554138303; bh=pp7mW8KiaJh6Vc7/4sPgOBf8Wfjuy8rkr3VSZkUtwJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WT/GXG6lorqWexvWrQDf7LyQNsH4mgN2VmNyQ11fbki7QzAY42f6yMzwQb3tZKTMs 1wi/ztAJbjV/cATJuUoXAoX97DYgMik1OBtepIytes4iTyXhg19J8bCt6QAcJRh8Zq 3sk9S+zchsDiWzJG50TqiHK52IeSHWCSRF5KxMFI= 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 5.0 026/146] tun: properly test for IFF_UP Date: Mon, 1 Apr 2019 19:00:38 +0200 Message-Id: <20190401170050.743979500@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170048.449559024@linuxfoundation.org> References: <20190401170048.449559024@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 5.0-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 @@ -1763,9 +1763,6 @@ static ssize_t tun_get_user(struct tun_s int skb_xdp = 1; bool frags = tun_napi_frags_enabled(tfile); - if (!(tun->dev->flags & IFF_UP)) - return -EIO; - if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; @@ -1867,6 +1864,8 @@ 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); if (frags) { @@ -1874,7 +1873,7 @@ static ssize_t tun_get_user(struct tun_s mutex_unlock(&tfile->napi_mutex); } - return -EFAULT; + return err; } } @@ -1958,6 +1957,12 @@ static ssize_t tun_get_user(struct tun_s !tfile->detached) rxhash = __skb_get_hash_symmetric(skb); + rcu_read_lock(); + if (unlikely(!(tun->dev->flags & IFF_UP))) { + err = -EIO; + goto drop; + } + if (frags) { /* Exercise flow dissector code path. */ u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb)); @@ -1965,6 +1970,7 @@ static ssize_t tun_get_user(struct tun_s if (unlikely(headlen > skb_headlen(skb))) { this_cpu_inc(tun->pcpu_stats->rx_dropped); napi_free_frags(&tfile->napi); + rcu_read_unlock(); mutex_unlock(&tfile->napi_mutex); WARN_ON(1); return -ENOMEM; @@ -1992,6 +1998,7 @@ static ssize_t tun_get_user(struct tun_s } else { netif_rx_ni(skb); } + rcu_read_unlock(); stats = get_cpu_ptr(tun->pcpu_stats); u64_stats_update_begin(&stats->syncp);