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 242A7C10F11 for ; Wed, 24 Apr 2019 17:30:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAE8921907 for ; Wed, 24 Apr 2019 17:30:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556127052; bh=UbP5meTzwPoeWdYfw4apo4hE7nfdCAIBcC8WVUVWmAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vO7rDT1Oo51doOcxxYqtZjqqb0F+wUkn/xfFJo0uf3roNRq9a69wUF7M0KR4g9cp0 mxUm5ZqZRQklLHKhRflQ1e/rU492MgKpUXhrpnr1LKJSDmge/e5lJB0tTyey67vili CsytrczUlgNguCx8GCSuVzxdobxnzvSWzU7ESDMo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391060AbfDXRau (ORCPT ); Wed, 24 Apr 2019 13:30:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:57132 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391046AbfDXRar (ORCPT ); Wed, 24 Apr 2019 13:30:47 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (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 43FFC2054F; Wed, 24 Apr 2019 17:30:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556127046; bh=UbP5meTzwPoeWdYfw4apo4hE7nfdCAIBcC8WVUVWmAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gnLYcZzZk6+Zj7TxUiwviBNQ9p4SJJpKQtqyIn3vAj2dtIy3SGKy+U2juOai+exfi 8JkbhXo8+sS3GAwaRNO2d8CPpheruG1oOPOb8KyPp0TJOWkYsktdTi6eW0emJr/UiY 8e1yKMf5bzmAdjjLODUp/Iyi26PyyPoCeQK7wooc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 4.19 04/96] net: bridge: fix per-port af_packet sockets Date: Wed, 24 Apr 2019 19:09:09 +0200 Message-Id: <20190424170920.134760488@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170919.829037226@linuxfoundation.org> References: <20190424170919.829037226@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Nikolay Aleksandrov [ Upstream commit 3b2e2904deb314cc77a2192f506f2fd44e3d10d0 ] When the commit below was introduced it changed two visible things: - the skb was no longer passed through the protocol handlers with the original device - the skb was passed up the stack with skb->dev = bridge The first change broke af_packet sockets on bridge ports. For example we use them for hostapd which listens for ETH_P_PAE packets on the ports. We discussed two possible fixes: - create a clone and pass it through NF_HOOK(), act on the original skb based on the result - somehow signal to the caller from the okfn() that it was called, meaning the skb is ok to be passed, which this patch is trying to implement via returning 1 from the bridge link-local okfn() Note that we rely on the fact that NF_QUEUE/STOLEN would return 0 and drop/error would return < 0 thus the okfn() is called only when the return was 1, so we signal to the caller that it was called by preserving the return value from nf_hook(). Fixes: 8626c56c8279 ("bridge: fix potential use-after-free when hook returns QUEUE or STOLEN verdict") Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_input.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -195,13 +195,10 @@ static void __br_handle_local_finish(str /* note: already called with rcu_read_lock */ static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { - struct net_bridge_port *p = br_port_get_rcu(skb->dev); - __br_handle_local_finish(skb); - BR_INPUT_SKB_CB(skb)->brdev = p->br->dev; - br_pass_frame_up(skb); - return 0; + /* return 1 to signal the okfn() was called so it's ok to use the skb */ + return 1; } /* @@ -278,10 +275,18 @@ rx_handler_result_t br_handle_frame(stru goto forward; } - /* Deliver packet to local host only */ - NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev), - NULL, skb, skb->dev, NULL, br_handle_local_finish); - return RX_HANDLER_CONSUMED; + /* The else clause should be hit when nf_hook(): + * - returns < 0 (drop/error) + * - returns = 0 (stolen/nf_queue) + * Thus return 1 from the okfn() to signal the skb is ok to pass + */ + if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, + dev_net(skb->dev), NULL, skb, skb->dev, NULL, + br_handle_local_finish) == 1) { + return RX_HANDLER_PASS; + } else { + return RX_HANDLER_CONSUMED; + } } forward: