From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40253 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758522AbcATWBb (ORCPT ); Wed, 20 Jan 2016 17:01:31 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Daniel Borkmann , Willem de Bruijn , "David S. Miller" Subject: [PATCH 3.14 05/47] packet: infer protocol from ethernet header if unset Date: Wed, 20 Jan 2016 14:00:37 -0800 Message-Id: <20160120215508.396172478@linuxfoundation.org> In-Reply-To: <20160120215507.575738941@linuxfoundation.org> References: <20160120215507.575738941@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit c72219b75fde768efccf7666342282fab7f9e4e7 ] In case no struct sockaddr_ll has been passed to packet socket's sendmsg() when doing a TX_RING flush run, then skb->protocol is set to po->num instead, which is the protocol passed via socket(2)/bind(2). Applications only xmitting can go the path of allocating the socket as socket(PF_PACKET, , 0) and do a bind(2) on the TX_RING with sll_protocol of 0. That way, register_prot_hook() is neither called on creation nor on bind time, which saves cycles when there's no interest in capturing anyway. That leaves us however with po->num 0 instead and therefore the TX_RING flush run sets skb->protocol to 0 as well. Eric reported that this leads to problems when using tools like trafgen over bonding device. I.e. the bonding's hash function could invoke the kernel's flow dissector, which depends on skb->protocol being properly set. In the current situation, all the traffic is then directed to a single slave. Fix it up by inferring skb->protocol from the Ethernet header when not set and we have ARPHRD_ETHER device type. This is only done in case of SOCK_RAW and where we have a dev->hard_header_len length. In case of ARPHRD_ETHER devices, this is guaranteed to cover ETH_HLEN, and therefore being accessed on the skb after the skb_store_bits(). Reported-by: Eric Dumazet Signed-off-by: Daniel Borkmann Acked-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2091,6 +2091,15 @@ static void tpacket_destruct_skb(struct sock_wfree(skb); } +static void tpacket_set_protocol(const struct net_device *dev, + struct sk_buff *skb) +{ + if (dev->type == ARPHRD_ETHER) { + skb_reset_mac_header(skb); + skb->protocol = eth_hdr(skb)->h_proto; + } +} + static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, void *frame, struct net_device *dev, int size_max, __be16 proto, unsigned char *addr, int hlen) @@ -2176,6 +2185,8 @@ static int tpacket_fill_skb(struct packe dev->hard_header_len); if (unlikely(err)) return err; + if (!skb->protocol) + tpacket_set_protocol(dev, skb); data += dev->hard_header_len; to_write -= dev->hard_header_len;