This is a note to let you know that I've just added the patch titled packet: only allow extra vlan len on ethernet devices to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: packet-only-allow-extra-vlan-len-on-ethernet-devices.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Fri Dec 11 11:39:13 EST 2015 From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Date: Wed, 11 Nov 2015 23:25:42 +0100 Subject: packet: only allow extra vlan len on ethernet devices From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> [ Upstream commit 3c70c132488794e2489ab045559b0ce0afcf17de ] Packet sockets can be used by various net devices and are not really restricted to ARPHRD_ETHER device types. However, when currently checking for the extra 4 bytes that can be transmitted in VLAN case, our assumption is that we generally probe on ARPHRD_ETHER devices. Therefore, before looking into Ethernet header, check the device type first. This also fixes the issue where non-ARPHRD_ETHER devices could have no dev->hard_header_len in TX_RING SOCK_RAW case, and thus the check would test unfilled linear part of the skb (instead of non-linear). Fixes: 57f89bfa2140 ("network: Allow af_packet to transmit +4 bytes for VLAN packets.") Fixes: 52f1454f629f ("packet: allow to transmit +4 byte in TX_RING slot for VLAN case") Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/packet/af_packet.c | 60 ++++++++++++++++++++----------------------------- 1 file changed, 25 insertions(+), 35 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1524,6 +1524,20 @@ static void fanout_release(struct sock * mutex_unlock(&fanout_mutex); } +static bool packet_extra_vlan_len_allowed(const struct net_device *dev, + struct sk_buff *skb) +{ + /* Earlier code assumed this would be a VLAN pkt, double-check + * this now that we have the actual packet in hand. We can only + * do this check on Ethernet devices. + */ + if (unlikely(dev->type != ARPHRD_ETHER)) + return false; + + skb_reset_mac_header(skb); + return likely(eth_hdr(skb)->h_proto == htons(ETH_P_8021Q)); +} + static const struct proto_ops packet_ops; static const struct proto_ops packet_ops_spkt; @@ -1685,18 +1699,10 @@ retry: goto retry; } - if (len > (dev->mtu + dev->hard_header_len + extra_len)) { - /* Earlier code assumed this would be a VLAN pkt, - * double-check this now that we have the actual - * packet in hand. - */ - struct ethhdr *ehdr; - skb_reset_mac_header(skb); - ehdr = eth_hdr(skb); - if (ehdr->h_proto != htons(ETH_P_8021Q)) { - err = -EMSGSIZE; - goto out_unlock; - } + if (len > (dev->mtu + dev->hard_header_len + extra_len) && + !packet_extra_vlan_len_allowed(dev, skb)) { + err = -EMSGSIZE; + goto out_unlock; } skb->protocol = proto; @@ -2308,18 +2314,10 @@ static int tpacket_snd(struct packet_soc tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto, addr, hlen); if (likely(tp_len >= 0) && - tp_len > dev->mtu + dev->hard_header_len) { - struct ethhdr *ehdr; - /* Earlier code assumed this would be a VLAN pkt, - * double-check this now that we have the actual - * packet in hand. - */ + tp_len > dev->mtu + dev->hard_header_len && + !packet_extra_vlan_len_allowed(dev, skb)) + tp_len = -EMSGSIZE; - skb_reset_mac_header(skb); - ehdr = eth_hdr(skb); - if (ehdr->h_proto != htons(ETH_P_8021Q)) - tp_len = -EMSGSIZE; - } if (unlikely(tp_len < 0)) { if (po->tp_loss) { __packet_set_status(po, ph, @@ -2540,18 +2538,10 @@ static int packet_snd(struct socket *soc sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags); - if (!gso_type && (len > dev->mtu + reserve + extra_len)) { - /* Earlier code assumed this would be a VLAN pkt, - * double-check this now that we have the actual - * packet in hand. - */ - struct ethhdr *ehdr; - skb_reset_mac_header(skb); - ehdr = eth_hdr(skb); - if (ehdr->h_proto != htons(ETH_P_8021Q)) { - err = -EMSGSIZE; - goto out_free; - } + if (!gso_type && (len > dev->mtu + reserve + extra_len) && + !packet_extra_vlan_len_allowed(dev, skb)) { + err = -EMSGSIZE; + goto out_free; } skb->protocol = proto; Patches currently in stable-queue which might be from daniel@xxxxxxxxxxxxx are queue-4.1/packet-infer-protocol-from-ethernet-header-if-unset.patch queue-4.1/bpf-array-fix-heap-out-of-bounds-access-when-updating-elements.patch queue-4.1/ipv6-sctp-implement-sctp_v6_destroy_sock.patch queue-4.1/packet-only-allow-extra-vlan-len-on-ethernet-devices.patch queue-4.1/net-scm-fix-pax-detected-msg_controllen-overflow-in-scm_detach_fds.patch queue-4.1/packet-fix-tpacket_snd-max-frame-len.patch queue-4.1/packet-always-probe-for-transport-header.patch queue-4.1/packet-do-skb_probe_transport_header-when-we-actually-have-data.patch queue-4.1/tools-net-use-include-uapi-with-__exported_headers__.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html