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packet: only allow extra vlan len on ethernet devices

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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@iogearbox.net>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2015-11-11 23:25:42 +01:00 committed by David S. Miller
parent 8fd6c80d9d
commit 3c70c13248
1 changed files with 25 additions and 35 deletions
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60
net/packet/af_packet.c
View File

@ -1741,6 +1741,20 @@ static void fanout_release(struct sock *sk)
kfree_rcu(po->rollover, rcu);
}
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;
@ -1902,18 +1916,10 @@ 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;
@ -2525,18 +2531,10 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
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,
@ -2765,18 +2763,10 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
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;