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packet: make packet_snd fail on len smaller than l2 header 

When sending packets out with PF_PACKET, SOCK_RAW, ensure that the
packet is at least as long as the device's expected link layer header.
This check already exists in tpacket_snd, but not in packet_snd.
Also rate limit the warning in tpacket_snd.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn 2014-11-19 13:10:16 -05:00 committed by David S. Miller
parent df6ce47091
commit 9c7077622d
1 changed files with 21 additions and 8 deletions
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29
net/packet/af_packet.c
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@ -2095,6 +2095,18 @@ static void tpacket_destruct_skb(struct sk_buff *skb)
sock_wfree(skb);
}
static bool ll_header_truncated(const struct net_device *dev, int len)
{
/* net device doesn't like empty head */
if (unlikely(len <= dev->hard_header_len)) {
net_warn_ratelimited("%s: packet size is too short (%d < %d)\n",
current->comm, len, dev->hard_header_len);
return true;
}
return false;
}
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)
@ -2170,12 +2182,8 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
if (unlikely(err < 0))
return -EINVAL;
} else if (dev->hard_header_len) {
/* net device doesn't like empty head */
if (unlikely(tp_len <= dev->hard_header_len)) {
pr_err("packet size is too short (%d < %d)\n",
tp_len, dev->hard_header_len);
if (ll_header_truncated(dev, tp_len))
return -EINVAL;
}
skb_push(skb, dev->hard_header_len);
err = skb_store_bits(skb, 0, data,
@ -2500,9 +2508,14 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
skb_set_network_header(skb, reserve);
err = -EINVAL;
if (sock->type == SOCK_DGRAM &&
(offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len)) < 0)
goto out_free;
if (sock->type == SOCK_DGRAM) {
offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);
if (unlikely(offset) < 0)
goto out_free;
} else {
if (ll_header_truncated(dev, len))
goto out_free;
}
/* Returns -EFAULT on error */
err = skb_copy_datagram_from_iovec(skb, offset, msg->msg_iov, 0, len);