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Commit da7c9561 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

packet: only test po->has_vnet_hdr once in packet_snd 



Packet socket option po->has_vnet_hdr can be updated concurrently with
other operations if no ring is attached.

Do not test the option twice in packet_snd, as the value may change in
between calls. A race on setsockopt disable may cause a packet > mtu
to be sent without having GSO options set.

Fixes: bfd5f4a3 ("packet: Add GSO/csum offload support.")
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4971613c

net/packet/af_packet.c

+3 −1
Original line number Diff line number Diff line
@@ -2840,6 +2840,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
	struct virtio_net_hdr vnet_hdr = { 0 };

	int offset = 0;

	struct packet_sock *po = pkt_sk(sk);

	bool has_vnet_hdr = false;

	int hlen, tlen, linear;

	int extra_len = 0;
@@ -2883,6 +2884,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
		err = packet_snd_vnet_parse(msg, &len, &vnet_hdr);

		if (err)

			goto out_unlock;

		has_vnet_hdr = true;

	}



	if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
@@ -2941,7 +2943,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 
	skb->priority = sk->sk_priority;

	skb->mark = sockc.mark;



	if (po->has_vnet_hdr) {

	if (has_vnet_hdr) {

		err = virtio_net_hdr_to_skb(skb, &vnet_hdr, vio_le());

		if (err)

			goto out_free;