| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.13 037/160] packet: only test po->has_vnet_hdr once in packet_snd | Date | Tue, 10 Oct 2017 21:49:25 +0200 |
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4.13-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn <willemb@google.com>
[ Upstream commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 ]
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: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/packet/af_packet.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2842,6 +2842,7 @@ static int packet_snd(struct socket *soc 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; @@ -2885,6 +2886,7 @@ static int packet_snd(struct socket *soc 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))) { @@ -2943,7 +2945,7 @@ static int packet_snd(struct socket *soc 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;
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