3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn willemb@google.com
commit da7c9561015e93d10fe6aab73e9288e0d09d65a6 upstream.
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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- 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 @@ -2432,6 +2432,7 @@ static int packet_snd(struct socket *soc int offset = 0; int vnet_hdr_len; struct packet_sock *po = pkt_sk(sk); + bool has_vnet_hdr = false; unsigned short gso_type = 0; int hlen, tlen; int extra_len = 0; @@ -2466,6 +2467,7 @@ static int packet_snd(struct socket *soc reserve = dev->hard_header_len; if (po->has_vnet_hdr) { vnet_hdr_len = sizeof(vnet_hdr); + has_vnet_hdr = true;
err = -EINVAL; if (len < vnet_hdr_len) @@ -2557,7 +2559,7 @@ static int packet_snd(struct socket *soc skb->priority = sk->sk_priority; skb->mark = sk->sk_mark;
- if (po->has_vnet_hdr) { + if (has_vnet_hdr) { if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (!skb_partial_csum_set(skb, vnet_hdr.csum_start, vnet_hdr.csum_offset)) {