3.2.97-rc1 review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn <willemb@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -2231,6 +2231,7 @@ 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;
/*
@@ -2263,6 +2264,7 @@ 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)
@@ -2354,7 +2356,7 @@ 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)) {