[PATCH 5.0 022/146] tcp: do not use ipv6 header for ipv4 flow

From: Greg Kroah-Hartman
Date: Mon Apr 01 2019 - 13:05:11 EST


5.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 89e4130939a20304f4059ab72179da81f5347528 ]

When a dual stack tcp listener accepts an ipv4 flow,
it should not attempt to use an ipv6 header or tcp_v6_iif() helper.

Fixes: 1397ed35f22d ("ipv6: add flowinfo for tcp6 pkt_options for all cases")
Fixes: df3687ffc665 ("ipv6: add the IPV6_FL_F_REFLECT flag to IPV6_FL_A_GET")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/tcp_ipv6.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1112,11 +1112,11 @@ static struct sock *tcp_v6_syn_recv_sock
newnp->ipv6_fl_list = NULL;
newnp->pktoptions = NULL;
newnp->opt = NULL;
- newnp->mcast_oif = tcp_v6_iif(skb);
- newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
- newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
+ newnp->mcast_oif = inet_iif(skb);
+ newnp->mcast_hops = ip_hdr(skb)->ttl;
+ newnp->rcv_flowinfo = 0;
if (np->repflow)
- newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
+ newnp->flow_label = 0;

/*
* No need to charge this sock to the relevant IPv6 refcnt debug socks count