4.20-stable review patch. If anyone has any objections, please let me know.
------------------ From: Lorenzo Bianconi <[email protected]> [ Upstream commit feaf5c796b3f0240f10d0d6d0b686715fd58a05b ] Erspan protocol (version 1 and 2) relies on o_key to configure session id header field. However TUNNEL_KEY bit is cleared in erspan_xmit since ERSPAN protocol does not set the key field of the external GRE header and so the configured o_key is not reported to userspace. The issue can be triggered with the following reproducer: $ip link add erspan1 type erspan local 192.168.0.1 remote 192.168.0.2 \ key 1 seq erspan_ver 1 $ip link set erspan1 up $ip -d link sh erspan1 erspan1@NONE: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc pfifo_fast state UNKNOWN mode DEFAULT link/ether 52:aa:99:95:9a:b5 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 1500 erspan remote 192.168.0.2 local 192.168.0.1 ttl inherit ikey 0.0.0.1 iseq oseq erspan_index 0 Fix the issue adding TUNNEL_KEY bit to the o_flags parameter in ipgre_fill_info Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") Signed-off-by: Lorenzo Bianconi <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/ipv4/ip_gre.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1468,12 +1468,17 @@ static int ipgre_fill_info(struct sk_buf { struct ip_tunnel *t = netdev_priv(dev); struct ip_tunnel_parm *p = &t->parms; + __be16 o_flags = p->o_flags; + + if ((t->erspan_ver == 1 || t->erspan_ver == 2) && + !t->collect_md) + o_flags |= TUNNEL_KEY; if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) || nla_put_be16(skb, IFLA_GRE_IFLAGS, gre_tnl_flags_to_gre_flags(p->i_flags)) || nla_put_be16(skb, IFLA_GRE_OFLAGS, - gre_tnl_flags_to_gre_flags(p->o_flags)) || + gre_tnl_flags_to_gre_flags(o_flags)) || nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) || nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) || nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
