From 26cc831b75b450da00ef50c320f7cb9067748c3d Mon Sep 17 00:00:00 2001 From: William Dauchy <w.dauchy@criteo.com> Date: Fri, 27 Mar 2020 19:56:39 +0100 Subject: [PATCH] net, ip_tunnel: fix interface lookup with no key BugLink: https://bugs.launchpad.net/bugs/1874045 [ Upstream commit 25629fdaff2ff509dd0b3f5ff93d70a75e79e0a1 ] when creating a new ipip interface with no local/remote configuration, the lookup is done with TUNNEL_NO_KEY flag, making it impossible to match the new interface (only possible match being fallback or metada case interface); e.g: `ip link add tunl1 type ipip dev eth0` To fix this case, adding a flag check before the key comparison so we permit to match an interface with no local/remote config; it also avoids breaking possible userland tools relying on TUNNEL_NO_KEY flag and uninitialised key. context being on my side, I'm creating an extra ipip interface attached to the physical one, and moving it to a dedicated namespace. Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: William Dauchy <w.dauchy@criteo.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com> --- net/ipv4/ip_tunnel.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index e4f1349983b2..93ba62cb39b9 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -155,11 +155,8 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, cand = t; } - if (flags & TUNNEL_NO_KEY) - goto skip_key_lookup; - hlist_for_each_entry_rcu(t, head, hash_node) { - if (t->parms.i_key != key || + if ((!(flags & TUNNEL_NO_KEY) && t->parms.i_key != key) || t->parms.iph.saddr != 0 || t->parms.iph.daddr != 0 || !(t->dev->flags & IFF_UP)) @@ -171,7 +168,6 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, cand = t; } -skip_key_lookup: if (cand) return cand; -- 2.30.9