From 25629fdaff2ff509dd0b3f5ff93d70a75e79e0a1 Mon Sep 17 00:00:00 2001 From: William Dauchy Date: Fri, 27 Mar 2020 19:56:39 +0100 Subject: [PATCH] net, ip_tunnel: fix interface lookup with no key 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 Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller --- 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 74e1d964a615..cd4b84310d92 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -142,11 +142,8 @@ 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)) @@ -158,7 +155,6 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn, cand = t; } -skip_key_lookup: if (cand) return cand;