Commit 25629fda authored Mar 27, 2020 by William Dauchy Committed by David S. Miller Mar 29, 2020

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: c5441932 ("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>

parent 582eea23

net/ipv4/ip_tunnel.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -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;

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