From 51622648d65875765f2ab12710f417476cac3be8 Mon Sep 17 00:00:00 2001 From: Paul Chaignon Date: Mon, 25 Jul 2022 16:32:34 +0200 Subject: [PATCH] bpf: Set flow flag to allow any source IP in bpf_tunnel_key [ Upstream commit b8fff748521c7178b9a7d32b5a34a81cec8396f3 ] Commit 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"") added support for getting and setting the outer source IP of encapsulated packets via the bpf_skb_{get,set}_tunnel_key BPF helper. This change allows BPF programs to set any IP address as the source, including for example the IP address of a container running on the same host. In that last case, however, the encapsulated packets are dropped when looking up the route because the source IP address isn't assigned to any interface on the host. To avoid this, we need to set the FLOWI_FLAG_ANYSRC flag. Fixes: 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"") Signed-off-by: Paul Chaignon Signed-off-by: Daniel Borkmann Reviewed-by: Nikolay Aleksandrov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/76873d384e21288abe5767551a0799ac93ec07fb.1658759380.git.paul@isovalent.com Signed-off-by: Sasha Levin --- net/core/filter.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/filter.c b/net/core/filter.c index 7950f7520765..5978984b752f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4653,6 +4653,7 @@ BPF_CALL_4(bpf_skb_set_tunnel_key, struct sk_buff *, skb, } else { info->key.u.ipv4.dst = cpu_to_be32(from->remote_ipv4); info->key.u.ipv4.src = cpu_to_be32(from->local_ipv4); + info->key.flow_flags = FLOWI_FLAG_ANYSRC; } return 0;