Patch "bpf: Set flow flag to allow any source IP in bpf_tunnel_key" has been added to the 5.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    bpf: Set flow flag to allow any source IP in bpf_tunnel_key

to the 5.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bpf-set-flow-flag-to-allow-any-source-ip-in-bpf_tunn.patch
and it can be found in the queue-5.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 98b89a07f3f91186dc4f8eb42d473f9ca5ae4477
Author: Paul Chaignon <paul@xxxxxxxxxxxxx>
Date:   Mon Jul 25 16:32:34 2022 +0200

    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 <paul@xxxxxxxxxxxxx>
    Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
    Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
    Acked-by: Martin KaFai Lau <kafai@xxxxxx>
    Link: https://lore.kernel.org/bpf/76873d384e21288abe5767551a0799ac93ec07fb.1658759380.git.paul@xxxxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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;