linux-kernel - Re: [PATCH 5.19 0537/1157] bpf: Set flow flag to allow any source IP in bpf_tunnel

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Message-ID: <YvuuAprVhybi0CMj@kroah.com>
Date:   Tue, 16 Aug 2022 16:47:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Paul Chaignon <paul@...valent.com>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Daniel Borkmann <daniel@...earbox.net>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Martin KaFai Lau <kafai@...com>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 5.19 0537/1157] bpf: Set flow flag to allow any source IP
 in bpf_tunnel_key

On Tue, Aug 16, 2022 at 04:35:54PM +0200, Paul Chaignon wrote:
> On Mon, Aug 15, 2022 at 07:58:13PM +0200, Greg Kroah-Hartman wrote:
> > From: Paul Chaignon <paul@...valent.com>
> > 
> > [ 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.
> 
> This fix will also require upstream commits 861396ac0b47 ("geneve: Use
> ip_tunnel_key flow flags in route lookups") and 7e2fb8bc7ef6 ("vxlan:
> Use ip_tunnel_key flow flags in route lookups") to have the intended
> effect. In short, these two commits "consume" the new field introduced
> in 451ef36bd229 ("ip_tunnels: Add new flow flags field to
> ip_tunnel_key") and populated in the present commit.

Ick.  Is it better to just drop this commit instead?  Or is it ok to
also backport those 2 patches to 5.19.y?

thanks,

greg k-h