From: Willem de Bruijn <willemdebruijn.kernel@gmail•com>
To: Jakub Kicinski <kuba@kernel•org>, bpf@vger•kernel.org
Cc: netdev@vger•kernel.org, davem@davemloft•net,
edumazet@google•com, pabeni@redhat•com, andrew+netdev@lunn•ch,
horms@kernel•org, Jakub Kicinski <kuba@kernel•org>,
maze@google•com, willemdebruijn.kernel@gmail•com,
ast@kernel•org, daniel@iogearbox•net, andrii@kernel•org,
martin.lau@linux•dev, eddyz87@gmail•com, song@kernel•org,
yonghong.song@linux•dev, john.fastabend@gmail•com,
kpsingh@kernel•org, sdf@fomichev•me, haoluo@google•com,
jolsa@kernel•org
Subject: Re: [PATCH bpf-next v2 1/2] net: clear the dst when performing encap / decap
Date: Mon, 30 Mar 2026 09:42:26 -0400 [thread overview]
Message-ID: <willemdebruijn.kernel.15a62f8f2870@gmail.com> (raw)
In-Reply-To: <20260329180428.2657785-1-kuba@kernel.org>
Jakub Kicinski wrote:
> Commit ba9db6f907ac ("net: clear the dst when changing skb protocol")
> added dst clearing when a BPF program changes the skb protocol
> (e.g. IPv4 to IPv6). Since that was a fix we only cleared the dst when
> the L3 protocol actually changes to keep it minimal. As suggested during
> the discussion (see Link) encap or decap operation which wraps or unwraps
> a same-protocol header may also render the existing dst incorrect - even
> if that doesn't result in a crash, just the wrong route for the now-outermost
> IP dst.
>
> Make dropping dst unconditional for bpf_skb_change_proto() and all
> L3 encap / decap ops.
>
> Link: https://lore.kernel.org/CANP3RGfRaYwve_xgxH6Tp2zenzKn2-DjZ9tg023WVzfdJF3p_w@mail.gmail.com
> Signed-off-by: Jakub Kicinski <kuba@kernel•org>
Reviewed-by: Willem de Bruijn <willemb@google•com>
next prev parent reply other threads:[~2026-03-30 13:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-29 18:04 [PATCH bpf-next v2 1/2] net: clear the dst when performing encap / decap Jakub Kicinski
2026-03-29 18:04 ` [PATCH bpf-next v2 2/2] selftests/bpf: test that dst is cleared on same-protocol encap Jakub Kicinski
2026-03-30 8:03 ` Daniel Borkmann
2026-03-30 23:29 ` Jakub Kicinski
2026-03-31 0:29 ` Martin KaFai Lau
2026-03-30 7:48 ` [PATCH bpf-next v2 1/2] net: clear the dst when performing encap / decap Daniel Borkmann
2026-03-30 13:42 ` Willem de Bruijn [this message]
2026-03-30 22:20 ` patchwork-bot+netdevbpf
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