flow_dissector: lookup netns by skb->sk if skb->dev is NULL

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BPF flow dissectors are configured per network namespace.
__skb_flow_dissect looks up the netns through dev_net(skb->dev).

In some dissector paths skb->dev is NULL, such as for Unix sockets.
In these cases fall back to looking up the netns by socket.

Analyzing the codepaths leading to __skb_flow_dissect I did not find
a case where both skb->dev and skb->sk are NULL. Warn and fall back to
standard flow dissector if one is found.

Fixes: d58e468b11 ("flow_dissector: implements flow dissector BPF hook")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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Willem de Bruijn 2018-09-24 16:49:57 -04:00 • committed by Daniel Borkmann

parent 7ea3c40605

commit d0e13a1488

1 changed files with 9 additions and 3 deletions

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net/core/flow_dissector.c

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