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| author |   Willem de Bruijn <willemb@google.com> | 2018-09-24 16:49:57 -0400 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2018-09-25 17:31:19 +0200 |
| commit | d0e13a1488ad30dc3c2c9347b931cb10f892e3a4 (patch) | |
| tree | 1a15d2fdf34411e490eb568710becbf156b97dac /net/core/flow_dissector.c | |
| parent | bpftool: add support for BPF_MAP_TYPE_REUSEPORT_SOCKARRAY maps (diff) | |
| download | linux-dev-d0e13a1488ad30dc3c2c9347b931cb10f892e3a4.tar.xz linux-dev-d0e13a1488ad30dc3c2c9347b931cb10f892e3a4.zip | |
flow_dissector: lookup netns by skb->sk if skb->dev is NULL
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: d58e468b1112 ("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>
Diffstat (limited to 'net/core/flow_dissector.c')
| -rw-r--r-- | net/core/flow_dissector.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 5c5dd74b5b3b..738c7562e1e0 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -714,7 +714,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector_key_vlan *key_vlan; enum flow_dissect_ret fdret; enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; - struct bpf_prog *attached; + struct bpf_prog *attached = NULL; int num_hdrs = 0; u8 ip_proto = 0; bool ret; @@ -755,8 +755,14 @@ bool __skb_flow_dissect(const struct sk_buff *skb, target_container); rcu_read_lock(); - attached = skb ? rcu_dereference(dev_net(skb->dev)->flow_dissector_prog) - : NULL; + if (skb) { + if (skb->dev) + attached = rcu_dereference(dev_net(skb->dev)->flow_dissector_prog); + else if (skb->sk) + attached = rcu_dereference(sock_net(skb->sk)->flow_dissector_prog); + else + WARN_ON_ONCE(1); + } if (attached) { /* Note that even though the const qualifier is discarded * throughout the execution of the BPF program, all changes(the |