diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-02-05 15:51:17 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-02-06 16:14:15 -0800 |
| commit | afec62cd0a4191cde6dd3a75382be4d51a38ce9b (patch) | |
| tree | 30a1080ffa04fdfd490e05ce0364a160cafbac22 | |
| parent | 4b8474a0951e605d2a27a2c483da4eb4b8c63760 (diff) | |
flow_dissector: use RCU protection to fetch dev_net()
__skb_flow_dissect() can be called from arbitrary contexts.
It must extend its RCU protection section to include
the call to dev_net(), which can become dev_net_rcu().
This makes sure the net structure can not disappear under us.
Fixes: 9b52e3f267a6 ("flow_dissector: handle no-skb use case")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250205155120.1676781-10-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/flow_dissector.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 0e638a37aa09..5db41bf2ed93 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1108,10 +1108,12 @@ bool __skb_flow_dissect(const struct net *net, FLOW_DISSECTOR_KEY_BASIC, target_container); + rcu_read_lock(); + if (skb) { if (!net) { if (skb->dev) - net = dev_net(skb->dev); + net = dev_net_rcu(skb->dev); else if (skb->sk) net = sock_net(skb->sk); } @@ -1122,7 +1124,6 @@ bool __skb_flow_dissect(const struct net *net, enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR; struct bpf_prog_array *run_array; - rcu_read_lock(); run_array = rcu_dereference(init_net.bpf.run_array[type]); if (!run_array) run_array = rcu_dereference(net->bpf.run_array[type]); @@ -1150,17 +1151,17 @@ bool __skb_flow_dissect(const struct net *net, prog = READ_ONCE(run_array->items[0].prog); result = bpf_flow_dissect(prog, &ctx, n_proto, nhoff, hlen, flags); - if (result == BPF_FLOW_DISSECTOR_CONTINUE) - goto dissect_continue; - __skb_flow_bpf_to_target(&flow_keys, flow_dissector, - target_container); - rcu_read_unlock(); - return result == BPF_OK; + if (result != BPF_FLOW_DISSECTOR_CONTINUE) { + __skb_flow_bpf_to_target(&flow_keys, flow_dissector, + target_container); + rcu_read_unlock(); + return result == BPF_OK; + } } -dissect_continue: - rcu_read_unlock(); } + rcu_read_unlock(); + if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ETH_ADDRS)) { struct ethhdr *eth = eth_hdr(skb); |