UPSTREAM: bpf: Allow any port in bpf_bind helper

We want to have a tighter control on what ports we bind to in
the BPF_CGROUP_INET{4,6}_CONNECT hooks even if it means
connect() becomes slightly more expensive. The expensive part
comes from the fact that we now need to call inet_csk_get_port()
that verifies that the port is not used and allocates an entry
in the hash table for it.

Since we can't rely on "snum || !bind_address_no_port" to prevent
us from calling POST_BIND hook anymore, let's add another bind flag
to indicate that the call site is BPF program.

v5:
* fix wrong AF_INET (should be AF_INET6) in the bpf program for v6

v3:
* More bpf_bind documentation refinements (Martin KaFai Lau)
* Add UDP tests as well (Martin KaFai Lau)
* Don't start the thread, just do socket+bind+listen (Martin KaFai Lau)

v2:
* Update documentation (Andrey Ignatov)
* Pass BIND_FORCE_ADDRESS_NO_PORT conditionally (Andrey Ignatov)

Change-Id: Ia0d7052ae78cb82da3a0a7eea21afef9b174d26e
Signed-off-by: Stanislav Fomichev <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Andrey Ignatov <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
This commit is contained in:
Stanislav Fomichev 2020-05-08 10:46:11 -07:00 • committed by basamaryan
commit bf3c1fa865
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9 changed files with 203 additions and 28 deletions

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@ -413,11 +413,13 @@ static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
err = -EADDRINUSE;
goto out;
}
err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk);
if (err) {
sk->sk_ipv6only = saved_ipv6only;
inet_reset_saddr(sk);
goto out;
if (!(flags & BIND_FROM_BPF)) {
err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk);
if (err) {
sk->sk_ipv6only = saved_ipv6only;
inet_reset_saddr(sk);
goto out;
}
}
}