diff options
author | Stanislav Fomichev <sdf@google.com> | 2020-05-08 10:46:11 -0700 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-05-09 00:48:20 +0200 |
commit | 8086fbaf49345f988deec539ec8e182b02914401 (patch) | |
tree | 0c7f078dca26060f1ef9217c2f959cb058614a37 /net/core/filter.c | |
parent | cb0721c7e200750907bb8ef59b12646a5cb2dadf (diff) |
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)
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-5-sdf@google.com
Diffstat (limited to 'net/core/filter.c')
-rw-r--r-- | net/core/filter.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index fa9ddab5dd1f..da0634979f53 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4525,32 +4525,28 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr, { #ifdef CONFIG_INET struct sock *sk = ctx->sk; + u32 flags = BIND_FROM_BPF; int err; - /* Binding to port can be expensive so it's prohibited in the helper. - * Only binding to IP is supported. - */ err = -EINVAL; if (addr_len < offsetofend(struct sockaddr, sa_family)) return err; if (addr->sa_family == AF_INET) { if (addr_len < sizeof(struct sockaddr_in)) return err; - if (((struct sockaddr_in *)addr)->sin_port != htons(0)) - return err; - return __inet_bind(sk, addr, addr_len, - BIND_FORCE_ADDRESS_NO_PORT); + if (((struct sockaddr_in *)addr)->sin_port == htons(0)) + flags |= BIND_FORCE_ADDRESS_NO_PORT; + return __inet_bind(sk, addr, addr_len, flags); #if IS_ENABLED(CONFIG_IPV6) } else if (addr->sa_family == AF_INET6) { if (addr_len < SIN6_LEN_RFC2133) return err; - if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0)) - return err; + if (((struct sockaddr_in6 *)addr)->sin6_port == htons(0)) + flags |= BIND_FORCE_ADDRESS_NO_PORT; /* ipv6_bpf_stub cannot be NULL, since it's called from * bpf_cgroup_inet6_connect hook and ipv6 is already loaded */ - return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, - BIND_FORCE_ADDRESS_NO_PORT); + return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, flags); #endif /* CONFIG_IPV6 */ } #endif /* CONFIG_INET */ |