[bpf PATCH 2/6] bpf: sockmap only allow ESTABLISHED sock state
From: John Fastabend <john.fastabend@gmail.com>
Date: 2018-06-13 17:50:36
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Per the note in the TLS ULP (which is actually a generic statement regarding ULPs) /* The TLS ulp is currently supported only for TCP sockets * in ESTABLISHED state. * Supporting sockets in LISTEN state will require us * to modify the accept implementation to clone rather then * share the ulp context. */ After this patch we only allow socks that are in ESTABLISHED state or are being added via a sock_ops event that is transitioning into an ESTABLISHED state. By allowing sock_ops events we allow users to manage sockmaps directly from sock ops programs. The two supported sock_ops ops are BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB and BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB. Also tested with 'netserver -6' and 'netperf -H [IPv6]' as well as 'netperf -H [IPv4]'. Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- kernel/bpf/sockmap.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index f6dd4cd..e5bab52 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c@@ -1976,8 +1976,12 @@ static int sock_map_update_elem(struct bpf_map *map, return -EINVAL; } + /* ULPs are currently supported only for TCP sockets in ESTABLISHED + * state. + */ if (skops.sk->sk_type != SOCK_STREAM || - skops.sk->sk_protocol != IPPROTO_TCP) { + skops.sk->sk_protocol != IPPROTO_TCP || + skops.sk->sk_state != TCP_ESTABLISHED) { fput(socket->file); return -EOPNOTSUPP; }
@@ -2338,6 +2342,16 @@ static int sock_hash_update_elem(struct bpf_map *map, return -EINVAL; } + /* ULPs are currently supported only for TCP sockets in ESTABLISHED + * state. + */ + if (skops.sk->sk_type != SOCK_STREAM || + skops.sk->sk_protocol != IPPROTO_TCP || + skops.sk->sk_state != TCP_ESTABLISHED) { + fput(socket->file); + return -EOPNOTSUPP; + } + err = sock_hash_ctx_update_elem(&skops, map, key, flags); fput(socket->file); return err;
@@ -2423,10 +2437,19 @@ struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key) .map_delete_elem = sock_hash_delete_elem, }; +static bool bpf_is_valid_sock(struct bpf_sock_ops_kern *ops) +{ + return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB || + ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB; +} + BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, struct bpf_map *, map, void *, key, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); + + if (!bpf_is_valid_sock(bpf_sock)) + return -EOPNOTSUPP; return sock_map_ctx_update_elem(bpf_sock, map, key, flags); }
@@ -2445,6 +2468,9 @@ struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key) struct bpf_map *, map, void *, key, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); + + if (!bpf_is_valid_sock(bpf_sock)) + return -EOPNOTSUPP; return sock_hash_ctx_update_elem(bpf_sock, map, key, flags); }