From 8ca30379a40103bf6734ae127ec940da798534dd Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Tue, 18 Feb 2020 17:10:16 +0000 Subject: [PATCH] bpf, sockmap: Allow inserting listening TCP sockets into sockmap In order for sockmap/sockhash types to become generic collections for storing TCP sockets we need to loosen the checks during map update, while tightening the checks in redirect helpers. Currently sock{map,hash} require the TCP socket to be in established state, which prevents inserting listening sockets. Change the update pre-checks so the socket can also be in listening state. Since it doesn't make sense to redirect with sock{map,hash} to listening sockets, add appropriate socket state checks to BPF redirect helpers too. Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200218171023.844439-5-jakub@cloudflare.com --- net/core/sock_map.c | 59 ++++++++++++++++++------- tools/testing/selftests/bpf/test_maps.c | 6 +-- 2 files changed, 45 insertions(+), 20 deletions(-) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 3a7a96ab088a..dd92a3556d73 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -391,7 +391,8 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx, static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops) { return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB || - ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB; + ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB || + ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB; } static bool sock_map_sk_is_suitable(const struct sock *sk) @@ -400,6 +401,16 @@ static bool sock_map_sk_is_suitable(const struct sock *sk) sk->sk_protocol == IPPROTO_TCP; } +static bool sock_map_sk_state_allowed(const struct sock *sk) +{ + return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN); +} + +static bool sock_map_redirect_allowed(const struct sock *sk) +{ + return sk->sk_state != TCP_LISTEN; +} + static int sock_map_update_elem(struct bpf_map *map, void *key, void *value, u64 flags) { @@ -423,7 +434,7 @@ static int sock_map_update_elem(struct bpf_map *map, void *key, } sock_map_sk_acquire(sk); - if (sk->sk_state != TCP_ESTABLISHED) + if (!sock_map_sk_state_allowed(sk)) ret = -EOPNOTSUPP; else ret = sock_map_update_common(map, idx, sk, flags); @@ -460,13 +471,17 @@ BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb, struct bpf_map *, map, u32, key, u64, flags) { struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); + struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; - tcb->bpf.flags = flags; - tcb->bpf.sk_redir = __sock_map_lookup_elem(map, key); - if (!tcb->bpf.sk_redir) + + sk = __sock_map_lookup_elem(map, key); + if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; + + tcb->bpf.flags = flags; + tcb->bpf.sk_redir = sk; return SK_PASS; } @@ -483,12 +498,17 @@ const struct bpf_func_proto bpf_sk_redirect_map_proto = { BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg, struct bpf_map *, map, u32, key, u64, flags) { + struct sock *sk; + if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; - msg->flags = flags; - msg->sk_redir = __sock_map_lookup_elem(map, key); - if (!msg->sk_redir) + + sk = __sock_map_lookup_elem(map, key); + if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; + + msg->flags = flags; + msg->sk_redir = sk; return SK_PASS; } @@ -748,7 +768,7 @@ static int sock_hash_update_elem(struct bpf_map *map, void *key, } sock_map_sk_acquire(sk); - if (sk->sk_state != TCP_ESTABLISHED) + if (!sock_map_sk_state_allowed(sk)) ret = -EOPNOTSUPP; else ret = sock_hash_update_common(map, key, sk, flags); @@ -916,13 +936,17 @@ BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb, struct bpf_map *, map, void *, key, u64, flags) { struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); + struct sock *sk; if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; - tcb->bpf.flags = flags; - tcb->bpf.sk_redir = __sock_hash_lookup_elem(map, key); - if (!tcb->bpf.sk_redir) + + sk = __sock_hash_lookup_elem(map, key); + if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; + + tcb->bpf.flags = flags; + tcb->bpf.sk_redir = sk; return SK_PASS; } @@ -939,12 +963,17 @@ const struct bpf_func_proto bpf_sk_redirect_hash_proto = { BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg, struct bpf_map *, map, void *, key, u64, flags) { + struct sock *sk; + if (unlikely(flags & ~(BPF_F_INGRESS))) return SK_DROP; - msg->flags = flags; - msg->sk_redir = __sock_hash_lookup_elem(map, key); - if (!msg->sk_redir) + + sk = __sock_hash_lookup_elem(map, key); + if (unlikely(!sk || !sock_map_redirect_allowed(sk))) return SK_DROP; + + msg->flags = flags; + msg->sk_redir = sk; return SK_PASS; } diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c index 02eae1e864c2..c6766b2cff85 100644 --- a/tools/testing/selftests/bpf/test_maps.c +++ b/tools/testing/selftests/bpf/test_maps.c @@ -756,11 +756,7 @@ static void test_sockmap(unsigned int tasks, void *data) /* Test update without programs */ for (i = 0; i < 6; i++) { err = bpf_map_update_elem(fd, &i, &sfd[i], BPF_ANY); - if (i < 2 && !err) { - printf("Allowed update sockmap '%i:%i' not in ESTABLISHED\n", - i, sfd[i]); - goto out_sockmap; - } else if (i >= 2 && err) { + if (err) { printf("Failed noprog update sockmap '%i:%i'\n", i, sfd[i]); goto out_sockmap;