bpf: sockmap: Only check ULP for TCP sockets

The sock map code checks that a socket does not have an active upper
layer protocol before inserting it into the map. This requires casting
via inet_csk, which isn't valid for UDP sockets.

Guard checks for ULP by checking inet_sk(sk)->is_icsk first.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-2-lmb@cloudflare.com

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 112765b..4d3d75d 100644 (file)
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -360,7 +360,13 @@ static inline void sk_psock_restore_proto(struct sock *sk,
                                          struct sk_psock *psock)
 {
        sk->sk_prot->unhash = psock->saved_unhash;
-       tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
+       if (inet_csk_has_ulp(sk)) {
+               tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
+       } else {
+               sk->sk_write_space = psock->saved_write_space;
+               /* Pairs with lockless read in sk_clone_lock() */
+               WRITE_ONCE(sk->sk_prot, psock->sk_proto);
+       }
 }
 
 static inline void sk_psock_set_state(struct sk_psock *psock,

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 8955460..a3f076b 100644 (file)
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -335,4 +335,10 @@ static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
        if (icsk->icsk_ack.pingpong < U8_MAX)
                icsk->icsk_ack.pingpong++;
 }
+
+static inline bool inet_csk_has_ulp(struct sock *sk)
+{
+       return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
+}
+
 #endif /* _INET_CONNECTION_SOCK_H */

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 2e0f465..cb8f740 100644 (file)
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -384,7 +384,6 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx,
                                  struct sock *sk, u64 flags)
 {
        struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
-       struct inet_connection_sock *icsk = inet_csk(sk);
        struct sk_psock_link *link;
        struct sk_psock *psock;
        struct sock *osk;
@@ -395,7 +394,7 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx,
                return -EINVAL;
        if (unlikely(idx >= map->max_entries))
                return -E2BIG;
-       if (unlikely(rcu_access_pointer(icsk->icsk_ulp_data)))
+       if (inet_csk_has_ulp(sk))
                return -EINVAL;
 
        link = sk_psock_init_link();
@@ -738,7 +737,6 @@ static int sock_hash_update_common(struct bpf_map *map, void *key,
                                   struct sock *sk, u64 flags)
 {
        struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
-       struct inet_connection_sock *icsk = inet_csk(sk);
        u32 key_size = map->key_size, hash;
        struct bpf_htab_elem *elem, *elem_new;
        struct bpf_htab_bucket *bucket;
@@ -749,7 +747,7 @@ static int sock_hash_update_common(struct bpf_map *map, void *key,
        WARN_ON_ONCE(!rcu_read_lock_held());
        if (unlikely(flags > BPF_EXIST))
                return -EINVAL;
-       if (unlikely(icsk->icsk_ulp_data))
+       if (inet_csk_has_ulp(sk))
                return -EINVAL;
 
        link = sk_psock_init_link();

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 2703f24..7c27aa6 100644 (file)
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -105,13 +105,6 @@ void tcp_update_ulp(struct sock *sk, struct proto *proto,
 {
        struct inet_connection_sock *icsk = inet_csk(sk);
 
-       if (!icsk->icsk_ulp_ops) {
-               sk->sk_write_space = write_space;
-               /* Pairs with lockless read in sk_clone_lock() */
-               WRITE_ONCE(sk->sk_prot, proto);
-               return;
-       }
-
        if (icsk->icsk_ulp_ops->update)
                icsk->icsk_ulp_ops->update(sk, proto, write_space);
 }