Commit 7b70973d authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Daniel Borkmann
Browse files

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: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-2-lmb@cloudflare.com
parent 3e7c67d9

include/linux/skmsg.h

+7 −1
Original line number Diff line number Diff line
@@ -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;

	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,

include/net/inet_connection_sock.h

+6 −0
Original line number Diff line number Diff line
@@ -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 */

net/core/sock_map.c

+2 −4
Original line number Diff line number Diff line
@@ -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();

net/ipv4/tcp_ulp.c

+0 −7
Original line number Diff line number Diff line
@@ -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);

}

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