From 7b70973d7edb2f005511102d5a2e0116464a46a1 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Mon, 9 Mar 2020 11:12:32 +0000 Subject: [PATCH] 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 Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200309111243.6982-2-lmb@cloudflare.com --- include/linux/skmsg.h | 8 +++++++- include/net/inet_connection_sock.h | 6 ++++++ net/core/sock_map.c | 6 ++---- net/ipv4/tcp_ulp.c | 7 ------- 4 files changed, 15 insertions(+), 12 deletions(-) diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index 112765bd146d..4d3d75d63066 100644 --- 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 895546058a20..a3f076befa4f 100644 --- 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 2e0f465295c3..cb8f740f7949 100644 --- 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 2703f24c5d1a..7c27aa629af1 100644 --- 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); } -- 2.30.2