diff options
author | Lorenz Bauer <lmb@cloudflare.com> | 2020-03-09 11:12:34 +0000 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-03-09 22:34:58 +0100 |
commit | d19da360ee0f3e6c1375391db1a724b66fd43312 (patch) | |
tree | b21f3e34ff2a865b68592c282f2148040cde2494 /net/ipv4 | |
parent | 1a2e20132db7bb76dd4f97b8364bd167227dd15f (diff) |
bpf: tcp: Move assertions into tcp_bpf_get_proto
We need to ensure that sk->sk_prot uses certain callbacks, so that
code that directly calls e.g. tcp_sendmsg in certain corner cases
works. To avoid spurious asserts, we must to do this only if
sk_psock_update_proto has not yet been called. The same invariants
apply for tcp_bpf_check_v6_needs_rebuild, so move the call as well.
Doing so allows us to merge tcp_bpf_init and tcp_bpf_reinit.
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/20200309111243.6982-4-lmb@cloudflare.com
Diffstat (limited to 'net/ipv4')
-rw-r--r-- | net/ipv4/tcp_bpf.c | 42 |
1 files changed, 22 insertions, 20 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 3327afa05c3d..ed8a8f3c9afe 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -629,14 +629,6 @@ static int __init tcp_bpf_v4_build_proto(void) } core_initcall(tcp_bpf_v4_build_proto); -static void tcp_bpf_update_sk_prot(struct sock *sk, struct sk_psock *psock) -{ - int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; - int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; - - sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config]); -} - static int tcp_bpf_assert_proto_ops(struct proto *ops) { /* In order to avoid retpoline, we make assumptions when we call @@ -648,34 +640,44 @@ static int tcp_bpf_assert_proto_ops(struct proto *ops) ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; } -void tcp_bpf_reinit(struct sock *sk) +static struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) { - struct sk_psock *psock; + int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; + int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; - sock_owned_by_me(sk); + if (!psock->sk_proto) { + struct proto *ops = READ_ONCE(sk->sk_prot); - rcu_read_lock(); - psock = sk_psock(sk); - tcp_bpf_update_sk_prot(sk, psock); - rcu_read_unlock(); + if (tcp_bpf_assert_proto_ops(ops)) + return ERR_PTR(-EINVAL); + + tcp_bpf_check_v6_needs_rebuild(sk, ops); + } + + return &tcp_bpf_prots[family][config]; } int tcp_bpf_init(struct sock *sk) { - struct proto *ops = READ_ONCE(sk->sk_prot); struct sk_psock *psock; + struct proto *prot; sock_owned_by_me(sk); rcu_read_lock(); psock = sk_psock(sk); - if (unlikely(!psock || psock->sk_proto || - tcp_bpf_assert_proto_ops(ops))) { + if (unlikely(!psock)) { rcu_read_unlock(); return -EINVAL; } - tcp_bpf_check_v6_needs_rebuild(sk, ops); - tcp_bpf_update_sk_prot(sk, psock); + + prot = tcp_bpf_get_proto(sk, psock); + if (IS_ERR(prot)) { + rcu_read_unlock(); + return PTR_ERR(prot); + } + + sk_psock_update_proto(sk, psock, prot); rcu_read_unlock(); return 0; } |