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authorLorenz Bauer <lmb@cloudflare.com>2020-03-09 11:12:34 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2020-03-09 22:34:58 +0100
commitd19da360ee0f3e6c1375391db1a724b66fd43312 (patch)
treeb21f3e34ff2a865b68592c282f2148040cde2494 /net/ipv4
parent1a2e20132db7bb76dd4f97b8364bd167227dd15f (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.c42
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;
}