bpf: Sockmap/tls, push write_space updates through ulp updates

When sockmap sock with TLS enabled is removed we cleanup bpf/psock state
and call tcp_update_ulp() to push updates to TLS ULP on top. However, we
don't push the write_space callback up and instead simply overwrite the
op with the psock stored previous op. This may or may not be correct so
to ensure we don't overwrite the TLS write space hook pass this field to
the ULP and have it fixup the ctx.

This completes a previous fix that pushed the ops through to the ULP
but at the time missed doing this for write_space, presumably because
write_space TLS hook was added around the same time.

Fixes: 95fa145479fbc ("bpf: sockmap/tls, close can race with map free")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-4-john.fastabend@gmail.com

1 files changed, 4 insertions, 2 deletions

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 12ab5db2b71c..38d3ad141161 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -99,17 +99,19 @@ void tcp_get_available_ulp(char *buf, size_t maxlen)
 	rcu_read_unlock();
 }
 
-void tcp_update_ulp(struct sock *sk, struct proto *proto)
+void tcp_update_ulp(struct sock *sk, struct proto *proto,
+		    void (*write_space)(struct sock *sk))
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
 	if (!icsk->icsk_ulp_ops) {
+		sk->sk_write_space = write_space;
 		sk->sk_prot = proto;
 		return;
 	}
 
 	if (icsk->icsk_ulp_ops->update)
-		icsk->icsk_ulp_ops->update(sk, proto);
+		icsk->icsk_ulp_ops->update(sk, proto, write_space);
 }
 
 void tcp_cleanup_ulp(struct sock *sk)