[PATCH AUTOSEL 5.2 027/123] bpf: sockmap, only create entry if ulp is not already enabled

[Sasha Levin]

From: John Fastabend <john.fastabend@xxxxxxxxx>

[ Upstream commit 0e858739c2d2eedeeac1d35bfa0ec3cc2a7190d8 ]

Sockmap does not currently support adding sockets after TLS has been
enabled. There never was a real use case for this so it was never
added. But, we lost the test for ULP at some point so add it here
and fail the socket insert if TLS is enabled. Future work could
make sockmap support this use case but fixup the bug here.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/core/sock_map.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index bbc91597d8364..8a4a45e7c29df 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -339,6 +339,7 @@ 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;
@@ -349,6 +350,8 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx,
 		return -EINVAL;
 	if (unlikely(idx >= map->max_entries))
 		return -E2BIG;
+	if (unlikely(icsk->icsk_ulp_data))
+		return -EINVAL;
 
 	link = sk_psock_init_link();
 	if (!link)
-- 
2.20.1