mptcp: fix security context on server socket

stable inclusion
from stable-5.10.5
commit aeab3d7a04f8127fa81e3e763914122ad260c930
bugzilla: 46931

--------------------------------

[ Upstream commit 0c148460 ]

Currently MPTCP is not propagating the security context
from the ingress request socket to newly created msk
at clone time.

Address the issue invoking the missing security helper.

Fixes: cf7da0d6 ("mptcp: Create SUBFLOW socket for incoming connections")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

net/mptcp/protocol.c

@@ -2081,6 +2081,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	sock_reset_flag(nsk, SOCK_RCU_FREE);
 	/* will be fully established after successful MPC subflow creation */
 	inet_sk_state_store(nsk, TCP_SYN_RECV);
+
+	security_inet_csk_clone(nsk, req);
 	bh_unlock_sock(nsk);
 
 	/* keep a single reference */