IB/core: Fix potential memory leak while creating MAD agents

commit 6e88e672b69f0e627acdae74a527b730ea224b6b upstream.

If the MAD agents isn't allowed to manage the subnet, or fails to register
for the LSM notifier, the security context is leaked. Free the context in
these cases.

Fixes: 47a2b338 ("IB/core: Enforce security on management datagrams")
Signed-off-by: NDaniel Jurgens <danielj@mellanox.com>
Reviewed-by: NParav Pandit <parav@mellanox.com>
Reported-by: NParav Pandit <parav@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/infiniband/core/security.c

@@ -711,16 +711,20 @@ int ib_mad_agent_security_setup(struct ib_mad_agent *agent,
 						agent->device->name,
 						agent->port_num);
 	if (ret)
-		return ret;
+		goto free_security;
 
 	agent->lsm_nb.notifier_call = ib_mad_agent_security_change;
 	ret = register_lsm_notifier(&agent->lsm_nb);
 	if (ret)
-		return ret;
+		goto free_security;
 
 	agent->smp_allowed = true;
 	agent->lsm_nb_reg = true;
 	return 0;
+
+free_security:
+	security_ib_free_security(agent->security);
+	return ret;
 }
 
 void ib_mad_agent_security_cleanup(struct ib_mad_agent *agent)