Subject: [PATCH v3 net 4/6] mctp: Handle error of rtnl_register_module().

From: Kuniyuki Iwashima <[email-masked]>
Date: Mon, 7 Oct 2024 05:44:57 -0700

Since introduced, mctp has been ignoring the returned value
of rtnl_register_module(), which could fail.

Let's handle the errors by rtnl_register_many().

Fixes: 583be982d934 ("mctp: Add device handling and netlink interface")
Fixes: 831119f88781 ("mctp: Add neighbour netlink interface")
Fixes: 06d2f4c583a7 ("mctp: Add netlink route management")
Signed-off-by: Kuniyuki Iwashima <[email-masked]>
Reviewed-by: Jeremy Kerr <[email-masked]>
---
Cc: Matt Johnston <[email-masked]>
---
 include/net/mctp.h |  2 +-
 net/mctp/af_mctp.c |  6 +++++-
 net/mctp/device.c  | 30 ++++++++++++++++++------------
 net/mctp/neigh.c   | 31 +++++++++++++++++++------------
 net/mctp/route.c   | 33 +++++++++++++++++++++++----------
 5 files changed, 66 insertions(+), 36 deletions(-)

diff --git a/include/net/mctp.h b/include/net/mctp.h
index 7b17c52e8ce2..28d59ae94ca3 100644
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -295,7 +295,7 @@ void mctp_neigh_remove_dev(struct mctp_dev *mdev);
 int mctp_routes_init(void);
 void mctp_routes_exit(void);
 
-void mctp_device_init(void);
+int mctp_device_init(void);
 void mctp_device_exit(void);
 
 #endif /* __NET_MCTP_H */
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index 43288b408fde..f6de136008f6 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -756,10 +756,14 @@ static __init int mctp_init(void)
 	if (rc)
 		goto err_unreg_routes;
 
-	mctp_device_init();
+	rc = mctp_device_init();
+	if (rc)
+		goto err_unreg_neigh;
 
 	return 0;
 
+err_unreg_neigh:
+	mctp_neigh_exit();
 err_unreg_routes:
 	mctp_routes_exit();
 err_unreg_proto:
diff --git a/net/mctp/device.c b/net/mctp/device.c
index acb97b257428..85cc5f31f1e7 100644
--- a/net/mctp/device.c
+++ b/net/mctp/device.c
@@ -524,25 +524,31 @@ static struct notifier_block mctp_dev_nb = {
 	.priority = ADDRCONF_NOTIFY_PRIORITY,
 };
 
-void __init mctp_device_init(void)
+static const struct rtnl_msg_handler mctp_device_rtnl_msg_handlers[] = {
+	{THIS_MODULE, PF_MCTP, RTM_NEWADDR, mctp_rtm_newaddr, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_DELADDR, mctp_rtm_deladdr, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_GETADDR, NULL, mctp_dump_addrinfo, 0},
+};
+
+int __init mctp_device_init(void)
 {
-	register_netdevice_notifier(&mctp_dev_nb);
+	int err;
 
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETADDR,
-			     NULL, mctp_dump_addrinfo, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWADDR,
-			     mctp_rtm_newaddr, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELADDR,
-			     mctp_rtm_deladdr, NULL, 0);
+	register_netdevice_notifier(&mctp_dev_nb);
 	rtnl_af_register(&mctp_af_ops);
+
+	err = rtnl_register_many(mctp_device_rtnl_msg_handlers);
+	if (err) {
+		rtnl_af_unregister(&mctp_af_ops);
+		unregister_netdevice_notifier(&mctp_dev_nb);
+	}
+
+	return err;
 }
 
 void __exit mctp_device_exit(void)
 {
+	rtnl_unregister_many(mctp_device_rtnl_msg_handlers);
 	rtnl_af_unregister(&mctp_af_ops);
-	rtnl_unregister(PF_MCTP, RTM_DELADDR);
-	rtnl_unregister(PF_MCTP, RTM_NEWADDR);
-	rtnl_unregister(PF_MCTP, RTM_GETADDR);
-
 	unregister_netdevice_notifier(&mctp_dev_nb);
 }
diff --git a/net/mctp/neigh.c b/net/mctp/neigh.c
index ffa0f9e0983f..590f642413e4 100644
--- a/net/mctp/neigh.c
+++ b/net/mctp/neigh.c
@@ -322,22 +322,29 @@ static struct pernet_operations mctp_net_ops = {
 	.exit = mctp_neigh_net_exit,
 };
 
+static const struct rtnl_msg_handler mctp_neigh_rtnl_msg_handlers[] = {
+	{THIS_MODULE, PF_MCTP, RTM_NEWNEIGH, mctp_rtm_newneigh, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_DELNEIGH, mctp_rtm_delneigh, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_GETNEIGH, NULL, mctp_rtm_getneigh, 0},
+};
+
 int __init mctp_neigh_init(void)
 {
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWNEIGH,
-			     mctp_rtm_newneigh, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELNEIGH,
-			     mctp_rtm_delneigh, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETNEIGH,
-			     NULL, mctp_rtm_getneigh, 0);
-
-	return register_pernet_subsys(&mctp_net_ops);
+	int err;
+
+	err = register_pernet_subsys(&mctp_net_ops);
+	if (err)
+		return err;
+
+	err = rtnl_register_many(mctp_neigh_rtnl_msg_handlers);
+	if (err)
+		unregister_pernet_subsys(&mctp_net_ops);
+
+	return err;
 }
 
-void __exit mctp_neigh_exit(void)
+void mctp_neigh_exit(void)
 {
+	rtnl_unregister_many(mctp_neigh_rtnl_msg_handlers);
 	unregister_pernet_subsys(&mctp_net_ops);
-	rtnl_unregister(PF_MCTP, RTM_GETNEIGH);
-	rtnl_unregister(PF_MCTP, RTM_DELNEIGH);
-	rtnl_unregister(PF_MCTP, RTM_NEWNEIGH);
 }
diff --git a/net/mctp/route.c b/net/mctp/route.c
index eefd7834d9a0..597e9cf5aa64 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -1474,26 +1474,39 @@ static struct pernet_operations mctp_net_ops = {
 	.exit = mctp_routes_net_exit,
 };
 
+static const struct rtnl_msg_handler mctp_route_rtnl_msg_handlers[] = {
+	{THIS_MODULE, PF_MCTP, RTM_NEWROUTE, mctp_newroute, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_DELROUTE, mctp_delroute, NULL, 0},
+	{THIS_MODULE, PF_MCTP, RTM_GETROUTE, NULL, mctp_dump_rtinfo, 0},
+};
+
 int __init mctp_routes_init(void)
 {
+	int err;
+
 	dev_add_pack(&mctp_packet_type);
 
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETROUTE,
-			     NULL, mctp_dump_rtinfo, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWROUTE,
-			     mctp_newroute, NULL, 0);
-	rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELROUTE,
-			     mctp_delroute, NULL, 0);
+	err = register_pernet_subsys(&mctp_net_ops);
+	if (err)
+		goto err_pernet;
+
+	err = rtnl_register_many(mctp_route_rtnl_msg_handlers);
+	if (err)
+		goto err_rtnl;
 
-	return register_pernet_subsys(&mctp_net_ops);
+	return 0;
+
+err_rtnl:
+	unregister_pernet_subsys(&mctp_net_ops);
+err_pernet:
+	dev_remove_pack(&mctp_packet_type);
+	return err;
 }
 
 void mctp_routes_exit(void)
 {
+	rtnl_unregister_many(mctp_route_rtnl_msg_handlers);
 	unregister_pernet_subsys(&mctp_net_ops);
-	rtnl_unregister(PF_MCTP, RTM_DELROUTE);
-	rtnl_unregister(PF_MCTP, RTM_NEWROUTE);
-	rtnl_unregister(PF_MCTP, RTM_GETROUTE);
 	dev_remove_pack(&mctp_packet_type);
 }
 
-- 
2.30.2