1 files changed, 58 insertions, 3 deletions

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index f6197774048b..9c01c642cf9e 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -175,6 +175,14 @@ static int change_carrier(struct net_device *dev, unsigned long new_carrier)
 static ssize_t carrier_store(struct device *dev, struct device_attribute *attr,
 			     const char *buf, size_t len)
 {
+	struct net_device *netdev = to_net_dev(dev);
+
+	/* The check is also done in change_carrier; this helps returning early
+	 * without hitting the trylock/restart in netdev_store.
+	 */
+	if (!netdev->netdev_ops->ndo_change_carrier)
+		return -EOPNOTSUPP;
+
 	return netdev_store(dev, attr, buf, len, change_carrier);
 }
 
@@ -196,6 +204,12 @@ static ssize_t speed_show(struct device *dev,
 	struct net_device *netdev = to_net_dev(dev);
 	int ret = -EINVAL;
 
+	/* The check is also done in __ethtool_get_link_ksettings; this helps
+	 * returning early without hitting the trylock/restart below.
+	 */
+	if (!netdev->ethtool_ops->get_link_ksettings)
+		return ret;
+
 	if (!rtnl_trylock())
 		return restart_syscall();
 
@@ -216,6 +230,12 @@ static ssize_t duplex_show(struct device *dev,
 	struct net_device *netdev = to_net_dev(dev);
 	int ret = -EINVAL;
 
+	/* The check is also done in __ethtool_get_link_ksettings; this helps
+	 * returning early without hitting the trylock/restart below.
+	 */
+	if (!netdev->ethtool_ops->get_link_ksettings)
+		return ret;
+
 	if (!rtnl_trylock())
 		return restart_syscall();
 
@@ -468,6 +488,14 @@ static ssize_t proto_down_store(struct device *dev,
 				struct device_attribute *attr,
 				const char *buf, size_t len)
 {
+	struct net_device *netdev = to_net_dev(dev);
+
+	/* The check is also done in change_proto_down; this helps returning
+	 * early without hitting the trylock/restart in netdev_store.
+	 */
+	if (!netdev->netdev_ops->ndo_change_proto_down)
+		return -EOPNOTSUPP;
+
 	return netdev_store(dev, attr, buf, len, change_proto_down);
 }
 NETDEVICE_SHOW_RW(proto_down, fmt_dec);
@@ -478,6 +506,12 @@ static ssize_t phys_port_id_show(struct device *dev,
 	struct net_device *netdev = to_net_dev(dev);
 	ssize_t ret = -EINVAL;
 
+	/* The check is also done in dev_get_phys_port_id; this helps returning
+	 * early without hitting the trylock/restart below.
+	 */
+	if (!netdev->netdev_ops->ndo_get_phys_port_id)
+		return -EOPNOTSUPP;
+
 	if (!rtnl_trylock())
 		return restart_syscall();
 
@@ -500,6 +534,13 @@ static ssize_t phys_port_name_show(struct device *dev,
 	struct net_device *netdev = to_net_dev(dev);
 	ssize_t ret = -EINVAL;
 
+	/* The checks are also done in dev_get_phys_port_name; this helps
+	 * returning early without hitting the trylock/restart below.
+	 */
+	if (!netdev->netdev_ops->ndo_get_phys_port_name &&
+	    !netdev->netdev_ops->ndo_get_devlink_port)
+		return -EOPNOTSUPP;
+
 	if (!rtnl_trylock())
 		return restart_syscall();
 
@@ -522,6 +563,14 @@ static ssize_t phys_switch_id_show(struct device *dev,
 	struct net_device *netdev = to_net_dev(dev);
 	ssize_t ret = -EINVAL;
 
+	/* The checks are also done in dev_get_phys_port_name; this helps
+	 * returning early without hitting the trylock/restart below. This works
+	 * because recurse is false when calling dev_get_port_parent_id.
+	 */
+	if (!netdev->netdev_ops->ndo_get_port_parent_id &&
+	    !netdev->netdev_ops->ndo_get_devlink_port)
+		return -EOPNOTSUPP;
+
 	if (!rtnl_trylock())
 		return restart_syscall();
 
@@ -1226,6 +1275,12 @@ static ssize_t tx_maxrate_store(struct netdev_queue *queue,
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
+	/* The check is also done later; this helps returning early without
+	 * hitting the trylock/restart below.
+	 */
+	if (!dev->netdev_ops->ndo_set_tx_maxrate)
+		return -EOPNOTSUPP;
+
 	err = kstrtou32(buf, 10, &rate);
 	if (err < 0)
 		return err;
@@ -1869,7 +1924,7 @@ static struct class net_class __ro_after_init = {
 	.get_ownership = net_get_ownership,
 };
 
-#ifdef CONFIG_OF_NET
+#ifdef CONFIG_OF
 static int of_dev_node_match(struct device *dev, const void *data)
 {
 	for (; dev; dev = dev->parent) {
@@ -1973,9 +2028,9 @@ int netdev_register_kobject(struct net_device *ndev)
 int netdev_change_owner(struct net_device *ndev, const struct net *net_old,
 			const struct net *net_new)
 {
+	kuid_t old_uid = GLOBAL_ROOT_UID, new_uid = GLOBAL_ROOT_UID;
+	kgid_t old_gid = GLOBAL_ROOT_GID, new_gid = GLOBAL_ROOT_GID;
 	struct device *dev = &ndev->dev;
-	kuid_t old_uid, new_uid;
-	kgid_t old_gid, new_gid;
 	int error;
 
 	net_ns_get_ownership(net_old, &old_uid, &old_gid);