Commit 0decb97c authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'net-more-heap-allocation-and-split-of-rtnl_newlink' 

Jakub Kicinski says:

====================
net: more heap allocation and split of rtnl_newlink()

Small refactoring of rtnl_newlink() to fix a stack usage warning
and make the function shorter.
====================

Link: https://lore.kernel.org/r/20220429235508.268349-1-kuba@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents d7ab15ab 02839cc8

net/core/rtnetlink.c

+109 −91
Original line number Diff line number Diff line
@@ -3302,23 +3302,116 @@ static int rtnl_group_changelink(const struct sk_buff *skb, 
	return 0;

}



static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			  struct nlattr **attr, struct netlink_ext_ack *extack)

static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,

			       const struct rtnl_link_ops *ops,

			       struct nlattr **tb, struct nlattr **data,

			       struct netlink_ext_ack *extack)

{

	struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];

	unsigned char name_assign_type = NET_NAME_USER;

	struct net *net = sock_net(skb->sk);

	struct net *dest_net, *link_net;

	struct net_device *dev;

	char ifname[IFNAMSIZ];

	int err;



	if (!ops->alloc && !ops->setup)

		return -EOPNOTSUPP;



	if (tb[IFLA_IFNAME]) {

		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);

	} else {

		snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);

		name_assign_type = NET_NAME_ENUM;

	}



	dest_net = rtnl_link_get_net_capable(skb, net, tb, CAP_NET_ADMIN);

	if (IS_ERR(dest_net))

		return PTR_ERR(dest_net);



	if (tb[IFLA_LINK_NETNSID]) {

		int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);



		link_net = get_net_ns_by_id(dest_net, id);

		if (!link_net) {

			NL_SET_ERR_MSG(extack, "Unknown network namespace id");

			err =  -EINVAL;

			goto out;

		}

		err = -EPERM;

		if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN))

			goto out;

	} else {

		link_net = NULL;

	}



	dev = rtnl_create_link(link_net ? : dest_net, ifname,

			       name_assign_type, ops, tb, extack);

	if (IS_ERR(dev)) {

		err = PTR_ERR(dev);

		goto out;

	}



	dev->ifindex = ifm->ifi_index;



	if (ops->newlink)

		err = ops->newlink(link_net ? : net, dev, tb, data, extack);

	else

		err = register_netdevice(dev);

	if (err < 0) {

		free_netdev(dev);

		goto out;

	}



	err = rtnl_configure_link(dev, ifm);

	if (err < 0)

		goto out_unregister;

	if (link_net) {

		err = dev_change_net_namespace(dev, dest_net, ifname);

		if (err < 0)

			goto out_unregister;

	}

	if (tb[IFLA_MASTER]) {

		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);

		if (err)

			goto out_unregister;

	}

out:

	if (link_net)

		put_net(link_net);

	put_net(dest_net);

	return err;

out_unregister:

	if (ops->newlink) {

		LIST_HEAD(list_kill);



		ops->dellink(dev, &list_kill);

		unregister_netdevice_many(&list_kill);

	} else {

		unregister_netdevice(dev);

	}

	goto out;

}



struct rtnl_newlink_tbs {

	struct nlattr *tb[IFLA_MAX + 1];

	struct nlattr *attr[RTNL_MAX_TYPE + 1];

	struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];

};



static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			  struct rtnl_newlink_tbs *tbs,

			  struct netlink_ext_ack *extack)

{

	struct nlattr *linkinfo[IFLA_INFO_MAX + 1];

	struct nlattr ** const tb = tbs->tb;

	const struct rtnl_link_ops *m_ops;

	struct net_device *master_dev;

	struct net *net = sock_net(skb->sk);

	const struct rtnl_link_ops *ops;

	struct nlattr *tb[IFLA_MAX + 1];

	struct net *dest_net, *link_net;

	struct nlattr **slave_data;

	char kind[MODULE_NAME_LEN];

	struct net_device *dev;

	struct ifinfomsg *ifm;

	char ifname[IFNAMSIZ];

	struct nlattr **data;

	bool link_specified;

	int err;
@@ -3382,12 +3475,12 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
			return -EINVAL;



		if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {

			err = nla_parse_nested_deprecated(attr, ops->maxtype,

			err = nla_parse_nested_deprecated(tbs->attr, ops->maxtype,

							  linkinfo[IFLA_INFO_DATA],

							  ops->policy, extack);

			if (err < 0)

				return err;

			data = attr;

			data = tbs->attr;

		}

		if (ops->validate) {

			err = ops->validate(tb, data, extack);
@@ -3403,14 +3496,14 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 


		if (m_ops->slave_maxtype &&

		    linkinfo[IFLA_INFO_SLAVE_DATA]) {

			err = nla_parse_nested_deprecated(slave_attr,

			err = nla_parse_nested_deprecated(tbs->slave_attr,

							  m_ops->slave_maxtype,

							  linkinfo[IFLA_INFO_SLAVE_DATA],

							  m_ops->slave_policy,

							  extack);

			if (err < 0)

				return err;

			slave_data = slave_attr;

			slave_data = tbs->slave_attr;

		}

	}
@@ -3478,96 +3571,21 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
		return -EOPNOTSUPP;

	}



	if (!ops->alloc && !ops->setup)

		return -EOPNOTSUPP;



	if (tb[IFLA_IFNAME]) {

		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);

	} else {

		snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);

		name_assign_type = NET_NAME_ENUM;

	}



	dest_net = rtnl_link_get_net_capable(skb, net, tb, CAP_NET_ADMIN);

	if (IS_ERR(dest_net))

		return PTR_ERR(dest_net);



	if (tb[IFLA_LINK_NETNSID]) {

		int id = nla_get_s32(tb[IFLA_LINK_NETNSID]);



		link_net = get_net_ns_by_id(dest_net, id);

		if (!link_net) {

			NL_SET_ERR_MSG(extack, "Unknown network namespace id");

			err =  -EINVAL;

			goto out;

		}

		err = -EPERM;

		if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN))

			goto out;

	} else {

		link_net = NULL;

	}



	dev = rtnl_create_link(link_net ? : dest_net, ifname,

			       name_assign_type, ops, tb, extack);

	if (IS_ERR(dev)) {

		err = PTR_ERR(dev);

		goto out;

	}



	dev->ifindex = ifm->ifi_index;



	if (ops->newlink)

		err = ops->newlink(link_net ? : net, dev, tb, data, extack);

	else

		err = register_netdevice(dev);

	if (err < 0) {

		free_netdev(dev);

		goto out;

	}



	err = rtnl_configure_link(dev, ifm);

	if (err < 0)

		goto out_unregister;

	if (link_net) {

		err = dev_change_net_namespace(dev, dest_net, ifname);

		if (err < 0)

			goto out_unregister;

	}

	if (tb[IFLA_MASTER]) {

		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);

		if (err)

			goto out_unregister;

	}

out:

	if (link_net)

		put_net(link_net);

	put_net(dest_net);

	return err;

out_unregister:

	if (ops->newlink) {

		LIST_HEAD(list_kill);



		ops->dellink(dev, &list_kill);

		unregister_netdevice_many(&list_kill);

	} else {

		unregister_netdevice(dev);

	}

	goto out;

	return rtnl_newlink_create(skb, ifm, ops, tb, data, extack);

}



static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			struct netlink_ext_ack *extack)

{

	struct nlattr **attr;

	struct rtnl_newlink_tbs *tbs;

	int ret;



	attr = kmalloc_array(RTNL_MAX_TYPE + 1, sizeof(*attr), GFP_KERNEL);

	if (!attr)

	tbs = kmalloc(sizeof(*tbs), GFP_KERNEL);

	if (!tbs)

		return -ENOMEM;



	ret = __rtnl_newlink(skb, nlh, attr, extack);

	kfree(attr);

	ret = __rtnl_newlink(skb, nlh, tbs, extack);

	kfree(tbs);

	return ret;

}