Commit 98d3a6f6 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

net: fib_rules: Convert RTM_NEWRULE to per-netns RTNL. 



fib_nl_newrule() is the doit() handler for RTM_NEWRULE but also called
from vrf_newlink().

In the latter case, RTNL is already held and the 4th arg is true.

Let's hold per-netns RTNL in fib_newrule() if rtnl_held is false.

Note that we call fib_rule_get() before releasing per-netns RTNL to call
notify_rule_change() without RTNL and prevent freeing the new rule.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Tested-by: default avatarIdo Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250207072502.87775-7-kuniyu@amazon.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a0596c2c

net/core/fib_rules.c

+14 −2
Original line number Diff line number Diff line
@@ -816,6 +816,9 @@ int fib_newrule(struct net *net, struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (err)

		goto errout;



	if (!rtnl_held)

		rtnl_net_lock(net);



	err = fib_nl2rule_rtnl(rule, ops, tb, extack);

	if (err)

		goto errout_free;
@@ -881,12 +884,20 @@ int fib_newrule(struct net *net, struct sk_buff *skb, struct nlmsghdr *nlh, 
	if (rule->tun_id)

		ip_tunnel_need_metadata();



	fib_rule_get(rule);



	if (!rtnl_held)

		rtnl_net_unlock(net);



	notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);

	fib_rule_put(rule);

	flush_route_cache(ops);

	rules_ops_put(ops);

	return 0;



errout_free:

	if (!rtnl_held)

		rtnl_net_unlock(net);

	kfree(rule);

errout:

	rules_ops_put(ops);
@@ -897,7 +908,7 @@ EXPORT_SYMBOL_GPL(fib_newrule); 
static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,

			  struct netlink_ext_ack *extack)

{

	return fib_newrule(sock_net(skb->sk), skb, nlh, extack, true);

	return fib_newrule(sock_net(skb->sk), skb, nlh, extack, false);

}



int fib_delrule(struct net *net, struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -1320,7 +1331,8 @@ static struct pernet_operations fib_rules_net_ops = { 
};



static const struct rtnl_msg_handler fib_rules_rtnl_msg_handlers[] __initconst = {

	{.msgtype = RTM_NEWRULE, .doit = fib_nl_newrule},

	{.msgtype = RTM_NEWRULE, .doit = fib_nl_newrule,

	 .flags = RTNL_FLAG_DOIT_PERNET},

	{.msgtype = RTM_DELRULE, .doit = fib_nl_delrule},

	{.msgtype = RTM_GETRULE, .dumpit = fib_nl_dumprule,

	 .flags = RTNL_FLAG_DUMP_UNLOCKED},