Commit cb827db5 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: fib_rules: annotate data-races around rule->[io]ifindex 



rule->iifindex and rule->oifindex can be read without holding RTNL.

Add READ_ONCE()/WRITE_ONCE() annotations where needed.

Fixes: 32affa55 ("fib: rules: no longer hold RTNL in fib_nl_dumprule()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250206083051.2494877-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1438f5d0

net/core/fib_rules.c

+13 −11
Original line number Diff line number Diff line
@@ -37,8 +37,8 @@ static const struct fib_kuid_range fib_kuid_range_unset = { 


bool fib_rule_matchall(const struct fib_rule *rule)

{

	if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||

	    rule->flags)

	if (READ_ONCE(rule->iifindex) || READ_ONCE(rule->oifindex) ||

	    rule->mark || rule->tun_id || rule->flags)

		return false;

	if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)

		return false;
@@ -261,12 +261,14 @@ static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops, 
			  struct flowi *fl, int flags,

			  struct fib_lookup_arg *arg)

{

	int ret = 0;

	int iifindex, oifindex, ret = 0;



	if (rule->iifindex && (rule->iifindex != fl->flowi_iif))

	iifindex = READ_ONCE(rule->iifindex);

	if (iifindex && (iifindex != fl->flowi_iif))

		goto out;



	if (rule->oifindex && (rule->oifindex != fl->flowi_oif))

	oifindex = READ_ONCE(rule->oifindex);

	if (oifindex && (oifindex != fl->flowi_oif))

		goto out;



	if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
@@ -1041,14 +1043,14 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, 
	if (rule->iifname[0]) {

		if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))

			goto nla_put_failure;

		if (rule->iifindex == -1)

		if (READ_ONCE(rule->iifindex) == -1)

			frh->flags |= FIB_RULE_IIF_DETACHED;

	}



	if (rule->oifname[0]) {

		if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))

			goto nla_put_failure;

		if (rule->oifindex == -1)

		if (READ_ONCE(rule->oifindex) == -1)

			frh->flags |= FIB_RULE_OIF_DETACHED;

	}
@@ -1220,10 +1222,10 @@ static void attach_rules(struct list_head *rules, struct net_device *dev) 
	list_for_each_entry(rule, rules, list) {

		if (rule->iifindex == -1 &&

		    strcmp(dev->name, rule->iifname) == 0)

			rule->iifindex = dev->ifindex;

			WRITE_ONCE(rule->iifindex, dev->ifindex);

		if (rule->oifindex == -1 &&

		    strcmp(dev->name, rule->oifname) == 0)

			rule->oifindex = dev->ifindex;

			WRITE_ONCE(rule->oifindex, dev->ifindex);

	}

}
@@ -1233,9 +1235,9 @@ static void detach_rules(struct list_head *rules, struct net_device *dev) 


	list_for_each_entry(rule, rules, list) {

		if (rule->iifindex == dev->ifindex)

			rule->iifindex = -1;

			WRITE_ONCE(rule->iifindex, -1);

		if (rule->oifindex == dev->ifindex)

			rule->oifindex = -1;

			WRITE_ONCE(rule->oifindex, -1);

	}

}