Commit bdf00bf2 authored Jul 11, 2022 by Kuniyuki Iwashima Committed by David S. Miller Jul 13, 2022

nexthop: Fix data-races around nexthop_compat_mode.



While reading nexthop_compat_mode, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 4f80116d ("net: ipv4: add sysctl for nexthop api compatibility mode")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e49e4aff

net/ipv4/fib_semantics.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1811,7 +1811,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
	goto nla_put_failure;		goto nla_put_failure;
	if (nexthop_is_blackhole(fi->nh))		if (nexthop_is_blackhole(fi->nh))
	rtm->rtm_type = RTN_BLACKHOLE;		rtm->rtm_type = RTN_BLACKHOLE;
	if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)		if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
	goto offload;		goto offload;
	}		}

net/ipv4/nexthop.c

+3 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1858,7 +1858,7 @@ static void __remove_nexthop_fib(struct net net, struct nexthop nh)
	/* __ip6_del_rt does a release, so do a hold here */		/* __ip6_del_rt does a release, so do a hold here */
	fib6_info_hold(f6i);		fib6_info_hold(f6i);
	ipv6_stub->ip6_del_rt(net, f6i,		ipv6_stub->ip6_del_rt(net, f6i,
	!net->ipv4.sysctl_nexthop_compat_mode);		!READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
	}		}
	}		}

	@@ -2361,7 +2361,8 @@ static int insert_nexthop(struct net net, struct nexthop new_nh,
	if (!rc) {		if (!rc) {
	nh_base_seq_inc(net);		nh_base_seq_inc(net);
	nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);		nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
	if (replace_notify && net->ipv4.sysctl_nexthop_compat_mode)		if (replace_notify &&
			READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode))
	nexthop_replace_notify(net, new_nh, &cfg->nlinfo);		nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
	}		}

net/ipv6/route.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -5741,7 +5741,7 @@ static int rt6_fill_node(struct net net, struct sk_buff skb,
	if (nexthop_is_blackhole(rt->nh))		if (nexthop_is_blackhole(rt->nh))
	rtm->rtm_type = RTN_BLACKHOLE;		rtm->rtm_type = RTN_BLACKHOLE;

	if (net->ipv4.sysctl_nexthop_compat_mode &&		if (READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode) &&
	rt6_fill_node_nexthop(skb, rt->nh, &nh_flags) < 0)		rt6_fill_node_nexthop(skb, rt->nh, &nh_flags) < 0)
	goto nla_put_failure;		goto nla_put_failure;