nexthop: Fix data-races around nexthop_compat_mode.

[ Upstream commit bdf00bf24bef9be1ca641a6390fd5487873e0d2e ]

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

Fixes: 4f80116d3d ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-11 17:15:33 -07:00 committed by Greg Kroah-Hartman
parent 2c56958de8
commit a51040d4b1
3 changed files with 5 additions and 4 deletions

View File

@ -1831,7 +1831,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
goto nla_put_failure;
if (nexthop_is_blackhole(fi->nh))
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;
}

View File

@ -882,7 +882,7 @@ static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
/* __ip6_del_rt does a release, so do a hold here */
fib6_info_hold(f6i);
ipv6_stub->ip6_del_rt(net, f6i,
!net->ipv4.sysctl_nexthop_compat_mode);
!READ_ONCE(net->ipv4.sysctl_nexthop_compat_mode));
}
}
@ -1194,7 +1194,8 @@ static int insert_nexthop(struct net *net, struct nexthop *new_nh,
if (!rc) {
nh_base_seq_inc(net);
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);
}

View File

@ -5641,7 +5641,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb,
if (nexthop_is_blackhole(rt->nh))
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)
goto nla_put_failure;