ipv6: use READ_ONCE() in ipv6_flowlabel_get()

ipv6_flowlabel_get() reads flowlabel_consistency and
flowlabel_state_ranges locklessly.

Use READ_ONCE() for these sysctl accesses.

Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260602002506.1519901-1-runyu.xiao@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index b1ccdf0dc64699f55ce1cd0c0cc92eaef3909e28..1ab5ad0dcf24fd7aacbee8a787ce932985c7f81a 100644 (file)
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -620,7 +620,7 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
        int err;
 
        if (freq->flr_flags & IPV6_FL_F_REFLECT) {
-               if (net->ipv6.sysctl.flowlabel_consistency) {
+               if (READ_ONCE(net->ipv6.sysctl.flowlabel_consistency)) {
                        net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
                        return -EPERM;
                }
@@ -633,7 +633,7 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 
        if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
                return -EINVAL;
-       if (net->ipv6.sysctl.flowlabel_state_ranges &&
+       if (READ_ONCE(net->ipv6.sysctl.flowlabel_state_ranges) &&
            (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
                return -ERANGE;