From bb7bb35a63b4812da8e3aff587773678e31d23e3 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 11 Jul 2022 17:15:22 -0700 Subject: [PATCH] icmp: Fix a data-race around sysctl_icmp_echo_ignore_all. While reading sysctl_icmp_echo_ignore_all, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- net/ipv4/icmp.c | 2 +- net/ipv4/sysctl_net_ipv4.c | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 0f9e61d29f73..1df4aae310e0 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -993,7 +993,7 @@ static enum skb_drop_reason icmp_echo(struct sk_buff *skb) net = dev_net(skb_dst(skb)->dev); /* should there be an ICMP stat for ignored echos? */ - if (net->ipv4.sysctl_icmp_echo_ignore_all) + if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all)) return SKB_NOT_DROPPED_YET; icmp_param.data.icmph = *icmp_hdr(skb); diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index cd448cdd3b38..64682a01914a 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -599,6 +599,8 @@ static struct ctl_table ipv4_net_table[] = { .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE }, { .procname = "icmp_echo_enable_probe", -- 2.11.0