From 5af6d9226376fbd0dba6876139385e770342726f Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 13 Jul 2022 13:51:52 -0700 Subject: [PATCH] ip: Fix data-races around sysctl_ip_no_pmtu_disc. [ Upstream commit 0968d2a441bf6afb551fd99e60fa65ed67068963 ] While reading sysctl_ip_no_pmtu_disc, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/af_inet.c | 2 +- net/ipv4/icmp.c | 2 +- net/ipv6/af_inet6.c | 2 +- net/xfrm/xfrm_state.c | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 9ab73fcc7411..06153386776d 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -337,7 +337,7 @@ lookup_protocol: inet->hdrincl = 1; } - if (net->ipv4.sysctl_ip_no_pmtu_disc) + if (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) inet->pmtudisc = IP_PMTUDISC_DONT; else inet->pmtudisc = IP_PMTUDISC_WANT; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 9bc01411be4c..b44f51e404ae 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -886,7 +886,7 @@ static bool icmp_unreach(struct sk_buff *skb) * values please see * Documentation/networking/ip-sysctl.txt */ - switch (net->ipv4.sysctl_ip_no_pmtu_disc) { + switch (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) { default: net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n", &iph->daddr); diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 942da168f18f..56f396ecc26b 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -222,7 +222,7 @@ lookup_protocol: inet->mc_list = NULL; inet->rcv_tos = 0; - if (net->ipv4.sysctl_ip_no_pmtu_disc) + if (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) inet->pmtudisc = IP_PMTUDISC_DONT; else inet->pmtudisc = IP_PMTUDISC_WANT; diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 268bba29bb60..bee1a8143d75 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2488,7 +2488,7 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload) int err; if (family == AF_INET && - xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc) + READ_ONCE(xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc)) x->props.flags |= XFRM_STATE_NOPMTUDISC; err = -EPROTONOSUPPORT;