From 5e343e3ef464a5dbcc8fd3a99830908e31a4a61d 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 e77283069c7b..9d1ff3baa213 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -338,7 +338,7 @@ static int inet_create(struct net *net, struct socket *sock, int 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 0fa0da1d71f5..a1aacf5e75a6 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -887,7 +887,7 @@ static bool icmp_unreach(struct sk_buff *skb) * values please see * Documentation/networking/ip-sysctl.rst */ - 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 890a9cfc6ce2..d30c9d949c1b 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -225,7 +225,7 @@ static int inet6_create(struct net *net, struct socket *sock, int 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 717db5ecd0bd..bc0bbb1571ce 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2587,7 +2587,7 @@ 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;