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 <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 44f21278003d172b06524d7de7839dff9f0f3c80..781c595f6880d56c1d7d655cf15772fa5ab4b009 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -338,7 +338,7 @@ 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 a5cc89506c1e49b2c2c2341ba494d85679aaff25..609c4ff7edc6944b16ff0b7d2dfb38ce1abeeb52 100644 (file)
--- 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 dab4a047590b73e5839a06e07c2ed1eb7447a26f..3a91d0d40aecc14dc1ca30cdda775f597fb1ece2 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -226,7 +226,7 @@ lookup_protocol:
        RCU_INIT_POINTER(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 f7bfa19169688d4fcd476f74b8138e807cc32a6a..b1a04a22166f76f235cad363e085b91982c52657 100644 (file)
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2619,7 +2619,7 @@ 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;