ip: Fix data-races around sysctl_ip_no_pmtu_disc.

[ Upstream commit a5960449abf361dafaffe81b5652c64e210accca ]

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 9ab73fcc7411cd3c5cfec01dbb0817db228b39a6..06153386776dfb117082cbc3fadaa1bd68fdfa97 100644 (file)
--- 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 9bc01411be4cc3f699481d50b83a242e0ea1b5ff..b44f51e404aee562881dedb4d9aae12280c9c520 100644 (file)
--- 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 942da168f18fb74e2d62f9ae2636864d7493829c..56f396ecc26b7f46a6d19f542d1358b0bd00868a 100644 (file)
--- 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 268bba29bb6039f4a80ec1f2fa6707337be650e3..bee1a8143d75fb41d97695a5d8276bca14f230f3 100644 (file)
--- 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;