Commit 0968d2a4 authored Jul 13, 2022 by Kuniyuki Iwashima Committed by David S. Miller Jul 15, 2022

ip: Fix data-races around sysctl_ip_no_pmtu_disc.



While reading sysctl_ip_no_pmtu_disc, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 8281b7ec

net/ipv4/af_inet.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -335,7 +335,7 @@ 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;

net/ipv4/icmp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -881,7 +881,7 @@ static enum skb_drop_reason 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);

net/ipv6/af_inet6.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -226,7 +226,7 @@ static int inet6_create(struct net net, struct socket sock, int 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;

net/xfrm/xfrm_state.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2620,7 +2620,7 @@ 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;