Commit 4785a667 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

tcp: Fix data-races around sysctl_tcp_ecn. 



While reading sysctl_tcp_ecn, 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: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1dace014

drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c

+1 −1
Original line number Diff line number Diff line
@@ -1392,7 +1392,7 @@ static void chtls_pass_accept_request(struct sock *sk, 
	th_ecn = tcph->ece && tcph->cwr;

	if (th_ecn) {

		ect = !INET_ECN_is_not_ect(ip_dsfield);

		ecn_ok = sock_net(sk)->ipv4.sysctl_tcp_ecn;

		ecn_ok = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn);

		if ((!ect && ecn_ok) || tcp_ca_needs_ecn(sk))

			inet_rsk(oreq)->ecn_ok = 1;

	}

net/ipv4/syncookies.c

+1 −1
Original line number Diff line number Diff line
@@ -273,7 +273,7 @@ bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt, 
	if (!ecn_ok)

		return false;



	if (net->ipv4.sysctl_tcp_ecn)

	if (READ_ONCE(net->ipv4.sysctl_tcp_ecn))

		return true;



	return dst_feature(dst, RTAX_FEATURE_ECN);

net/ipv4/sysctl_net_ipv4.c

+2 −0
Original line number Diff line number Diff line
@@ -676,6 +676,8 @@ static struct ctl_table ipv4_net_table[] = { 
		.maxlen		= sizeof(u8),

		.mode		= 0644,

		.proc_handler	= proc_dou8vec_minmax,

		.extra1		= SYSCTL_ZERO,

		.extra2		= SYSCTL_TWO,

	},

	{

		.procname	= "tcp_ecn_fallback",

net/ipv4/tcp_input.c

+1 −1
Original line number Diff line number Diff line
@@ -6729,7 +6729,7 @@ static void tcp_ecn_create_request(struct request_sock *req, 


	ect = !INET_ECN_is_not_ect(TCP_SKB_CB(skb)->ip_dsfield);

	ecn_ok_dst = dst_feature(dst, DST_FEATURE_ECN_MASK);

	ecn_ok = net->ipv4.sysctl_tcp_ecn || ecn_ok_dst;

	ecn_ok = READ_ONCE(net->ipv4.sysctl_tcp_ecn) || ecn_ok_dst;



	if (((!ect || th->res1) && ecn_ok) || tcp_ca_needs_ecn(listen_sk) ||

	    (ecn_ok_dst & DST_FEATURE_ECN_CA) ||

net/ipv4/tcp_output.c

+1 −1
Original line number Diff line number Diff line
@@ -324,7 +324,7 @@ static void tcp_ecn_send_syn(struct sock *sk, struct sk_buff *skb) 
{

	struct tcp_sock *tp = tcp_sk(sk);

	bool bpf_needs_ecn = tcp_bpf_ca_needs_ecn(sk);

	bool use_ecn = sock_net(sk)->ipv4.sysctl_tcp_ecn == 1 ||

	bool use_ecn = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn) == 1 ||

		tcp_ca_needs_ecn(sk) || bpf_needs_ecn;



	if (!use_ecn) {