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From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	David Ahern <dsahern@kernel.org>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Iurii Zaikin <yzaikin@google.com>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>,
	Kuniyuki Iwashima <kuni1840@gmail.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	Ayush Sawal <ayush.sawal@chelsio.com>
Subject: [PATCH v1 net 12/15] tcp: Fix data-races around sysctl_tcp_ecn.
Date: Mon, 11 Jul 2022 17:15:30 -0700	[thread overview]
Message-ID: <20220712001533.89927-13-kuniyu@amazon.com> (raw)
In-Reply-To: <20220712001533.89927-1-kuniyu@amazon.com>

While reading sysctl_tcp_ecn, 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>
---
CC: Ayush Sawal <ayush.sawal@chelsio.com>
---
 drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c | 2 +-
 net/ipv4/syncookies.c                                       | 2 +-
 net/ipv4/sysctl_net_ipv4.c                                  | 2 ++
 net/ipv4/tcp_input.c                                        | 2 +-
 net/ipv4/tcp_output.c                                       | 2 +-
 5 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
index 4af5561cbfc5..7c760aa65540 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
@@ -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;
 	}
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index f33c31dd7366..b387c4835155 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -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);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 66159d49a575..5e308c1715af 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -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",
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2e2a9ece9af2..3ec4edc37313 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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) ||
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1c054431e358..3dc17551ce25 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -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) {
-- 
2.30.2


  parent reply	other threads:[~2022-07-12  0:21 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-12  0:15 [PATCH v1 net 00/15] sysctl: Fix data-races around ipv4_net_table (Round 1) Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 01/15] sysctl: Fix data-races in proc_dou8vec_minmax() Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 02/15] sysctl: Fix data-races in proc_dointvec_ms_jiffies() Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 03/15] tcp: Fix a data-race around sysctl_max_tw_buckets Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 04/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_all Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 05/15] icmp: Fix data-races around sysctl_icmp_echo_enable_probe Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 06/15] icmp: Fix a data-race around sysctl_icmp_echo_ignore_broadcasts Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 07/15] icmp: Fix a data-race around sysctl_icmp_ignore_bogus_error_responses Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 08/15] icmp: Fix a data-race around sysctl_icmp_errors_use_inbound_ifaddr Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 09/15] icmp: Fix a data-race around sysctl_icmp_ratelimit Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 10/15] icmp: Fix a data-race around sysctl_icmp_ratemask Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 11/15] raw: Fix a data-race around sysctl_raw_l3mdev_accept Kuniyuki Iwashima
2022-07-12  0:15 ` Kuniyuki Iwashima [this message]
2022-07-12  0:15 ` [PATCH v1 net 13/15] tcp: Fix a data-race around sysctl_tcp_ecn_fallback Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 14/15] ipv4: Fix data-races around sysctl_ip_dynaddr Kuniyuki Iwashima
2022-07-12  0:15 ` [PATCH v1 net 15/15] nexthop: Fix data-races around nexthop_compat_mode Kuniyuki Iwashima
2022-07-13 12:30 ` [PATCH v1 net 00/15] sysctl: Fix data-races around ipv4_net_table (Round 1) patchwork-bot+netdevbpf

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