From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Mon, 18 Jul 2022 17:26:51 +0000 (-0700)
Subject: tcp: Fix a data-race around sysctl_tcp_rfc1337.
X-Git-Tag: v5.15.73~1980
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=46d05dab1b4f99bca838a85811f321b9997ac957;p=platform%2Fkernel%2Flinux-rpi.git

tcp: Fix a data-race around sysctl_tcp_rfc1337.

[ Upstream commit 0b484c91911e758e53656d570de58c2ed81ec6f2 ]

While reading sysctl_tcp_rfc1337, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

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/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 13783fc..39d8101 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -180,7 +180,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
 			 * Oh well... nobody has a sufficient solution to this
 			 * protocol bug yet.
 			 */
-			if (twsk_net(tw)->ipv4.sysctl_tcp_rfc1337 == 0) {
+			if (!READ_ONCE(twsk_net(tw)->ipv4.sysctl_tcp_rfc1337)) {
 kill:
 				inet_twsk_deschedule_put(tw);
 				return TCP_TW_SUCCESS;