From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed, 13 Jul 2022 20:51:56 +0000 (-0700)
Subject: ip: Fix a data-race around sysctl_ip_autobind_reuse.
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=87ceaa199a72c5856d49a030941fabcd5c3928d4;p=linux.git

ip: Fix a data-race around sysctl_ip_autobind_reuse.

[ Upstream commit 0db232765887d9807df8bcb7b6f29b2871539eab ]

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

Fixes: 4b01a9674231 ("tcp: bind(0) remove the SO_REUSEADDR restriction when ephemeral ports are exhausted.")
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/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 62a67fdc344cd..d3bbb344bbe12 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -259,7 +259,7 @@ next_port:
 		goto other_half_scan;
 	}
 
-	if (net->ipv4.sysctl_ip_autobind_reuse && !relax) {
+	if (READ_ONCE(net->ipv4.sysctl_ip_autobind_reuse) && !relax) {
 		/* We still have a chance to connect to different destinations */
 		relax = true;
 		goto ports_exhausted;