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 7785a4775e58aaf0bedb65c9e0b282991023d62c..4d97133240036a76ee10c6f742a4157adb3feb25 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -251,7 +251,7 @@ 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;