[PATCH 5.4 34/77] net: Fix a data-race around sysctl_somaxconn.

Greg Kroah-Hartman
2022-09-02T12:36:11Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 3c9ba81d72047f2e81bb535d42856517b613aba7 ]

While reading sysctl_somaxconn, 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>
---
net/socket.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/socket.c b/net/socket.c
index 94358566c9d10..02feaf5bd84a3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1661,7 +1661,7 @@ int __sys_listen(int fd, int backlog)

sock = sockfd_lookup_light(fd, &err, &fput_needed);
if (sock) {
- somaxconn = sock_net(sock->sk)->core.sysctl_somaxconn;
+ somaxconn = READ_ONCE(sock_net(sock->sk)->core.sysctl_somaxconn);
if ((unsigned int)backlog > somaxconn)
backlog = somaxconn;

--
2.35.1