[PATCH 5.10 075/105] tcp: Fix a data-race around sysctl_tcp_rfc1337.

Greg Kroah-Hartman
2022-07-27T16:55:19Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ 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>
---
net/ipv4/tcp_minisocks.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 62f5ef9e6f93..e42312321191 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;
--
2.35.1