This is a note to let you know that I've just added the patch titled
tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit.
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-fix-a-data-race-around-sysctl_tcp_challenge_ack_limit.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From db3815a2fa691da145cfbe834584f31ad75df9ff Mon Sep 17 00:00:00 2001
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Wed, 20 Jul 2022 09:50:21 -0700
Subject: tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit.
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
commit db3815a2fa691da145cfbe834584f31ad75df9ff upstream.
While reading sysctl_tcp_challenge_ack_limit, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its reader.
Fixes: 282f23c6ee34 ("tcp: implement RFC 5961 3.2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_input.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3468,7 +3468,7 @@ static void tcp_send_challenge_ack(struc
/* Then check host-wide RFC 5961 rate limit. */
now = jiffies / HZ;
if (now != challenge_timestamp) {
- u32 ack_limit = net->ipv4.sysctl_tcp_challenge_ack_limit;
+ u32 ack_limit = READ_ONCE(net->ipv4.sysctl_tcp_challenge_ack_limit);
u32 half = (ack_limit + 1) >> 1;
challenge_timestamp = now;
Patches currently in stable-queue which might be from kuniyu@xxxxxxxxxx are
queue-4.19/tcp-fix-a-data-race-around-sysctl_tcp_app_win.patch
queue-4.19/tcp-fix-a-data-race-around-sysctl_tcp_nometrics_save.patch
queue-4.19/tcp-fix-a-data-race-around-sysctl_tcp_adv_win_scale.patch
queue-4.19/tcp-fix-a-data-race-around-sysctl_tcp_frto.patch
queue-4.19/tcp-fix-data-races-around-sysctl_tcp_dsack.patch
queue-4.19/tcp-fix-a-data-race-around-sysctl_tcp_challenge_ack_limit.patch
queue-4.19/net-ping6-fix-memleak-in-ipv6_renew_options.patch
