From 572f25eff48f7064f8d7ad9a44d577c7c545ebfd Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 10 Nov 2022 20:26:05 +0800 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit. stable inclusion from stable-v5.10.135 commit c37c7f35d7b707c2db656b0ab60419d4fb45b5c5 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5ZWFM Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c37c7f35d7b707c2db656b0ab60419d4fb45b5c5 -------------------------------- 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Zheng Zengkai Reviewed-by: Wei Li --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a9f0e646e92e..255493c4acc3 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3576,7 +3576,7 @@ static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb) /* 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; -- GitLab