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tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit.

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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@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-20 09:50:21 -07:00 committed by Greg Kroah-Hartman
parent a88de75673
commit ff2932ac8e
1 changed files with 1 additions and 1 deletions
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2
net/ipv4/tcp_input.c
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@ -3622,7 +3622,7 @@ 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;