tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit.
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: 282f23c6ee
("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:

committed by
Greg Kroah-Hartman

parent
9ffb4fdfd8
commit
c37c7f35d7
@@ -3576,7 +3576,7 @@ static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
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/* Then check host-wide RFC 5961 rate limit. */
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/* Then check host-wide RFC 5961 rate limit. */
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now = jiffies / HZ;
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now = jiffies / HZ;
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if (now != challenge_timestamp) {
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if (now != challenge_timestamp) {
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u32 ack_limit = net->ipv4.sysctl_tcp_challenge_ack_limit;
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u32 ack_limit = READ_ONCE(net->ipv4.sysctl_tcp_challenge_ack_limit);
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u32 half = (ack_limit + 1) >> 1;
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u32 half = (ack_limit + 1) >> 1;
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challenge_timestamp = now;
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challenge_timestamp = now;
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