tcp: Fix data-races around sysctl_tcp_base_mss.
[ Upstream commit 88d78bc097cd8ebc6541e93316c9d9bf651b13e8 ]
While reading sysctl_tcp_base_mss, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.
Fixes: 5d424d5a67
("[TCP]: MTU probing")
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>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
77a04845f0
commit
514d2254c7
@@ -1766,7 +1766,7 @@ void tcp_mtup_init(struct sock *sk)
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icsk->icsk_mtup.enabled = READ_ONCE(net->ipv4.sysctl_tcp_mtu_probing) > 1;
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icsk->icsk_mtup.enabled = READ_ONCE(net->ipv4.sysctl_tcp_mtu_probing) > 1;
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icsk->icsk_mtup.search_high = tp->rx_opt.mss_clamp + sizeof(struct tcphdr) +
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icsk->icsk_mtup.search_high = tp->rx_opt.mss_clamp + sizeof(struct tcphdr) +
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icsk->icsk_af_ops->net_header_len;
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icsk->icsk_af_ops->net_header_len;
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icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, net->ipv4.sysctl_tcp_base_mss);
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icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, READ_ONCE(net->ipv4.sysctl_tcp_base_mss));
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icsk->icsk_mtup.probe_size = 0;
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icsk->icsk_mtup.probe_size = 0;
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if (icsk->icsk_mtup.enabled)
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if (icsk->icsk_mtup.enabled)
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icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
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icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
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@@ -171,7 +171,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
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icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
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icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
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} else {
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} else {
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mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
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mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
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mss = min(net->ipv4.sysctl_tcp_base_mss, mss);
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mss = min(READ_ONCE(net->ipv4.sysctl_tcp_base_mss), mss);
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mss = max(mss, net->ipv4.sysctl_tcp_mtu_probe_floor);
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mss = max(mss, net->ipv4.sysctl_tcp_mtu_probe_floor);
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mss = max(mss, net->ipv4.sysctl_tcp_min_snd_mss);
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mss = max(mss, net->ipv4.sysctl_tcp_min_snd_mss);
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icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
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icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
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