Commit 2d303753 authored Jul 20, 2022 by Kuniyuki Iwashima Committed by Greg Kroah-Hartman Aug 03, 2022

tcp: Fix a data-race around sysctl_tcp_invalid_ratelimit.



[ Upstream commit 2afdbe7b8de84c28e219073a6661080e1b3ded48 ]

While reading sysctl_tcp_invalid_ratelimit, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: 032ee423 ("tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks")
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>

parent 5d235c2f

net/ipv4/tcp_input.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -3436,7 +3436,8 @@ static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
		if (*last_oow_ack_time) {
		s32 elapsed = (s32)(tcp_jiffies32 - *last_oow_ack_time);

		if (0 <= elapsed && elapsed < net->ipv4.sysctl_tcp_invalid_ratelimit) {
		if (0 <= elapsed &&
		elapsed < READ_ONCE(net->ipv4.sysctl_tcp_invalid_ratelimit)) {
		NET_INC_STATS(net, mib_idx);
		return true; /* rate-limited: don't send yet! */
		}