From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Tue, 23 Aug 2022 17:46:50 +0000 (-0700)
Subject: net: Fix a data-race around sysctl_tstamp_allow_data.
X-Git-Tag: v5.19.6~88
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6fc89f990716ec516dfd817c785daab5be6d98aa;p=thirdparty%2Fkernel%2Fstable.git

net: Fix a data-race around sysctl_tstamp_allow_data.

[ Upstream commit d2154b0afa73c0159b2856f875c6b4fe7cf6a95e ]

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

Fixes: b245be1f4db1 ("net-timestamp: no-payload only sysctl")
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>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 5b3559cb1d827..bebf58464d667 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4772,7 +4772,7 @@ static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
 {
 	bool ret;
 
-	if (likely(sysctl_tstamp_allow_data || tsonly))
+	if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly))
 		return true;
 
 	read_lock_bh(&sk->sk_callback_lock);