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authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-18 10:26:50 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-07-29 17:10:34 +0200
commite570964c9f36fa386db95cc776d2e1dc16e69496 (patch)
treee6f396916bb87f1f044f999cccaffc2203227942
parentd4a90eb32681c79a140ff2600b52fce291cf4e91 (diff)
tcp: Fix a data-race around sysctl_tcp_stdurg.
[ Upstream commit 4e08ed41cb1194009fc1a916a59ce3ed4afd77cd ] While reading sysctl_tcp_stdurg, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") 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>
-rw-r--r--net/ipv4/tcp_input.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 731c4d220905..3b63e05c3486 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5292,7 +5292,7 @@ static void tcp_check_urg(struct sock *sk, const struct tcphdr *th)
struct tcp_sock *tp = tcp_sk(sk);
u32 ptr = ntohs(th->urg_ptr);
- if (ptr && !sock_net(sk)->ipv4.sysctl_tcp_stdurg)
+ if (ptr && !READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_stdurg))
ptr--;
ptr += ntohl(th->seq);