tcp: Fix data-races around sysctl_tcp_syncookies.

[ Upstream commit f2e383b5bb6bbc60a0b94b87b3e49a2b1aefd11e ]

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

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:47 -07:00 • committed by Greg Kroah-Hartman
commit b222de2560
4 changed files with 18 additions and 12 deletions

View file

@ -141,7 +141,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
__u8 rcv_wscale;
u32 tsoff = 0;
if (!sock_net(sk)->ipv4.sysctl_tcp_syncookies || !th->ack || th->rst)
if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_syncookies) ||
!th->ack || th->rst)
goto out;
if (tcp_synq_no_recent_overflow(sk))