Commit cbfc6495 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

tcp: Fix a data-race around sysctl_tcp_tw_reuse. 



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

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 55be8736

net/ipv4/tcp_ipv4.c

+1 −1
Original line number Diff line number Diff line
@@ -108,10 +108,10 @@ static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) 


int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)

{

	int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse);

	const struct inet_timewait_sock *tw = inet_twsk(sktw);

	const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);

	struct tcp_sock *tp = tcp_sk(sk);

	int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse;



	if (reuse == 2) {

		/* Still does not detect *everything* that goes through