Commit 4177f545 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

tcp: Fix data-races around sysctl_tcp_migrate_req. 



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

Fixes: f9ac779f ("net: Introduce net.ipv4.tcp_migrate_req.")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f2e383b5

net/core/sock_reuseport.c

+2 −2
Original line number Diff line number Diff line
@@ -387,7 +387,7 @@ void reuseport_stop_listen_sock(struct sock *sk) 
		prog = rcu_dereference_protected(reuse->prog,

						 lockdep_is_held(&reuseport_lock));



		if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req ||

		if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_migrate_req) ||

		    (prog && prog->expected_attach_type == BPF_SK_REUSEPORT_SELECT_OR_MIGRATE)) {

			/* Migration capable, move sk from the listening section

			 * to the closed section.
@@ -545,7 +545,7 @@ struct sock *reuseport_migrate_sock(struct sock *sk, 
	hash = migrating_sk->sk_hash;

	prog = rcu_dereference(reuse->prog);

	if (!prog || prog->expected_attach_type != BPF_SK_REUSEPORT_SELECT_OR_MIGRATE) {

		if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req)

		if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_migrate_req))

			goto select_by_hash;

		goto failure;

	}