Commit 893c49a7 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable(). 



mptcp_active_enable() is called from subflow_finish_connect(),
which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always
under RCU.

Using sk_dst_get(sk)->dev could trigger UAF.

Let's use __sk_dst_get() and dst_dev_rcu().

Fixes: 27069e7c ("mptcp: disable active MPTCP in case of blackhole")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250916214758.650211-8-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 108a86c7

net/mptcp/ctrl.c

+7 −4
Original line number Diff line number Diff line
@@ -501,12 +501,15 @@ void mptcp_active_enable(struct sock *sk) 
	struct mptcp_pernet *pernet = mptcp_get_pernet(sock_net(sk));



	if (atomic_read(&pernet->active_disable_times)) {

		struct dst_entry *dst = sk_dst_get(sk);

		struct net_device *dev;

		struct dst_entry *dst;



		if (dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK))

		rcu_read_lock();

		dst = __sk_dst_get(sk);

		dev = dst ? dst_dev_rcu(dst) : NULL;

		if (dev && (dev->flags & IFF_LOOPBACK))

			atomic_set(&pernet->active_disable_times, 0);



		dst_release(dst);

		rcu_read_unlock();

	}

}