ipv6: tcp: add rcu locking in tcp_v6_send_synack() (3e4006f0) · Commits · 戴 / test

When first SYNACK is sent, we already hold rcu_read_lock(), but this is not true if a SYNACK is retransmitted, as a timer (soft) interrupt does not hold rcu_read_lock() Fixes: ("ipv6: add complete rcu protection around np->opt") Reported-by:

Dave Jones <davej@codemonkey.org.uk> Signed-off-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv6/tcp_ipv6.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -462,8 +462,10 @@ static int tcp_v6_send_synack(const struct sock sk, struct dst_entry dst,
	if (np->repflow && ireq->pktopts)		if (np->repflow && ireq->pktopts)
	fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));		fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));

			rcu_read_lock();
	err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),		err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
	np->tclass);		np->tclass);
			rcu_read_unlock();
	err = net_xmit_eval(err);		err = net_xmit_eval(err);
	}		}

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