iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ipv6: tcp: add rcu locking in tcp_v6_send_synack()

Browse Source 
[ Upstream commit 3e4006f0b86a5ae5eb0e8215f9a9e1db24506977 ]

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: 45f6fad84cc30 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Dumazet 2016-01-08 09:35:51 -08:00 committed by Greg Kroah-Hartman
parent 8534537d0b
commit 7caad825e2
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/ipv6/tcp_ipv6.c
View File

@ -462,8 +462,10 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
if (np->repflow && ireq->pktopts)
fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
rcu_read_lock();
err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
np->tclass);
rcu_read_unlock();
err = net_xmit_eval(err);
}