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ipv6: flowlabel: fl6_sock_lookup() must use atomic_inc_not_zero

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[ Upstream commit 65a3c497c0e965a552008db8bc2653f62bc925a1 ]

Before taking a refcount, make sure the object is not already
scheduled for deletion.

Same fix is needed in ipv6_flowlabel_opt()

Fixes: 18367681a1 ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@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 2019-06-06 14:32:34 -07:00 committed by Greg Kroah-Hartman
parent a5ae592042
commit 7eadfacd2b
1 changed files with 4 additions and 3 deletions
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7
net/ipv6/ip6_flowlabel.c
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@ -254,9 +254,9 @@ struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label)
rcu_read_lock_bh();
for_each_sk_fl_rcu(np, sfl) {
struct ip6_flowlabel *fl = sfl->fl;
if (fl->label == label) {
if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
fl->lastuse = jiffies;
atomic_inc(&fl->users);
rcu_read_unlock_bh();
return fl;
}
@ -622,7 +622,8 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
goto done;
}
fl1 = sfl->fl;
atomic_inc(&fl1->users);
if (!atomic_inc_not_zero(&fl1->users))
fl1 = NULL;
break;
}
}