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Commit 639739b5 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
Browse files

ipv6: fix null pointer dereference in __ip6addrlbl_add 



Commit b67bfe0d ("hlist: drop
the node parameter from iterators") changed the behavior of
hlist_for_each_entry_safe to leave the p argument NULL.

Fix this up by tracking the last argument.

Reported-by: default avatarMichele Baldessari <michele@acksyn.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Tested-by: default avatarMichele Baldessari <michele@acksyn.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a8e9fd0f

net/ipv6/addrlabel.c

+23 −25
Original line number Diff line number Diff line
@@ -251,19 +251,14 @@ static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net, 
/* add a label */

static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)

{

	struct hlist_node *n;

	struct ip6addrlbl_entry *last = NULL, *p = NULL;

	int ret = 0;



	ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n",

			__func__,

			newp, replace);

	ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n", __func__, newp,

		  replace);



	if (hlist_empty(&ip6addrlbl_table.head)) {

		hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);

	} else {

		struct hlist_node *n;

		struct ip6addrlbl_entry *p = NULL;

		hlist_for_each_entry_safe(p, n,

					  &ip6addrlbl_table.head, list) {

	hlist_for_each_entry_safe(p, n,	&ip6addrlbl_table.head, list) {

		if (p->prefixlen == newp->prefixlen &&

		    net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&

		    p->ifindex == newp->ifindex &&
@@ -280,9 +275,12 @@ static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace) 
			hlist_add_before_rcu(&newp->list, &p->list);

			goto out;

		}

		last = p;

	}

		hlist_add_after_rcu(&p->list, &newp->list);

	}

	if (last)

		hlist_add_after_rcu(&last->list, &newp->list);

	else

		hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);

out:

	if (!ret)

		ip6addrlbl_table.seq++;