From ef1f8bcdc2febd53978905b5b0a5201104cce653 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Tue, 3 Sep 2013 02:13:31 +0200 Subject: [PATCH] ipv6: fix null pointer dereference in __ip6addrlbl_add [ Upstream commit 639739b5e609a5074839bb22fc061b37baa06269 ] Commit b67bfe0d42cac56c512dd5da4b1b347a23f4b70a ("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: Michele Baldessari Cc: Hideaki YOSHIFUJI Cc: Sasha Levin Signed-off-by: Hannes Frederic Sowa Tested-by: Michele Baldessari Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/addrlabel.c | 48 +++++++++++++++++++++----------------------- 1 file changed, 23 insertions(+), 25 deletions(-) diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c index f083a583a05c..b30ad3741b46 100644 --- a/net/ipv6/addrlabel.c +++ b/net/ipv6/addrlabel.c @@ -251,38 +251,36 @@ 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) { - if (p->prefixlen == newp->prefixlen && - net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) && - p->ifindex == newp->ifindex && - ipv6_addr_equal(&p->prefix, &newp->prefix)) { - if (!replace) { - ret = -EEXIST; - goto out; - } - hlist_replace_rcu(&p->list, &newp->list); - ip6addrlbl_put(p); - goto out; - } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) || - (p->prefixlen < newp->prefixlen)) { - hlist_add_before_rcu(&newp->list, &p->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 && + ipv6_addr_equal(&p->prefix, &newp->prefix)) { + if (!replace) { + ret = -EEXIST; goto out; } + hlist_replace_rcu(&p->list, &newp->list); + ip6addrlbl_put(p); + goto out; + } else if ((p->prefixlen == newp->prefixlen && !p->ifindex) || + (p->prefixlen < newp->prefixlen)) { + hlist_add_before_rcu(&newp->list, &p->list); + goto out; } - hlist_add_after_rcu(&p->list, &newp->list); + last = p; } + 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++; -- 2.34.1