ipv6: fix null pointer dereference in __ip6addrlbl_add
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 <michele@acksyn.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Tested-by: Michele Baldessari <michele@acksyn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index f083a58..b30ad37 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -251,38 +251,36 @@
/* 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++;