ipv6: initialize route null entry in addrconf_init()

Andrey reported a crash on init_net.ipv6.ip6_null_entry->rt6i_idev
since it is always NULL.

This is clearly wrong, we have code to initialize it to loopback_dev,
unfortunately the order is still not correct.

loopback_dev is registered very early during boot, we lose a chance
to re-initialize it in notifier. addrconf_init() is called after
ip6_route_init(), which means we have no chance to correct it.

Fix it by moving this initialization explicitly after
ipv6_add_dev(init_net.loopback_dev) in addrconf_init().

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 9dc2c182a263218ad63ceb326893b4c86c21ff95..f5e625f5336799d88c15df94d8776680dddcfe19 100644 (file)
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -84,6 +84,7 @@ struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
                               int ifindex, struct flowi6 *fl6, int flags);
 
+void ip6_route_init_special_entries(void);
 int ip6_route_init(void);
 void ip6_route_cleanup(void);
 

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index a2a370b7124980f43101102235b0e9f88d8a6e67..77a4bd526d6e421cb8d384e2d9febd55700aec8e 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -6573,6 +6573,8 @@ int __init addrconf_init(void)
                goto errlo;
        }
 
+       ip6_route_init_special_entries();
+
        for (i = 0; i < IN6_ADDR_HSIZE; i++)
                INIT_HLIST_HEAD(&inet6_addr_lst[i]);
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index a1bf426c959ba13d07798d9c66394cf8e6e5f2a4..2f1136627dcbd7135b887a0b4b077fb8e854811d 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4027,6 +4027,21 @@ static struct notifier_block ip6_route_dev_notifier = {
        .priority = 0,
 };
 
+void __init ip6_route_init_special_entries(void)
+{
+       /* Registering of the loopback is done before this portion of code,
+        * the loopback reference in rt6_info will not be taken, do it
+        * manually for init_net */
+       init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev;
+       init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
+  #ifdef CONFIG_IPV6_MULTIPLE_TABLES
+       init_net.ipv6.ip6_prohibit_entry->dst.dev = init_net.loopback_dev;
+       init_net.ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
+       init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev;
+       init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
+  #endif
+}
+
 int __init ip6_route_init(void)
 {
        int ret;
@@ -4053,17 +4068,6 @@ int __init ip6_route_init(void)
 
        ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops_template.kmem_cachep;
 
-       /* Registering of the loopback is done before this portion of code,
-        * the loopback reference in rt6_info will not be taken, do it
-        * manually for init_net */
-       init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev;
-       init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
-  #ifdef CONFIG_IPV6_MULTIPLE_TABLES
-       init_net.ipv6.ip6_prohibit_entry->dst.dev = init_net.loopback_dev;
-       init_net.ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
-       init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev;
-       init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
-  #endif
        ret = fib6_init();
        if (ret)
                goto out_register_subsys;