releases/3.4.5/ipv6-move-ipv6-proc-file-registration-to-end-of-init-order.patch

   1 From 5413590847cdbd348b79c5d642fe782c0b9bcdc4 Mon Sep 17 00:00:00 2001
   2 From: Thomas Graf <tgraf@suug.ch>
   3 Date: Mon, 18 Jun 2012 12:08:33 +0000
   4 Subject: ipv6: Move ipv6 proc file registration to end of init order
   5
   6
   7 From: Thomas Graf <tgraf@suug.ch>
   8
   9 [ Upstream commit d189634ecab947c10f6f832258b103d0bbfe73cc ]
  10
  11 /proc/net/ipv6_route reflects the contents of fib_table_hash. The proc
  12 handler is installed in ip6_route_net_init() whereas fib_table_hash is
  13 allocated in fib6_net_init() _after_ the proc handler has been installed.
  14
  15 This opens up a short time frame to access fib_table_hash with its pants
  16 down.
  17
  18 Move the registration of the proc files to a later point in the init
  19 order to avoid the race.
  20
  21 Tested :-)
  22
  23 Signed-off-by: Thomas Graf <tgraf@suug.ch>
  24 Signed-off-by: David S. Miller <davem@davemloft.net>
  25 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  26 ---
  27  net/ipv6/route.c |   41 +++++++++++++++++++++++++++++++----------
  28  1 file changed, 31 insertions(+), 10 deletions(-)
  29
  30 --- a/net/ipv6/route.c
  31 +++ b/net/ipv6/route.c
  32 @@ -2953,10 +2953,6 @@ static int __net_init ip6_route_net_init
  33         net->ipv6.sysctl.ip6_rt_mtu_expires = 10*60*HZ;
  34         net->ipv6.sysctl.ip6_rt_min_advmss = IPV6_MIN_MTU - 20 - 40;
  35
  36 -#ifdef CONFIG_PROC_FS
  37 -       proc_net_fops_create(net, "ipv6_route", 0, &ipv6_route_proc_fops);
  38 -       proc_net_fops_create(net, "rt6_stats", S_IRUGO, &rt6_stats_seq_fops);
  39 -#endif
  40         net->ipv6.ip6_rt_gc_expire = 30*HZ;
  41
  42         ret = 0;
  43 @@ -2977,10 +2973,6 @@ out_ip6_dst_ops:
  44
  45  static void __net_exit ip6_route_net_exit(struct net *net)
  46  {
  47 -#ifdef CONFIG_PROC_FS
  48 -       proc_net_remove(net, "ipv6_route");
  49 -       proc_net_remove(net, "rt6_stats");
  50 -#endif
  51         kfree(net->ipv6.ip6_null_entry);
  52  #ifdef CONFIG_IPV6_MULTIPLE_TABLES
  53         kfree(net->ipv6.ip6_prohibit_entry);
  54 @@ -2989,11 +2981,33 @@ static void __net_exit ip6_route_net_exi
  55         dst_entries_destroy(&net->ipv6.ip6_dst_ops);
  56  }
  57
  58 +static int __net_init ip6_route_net_init_late(struct net *net)
  59 +{
  60 +#ifdef CONFIG_PROC_FS
  61 +       proc_net_fops_create(net, "ipv6_route", 0, &ipv6_route_proc_fops);
  62 +       proc_net_fops_create(net, "rt6_stats", S_IRUGO, &rt6_stats_seq_fops);
  63 +#endif
  64 +       return 0;
  65 +}
  66 +
  67 +static void __net_exit ip6_route_net_exit_late(struct net *net)
  68 +{
  69 +#ifdef CONFIG_PROC_FS
  70 +       proc_net_remove(net, "ipv6_route");
  71 +       proc_net_remove(net, "rt6_stats");
  72 +#endif
  73 +}
  74 +
  75  static struct pernet_operations ip6_route_net_ops = {
  76         .init = ip6_route_net_init,
  77         .exit = ip6_route_net_exit,
  78  };
  79
  80 +static struct pernet_operations ip6_route_net_late_ops = {
  81 +       .init = ip6_route_net_init_late,
  82 +       .exit = ip6_route_net_exit_late,
  83 +};
  84 +
  85  static struct notifier_block ip6_route_dev_notifier = {
  86         .notifier_call = ip6_route_dev_notify,
  87         .priority = 0,
  88 @@ -3043,19 +3057,25 @@ int __init ip6_route_init(void)
  89         if (ret)
  90                 goto xfrm6_init;
  91
  92 +       ret = register_pernet_subsys(&ip6_route_net_late_ops);
  93 +       if (ret)
  94 +               goto fib6_rules_init;
  95 +
  96         ret = -ENOBUFS;
  97         if (__rtnl_register(PF_INET6, RTM_NEWROUTE, inet6_rtm_newroute, NULL, NULL) ||
  98             __rtnl_register(PF_INET6, RTM_DELROUTE, inet6_rtm_delroute, NULL, NULL) ||
  99             __rtnl_register(PF_INET6, RTM_GETROUTE, inet6_rtm_getroute, NULL, NULL))
 100 -               goto fib6_rules_init;
 101 +               goto out_register_late_subsys;
 102
 103         ret = register_netdevice_notifier(&ip6_route_dev_notifier);
 104         if (ret)
 105 -               goto fib6_rules_init;
 106 +               goto out_register_late_subsys;
 107
 108  out:
 109         return ret;
 110
 111 +out_register_late_subsys:
 112 +       unregister_pernet_subsys(&ip6_route_net_late_ops);
 113  fib6_rules_init:
 114         fib6_rules_cleanup();
 115  xfrm6_init:
 116 @@ -3074,6 +3094,7 @@ out_kmem_cache:
 117  void ip6_route_cleanup(void)
 118  {
 119         unregister_netdevice_notifier(&ip6_route_dev_notifier);
 120 +       unregister_pernet_subsys(&ip6_route_net_late_ops);
 121         fib6_rules_cleanup();
 122         xfrm6_fini();
 123         fib6_gc_cleanup();