patches/0004-batman-adv-Fix-NULL-pointer-dereference-in-DAT-hash-.patch

   1 From 9f1fb6914d66e282c2b1f51aa2d4a231c84df84d Mon Sep 17 00:00:00 2001
   2 From: Pau Koning <paukoning@gmail.com>
   3 Date: Fri, 15 Feb 2013 00:18:56 +0100
   4 Subject: [PATCH 4/4] batman-adv: Fix NULL pointer dereference in DAT hash
   5  collision avoidance
   6
   7 An entry in DAT with the hashed position of 0 can cause a NULL pointer
   8 dereference when the first entry is checked by batadv_choose_next_candidate.
   9 This first candidate automatically has the max value of 0 and the max_orig_node
  10 of NULL. Not checking max_orig_node for NULL in batadv_is_orig_node_eligible
  11 will lead to a NULL pointer dereference when checking for the lowest address.
  12
  13 This problem was added in 785ea1144182c341b8b85b0f8180291839d176a8
  14 ("batman-adv: Distributed ARP Table - create DHT helper functions").
  15
  16 Signed-off-by: Pau Koning <paukoning@gmail.com>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
  19 ---
  20  distributed-arp-table.c |    2 +-
  21  1 file changed, 1 insertion(+), 1 deletion(-)
  22
  23 diff --git a/distributed-arp-table.c b/distributed-arp-table.c
  24 index ea0bd31..761a590 100644
  25 --- a/distributed-arp-table.c
  26 +++ b/distributed-arp-table.c
  27 @@ -440,7 +440,7 @@ static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res,
  28         /* this is an hash collision with the temporary selected node. Choose
  29          * the one with the lowest address
  30          */
  31 -       if ((tmp_max == max) &&
  32 +       if ((tmp_max == max) && max_orig_node &&
  33             (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0))
  34                 goto out;
  35
  36 --
  37 1.7.10.4
  38