From 9f1fb6914d66e282c2b1f51aa2d4a231c84df84d Mon Sep 17 00:00:00 2001 From: Pau Koning Date: Fri, 15 Feb 2013 00:18:56 +0100 Subject: [PATCH 4/4] batman-adv: Fix NULL pointer dereference in DAT hash collision avoidance An entry in DAT with the hashed position of 0 can cause a NULL pointer dereference when the first entry is checked by batadv_choose_next_candidate. This first candidate automatically has the max value of 0 and the max_orig_node of NULL. Not checking max_orig_node for NULL in batadv_is_orig_node_eligible will lead to a NULL pointer dereference when checking for the lowest address. This problem was added in 785ea1144182c341b8b85b0f8180291839d176a8 ("batman-adv: Distributed ARP Table - create DHT helper functions"). Signed-off-by: Pau Koning Signed-off-by: David S. Miller Signed-off-by: Marek Lindner --- distributed-arp-table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/distributed-arp-table.c b/distributed-arp-table.c index ea0bd31..761a590 100644 --- a/distributed-arp-table.c +++ b/distributed-arp-table.c @@ -440,7 +440,7 @@ static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res, /* this is an hash collision with the temporary selected node. Choose * the one with the lowest address */ - if ((tmp_max == max) && + if ((tmp_max == max) && max_orig_node && (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)) goto out; -- 1.7.10.4