From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pau Koning Subject: [PATCH] batman-adv: Fix NULL pointer dereference in DAT hash collision avoidance Date: Tue, 12 Feb 2013 11:18:45 +0100 Message-ID: <1360664325-7323-1-git-send-email-paukoning@gmail.com> Cc: netdev@vger.kernel.org, Pau Koning To: davem@davemloft.net Return-path: Received: from mail-ea0-f175.google.com ([209.85.215.175]:48487 "EHLO mail-ea0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758144Ab3BLKS6 (ORCPT ); Tue, 12 Feb 2013 05:18:58 -0500 Received: by mail-ea0-f175.google.com with SMTP id d1so75837eab.34 for ; Tue, 12 Feb 2013 02:18:56 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: 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 --- net/batman-adv/distributed-arp-table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c index 0e05ad4..d54188a 100644 --- a/net/batman-adv/distributed-arp-table.c +++ b/net/batman-adv/distributed-arp-table.c @@ -439,7 +439,7 @@ 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