Commit 816cd5b8 authored by Pau Koning's avatar Pau Koning Committed by David S. Miller

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 785ea114
("batman-adv: Distributed ARP Table - create DHT helper functions").
Signed-off-by: default avatarPau Koning <paukoning@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8770e91a
...@@ -440,7 +440,7 @@ static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res, ...@@ -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 /* this is an hash collision with the temporary selected node. Choose
* the one with the lowest address * 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)) (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0))
goto out; goto out;
......
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