diff mbox

batman-adv: Avoid nullptr derefence in batadv_v_neigh_is_sob

Message ID 1462526567-10019-1-git-send-email-sven@narfation.org (mailing list archive)
State Superseded, archived
Commit 036aa7b7181ee96ae6971eb31dd97b6ace7c0a80
Delegated to: Marek Lindner
Headers

Commit Message

Sven Eckelmann May 6, 2016, 9:22 a.m. UTC 
  batadv_neigh_ifinfo_get can return NULL when it cannot find (even when only
temporarily) anymore the neigh_ifinfo in the list neigh->ifinfo_list. This
has to be checked to avoid kernel Oopses when the ifinfo is dereferenced.

This a situation which isn't expected but is already handled by functions
like batadv_v_neigh_cmp. The same kind of warning is therefore used before
the function returns without dereferencing the pointers.

Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor comparison API calls")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/bat_v.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Sven Eckelmann May 6, 2016, 9:31 a.m. UTC | #1 
On Friday 06 May 2016 11:22:47 Sven Eckelmann wrote:
> batadv_neigh_ifinfo_get can return NULL when it cannot find (even when only
> temporarily) anymore the neigh_ifinfo in the list neigh->ifinfo_list. This
> has to be checked to avoid kernel Oopses when the ifinfo is dereferenced.
> 
> This a situation which isn't expected but is already handled by functions
> like batadv_v_neigh_cmp. The same kind of warning is therefore used before
> the function returns without dereferencing the pointers.
> 
> Fixes: b05bbab5e1fc ("batman-adv: B.A.T.M.A.N. V - implement neighbor
> comparison API calls") Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---

Looks like the reference counting is also completely broken in these functions 
:(

Kind regards,
	Sven
diff mbox

Patch

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index 927d405..f271ae8 100644
--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -286,6 +286,9 @@  static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
 	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
 
+	if (WARN_ON(!ifinfo1 || !ifinfo2))
+		return false;
+
 	threshold = ifinfo1->bat_v.throughput / 4;
 	threshold = ifinfo1->bat_v.throughput - threshold;