[PATCH] Fix divide zero crash when xmit with no enabled port

hash calculation in lb_transmit() cause divide zero crash when
xmit on teaming loadbalance mode with no team member port is enabled
(this situation means team->en_port_count = 0). Add check
team->en_port_count is not 0.

---
 drivers/net/team/team_mode_loadbalance.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/team/team_mode_loadbalance.c b/drivers/net/team/team_mode_loadbalance.c
index 86e8183..7b878d5 100644
--- a/drivers/net/team/team_mode_loadbalance.c
+++ b/drivers/net/team/team_mode_loadbalance.c

@@ -38,6 +38,8 @@ static bool lb_transmit(struct team *team, struct sk_buff *skb)
 	if (unlikely(!fp))
 		goto drop;
 	hash = SK_RUN_FILTER(fp, skb);
+	if (team->en_port_count < 1)
+		goto drop;
 	port_index = hash % team->en_port_count;
 	port = team_get_port_by_index_rcu(team, port_index);
 	if (unlikely(!port))

-- 
1.7.10.4

Sat, Jul 21, 2012 at 10:30:35PM CEST, ishikawa@hanzubon.jp wrote:

hash calculation in lb_transmit() cause divide zero crash when
xmit on teaming loadbalance mode with no team member port is enabled
(this situation means team->en_port_count = 0). Add check
team->en_port_count is not 0.

What kernel are you see the issue one?
I believe this is fixed in net-next already:

commit 122bb046bcfb8f3d2d94d9f7f6b74da187a740f2
Author: Jiri Pirko [off-list ref]
Date:   Tue Jun 26 06:52:45 2012 +0000

    team: fix team_adjust_ops with regard to enabled ports
    
    team_adjust_ops should check for enabled ports, not all ports.
    This may lead to division by zero. This patch fixes this.
    
    Signed-off-by: Jiri Pirko [off-list ref]
    Signed-off-by: David S. Miller [off-list ref]

quoted

quoted

quoted

quoted

In [off-list ref] 
Jiri Pirko [off-list ref] wrote:

Sat, Jul 21, 2012 at 10:30:35PM CEST, ishikawa@hanzubon.jp wrote:

quoted

hash calculation in lb_transmit() cause divide zero crash when
xmit on teaming loadbalance mode with no team member port is enabled
(this situation means team->en_port_count = 0). Add check
team->en_port_count is not 0.

What kernel are you see the issue one?
I believe this is fixed in net-next already:

 Oops, sorry. I've see it on linus's linux-2.6 git tree only.

-- 
ISHIKAWA Mutsumi
 [off-list ref], [off-list ref], [off-list ref]