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

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

[ISHIKAWA Mutsumi]

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

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

[Jiri Pirko]

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 <jpirko@redhat.com>
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 <jpirko@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>



>
>---
> 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
>

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

[ISHIKAWA Mutsumi]

>>>>> In <20120722135956.GA12129@minipsycho.orion> 
>>>>>	Jiri Pirko <jpirko@redhat.com> wrote:
>> 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:

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

-- 
ISHIKAWA Mutsumi
 <ishikawa@debian.org>, <ishikawa@hanzubon.jp>, <ishikawa@osdn.jp>