From: Sergei Shtylyov <sergei.shtylyov@cogentembedded•com>
To: Nikolay Aleksandrov <nikolay@redhat•com>
Cc: netdev@vger•kernel.org, andy@greyhouse•net, fubar@us•ibm.com,
davem@davemloft•net
Subject: Re: [PATCH 1/2] bonding: fix netdev event NULL pointer dereference
Date: Thu, 11 Apr 2013 17:40:01 +0400 [thread overview]
Message-ID: <5166BD31.5020404@cogentembedded.com> (raw)
In-Reply-To: <1365538644-1502-1-git-send-email-nikolay@redhat.com>
Hello.
On 10-04-2013 0:17, Nikolay Aleksandrov wrote:
> In commit 471cb5a33dcbd7c529684a2ac7ba4451414ee4a7 ("bonding: remove
> usage of dev->master") a bug was introduced which causes a NULL pointer
> dereference. If a bond device is in mode 6 (ALB) and a slave is added
> it will dereference a NULL pointer in bond_slave_netdev_event().
> This is because in bond_enslave we have bond_alb_init_slave() which
> changes the MAC address of the slave and causes a NETDEV_CHANGEADDR.
> Then we have in bond_slave_netdev_event():
> struct slave *slave = bond_slave_get_rtnl(slave_dev);
> struct bonding *bond = slave->bond;
> bond_slave_get_rtnl() dereferences slave_dev->rx_handler_data which at
> that time is NULL since netdev_rx_handler_register() is called later.
> This is fixed by checking if slave is NULL before dereferencing it.
> Signed-off-by: Nikolay Aleksandrov <nikolay@redhat•com>
[...]
Minor formatting nit.
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 171b10f..9995ddc 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -3168,11 +3168,21 @@ static int bond_slave_netdev_event(unsigned long event,
> struct net_device *slave_dev)
> {
> struct slave *slave = bond_slave_get_rtnl(slave_dev);
> - struct bonding *bond = slave->bond;
> - struct net_device *bond_dev = slave->bond->dev;
> + struct bonding *bond;
> + struct net_device *bond_dev;
> u32 old_speed;
> u8 old_duplex;
>
> + /*
> + * A netdev event can be generated while enslaving a device
> + * before netdev_rx_handler_register is called in which case
> + * slave will be NULL
> + */
The preferred multi-line comment style in the networking code is:
/* bla
* bla
*/
WBR, Sergei
next prev parent reply other threads:[~2013-04-11 13:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-09 20:17 [PATCH 1/2] bonding: fix netdev event NULL pointer dereference Nikolay Aleksandrov
2013-04-09 20:17 ` [PATCH 2/2] bonding: IFF_BONDING is not stripped on enslave failure Nikolay Aleksandrov
2013-04-11 13:40 ` Sergei Shtylyov [this message]
2013-04-11 13:45 ` [PATCHv2 1/2] bonding: fix netdev event NULL pointer dereference Nikolay Aleksandrov
2013-04-11 17:28 ` David Miller
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