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bonding: fix netdev event NULL pointer dereference

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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.

v2: Comment style changed.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
nikolay@redhat.com 2013-04-11 09:18:55 +00:00 committed by David S. Miller
parent d66954a066
commit 6101391d4a
1 changed files with 11 additions and 2 deletions
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13
drivers/net/bonding/bond_main.c
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@ -3168,11 +3168,20 @@ 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
*/
if (!slave)
return NOTIFY_DONE;
bond_dev = slave->bond->dev;
bond = slave->bond;
switch (event) {
case NETDEV_UNREGISTER:
if (bond->setup_by_slave)