| Message ID | 1365538644-1502-1-git-send-email-nikolay@redhat.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 + */ + if (!slave) + return NOTIFY_DONE; + bond_dev = slave->bond->dev; + bond = slave->bond; + switch (event) { case NETDEV_UNREGISTER: if (bond->setup_by_slave)
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> --- drivers/net/bonding/bond_main.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)