[PATCHv2 0/2] bonding: NULL pointer dereference and flag strip fixes

[PATCHv2 0/2] bonding: NULL pointer dereference and flag strip fixes

[Nikolay Aleksandrov]

 These 2 patches fix a NULL pointer dereference in the netdev event
 handling of the bond and flag that wasn't stripped on enslave failure.

v2: Fix comment style 

Nikolay Aleksandrov (2):
  bonding: fix netdev event NULL pointer dereference
  bonding: IFF_BONDING is not stripped on enslave failure

 drivers/net/bonding/bond_main.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

-- 
1.8.1.4

[PATCHv2 1/2] bonding: fix netdev event NULL pointer dereference

[Nikolay Aleksandrov]

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>
---
 drivers/net/bonding/bond_main.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 171b10f..15c675c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -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)
-- 
1.8.1.4

[PATCHv2 2/2] bonding: IFF_BONDING is not stripped on enslave failure

[Nikolay Aleksandrov]

While enslaving a new device and after IFF_BONDING flag is set, in case
of failure it is not stripped from the device's priv_flags while
cleaning up, which could lead to other problems.
Cleaning at err_close because the flag is set after dev_open().

v2: no change

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
---
 drivers/net/bonding/bond_main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 15c675c..232b129 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1906,6 +1906,7 @@ err_detach:
 	write_unlock_bh(&bond->lock);
 
 err_close:
+	slave_dev->priv_flags &= ~IFF_BONDING;
 	dev_close(slave_dev);
 
 err_unset_master:
-- 
1.8.1.4

Re: [PATCHv2 0/2] bonding: NULL pointer dereference and flag strip fixes

[David Miller]

From: Nikolay Aleksandrov <nikolay@redhat.com>
Date: Thu, 11 Apr 2013 21:18:54 +0200

>  These 2 patches fix a NULL pointer dereference in the netdev event
>  handling of the bond and flag that wasn't stripped on enslave failure.
> 
> v2: Fix comment style 
> 
> Nikolay Aleksandrov (2):
>   bonding: fix netdev event NULL pointer dereference
>   bonding: IFF_BONDING is not stripped on enslave failure

Both applied, thanks.