[PATCH] bonding: Fix use after free in unregister path

Jay Vosburgh
2007-06-19T18:12:33Z

The following patch (based on a patch from Stephen Hemminger
<shemminger@linux-foundation.org>) removes use after free conditions in
the unregister path for the bonding master. Without this patch, an
operation of the form "echo -bond0 > /sys/class/net/bonding_masters"
would trigger a NULL pointer dereference in sysfs. I was not able to
induce the failure with the non-sysfs code path, but for consistency I
updated that code as well.

I also did some testing of the bonding /proc file being open
while the bond is being deleted, and didn't see any problems there.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 223517d..6287ffb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4345,8 +4345,8 @@ static void bond_free_all(void)
bond_mc_list_destroy(bond);
/* Release the bonded slaves */
bond_release_all(bond_dev);
- unregister_netdevice(bond_dev);
bond_deinit(bond_dev);
+ unregister_netdevice(bond_dev);
}

#ifdef CONFIG_PROC_FS
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index a122baa..60cccf2 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -164,9 +164,9 @@ static ssize_t bonding_store_bonds(struct class *cls, const char *buffer, size_t
printk(KERN_INFO DRV_NAME
": %s is being deleted...\n",
bond->dev->name);
- unregister_netdevice(bond->dev);
bond_deinit(bond->dev);
bond_destroy_sysfs_entry(bond);
+ unregister_netdevice(bond->dev);
rtnl_unlock();
goto out;
}