bonding: fix race condition in bonding_store_slaves_active
Race between bonding_store_slaves_active() and slave manipulation
functions. The bond_for_each_slave use in bonding_store_slaves_active()
is not protected by any synchronization mechanism.
NULL pointer dereference is easy to reach.
Fixed by acquiring the bond->lock for the slave walk.
v2: Make description text < 75 columns
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 3327a07..1877ed7 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1568,6 +1568,7 @@
goto out;
}
+ read_lock(&bond->lock);
bond_for_each_slave(bond, slave, i) {
if (!bond_is_active_slave(slave)) {
if (new_value)
@@ -1576,6 +1577,7 @@
slave->inactive = 1;
}
}
+ read_unlock(&bond->lock);
out:
return ret;
}