From 3c9ef511b9fa128a4c62e3aa0aac4c6b190f0d55 Mon Sep 17 00:00:00 2001
From: Di Zhu <zhudi21@huawei.com>
Date: Tue, 22 Jun 2021 11:09:29 +0800
Subject: [PATCH] bonding: avoid adding slave device with IFF_MASTER flag
The following steps will definitely cause the kernel to crash:
ip link add vrf1 type vrf table 1
modprobe bonding.ko max_bonds=1
echo "+vrf1" >/sys/class/net/bond0/bonding/slaves
rmmod bonding
The root cause is that: When the VRF is added to the slave device,
it will fail, and some cleaning work will be done. because VRF device
has IFF_MASTER flag, cleanup process will not clear the IFF_BONDING flag.
Then, when we unload the bonding module, unregister_netdevice_notifier()
will treat the VRF device as a bond master device and treat netdev_priv()
as struct bonding{} which actually is struct net_vrf{}.
By analyzing the processing logic of bond_enslave(), it seems that
it is not allowed to add the slave device with the IFF_MASTER flag, so
we need to add a code check for this situation.
Signed-off-by: Di Zhu <zhudi21@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/bonding/bond_main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index c5a646d06102a..16840c9bc00d3 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1601,6 +1601,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
int link_reporting;
int res = 0, i;
+ if (slave_dev->flags & IFF_MASTER) {
+ netdev_err(bond_dev,
+ "Error: Device with IFF_MASTER cannot be enslaved\n");
+ return -EPERM;
+ }
+
if (!bond->params.use_carrier &&
slave_dev->ethtool_ops->get_link == NULL &&
slave_ops->ndo_do_ioctl == NULL) {
--
2.30.2