@@ -1475,6 +1475,18 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev,
return -EPERM;
}
+ /* CAN network devices hold device specific filter lists in
+ * netdev_priv() where dev->ml_priv sets a reference to.
+ * As bonding assumes to have some ethernet-like device it doesn't
+ * take care about these CAN specific filter lists today.
+ * So we deny the enslaving of CAN interfaces here.
+ */
+ if (slave_dev->type == ARPHRD_CAN) {
+ NL_SET_ERR_MSG(extack, "CAN devices can not be enslaved");
+ slave_err(bond_dev, slave_dev, "no bonding on CAN devices\n");
+ return -EINVAL;
+ }
+
/* set bonding device ether type by slave - bonding netdevices are
* created with ether_setup, so when the slave type is not ARPHRD_ETHER
* there is a need to override some of the type dependent attribs/funcs.
Since commit 8df9ffb888c ("can: make use of preallocated can_ml_priv for per device struct can_dev_rcv_lists") the device specific CAN receive filter lists are stored in netdev_priv() and dev->ml_priv points to these filters. In the bug report Syzkaller enslaved a vxcan1 CAN device and accessed the bonding device with a PF_CAN socket which lead to a crash due to an access of an unhandled bond_dev->ml_priv pointer. Deny to enslave CAN devices by the bonding driver as the resulting bond_dev pretends to be a CAN device by copying dev->type without really being one. Reported-by: syzbot+c3ea30e1e2485573f953@syzkaller.appspotmail.com Fixes: 8df9ffb888c ("can: make use of preallocated can_ml_priv for per device struct can_dev_rcv_lists") Cc: linux-stable <stable@vger.kernel.org> # >= v5.4 Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> --- drivers/net/bonding/bond_main.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)