ethtool: do not perform operations on net devices being unregistered

stable inclusion
from stable-v5.10.87
commit 7c26da3be1e9843a15b5318f90db8a564479d2ac
bugzilla: 186049 https://gitee.com/openeuler/kernel/issues/I4QVYL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7c26da3be1e9843a15b5318f90db8a564479d2ac

--------------------------------

commit dde91ccfa2 upstream.

There is a short period between a net device starts to be unregistered
and when it is actually gone. In that time frame ethtool operations
could still be performed, which might end up in unwanted or undefined
behaviours[1].

Do not allow ethtool operations after a net device starts its
unregistration. This patch targets the netlink part as the ioctl one
isn't affected: the reference to the net device is taken and the
operation is executed within an rtnl lock section and the net device
won't be found after unregister.

[1] For example adding Tx queues after unregister ends up in NULL
    pointer exceptions and UaFs, such as:

      BUG: KASAN: use-after-free in kobject_get+0x14/0x90
      Read of size 1 at addr ffff88801961248c by task ethtool/755

      CPU: 0 PID: 755 Comm: ethtool Not tainted 5.15.0-rc6+ #778
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/014
      Call Trace:
       dump_stack_lvl+0x57/0x72
       print_address_description.constprop.0+0x1f/0x140
       kasan_report.cold+0x7f/0x11b
       kobject_get+0x14/0x90
       kobject_add_internal+0x3d1/0x450
       kobject_init_and_add+0xba/0xf0
       netdev_queue_update_kobjects+0xcf/0x200
       netif_set_real_num_tx_queues+0xb4/0x310
       veth_set_channels+0x1c3/0x550
       ethnl_set_channels+0x524/0x610

Fixes: 041b1c5d4a ("ethtool: helper functions for netlink interface")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20211203101318.435618-1-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: hongrongxuan <hongrongxuan@huawei.com>
This commit is contained in:
Antoine Tenart 2022-01-14 19:34:31 +08:00 committed by Jianping Liu
parent 7260b733ff
commit 278b9dcaf7
1 changed files with 3 additions and 0 deletions

View File

@ -246,6 +246,9 @@ struct ethnl_reply_data {
static inline int ethnl_ops_begin(struct net_device *dev)
{
if (dev && dev->reg_state == NETREG_UNREGISTERING)
return -ENODEV;
if (dev && dev->ethtool_ops->begin)
return dev->ethtool_ops->begin(dev);
else