linux/drivers/net/bonding
Taehee Yoo ae9b15fbe6 net: fix stack overflow when LRO is disabled for virtual interfaces
When the virtual interface's feature is updated, it synchronizes the
updated feature for its own lower interface.
This propagation logic should be worked as the iteration, not recursively.
But it works recursively due to the netdev notification unexpectedly.
This problem occurs when it disables LRO only for the team and bonding
interface type.

       team0
         |
  +------+------+-----+-----+
  |      |      |     |     |
team1  team2  team3  ...  team200

If team0's LRO feature is updated, it generates the NETDEV_FEAT_CHANGE
event to its own lower interfaces(team1 ~ team200).
It is worked by netdev_sync_lower_features().
So, the NETDEV_FEAT_CHANGE notification logic of each lower interface
work iteratively.
But generated NETDEV_FEAT_CHANGE event is also sent to the upper
interface too.
upper interface(team0) generates the NETDEV_FEAT_CHANGE event for its own
lower interfaces again.
lower and upper interfaces receive this event and generate this
event again and again.
So, the stack overflow occurs.

But it is not the infinite loop issue.
Because the netdev_sync_lower_features() updates features before
generating the NETDEV_FEAT_CHANGE event.
Already synchronized lower interfaces skip notification logic.
So, it is just the problem that iteration logic is changed to the
recursive unexpectedly due to the notification mechanism.

Reproducer:

ip link add team0 type team
ethtool -K team0 lro on
for i in {1..200}
do
        ip link add team$i master team0 type team
        ethtool -K team$i lro on
done

ethtool -K team0 lro off

In order to fix it, the notifier_ctx member of bonding/team is introduced.

Reported-by: syzbot+60748c96cf5c6df8e581@syzkaller.appspotmail.com
Fixes: fd867d51f8 ("net/core: generic support for disabling netdev features down stack")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20230517143010.3596250-1-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-05-19 22:46:37 -07:00
..
bond_3ad.c drivers/net/bonding/bond_3ad: return when there's no aggregator 2023-01-03 09:17:12 +00:00
bond_alb.c bonding: fix reference count leak in balance-alb mode 2022-08-11 08:51:05 -07:00
bond_debugfs.c bonding: fix error checking in bond_debug_reregister() 2023-02-03 19:22:20 -08:00
bond_main.c net: fix stack overflow when LRO is disabled for virtual interfaces 2023-05-19 22:46:37 -07:00
bond_netlink.c bonding: fix send_peer_notif overflow 2023-05-10 09:27:20 +01:00
bond_options.c bonding: fix send_peer_notif overflow 2023-05-10 09:27:20 +01:00
bond_procfs.c bonding: show NS IPv6 targets in proc master info 2022-05-31 10:50:02 +02:00
bond_sysfs_slave.c net: bonding: Convert to use sysfs_emit()/sysfs_emit_at() APIs 2022-09-30 12:29:45 +01:00
bond_sysfs.c driver core: class: mark the struct class for sysfs callbacks as constant 2023-03-29 07:54:58 +02:00
bonding_priv.h drivers: Remove inclusion of vermagic header 2020-04-21 13:27:37 -07:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00