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author | Jamie Iles <jamie@nuviainc.com> | 2020-11-20 15:28:27 +0100 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-21 22:07:00 +0100 |
commit | b9ad3e9f5a7a760ab068e33e1f18d240ba32ce92 (patch) | |
tree | 190458a6bdd274cdfad65071580a7f3889c040cf /drivers/net/bonding/bond_main.c | |
parent | Merge branch 's390-qeth-fixes-2020-11-20' (diff) | |
download | linux-b9ad3e9f5a7a760ab068e33e1f18d240ba32ce92.tar.xz linux-b9ad3e9f5a7a760ab068e33e1f18d240ba32ce92.zip |
bonding: wait for sysfs kobject destruction before freeing struct slave
syzkaller found that with CONFIG_DEBUG_KOBJECT_RELEASE=y, releasing a
struct slave device could result in the following splat:
kobject: 'bonding_slave' (00000000cecdd4fe): kobject_release, parent 0000000074ceb2b2 (delayed 1000)
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: workqueue_select_cpu_near kernel/workqueue.c:1549 [inline]
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x98 kernel/workqueue.c:1600
WARNING: CPU: 1 PID: 842 at lib/debugobjects.c:485 debug_print_object+0x180/0x240 lib/debugobjects.c:485
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 842 Comm: kworker/u4:4 Tainted: G S 5.9.0-rc8+ #96
Hardware name: linux,dummy-virt (DT)
Workqueue: netns cleanup_net
Call trace:
dump_backtrace+0x0/0x4d8 include/linux/bitmap.h:239
show_stack+0x34/0x48 arch/arm64/kernel/traps.c:142
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x174/0x1f8 lib/dump_stack.c:118
panic+0x360/0x7a0 kernel/panic.c:231
__warn+0x244/0x2ec kernel/panic.c:600
report_bug+0x240/0x398 lib/bug.c:198
bug_handler+0x50/0xc0 arch/arm64/kernel/traps.c:974
call_break_hook+0x160/0x1d8 arch/arm64/kernel/debug-monitors.c:322
brk_handler+0x30/0xc0 arch/arm64/kernel/debug-monitors.c:329
do_debug_exception+0x184/0x340 arch/arm64/mm/fault.c:864
el1_dbg+0x48/0xb0 arch/arm64/kernel/entry-common.c:65
el1_sync_handler+0x170/0x1c8 arch/arm64/kernel/entry-common.c:93
el1_sync+0x80/0x100 arch/arm64/kernel/entry.S:594
debug_print_object+0x180/0x240 lib/debugobjects.c:485
__debug_check_no_obj_freed lib/debugobjects.c:967 [inline]
debug_check_no_obj_freed+0x200/0x430 lib/debugobjects.c:998
slab_free_hook mm/slub.c:1536 [inline]
slab_free_freelist_hook+0x190/0x210 mm/slub.c:1577
slab_free mm/slub.c:3138 [inline]
kfree+0x13c/0x460 mm/slub.c:4119
bond_free_slave+0x8c/0xf8 drivers/net/bonding/bond_main.c:1492
__bond_release_one+0xe0c/0xec8 drivers/net/bonding/bond_main.c:2190
bond_slave_netdev_event drivers/net/bonding/bond_main.c:3309 [inline]
bond_netdev_event+0x8f0/0xa70 drivers/net/bonding/bond_main.c:3420
notifier_call_chain+0xf0/0x200 kernel/notifier.c:83
__raw_notifier_call_chain kernel/notifier.c:361 [inline]
raw_notifier_call_chain+0x44/0x58 kernel/notifier.c:368
call_netdevice_notifiers_info+0xbc/0x150 net/core/dev.c:2033
call_netdevice_notifiers_extack net/core/dev.c:2045 [inline]
call_netdevice_notifiers net/core/dev.c:2059 [inline]
rollback_registered_many+0x6a4/0xec0 net/core/dev.c:9347
unregister_netdevice_many.part.0+0x2c/0x1c0 net/core/dev.c:10509
unregister_netdevice_many net/core/dev.c:10508 [inline]
default_device_exit_batch+0x294/0x338 net/core/dev.c:10992
ops_exit_list.isra.0+0xec/0x150 net/core/net_namespace.c:189
cleanup_net+0x44c/0x888 net/core/net_namespace.c:603
process_one_work+0x96c/0x18c0 kernel/workqueue.c:2269
worker_thread+0x3f0/0xc30 kernel/workqueue.c:2415
kthread+0x390/0x498 kernel/kthread.c:292
ret_from_fork+0x10/0x18 arch/arm64/kernel/entry.S:925
This is a potential use-after-free if the sysfs nodes are being accessed
whilst removing the struct slave, so wait for the object destruction to
complete before freeing the struct slave itself.
Fixes: 07699f9a7c8d ("bonding: add sysfs /slave dir for bond slave devices.")
Fixes: a068aab42258 ("bonding: Fix reference count leak in bond_sysfs_slave_add.")
Cc: Qiushi Wu <wu000273@umn.edu>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20201120142827.879226-1-jamie@nuviainc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/bonding/bond_main.c')
-rw-r--r-- | drivers/net/bonding/bond_main.c | 61 |
1 files changed, 43 insertions, 18 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 84ecbc6fa0ff..47afc5938c26 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1460,7 +1460,39 @@ static void bond_upper_dev_unlink(struct bonding *bond, struct slave *slave) slave->dev->flags &= ~IFF_SLAVE; } -static struct slave *bond_alloc_slave(struct bonding *bond) +static void slave_kobj_release(struct kobject *kobj) +{ + struct slave *slave = to_slave(kobj); + struct bonding *bond = bond_get_bond_by_slave(slave); + + cancel_delayed_work_sync(&slave->notify_work); + if (BOND_MODE(bond) == BOND_MODE_8023AD) + kfree(SLAVE_AD_INFO(slave)); + + kfree(slave); +} + +static struct kobj_type slave_ktype = { + .release = slave_kobj_release, +#ifdef CONFIG_SYSFS + .sysfs_ops = &slave_sysfs_ops, +#endif +}; + +static int bond_kobj_init(struct slave *slave) +{ + int err; + + err = kobject_init_and_add(&slave->kobj, &slave_ktype, + &(slave->dev->dev.kobj), "bonding_slave"); + if (err) + kobject_put(&slave->kobj); + + return err; +} + +static struct slave *bond_alloc_slave(struct bonding *bond, + struct net_device *slave_dev) { struct slave *slave = NULL; @@ -1468,11 +1500,17 @@ static struct slave *bond_alloc_slave(struct bonding *bond) if (!slave) return NULL; + slave->bond = bond; + slave->dev = slave_dev; + + if (bond_kobj_init(slave)) + return NULL; + if (BOND_MODE(bond) == BOND_MODE_8023AD) { SLAVE_AD_INFO(slave) = kzalloc(sizeof(struct ad_slave_info), GFP_KERNEL); if (!SLAVE_AD_INFO(slave)) { - kfree(slave); + kobject_put(&slave->kobj); return NULL; } } @@ -1481,17 +1519,6 @@ static struct slave *bond_alloc_slave(struct bonding *bond) return slave; } -static void bond_free_slave(struct slave *slave) -{ - struct bonding *bond = bond_get_bond_by_slave(slave); - - cancel_delayed_work_sync(&slave->notify_work); - if (BOND_MODE(bond) == BOND_MODE_8023AD) - kfree(SLAVE_AD_INFO(slave)); - - kfree(slave); -} - static void bond_fill_ifbond(struct bonding *bond, struct ifbond *info) { info->bond_mode = BOND_MODE(bond); @@ -1678,14 +1705,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, goto err_undo_flags; } - new_slave = bond_alloc_slave(bond); + new_slave = bond_alloc_slave(bond, slave_dev); if (!new_slave) { res = -ENOMEM; goto err_undo_flags; } - new_slave->bond = bond; - new_slave->dev = slave_dev; /* Set the new_slave's queue_id to be zero. Queue ID mapping * is set via sysfs or module option if desired. */ @@ -2007,7 +2032,7 @@ err_restore_mtu: dev_set_mtu(slave_dev, new_slave->original_mtu); err_free: - bond_free_slave(new_slave); + kobject_put(&new_slave->kobj); err_undo_flags: /* Enslave of first slave has failed and we need to fix master's mac */ @@ -2187,7 +2212,7 @@ static int __bond_release_one(struct net_device *bond_dev, if (!netif_is_bond_master(slave_dev)) slave_dev->priv_flags &= ~IFF_BONDING; - bond_free_slave(slave); + kobject_put(&slave->kobj); return 0; } |