Commits
Ido Schimmel committed 6d6f0383b69
netdevsim: Fix use-after-free during device dismantle
Commit da58f90f11f5 ("netdevsim: Add devlink-trap support") added
delayed work to netdevsim that periodically iterates over the registered
netdevsim ports and reports various packet traps via devlink.
While the delayed work takes the 'port_list_lock' mutex to protect
against concurrent addition / deletion of ports, during device creation
/ dismantle ports are added / deleted without this lock, which can
result in a use-after-free [1].
Fix this by making sure that the ports list is always modified under the
lock.
[1]
[ 59.205543] ==================================================================
[ 59.207748] BUG: KASAN: use-after-free in nsim_dev_trap_report_work+0xa67/0xad0
[ 59.210247] Read of size 8 at addr ffff8883cbdd3398 by task kworker/3:1/38
[ 59.212584]
[ 59.213148] CPU: 3 PID: 38 Comm: kworker/3:1 Not tainted 5.4.0-rc3-custom-16119-ge6abb5f0261e #2013
[ 59.215896] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20180724_192412-buildhw-07.phx2.fedoraproject.org-1.fc29 04/01/2014
[ 59.218384] Workqueue: events nsim_dev_trap_report_work
[ 59.219428] Call Trace:
[ 59.219924] dump_stack+0xa9/0x10e
[ 59.220623] print_address_description.constprop.4+0x21/0x340
[ 59.221976] ? vprintk_func+0x66/0x240
[ 59.222752] __kasan_report.cold.8+0x78/0x91
[ 59.223602] ? nsim_dev_trap_report_work+0xa67/0xad0
[ 59.224603] kasan_report+0xe/0x20
[ 59.225296] nsim_dev_trap_report_work+0xa67/0xad0
[ 59.226435] ? rcu_read_lock_sched_held+0xaf/0xe0
[ 59.227512] ? trace_event_raw_event_rcu_quiescent_state_report+0x360/0x360
[ 59.228851] process_one_work+0x98f/0x1760
[ 59.229684] ? pwq_dec_nr_in_flight+0x330/0x330
[ 59.230656] worker_thread+0x91/0xc40
[ 59.231587] ? process_one_work+0x1760/0x1760
[ 59.232451] kthread+0x34a/0x410
[ 59.233104] ? __kthread_queue_delayed_work+0x240/0x240
[ 59.234141] ret_from_fork+0x3a/0x50
[ 59.234982]
[ 59.235371] Allocated by task 187:
[ 59.236189] save_stack+0x19/0x80
[ 59.236853] __kasan_kmalloc.constprop.5+0xc1/0xd0
[ 59.237822] kmem_cache_alloc_trace+0x14c/0x380
[ 59.238769] __nsim_dev_port_add+0xaf/0x5c0
[ 59.239627] nsim_dev_probe+0x4fc/0x1140
[ 59.240550] really_probe+0x264/0xc00
[ 59.241418] driver_probe_device+0x208/0x2e0
[ 59.242255] __device_attach_driver+0x215/0x2d0
[ 59.243150] bus_for_each_drv+0x154/0x1d0
[ 59.243944] __device_attach+0x1ba/0x2b0
[ 59.244923] bus_probe_device+0x1dd/0x290
[ 59.245805] device_add+0xbac/0x1550
[ 59.246528] new_device_store+0x1f4/0x400
[ 59.247306] bus_attr_store+0x7b/0xa0
[ 59.248047] sysfs_kf_write+0x10f/0x170
[ 59.248941] kernfs_fop_write+0x283/0x430
[ 59.249843] __vfs_write+0x81/0x100
[ 59.250546] vfs_write+0x1ce/0x510
[ 59.251190] ksys_write+0x104/0x200
[ 59.251873] do_syscall_64+0xa4/0x4e0
[ 59.252642] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 59.253837]
[ 59.254203] Freed by task 187:
[ 59.254811] save_stack+0x19/0x80
[ 59.255463] __kasan_slab_free+0x125/0x170
[ 59.256265] kfree+0x100/0x440
[ 59.256870] nsim_dev_remove+0x98/0x100
[ 59.257651] nsim_bus_remove+0x16/0x20
[ 59.258382] device_release_driver_internal+0x20b/0x4d0
[ 59.259588] bus_remove_device+0x2e9/0x5a0
[ 59.260551] device_del+0x410/0xad0
[ 59.263777] device_unregister+0x26/0xc0
[ 59.264616] nsim_bus_dev_del+0x16/0x60
[ 59.265381] del_device_store+0x2d6/0x3c0
[ 59.266295] bus_attr_store+0x7b/0xa0
[ 59.267192] sysfs_kf_write+0x10f/0x170
[ 59.267960] kernfs_fop_write+0x283/0x430
[ 59.268800] __vfs_write+0x81/0x100
[ 59.269551] vfs_write+0x1ce/0x510
[ 59.270252] ksys_write+0x104/0x200
[ 59.270910] do_syscall_64+0xa4/0x4e0
[ 59.271680] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 59.272812]
[ 59.273211] The buggy address belongs to the object at ffff8883cbdd3200
[ 59.273211] which belongs to the cache kmalloc-512 of size 512
[ 59.275838] The buggy address is located 408 bytes inside of
[ 59.275838] 512-byte region [ffff8883cbdd3200, ffff8883cbdd3400)
[ 59.278151] The buggy address belongs to the page:
[ 59.279215] page:ffffea000f2f7400 refcount:1 mapcount:0 mapping:ffff8883ecc0ce00 index:0x0 compound_mapcount: 0
[ 59.281449] flags: 0x200000000010200(slab|head)
[ 59.282356] raw: 0200000000010200 ffffea000f2f3a08 ffffea000f2fd608 ffff8883ecc0ce00
[ 59.283949] raw: 0000000000000000 0000000000150015 00000001ffffffff 0000000000000000
[ 59.285608] page dumped because: kasan: bad access detected
[ 59.286981]
[ 59.287337] Memory state around the buggy address:
[ 59.288310] ffff8883cbdd3280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 59.289763] ffff8883cbdd3300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 59.291452] >ffff8883cbdd3380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 59.292945] ^
[ 59.293815] ffff8883cbdd3400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 59.295220] ffff8883cbdd3480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 59.296872] ==================================================================
Fixes: da58f90f11f5 ("netdevsim: Add devlink-trap support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: syzbot+9ed8f68ab30761f3678e@syzkaller.appspotmail.com
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>