Re: [dm-devel] dm: Fix use-after-free in dm_cleanup_zoned_dev()

[Kirill Tkhai <ktkhai@virtuozzo.com>]

On 01.02.2022 02:37, Damien Le Moal wrote:
> On 2022/02/01 1:21, Kirill Tkhai wrote:
>> dm_cleanup_zoned_dev() uses queue, so it must be called before blk_cleanup_disk() starts its killing:
>>
>> blk_cleanup_disk->blk_cleanup_queue()->kobject_put()->blk_release_queue()->...RCU...->blk_free_queue_rcu()->kmem_cache_free()
>>
>> Otherwise, RCU callback may be executed first, and dm_cleanup_zoned_dev() touches freed memory:
>>
>> [   85.074005] BUG: KASAN: use-after-free in dm_cleanup_zoned_dev+0x33/0xd0
>> [   85.075448] Read of size 8 at addr ffff88805ac6e430 by task dmsetup/681
>>
>> [   85.076102] CPU: 4 PID: 681 Comm: dmsetup Not tainted 5.17.0-rc2+ #6
>> [   85.076570] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
>> [   85.077150] Call Trace:
>> [   85.077332]  <TASK>
>> [   85.077478]  dump_stack_lvl+0x57/0x7d
>> [   85.077763]  print_address_description.constprop.0+0x1f/0x150
>> [   85.078229]  ? dm_cleanup_zoned_dev+0x33/0xd0
>> [   85.078579]  kasan_report.cold+0x7f/0x11b
>> [   85.078910]  ? dm_cleanup_zoned_dev+0x33/0xd0
>> [   85.079219]  dm_cleanup_zoned_dev+0x33/0xd0
>> [   85.079499]  __dm_destroy+0x26a/0x400
>> [   85.079781]  ? dm_blk_ioctl+0x230/0x230
>> [   85.080090]  ? up_write+0xd8/0x270
>> [   85.080364]  dev_remove+0x156/0x1d0
>> [   85.080639]  ctl_ioctl+0x269/0x530
>> [   85.080910]  ? table_clear+0x140/0x140
>> [   85.081209]  ? lock_release+0xb2/0x750
>> [   85.081518]  ? remove_all+0x40/0x40
>> [   85.081796]  ? rcu_read_lock_sched_held+0x12/0x70
>> [   85.082166]  ? lock_downgrade+0x3c0/0x3c0
>> [   85.082468]  ? rcu_read_lock_sched_held+0x12/0x70
>> [   85.082833]  dm_ctl_ioctl+0xa/0x10
>> [   85.083094]  __x64_sys_ioctl+0xb9/0xf0
>> [   85.083350]  do_syscall_64+0x3b/0x90
>> [   85.083595]  entry_SYSCALL_64_after_hwframe+0x44/0xae
>> [   85.083955] RIP: 0033:0x7fb6dfa95c27
>> [   85.084277] Code: 00 00 00 48 8b 05 69 92 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 92 0c 00 f7 d8 64 89 01 48
>> [   85.086009] RSP: 002b:00007fff882c6c28 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
>> [   85.086914] RAX: ffffffffffffffda RBX: 00007fb6dfb73a8e RCX: 00007fb6dfa95c27
>> [   85.087607] RDX: 00007fb6e01d7ca0 RSI: 00000000c138fd04 RDI: 0000000000000003
>> [   85.088272] RBP: 00007fff882c6ce0 R08: 00007fb6dfbc3558 R09: 00007fff882c6a90
>> [   85.088956] R10: 00007fb6dfbc28a2 R11: 0000000000000206 R12: 00007fb6dfbc28a2
>> [   85.089477] R13: 00007fb6dfbc28a2 R14: 00007fb6dfbc28a2 R15: 00007fb6dfbc28a2
>> [   85.090038]  </TASK>
>>
>> [   85.090348] Allocated by task 673:
>> [   85.090625]  kasan_save_stack+0x1e/0x40
>> [   85.090978]  __kasan_slab_alloc+0x66/0x80
>> [   85.091336]  kmem_cache_alloc_node+0x1ca/0x460
>> [   85.091742]  blk_alloc_queue+0x33/0x4e0
>> [   85.092112]  __blk_alloc_disk+0x1b/0x60
>> [   85.092464]  dm_create+0x368/0xa20
>> [   85.092764]  dev_create+0xb9/0x170
>> [   85.093118]  ctl_ioctl+0x269/0x530
>> [   85.093521]  dm_ctl_ioctl+0xa/0x10
>> [   85.093921]  __x64_sys_ioctl+0xb9/0xf0
>> [   85.094177]  do_syscall_64+0x3b/0x90
>> [   85.094420]  entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> [   85.094868] Freed by task 0:
>> [   85.095062]  kasan_save_stack+0x1e/0x40
>> [   85.095319]  kasan_set_track+0x21/0x30
>> [   85.095569]  kasan_set_free_info+0x20/0x30
>> [   85.095858]  __kasan_slab_free+0xfb/0x130
>> [   85.096141]  slab_free_freelist_hook+0x7d/0x150
>> [   85.096502]  kmem_cache_free+0x13c/0x340
>> [   85.096778]  rcu_do_batch+0x2d9/0x820
>> [   85.097049]  rcu_core+0x3b8/0x570
>> [   85.097330]  __do_softirq+0x1c4/0x63d
>>
>> [   85.097792] Last potentially related work creation:
>> [   85.098226]  kasan_save_stack+0x1e/0x40
>> [   85.098549]  __kasan_record_aux_stack+0x96/0xa0
>> [   85.098951]  call_rcu+0xc4/0x8f0
>> [   85.099220]  kobject_put+0xd9/0x270
>> [   85.099557]  disk_release+0xee/0x120
>> [   85.099864]  device_release+0x59/0xf0
>> [   85.100208]  kobject_put+0xd9/0x270
>> [   85.100509]  cleanup_mapped_device+0x12b/0x1b0
>> [   85.100910]  __dm_destroy+0x26a/0x400
>> [   85.101247]  dev_remove+0x156/0x1d0
>> [   85.101555]  ctl_ioctl+0x269/0x530
>> [   85.101859]  dm_ctl_ioctl+0xa/0x10
>> [   85.102198]  __x64_sys_ioctl+0xb9/0xf0
>> [   85.102527]  do_syscall_64+0x3b/0x90
>> [   85.102811]  entry_SYSCALL_64_after_hwframe+0x44/0xae
>>
>> [   85.103347] The buggy address belongs to the object at ffff88805ac6e180
>> 	    which belongs to the cache request_queue of size 2992
>> [   85.104338] The buggy address is located 688 bytes inside of
>> 	    2992-byte region [ffff88805ac6e180, ffff88805ac6ed30)
>> [   85.105255] The buggy address belongs to the page:
>> [   85.105633] page:000000000837df3c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5ac68
>> [   85.106363] head:000000000837df3c order:3 compound_mapcount:0 compound_pincount:0
>> [   85.106948] flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
>> [   85.107494] raw: 000fffffc0010200 0000000000000000 dead000000000122 ffff888001e58280
>> [   85.108091] raw: 0000000000000000 00000000800a000a 00000001ffffffff 0000000000000000
>> [   85.108695] page dumped because: kasan: bad access detected
>>
>> [   85.109257] Memory state around the buggy address:
>> [   85.109625]  ffff88805ac6e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [   85.110178]  ffff88805ac6e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [   85.110973] >ffff88805ac6e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [   85.111891]                                      ^
>> [   85.112353]  ffff88805ac6e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [   85.113036]  ffff88805ac6e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> [   85.113800] ==================================================================
>>
>> Fixes: bb37d77239af "dm: introduce zone append emulation"
>> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
>>
>> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
>> index dcbd6d201619..d472fe5dbc1d 100644
>> --- a/drivers/md/dm.c
>> +++ b/drivers/md/dm.c
>> @@ -1607,6 +1607,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
>>  		md->dax_dev = NULL;
>>  	}
>>  
>> +	dm_cleanup_zoned_dev(md);
>>  	if (md->disk) {
>>  		spin_lock(&_minor_lock);
>>  		md->disk->private_data = NULL;
>> @@ -1627,7 +1628,6 @@ static void cleanup_mapped_device(struct mapped_device *md)
>>  	mutex_destroy(&md->swap_bios_lock);
>>  
>>  	dm_mq_cleanup_mapped_device(md);
>> -	dm_cleanup_zoned_dev(md);
>>  }
>>  
>>  /*
>>
> 
> The commit message format is strange (long lines).
> Apart from that, the fix looks good to me.
> 
> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

This is for a reviewer convenience. All KASAN trace may be cut on commit if not needed.

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