WSL2-Linux-Kernel/block
Li Jinlin 858560b276 blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd
KASAN reports a use-after-free report when doing fuzz test:

[693354.104835] ==================================================================
[693354.105094] BUG: KASAN: use-after-free in bfq_io_set_weight_legacy+0xd3/0x160
[693354.105336] Read of size 4 at addr ffff888be0a35664 by task sh/1453338

[693354.105607] CPU: 41 PID: 1453338 Comm: sh Kdump: loaded Not tainted 4.18.0-147
[693354.105610] Hardware name: Huawei 2288H V5/BC11SPSCB0, BIOS 0.81 07/02/2018
[693354.105612] Call Trace:
[693354.105621]  dump_stack+0xf1/0x19b
[693354.105626]  ? show_regs_print_info+0x5/0x5
[693354.105634]  ? printk+0x9c/0xc3
[693354.105638]  ? cpumask_weight+0x1f/0x1f
[693354.105648]  print_address_description+0x70/0x360
[693354.105654]  kasan_report+0x1b2/0x330
[693354.105659]  ? bfq_io_set_weight_legacy+0xd3/0x160
[693354.105665]  ? bfq_io_set_weight_legacy+0xd3/0x160
[693354.105670]  bfq_io_set_weight_legacy+0xd3/0x160
[693354.105675]  ? bfq_cpd_init+0x20/0x20
[693354.105683]  cgroup_file_write+0x3aa/0x510
[693354.105693]  ? ___slab_alloc+0x507/0x540
[693354.105698]  ? cgroup_file_poll+0x60/0x60
[693354.105702]  ? 0xffffffff89600000
[693354.105708]  ? usercopy_abort+0x90/0x90
[693354.105716]  ? mutex_lock+0xef/0x180
[693354.105726]  kernfs_fop_write+0x1ab/0x280
[693354.105732]  ? cgroup_file_poll+0x60/0x60
[693354.105738]  vfs_write+0xe7/0x230
[693354.105744]  ksys_write+0xb0/0x140
[693354.105749]  ? __ia32_sys_read+0x50/0x50
[693354.105760]  do_syscall_64+0x112/0x370
[693354.105766]  ? syscall_return_slowpath+0x260/0x260
[693354.105772]  ? do_page_fault+0x9b/0x270
[693354.105779]  ? prepare_exit_to_usermode+0xf9/0x1a0
[693354.105784]  ? enter_from_user_mode+0x30/0x30
[693354.105793]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.105875] Allocated by task 1453337:
[693354.106001]  kasan_kmalloc+0xa0/0xd0
[693354.106006]  kmem_cache_alloc_node_trace+0x108/0x220
[693354.106010]  bfq_pd_alloc+0x96/0x120
[693354.106015]  blkcg_activate_policy+0x1b7/0x2b0
[693354.106020]  bfq_create_group_hierarchy+0x1e/0x80
[693354.106026]  bfq_init_queue+0x678/0x8c0
[693354.106031]  blk_mq_init_sched+0x1f8/0x460
[693354.106037]  elevator_switch_mq+0xe1/0x240
[693354.106041]  elevator_switch+0x25/0x40
[693354.106045]  elv_iosched_store+0x1a1/0x230
[693354.106049]  queue_attr_store+0x78/0xb0
[693354.106053]  kernfs_fop_write+0x1ab/0x280
[693354.106056]  vfs_write+0xe7/0x230
[693354.106060]  ksys_write+0xb0/0x140
[693354.106064]  do_syscall_64+0x112/0x370
[693354.106069]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.106114] Freed by task 1453336:
[693354.106225]  __kasan_slab_free+0x130/0x180
[693354.106229]  kfree+0x90/0x1b0
[693354.106233]  blkcg_deactivate_policy+0x12c/0x220
[693354.106238]  bfq_exit_queue+0xf5/0x110
[693354.106241]  blk_mq_exit_sched+0x104/0x130
[693354.106245]  __elevator_exit+0x45/0x60
[693354.106249]  elevator_switch_mq+0xd6/0x240
[693354.106253]  elevator_switch+0x25/0x40
[693354.106257]  elv_iosched_store+0x1a1/0x230
[693354.106261]  queue_attr_store+0x78/0xb0
[693354.106264]  kernfs_fop_write+0x1ab/0x280
[693354.106268]  vfs_write+0xe7/0x230
[693354.106271]  ksys_write+0xb0/0x140
[693354.106275]  do_syscall_64+0x112/0x370
[693354.106280]  entry_SYSCALL_64_after_hwframe+0x65/0xca

[693354.106329] The buggy address belongs to the object at ffff888be0a35580
                 which belongs to the cache kmalloc-1k of size 1024
[693354.106736] The buggy address is located 228 bytes inside of
                 1024-byte region [ffff888be0a35580, ffff888be0a35980)
[693354.107114] The buggy address belongs to the page:
[693354.107273] page:ffffea002f828c00 count:1 mapcount:0 mapping:ffff888107c17080 index:0x0 compound_mapcount: 0
[693354.107606] flags: 0x17ffffc0008100(slab|head)
[693354.107760] raw: 0017ffffc0008100 ffffea002fcbc808 ffffea0030bd3a08 ffff888107c17080
[693354.108020] raw: 0000000000000000 00000000001c001c 00000001ffffffff 0000000000000000
[693354.108278] page dumped because: kasan: bad access detected

[693354.108511] Memory state around the buggy address:
[693354.108671]  ffff888be0a35500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[693354.116396]  ffff888be0a35580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.124473] >ffff888be0a35600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.132421]                                                        ^
[693354.140284]  ffff888be0a35680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.147912]  ffff888be0a35700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.155281] ==================================================================

blkgs are protected by both queue and blkcg locks and holding
either should stabilize them. However, the path of destroying
blkg policy data is only protected by queue lock in
blkcg_activate_policy()/blkcg_deactivate_policy(). Other tasks
can get the blkg policy data before the blkg policy data is
destroyed, and use it after destroyed, which will result in a
use-after-free.

CPU0                             CPU1
blkcg_deactivate_policy
  spin_lock_irq(&q->queue_lock)
                                 bfq_io_set_weight_legacy
                                   spin_lock_irq(&blkcg->lock)
                                   blkg_to_bfqg(blkg)
                                     pd_to_bfqg(blkg->pd[pol->plid])
                                     ^^^^^^blkg->pd[pol->plid] != NULL
                                           bfqg != NULL
  pol->pd_free_fn(blkg->pd[pol->plid])
    pd_to_bfqg(blkg->pd[pol->plid])
    bfqg_put(bfqg)
      kfree(bfqg)
  blkg->pd[pol->plid] = NULL
  spin_unlock_irq(q->queue_lock);
                                   bfq_group_set_weight(bfqg, val, 0)
                                     bfqg->entity.new_weight
                                     ^^^^^^trigger uaf here
                                   spin_unlock_irq(&blkcg->lock);

Fix by grabbing the matching blkcg lock before trying to
destroy blkg policy data.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Li Jinlin <lijinlin3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210914042605.3260596-1-lijinlin3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-15 12:03:18 -06:00
..
partitions for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
Kconfig SCSI misc on 20210902 2021-09-02 15:09:46 -07:00
Kconfig.iosched Revert "block/mq-deadline: Add cgroup support" 2021-08-11 13:47:26 -06:00
Makefile block-5.15-2021-09-11 2021-09-11 10:19:51 -07:00
badblocks.c
bdev.c block: move fs/block_dev.c to block/bdev.c 2021-09-07 08:39:40 -06:00
bfq-cgroup.c
bfq-iosched.c block, bfq: honor already-setup queue merges 2021-09-02 06:36:58 -06:00
bfq-iosched.h block, bfq: cleanup the repeated declaration 2021-08-25 06:45:33 -06:00
bfq-wf2q.c block: Introduce IOPRIO_NR_LEVELS 2021-08-18 07:21:12 -06:00
bio-integrity.c block: use bvec_virt in bio_integrity_{process,free} 2021-08-16 10:50:32 -06:00
bio.c bio: fix kerneldoc documentation for bio_alloc_kiocb() 2021-09-03 07:42:13 -06:00
blk-cgroup-rwstat.c
blk-cgroup-rwstat.h
blk-cgroup.c blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd 2021-09-15 12:03:18 -06:00
blk-core.c io_uring-bio-cache.5-2021-08-30 2021-08-30 19:30:30 -07:00
blk-crypto-fallback.c
blk-crypto-internal.h
blk-crypto.c blk-crypto: fix check for too-large dun_bytes 2021-08-25 06:45:00 -06:00
blk-exec.c block: return errors from blk_execute_rq() 2021-06-30 15:35:45 -06:00
blk-flush.c blk-mq: fix is_flush_rq 2021-08-17 20:17:34 -06:00
blk-integrity.c block: flush the integrity workqueue in blk_integrity_unregister 2021-09-14 20:03:30 -06:00
blk-ioc.c
blk-iocost.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-iolatency.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-ioprio.c
blk-ioprio.h
blk-lib.c
blk-map.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
blk-merge.c io_uring-bio-cache.5-2021-08-30 2021-08-30 19:30:30 -07:00
blk-mq-cpumap.c
blk-mq-debugfs-zoned.c
blk-mq-debugfs.c
blk-mq-debugfs.h
blk-mq-pci.c
blk-mq-rdma.c
blk-mq-sched.c blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling 2021-07-27 16:44:38 -06:00
blk-mq-sched.h
blk-mq-sysfs.c block: remove blk-mq-sysfs dead code 2021-08-02 13:37:29 -06:00
blk-mq-tag.c blk-mq: avoid to iterate over stale request 2021-09-12 19:32:43 -06:00
blk-mq-tag.h
blk-mq-virtio.c
blk-mq.c block-5.15-2021-09-11 2021-09-11 10:19:51 -07:00
blk-mq.h
blk-pm.c
blk-pm.h
blk-rq-qos.c
blk-rq-qos.h
blk-settings.c block: add an explicit ->disk backpointer to the request_queue 2021-08-23 12:54:31 -06:00
blk-stat.c
blk-stat.h
blk-sysfs.c block: call blk_register_queue earlier in device_add_disk 2021-08-23 12:55:45 -06:00
blk-throttle.c blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() 2021-09-07 08:36:56 -06:00
blk-timeout.c
blk-wbt.c block: add an explicit ->disk backpointer to the request_queue 2021-08-23 12:54:31 -06:00
blk-wbt.h
blk-zoned.c blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN 2021-08-24 10:12:36 -06:00
blk.h block: split out operations on block special files 2021-09-07 08:39:29 -06:00
bounce.c block: use memcpy_from_bvec in __blk_queue_bounce 2021-08-02 13:37:28 -06:00
bsg-lib.c scsi: bsg-lib: Fix commands without data transfer in bsg_transport_sg_io_fn() 2021-08-01 13:21:40 -04:00
bsg.c scsi: bsg: Move the whole request execution into the SCSI/transport handlers 2021-07-30 22:22:36 -04:00
disk-events.c block: return errors from disk_alloc_events 2021-08-23 12:55:45 -06:00
elevator.c block: return ELEVATOR_DISCARD_MERGE if possible 2021-08-09 14:37:47 -06:00
fops.c block: split out operations on block special files 2021-09-07 08:39:29 -06:00
genhd.c block: genhd: don't call blkdev_show() with major_names_lock held 2021-09-07 08:36:21 -06:00
holder.c block: add back the bd_holder_dir reference in bd_link_disk_holder 2021-08-20 21:14:26 -06:00
ioctl.c block: pass a gendisk to bdev_resize_partition 2021-08-12 10:31:36 -06:00
ioprio.c block: fix default IO priority handling 2021-08-18 07:23:15 -06:00
keyslot-manager.c
kyber-iosched.c kyber: make trace_block_rq call consistent with documentation 2021-08-06 16:40:47 -06:00
mq-deadline.c block/mq-deadline: Move dd_queued() to fix defined but not used warning 2021-09-02 06:34:45 -06:00
opal_proto.h
sed-opal.c
t10-pi.c block: use bvec_kmap_local in t10_pi_type1_{prepare,complete} 2021-08-02 13:37:28 -06:00