Re: Linux Kernel: usb: A use-after-free Write in put_dev

[Gerald Lee <sundaywind2004 () gmail com>]

This was assigned CVE-2022-4382.

=*=*=*=*=*=*=*=*=     CREDIT     =*=*=*=*=*=*=*=*=

Zhixin Li from Zero-one Security <sundaywind2004 () gmail com>


Thanks.


On Tue, Dec 13, 2022 at 2:53 PM Gerald Lee <sundaywind2004 () gmail com> wrote:
> Hi all,
>
> =*=*=*=*=*=*=*=*=   BUG DETAILS  =*=*=*=*=*=*=*=*=
>
> This use-after-free violation is caused by a race among the superblock
> operations in the gadgetfs driver. The vulnerability may not be a big
> deal, because the normal user can't execute umount. It could be
> triggered by yanking out a device that is running the gadgetfs side,
> but I don't know how to do that.
>
> C repro is attached.
>
> =*=*=*=*=*=*=*=*=     BACKTRACE     =*=*=*=*=*=*=*=*=
> BUG: KASAN: use-after-free in instrument_atomic_read_write
> include/linux/instrumented.h:102 [inline]
> BUG: KASAN: use-after-free in atomic_fetch_sub_release
> include/linux/atomic/atomic-instrumented.h:176 [inline]
> BUG: KASAN: use-after-free in __refcount_sub_and_test
> include/linux/refcount.h:272 [inline]
> BUG: KASAN: use-after-free in __refcount_dec_and_test
> include/linux/refcount.h:315 [inline]
> BUG: KASAN: use-after-free in refcount_dec_and_test
> include/linux/refcount.h:333 [inline]
> BUG: KASAN: use-after-free in put_dev+0x22/0xd0
> drivers/usb/gadget/legacy/inode.c:159
> Write of size 4 at addr ffff8880436d2040 by task syz-executor.5/7587
>
> CPU: 1 PID: 7587 Comm: syz-executor.5 Not tainted 6.1.0-rc7 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.13.0-1ubuntu1.1 04/01/2014
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
>  print_address_description mm/kasan/report.c:284 [inline]
>  print_report+0x15e/0x45d mm/kasan/report.c:395
>  kasan_report+0xbf/0x1f0 mm/kasan/report.c:495
>  check_region_inline mm/kasan/generic.c:183 [inline]
>  kasan_check_range+0x141/0x190 mm/kasan/generic.c:189
>  instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
>  atomic_fetch_sub_release
> include/linux/atomic/atomic-instrumented.h:176 [inline]
>  __refcount_sub_and_test include/linux/refcount.h:272 [inline]
>  __refcount_dec_and_test include/linux/refcount.h:315 [inline]
>  refcount_dec_and_test include/linux/refcount.h:333 [inline]
>  put_dev+0x22/0xd0 drivers/usb/gadget/legacy/inode.c:159
>  gadgetfs_kill_sb+0x2e/0x60 drivers/usb/gadget/legacy/inode.c:2086
>  deactivate_locked_super+0x98/0x160 fs/super.c:332
>  vfs_get_super fs/super.c:1190 [inline]
>  get_tree_single+0x188/0x1d0 fs/super.c:1207
>  vfs_get_tree+0x8d/0x2f0 fs/super.c:1531
>  vfs_fsconfig_locked fs/fsopen.c:232 [inline]
>  __do_sys_fsconfig+0x8d6/0xc20 fs/fsopen.c:439
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f8d5129078d
> Code: c3 e8 17 32 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48
> 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
> 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f8d52024bd8 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
> RAX: ffffffffffffffda RBX: 00007f8d513cbf80 RCX: 00007f8d5129078d
> RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
> RBP: 00007f8d512feb02 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffd48293eff R14: 00007ffd48294090 R15: 00007f8d52024d80
>  </TASK>
>
> Allocated by task 7561:
>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>  kasan_set_track+0x25/0x30 mm/kasan/common.c:52
>  ____kasan_kmalloc mm/kasan/common.c:371 [inline]
>  ____kasan_kmalloc mm/kasan/common.c:330 [inline]
>  __kasan_kmalloc+0xa5/0xb0 mm/kasan/common.c:380
>  kmalloc include/linux/slab.h:553 [inline]
>  kzalloc include/linux/slab.h:689 [inline]
>  dev_new drivers/usb/gadget/legacy/inode.c:170 [inline]
>  gadgetfs_fill_super+0x1e4/0x460 drivers/usb/gadget/legacy/inode.c:2041
>  vfs_get_super fs/super.c:1169 [inline]
>  get_tree_single+0xd6/0x1d0 fs/super.c:1207
>  vfs_get_tree+0x8d/0x2f0 fs/super.c:1531
>  vfs_fsconfig_locked fs/fsopen.c:232 [inline]
>  __do_sys_fsconfig+0x8d6/0xc20 fs/fsopen.c:439
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Last potentially related work creation:
>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>  __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
>  call_rcu+0x9d/0x820 kernel/rcu/tree.c:2798
>  pwq_unbound_release_workfn+0x26b/0x340 kernel/workqueue.c:3736
>  process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>  worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>  kthread+0x2e8/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
>
> Second to last potentially related work creation:
>  kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
>  __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
>  call_rcu+0x9d/0x820 kernel/rcu/tree.c:2798
>  pwq_unbound_release_workfn+0x26b/0x340 kernel/workqueue.c:3736
>  process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>  worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>  kthread+0x2e8/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
>
> The buggy address belongs to the object at ffff8880436d2000
>  which belongs to the cache kmalloc-1k of size 1024
> The buggy address is located 64 bytes inside of
>  1024-byte region [ffff8880436d2000, ffff8880436d2400)
>
> The buggy address belongs to the physical page:
> page:ffffea00010db400 refcount:1 mapcount:0 mapping:0000000000000000
> index:0x0 pfn:0x436d0
> head:ffffea00010db400 order:3 compound_mapcount:0 compound_pincount:0
> flags: 0x4fff00000010200(slab|head|node=1|zone=1|lastcpupid=0x7ff)
> raw: 04fff00000010200 dead000000000100 dead000000000122 ffff888012041dc0
> raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 3, migratetype Unmovable, gfp_mask
> 0x52a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6599,
> tgid 6599 (syz-executor.0), ts 29294571719, free_ts 29285126043
>  prep_new_page mm/page_alloc.c:2539 [inline]
>  get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4291
>  __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5558
>  alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
>  alloc_slab_page mm/slub.c:1794 [inline]
>  allocate_slab+0x213/0x300 mm/slub.c:1939
>  new_slab mm/slub.c:1992 [inline]
>  ___slab_alloc+0xa9b/0x13e0 mm/slub.c:3180
>  __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3279
>  slab_alloc_node mm/slub.c:3364 [inline]
>  __kmem_cache_alloc_node+0x199/0x3e0 mm/slub.c:3437
>  kmalloc_trace+0x26/0x60 mm/slab_common.c:1045
>  kmalloc include/linux/slab.h:553 [inline]
>  kzalloc include/linux/slab.h:689 [inline]
>  batadv_hardif_add_interface net/batman-adv/hard-interface.c:864 [inline]
>  batadv_hard_if_event+0x8a1/0x1450 net/batman-adv/hard-interface.c:952
>  notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
>  call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945
>  call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
>  call_netdevice_notifiers net/core/dev.c:1997 [inline]
>  register_netdevice+0x10bf/0x1670 net/core/dev.c:10090
>  veth_newlink+0x4d1/0x990 drivers/net/veth.c:1795
>  rtnl_newlink_create net/core/rtnetlink.c:3364 [inline]
>  __rtnl_newlink+0x1084/0x17e0 net/core/rtnetlink.c:3581
>  rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3594
>  rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6091
> page last free stack trace:
>  reset_page_owner include/linux/page_owner.h:24 [inline]
>  free_pages_prepare mm/page_alloc.c:1459 [inline]
>  free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1509
>  free_unref_page_prepare mm/page_alloc.c:3387 [inline]
>  free_unref_page+0x1d/0x4d0 mm/page_alloc.c:3483
>  qlink_free mm/kasan/quarantine.c:168 [inline]
>  qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
>  kasan_quarantine_reduce+0x184/0x210 mm/kasan/quarantine.c:294
>  __kasan_slab_alloc+0x66/0x90 mm/kasan/common.c:302
>  kasan_slab_alloc include/linux/kasan.h:201 [inline]
>  slab_post_alloc_hook mm/slab.h:737 [inline]
>  slab_alloc_node mm/slub.c:3398 [inline]
>  __kmem_cache_alloc_node+0x2e2/0x3e0 mm/slub.c:3437
>  kmalloc_trace+0x26/0x60 mm/slab_common.c:1045
>  kmalloc include/linux/slab.h:553 [inline]
>  kzalloc include/linux/slab.h:689 [inline]
>  kset_create lib/kobject.c:937 [inline]
>  kset_create_and_add+0x4f/0x1a0 lib/kobject.c:980
>  register_queue_kobjects net/core/net-sysfs.c:1766 [inline]
>  netdev_register_kobject+0x1ca/0x400 net/core/net-sysfs.c:2019
>  register_netdevice+0xd99/0x1670 net/core/dev.c:10057
>  __ip_tunnel_create+0x398/0x570 net/ipv4/ip_tunnel.c:267
>  ip_tunnel_init_net+0x2ec/0x9f0 net/ipv4/ip_tunnel.c:1073
>  ops_init+0xb9/0x680 net/core/net_namespace.c:135
>  setup_net+0x5d1/0xc50 net/core/net_namespace.c:332
>  copy_net_ns+0x31c/0x760 net/core/net_namespace.c:478
>  create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
>
> Memory state around the buggy address:
>  ffff8880436d1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff8880436d1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff8880436d2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                            ^
>  ffff8880436d2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff8880436d2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
>
>
> =*=*=*=*=*=*=*=*=     PATCH     =*=*=*=*=*=*=*=*=
>
> The patch has been done by Alan Stern, and it can be found here:
> https://lore.kernel.org/linux-usb/Y5dV11OoM3ojxNHy () rowland harvard edu/
>
> Thanks.