Re: [syzbot] KASAN: use-after-free Read in rfkill_blocked

[Johannes Berg]

Looks like an NFC issue to me, Krzysztof?

I mean, rfkill got allocated by nfc_register_device(), freed by
nfc_unregister_device(), and then used by nfc_dev_up(). Seems like the
last bit shouldn't be possible after nfc_unregister_device()?

johannes

On Wed, 2022-11-23 at 22:24 -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    0966d385830d riscv: Fix auipc+jalr relocation range checks
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git fixes
> console output: https://syzkaller.appspot.com/x/log.txt?x=11196d0d880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6295d67591064921
> dashboard link: https://syzkaller.appspot.com/bug?extid=0299462c067009827b2a
> compiler:       riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: riscv64
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+0299462c067009827b2a@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ==================================================================
> BUG: KASAN: use-after-free in __lock_acquire+0x8ee/0x333e kernel/locking/lockdep.c:4897
> Read of size 8 at addr ffffaf8024249018 by task syz-executor.0/7946
> 
> CPU: 0 PID: 7946 Comm: syz-executor.0 Not tainted 5.17.0-rc1-syzkaller-00002-g0966d385830d #0
> Hardware name: riscv-virtio,qemu (DT)
> Call Trace:
> [<ffffffff8000a228>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:113
> [<ffffffff831668cc>] show_stack+0x34/0x40 arch/riscv/kernel/stacktrace.c:119
> [<ffffffff831756ba>] __dump_stack lib/dump_stack.c:88 [inline]
> [<ffffffff831756ba>] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:106
> [<ffffffff8047479e>] print_address_description.constprop.0+0x2a/0x330 mm/kasan/report.c:255
> [<ffffffff80474d4c>] __kasan_report mm/kasan/report.c:442 [inline]
> [<ffffffff80474d4c>] kasan_report+0x184/0x1e0 mm/kasan/report.c:459
> [<ffffffff80475b20>] check_region_inline mm/kasan/generic.c:183 [inline]
> [<ffffffff80475b20>] __asan_load8+0x6e/0x96 mm/kasan/generic.c:256
> [<ffffffff80112b70>] __lock_acquire+0x8ee/0x333e kernel/locking/lockdep.c:4897
> [<ffffffff80116582>] lock_acquire.part.0+0x1d0/0x424 kernel/locking/lockdep.c:5639
> [<ffffffff8011682a>] lock_acquire+0x54/0x6a kernel/locking/lockdep.c:5612
> [<ffffffff831afa2c>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> [<ffffffff831afa2c>] _raw_spin_lock_irqsave+0x3e/0x62 kernel/locking/spinlock.c:162
> [<ffffffff83034f0a>] rfkill_blocked+0x22/0x62 net/rfkill/core.c:941
> [<ffffffff830b8862>] nfc_dev_up+0x8e/0x26c net/nfc/core.c:102
> [<ffffffff830bb742>] nfc_genl_dev_up+0x5e/0x8a net/nfc/netlink.c:770
> [<ffffffff8296f9ae>] genl_family_rcv_msg_doit+0x19a/0x23c net/netlink/genetlink.c:731
> [<ffffffff82970420>] genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
> [<ffffffff82970420>] genl_rcv_msg+0x236/0x3ba net/netlink/genetlink.c:792
> [<ffffffff8296ded2>] netlink_rcv_skb+0xf8/0x2be net/netlink/af_netlink.c:2494
> [<ffffffff8296ecb2>] genl_rcv+0x36/0x4c net/netlink/genetlink.c:803
> [<ffffffff8296cbcc>] netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
> [<ffffffff8296cbcc>] netlink_unicast+0x40e/0x5fe net/netlink/af_netlink.c:1343
> [<ffffffff8296d29c>] netlink_sendmsg+0x4e0/0x994 net/netlink/af_netlink.c:1919
> [<ffffffff826d264e>] sock_sendmsg_nosec net/socket.c:705 [inline]
> [<ffffffff826d264e>] sock_sendmsg+0xa0/0xc4 net/socket.c:725
> [<ffffffff826d4dd4>] ____sys_sendmsg+0x46e/0x484 net/socket.c:2413
> [<ffffffff826d8bca>] ___sys_sendmsg+0x16c/0x1f6 net/socket.c:2467
> [<ffffffff826d8e78>] __sys_sendmsg+0xba/0x150 net/socket.c:2496
> [<ffffffff826d8f3a>] __do_sys_sendmsg net/socket.c:2505 [inline]
> [<ffffffff826d8f3a>] sys_sendmsg+0x2c/0x3a net/socket.c:2503
> [<ffffffff80005716>] ret_from_syscall+0x0/0x2
> 
> Allocated by task 7946:
>  stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
>  kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38
>  kasan_set_track mm/kasan/common.c:45 [inline]
>  set_alloc_info mm/kasan/common.c:436 [inline]
>  ____kasan_kmalloc mm/kasan/common.c:515 [inline]
>  ____kasan_kmalloc mm/kasan/common.c:474 [inline]
>  __kasan_kmalloc+0x80/0xb2 mm/kasan/common.c:524
>  kasan_kmalloc include/linux/kasan.h:270 [inline]
>  __kmalloc+0x190/0x318 mm/slub.c:4424
>  kmalloc include/linux/slab.h:586 [inline]
>  kzalloc include/linux/slab.h:715 [inline]
>  rfkill_alloc+0x96/0x1aa net/rfkill/core.c:983
>  nfc_register_device+0xe4/0x29e net/nfc/core.c:1129
>  nci_register_device+0x538/0x612 net/nfc/nci/core.c:1252
>  virtual_ncidev_open+0x82/0x12c drivers/nfc/virtual_ncidev.c:143
>  misc_open+0x272/0x2c8 drivers/char/misc.c:141
>  chrdev_open+0x1d4/0x478 fs/char_dev.c:414
>  do_dentry_open+0x2a4/0x7d4 fs/open.c:824
>  vfs_open+0x52/0x5e fs/open.c:959
>  do_open fs/namei.c:3476 [inline]
>  path_openat+0x12b6/0x189e fs/namei.c:3609
>  do_filp_open+0x10e/0x22a fs/namei.c:3636
>  do_sys_openat2+0x174/0x31e fs/open.c:1214
>  do_sys_open fs/open.c:1230 [inline]
>  __do_sys_openat fs/open.c:1246 [inline]
>  sys_openat+0xdc/0x164 fs/open.c:1241
>  ret_from_syscall+0x0/0x2
> 
> Freed by task 7944:
>  stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
>  kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38
>  kasan_set_track+0x1a/0x26 mm/kasan/common.c:45
>  kasan_set_free_info+0x1e/0x3a mm/kasan/generic.c:370
>  ____kasan_slab_free mm/kasan/common.c:366 [inline]
>  ____kasan_slab_free+0x15e/0x180 mm/kasan/common.c:328
>  __kasan_slab_free+0x10/0x18 mm/kasan/common.c:374
>  kasan_slab_free include/linux/kasan.h:236 [inline]
>  slab_free_hook mm/slub.c:1728 [inline]
>  slab_free_freelist_hook+0x8e/0x1cc mm/slub.c:1754
>  slab_free mm/slub.c:3509 [inline]
>  kfree+0xe0/0x3e4 mm/slub.c:4562
>  rfkill_release+0x20/0x2a net/rfkill/core.c:831
>  device_release+0x66/0x148 drivers/base/core.c:2229
>  kobject_cleanup lib/kobject.c:705 [inline]
>  kobject_release lib/kobject.c:736 [inline]
>  kref_put include/linux/kref.h:65 [inline]
>  kobject_put+0x1bc/0x38e lib/kobject.c:753
>  put_device+0x28/0x3a drivers/base/core.c:3512
>  rfkill_destroy+0x2a/0x3c net/rfkill/core.c:1142
>  nfc_unregister_device+0xac/0x232 net/nfc/core.c:1167
>  nci_unregister_device+0x168/0x182 net/nfc/nci/core.c:1298
>  virtual_ncidev_close+0x9c/0xbc drivers/nfc/virtual_ncidev.c:163
>  __fput+0x164/0x502 fs/file_table.c:311
>  ____fput+0x1a/0x24 fs/file_table.c:344
>  task_work_run+0xdc/0x154 kernel/task_work.c:164
>  tracehook_notify_resume include/linux/tracehook.h:188 [inline]
>  do_notify_resume+0x894/0xa56 arch/riscv/kernel/signal.c:320
>  ret_from_exception+0x0/0x10
> 
> Last potentially related work creation:
>  stack_trace_save+0xa6/0xd8 kernel/stacktrace.c:122
>  kasan_save_stack+0x2c/0x58 mm/kasan/common.c:38
>  __kasan_record_aux_stack+0xc4/0xdc mm/kasan/generic.c:348
>  kasan_record_aux_stack_noalloc+0xe/0x16 mm/kasan/generic.c:358
>  insert_work+0x40/0x1d4 kernel/workqueue.c:1368
>  __queue_work+0x4ec/0xed0 kernel/workqueue.c:1534
>  queue_work_on+0xe8/0xfe kernel/workqueue.c:1562
>  queue_work include/linux/workqueue.h:502 [inline]
>  schedule_work include/linux/workqueue.h:563 [inline]
>  rfkill_register+0x46e/0x60e net/rfkill/core.c:1089
>  nfc_register_device+0x10a/0x29e net/nfc/core.c:1132
>  nci_register_device+0x538/0x612 net/nfc/nci/core.c:1252
>  virtual_ncidev_open+0x82/0x12c drivers/nfc/virtual_ncidev.c:143
>  misc_open+0x272/0x2c8 drivers/char/misc.c:141
>  chrdev_open+0x1d4/0x478 fs/char_dev.c:414
>  do_dentry_open+0x2a4/0x7d4 fs/open.c:824
>  vfs_open+0x52/0x5e fs/open.c:959
>  do_open fs/namei.c:3476 [inline]
>  path_openat+0x12b6/0x189e fs/namei.c:3609
>  do_filp_open+0x10e/0x22a fs/namei.c:3636
>  do_sys_openat2+0x174/0x31e fs/open.c:1214
>  do_sys_open fs/open.c:1230 [inline]
>  __do_sys_openat fs/open.c:1246 [inline]
>  sys_openat+0xdc/0x164 fs/open.c:1241
>  ret_from_syscall+0x0/0x2
> 
> The buggy address belongs to the object at ffffaf8024249000
>  which belongs to the cache kmalloc-2k of size 2048
> The buggy address is located 24 bytes inside of
>  2048-byte region [ffffaf8024249000, ffffaf8024249800)
> The buggy address belongs to the page:
> page:ffffaf807b073440 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa4448
> head:ffffaf807b073440 order:3 compound_mapcount:0 compound_pincount:0
> flags: 0xa000010200(slab|head|section=20|node=0|zone=0)
> raw: 000000a000010200 0000000000000100 0000000000000122 ffffaf8007202000
> raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
> raw: 00000000000007ff
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 3932, ts 2633362768300, free_ts 2631908277000
>  __set_page_owner+0x48/0x136 mm/page_owner.c:183
>  set_page_owner include/linux/page_owner.h:31 [inline]
>  post_alloc_hook+0xd0/0x10a mm/page_alloc.c:2427
>  prep_new_page mm/page_alloc.c:2434 [inline]
>  get_page_from_freelist+0x8da/0x12d8 mm/page_alloc.c:4165
>  __alloc_pages+0x150/0x3b6 mm/page_alloc.c:5389
>  alloc_pages+0x132/0x2a6 mm/mempolicy.c:2271
>  alloc_slab_page.constprop.0+0xc2/0xfa mm/slub.c:1799
>  allocate_slab mm/slub.c:1944 [inline]
>  new_slab+0x25a/0x2cc mm/slub.c:2004
>  ___slab_alloc+0x56e/0x918 mm/slub.c:3018
>  __slab_alloc.constprop.0+0x50/0x8c mm/slub.c:3105
>  slab_alloc_node mm/slub.c:3196 [inline]
>  __kmalloc_node_track_caller+0x26c/0x362 mm/slub.c:4957
>  kmalloc_reserve net/core/skbuff.c:354 [inline]
>  __alloc_skb+0xee/0x2e4 net/core/skbuff.c:426
>  alloc_skb include/linux/skbuff.h:1158 [inline]
>  nlmsg_new include/net/netlink.h:953 [inline]
>  rtmsg_ifinfo_build_skb+0x62/0x142 net/core/rtnetlink.c:3829
>  unregister_netdevice_many+0x7dc/0xf50 net/core/dev.c:10419
>  default_device_exit_batch+0x28a/0x2dc net/core/dev.c:10945
>  ops_exit_list+0xcc/0xe8 net/core/net_namespace.c:173
>  cleanup_net+0x430/0x732 net/core/net_namespace.c:597
> page last free stack trace:
>  __reset_page_owner+0x4a/0xea mm/page_owner.c:142
>  reset_page_owner include/linux/page_owner.h:24 [inline]
>  free_pages_prepare mm/page_alloc.c:1352 [inline]
>  free_pcp_prepare+0x29c/0x45e mm/page_alloc.c:1404
>  free_unref_page_prepare mm/page_alloc.c:3325 [inline]
>  free_unref_page+0x6a/0x31e mm/page_alloc.c:3404
>  free_the_page mm/page_alloc.c:706 [inline]
>  __free_pages+0xe2/0x112 mm/page_alloc.c:5474
>  __free_slab+0x122/0x27c mm/slub.c:2028
>  free_slab mm/slub.c:2043 [inline]
>  discard_slab+0x4c/0x7a mm/slub.c:2049
>  __unfreeze_partials+0x16a/0x18e mm/slub.c:2536
>  put_cpu_partial+0xf6/0x162 mm/slub.c:2612
>  __slab_free+0x166/0x29c mm/slub.c:3378
>  do_slab_free mm/slub.c:3497 [inline]
>  ___cache_free+0x17c/0x354 mm/slub.c:3516
>  qlink_free mm/kasan/quarantine.c:157 [inline]
>  qlist_free_all+0x7c/0x132 mm/kasan/quarantine.c:176
>  kasan_quarantine_reduce+0x14c/0x1c8 mm/kasan/quarantine.c:283
>  __kasan_slab_alloc+0x5c/0x98 mm/kasan/common.c:446
>  kasan_slab_alloc include/linux/kasan.h:260 [inline]
>  slab_post_alloc_hook mm/slab.h:732 [inline]
>  slab_alloc_node mm/slub.c:3230 [inline]
>  kmem_cache_alloc_node+0x368/0x41c mm/slub.c:3266
>  __alloc_skb+0x234/0x2e4 net/core/skbuff.c:414
>  alloc_skb include/linux/skbuff.h:1158 [inline]
>  nlmsg_new include/net/netlink.h:953 [inline]
>  inet6_netconf_notify_devconf+0xb6/0x1f2 net/ipv6/addrconf.c:584
> 
> Memory state around the buggy address:
>  ffffaf8024248f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffffaf8024248f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffffaf8024249000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                             ^
>  ffffaf8024249080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffffaf8024249100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
> 
> syzbot will keep track of this issue. See:
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>