Re: KASAN: slab-out-of-bounds Read in usbhid_close

[Andrey Konovalov]

On Tue, Aug 6, 2019 at 3:18 PM syzbot
<syzbot+3268ee512f866a903602@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=117a9f42600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> dashboard link: https://syzkaller.appspot.com/bug?extid=3268ee512f866a903602
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+3268ee512f866a903602@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in __lock_acquire+0x302a/0x3b50
> kernel/locking/lockdep.c:3753
> Read of size 8 at addr ffff8881ceab68a0 by task syz-executor.0/3352
>
> CPU: 1 PID: 3352 Comm: syz-executor.0 Not tainted 5.3.0-rc2+ #25
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0xca/0x13e lib/dump_stack.c:113
>   print_address_description+0x6a/0x32c mm/kasan/report.c:351
>   __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
>   kasan_report+0xe/0x12 mm/kasan/common.c:612
>   __lock_acquire+0x302a/0x3b50 kernel/locking/lockdep.c:3753
>   lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412
>   __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
>   _raw_spin_lock_irq+0x2d/0x40 kernel/locking/spinlock.c:167
>   spin_lock_irq include/linux/spinlock.h:363 [inline]
>   usbhid_close+0x51/0x210 drivers/hid/usbhid/hid-core.c:740
>   hid_hw_close+0xa8/0xd0 drivers/hid/hid-core.c:2046
>   drop_ref.part.0+0x32/0xe0 drivers/hid/hidraw.c:337
>   drop_ref drivers/hid/hidraw.c:360 [inline]
>   hidraw_release+0x34f/0x440 drivers/hid/hidraw.c:356
>   __fput+0x2d7/0x840 fs/file_table.c:280
>   task_work_run+0x13f/0x1c0 kernel/task_work.c:113
>   exit_task_work include/linux/task_work.h:22 [inline]
>   do_exit+0x8ef/0x2c50 kernel/exit.c:878
>   do_group_exit+0x125/0x340 kernel/exit.c:982
>   get_signal+0x466/0x23d0 kernel/signal.c:2728
>   do_signal+0x88/0x14e0 arch/x86/kernel/signal.c:815
>   exit_to_usermode_loop+0x1a2/0x200 arch/x86/entry/common.c:159
>   prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
>   syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
>   do_syscall_64+0x45f/0x580 arch/x86/entry/common.c:299
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x459829
> Code: Bad RIP value.
> RSP: 002b:00007f123439dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
> RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 0000000000459829
> RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28
> RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c
> R13: 00007ffe9281699f R14: 00007f123439e9c0 R15: 000000000075bf2c
>
> Allocated by task 0:
> (stack is not available)
>
> Freed by task 0:
> (stack is not available)
>
> The buggy address belongs to the object at ffff8881ceab6880
>   which belongs to the cache shmem_inode_cache of size 1168
> The buggy address is located 32 bytes inside of
>   1168-byte region [ffff8881ceab6880, ffff8881ceab6d10)
> The buggy address belongs to the page:
> page:ffffea00073aad00 refcount:1 mapcount:0 mapping:ffff8881da115180
> index:0x0 compound_mapcount: 0
> flags: 0x200000000010200(slab|head)
> raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da115180
> raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881ceab6780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   ffff8881ceab6800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff8881ceab6880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>                                 ^
>   ffff8881ceab6900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>   ffff8881ceab6980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This bug is generated by a bot. It may contain errors.
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> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx
>
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Looks like the same bug:

#syz dup: KASAN: slab-out-of-bounds Read in hidraw_ioctl