Re: KASAN: use-after-free Write in usbhid_open

[Andrey Konovalov]

On Tue, Sep 3, 2019 at 2:08 PM syzbot
<syzbot+058e326a87dbb54f2426@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    eea39f24 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=16ab9982600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
> dashboard link: https://syzkaller.appspot.com/bug?extid=058e326a87dbb54f2426
> 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+058e326a87dbb54f2426@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> BUG: KASAN: use-after-free in clear_bit
> include/asm-generic/bitops-instrumented.h:56 [inline]
> BUG: KASAN: use-after-free in usbhid_open+0x263/0x390
> drivers/hid/usbhid/hid-core.c:727
> Write of size 8 at addr ffff8881c89228c0 by task syz-executor.1/10380
>
> CPU: 0 PID: 10380 Comm: syz-executor.1 Not tainted 5.3.0-rc5+ #28
> 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
>   check_memory_region_inline mm/kasan/generic.c:185 [inline]
>   check_memory_region+0x128/0x190 mm/kasan/generic.c:192
>   clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
>   usbhid_open+0x263/0x390 drivers/hid/usbhid/hid-core.c:727
>   hid_hw_open+0xd2/0x160 drivers/hid/hid-core.c:2023
>   hidraw_open+0x256/0x740 drivers/hid/hidraw.c:288
>   chrdev_open+0x219/0x5c0 fs/char_dev.c:414
>   do_dentry_open+0x494/0x1120 fs/open.c:797
>   do_last fs/namei.c:3416 [inline]
>   path_openat+0x1430/0x3f50 fs/namei.c:3533
>   do_filp_open+0x1a1/0x280 fs/namei.c:3563
>   do_sys_open+0x3c0/0x580 fs/open.c:1089
>   do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x413761
> Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48
> 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48
> 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
> RSP: 002b:00007f50d4f077a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
> RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000413761
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f50d4f07850
> RBP: 000000000075bf20 R08: 000000000000000f R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000293 R12: 00007f50d4f086d4
> R13: 00000000004c8c86 R14: 00000000004dfc10 R15: 00000000ffffffff
>
> The buggy address belongs to the page:
> page:ffffea0007224880 refcount:0 mapcount:0 mapping:0000000000000000
> index:0x0
> flags: 0x200000000000000()
> raw: 0200000000000000 0000000000000000 dead000000000122 0000000000000000
> raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881c8922780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>   ffff8881c8922800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > ffff8881c8922880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>                                             ^
>   ffff8881c8922900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>   ffff8881c8922980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ==================================================================
>
>
> ---
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>
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#syz dup: general protection fault in __pm_runtime_resume