Message-ID: <CACT4Y+bm+S-_b3saGichr3aA06rvsXyp28og_CONrh5fRhe8Eg@mail.gmail.com>
Date:   Thu, 3 Feb 2022 07:09:52 +0100
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     Hillf Danton <hdanton@...a.com>
Cc:     syzbot <syzbot+953a33deaf38c66a915e@...kaller.appspotmail.com>,
        benjamin.tissoires@...hat.com, jikos@...nel.org,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] general protection fault in hidraw_release

On Thu, 3 Feb 2022 at 05:02, Hillf Danton <hdanton@...a.com> wrote:
>
> On Tue, 01 Feb 2022 23:19:25 -0800
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit:    9f7fb8de5d9b Merge tag 'spi-fix-v5.17-rc2' of git://git.ke..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1653b6cbb00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3e56c9b92aaaee24
> > dashboard link: https://syzkaller.appspot.com/bug?extid=953a33deaf38c66a915e
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15fff530700000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=106469f0700000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+953a33deaf38c66a915e@...kaller.appspotmail.com
> >
> > ==================================================================
> > BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0xf0 lib/list_debug.c:51
> > Read of size 8 at addr ffff8880143e8eb0 by task syz-executor753/4862
> >
> > CPU: 0 PID: 4862 Comm: syz-executor753 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> >  <TASK>
> >  __dump_stack lib/dump_stack.c:88 [inline]
> >  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> >  print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
> >  __kasan_report mm/kasan/report.c:442 [inline]
> >  kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
> >  __list_del_entry_valid+0xe0/0xf0 lib/list_debug.c:51
> >  __list_del_entry include/linux/list.h:134 [inline]
> >  list_del include/linux/list.h:148 [inline]
>
> What is difficult to follow is syzbot instead did not complain at the spin_lock
> prior to list_del in regard to uaf.
>
> Any light on the difficulty is welcome.

Hi Hillf,

If you mean these lock/unlock:

spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
list_del(&list->node);
spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);

They seem to operate on a global hidraw_table locks.
I would assume only this file is corrupted/bad, but the global lock
table is fine.


> >  hidraw_release+0xd5/0x370 drivers/hid/hidraw.c:353
> >  __fput+0x286/0x9f0 fs/file_table.c:311
> >  task_work_run+0xdd/0x1a0 kernel/task_work.c:164
> >  exit_task_work include/linux/task_work.h:32 [inline]
> >  do_exit+0xb29/0x2a30 kernel/exit.c:806
> >  do_group_exit+0xd2/0x2f0 kernel/exit.c:935
> >  __do_sys_exit_group kernel/exit.c:946 [inline]
> >  __se_sys_exit_group kernel/exit.c:944 [inline]
> >  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944
> >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >  entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x7f4256d1c749
> > Code: Unable to access opcode bytes at RIP 0x7f4256d1c71f.
> > RSP: 002b:00007fffddc9a4e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> > RAX: ffffffffffffffda RBX: 00007f4256d913f0 RCX: 00007f4256d1c749
> > RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> > RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00007fffddc9a560
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4256d913f0
> > R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
> >  </TASK>
> >
> > Allocated by task 20:
> >  kasan_save_stack+0x1e/0x40 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+0xa6/0xd0 mm/kasan/common.c:524
> >  kasan_kmalloc include/linux/kasan.h:270 [inline]
> >  kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3567
> >  kmalloc include/linux/slab.h:581 [inline]
> >  kzalloc include/linux/slab.h:715 [inline]
> >  hidraw_connect+0x4b/0x440 drivers/hid/hidraw.c:543
> >  hid_connect+0x5be/0xbc0 drivers/hid/hid-core.c:1960
> >  hid_hw_start drivers/hid/hid-core.c:2059 [inline]
> >  hid_hw_start+0xa2/0x130 drivers/hid/hid-core.c:2050
> >  hid_generic_probe drivers/hid/hid-generic.c:67 [inline]
> >  hid_generic_probe+0x6d/0x90 drivers/hid/hid-generic.c:56
> >  hid_device_probe+0x2bd/0x3f0 drivers/hid/hid-core.c:2380
> >  call_driver_probe drivers/base/dd.c:517 [inline]
> >  really_probe+0x245/0xcc0 drivers/base/dd.c:596
> >  __driver_probe_device+0x338/0x4d0 drivers/base/dd.c:752
> >  driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:782
> >  __device_attach_driver+0x20b/0x2f0 drivers/base/dd.c:899
> >  bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:427
> >  __device_attach+0x228/0x4a0 drivers/base/dd.c:970
> >  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:487
> >  device_add+0xc17/0x1ee0 drivers/base/core.c:3405
> >  hid_add_device+0x344/0x9d0 drivers/hid/hid-core.c:2530
> >  uhid_device_add_worker+0x36/0x60 drivers/hid/uhid.c:73
> >  process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
> >  worker_thread+0x657/0x1110 kernel/workqueue.c:2454
> >  kthread+0x2e9/0x3a0 kernel/kthread.c:377
> >  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
> >
> > Freed by task 4861:
> >  kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> >  kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> >  kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> >  ____kasan_slab_free mm/kasan/common.c:366 [inline]
> >  ____kasan_slab_free mm/kasan/common.c:328 [inline]
> >  __kasan_slab_free+0xee/0x130 mm/kasan/common.c:374
> >  kasan_slab_free include/linux/kasan.h:236 [inline]
> >  __cache_free mm/slab.c:3437 [inline]
> >  kfree+0xf6/0x290 mm/slab.c:3794
> >  drop_ref+0x28f/0x390 drivers/hid/hidraw.c:335
> >  hidraw_release+0x255/0x370 drivers/hid/hidraw.c:357
> >  __fput+0x286/0x9f0 fs/file_table.c:311
> >  task_work_run+0xdd/0x1a0 kernel/task_work.c:164
> >  exit_task_work include/linux/task_work.h:32 [inline]
> >  do_exit+0xb29/0x2a30 kernel/exit.c:806
> >  do_group_exit+0xd2/0x2f0 kernel/exit.c:935
> >  __do_sys_exit_group kernel/exit.c:946 [inline]
> >  __se_sys_exit_group kernel/exit.c:944 [inline]
> >  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944
> >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >  entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > The buggy address belongs to the object at ffff8880143e8e00
> >  which belongs to the cache kmalloc-192 of size 192
> > The buggy address is located 176 bytes inside of
> >  192-byte region [ffff8880143e8e00, ffff8880143e8ec0)
> > The buggy address belongs to the page:
> > page:ffffea000050fa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x143e8
> > flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
> > raw: 00fff00000000200 ffffea000050f188 ffffea000050fc48 ffff888010c40000
> > raw: 0000000000000000 ffff8880143e8000 0000000100000010 0000000000000000
> > page dumped because: kasan: bad access detected
> > page_owner tracks the page as allocated
> > page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 1, ts 2151082992, free_ts 0
> >  prep_new_page mm/page_alloc.c:2434 [inline]
> >  get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
> >  __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
> >  __alloc_pages_node include/linux/gfp.h:572 [inline]
> >  kmem_getpages mm/slab.c:1378 [inline]
> >  cache_grow_begin+0x75/0x350 mm/slab.c:2584
> >  cache_alloc_refill+0x27f/0x380 mm/slab.c:2957
> >  ____cache_alloc mm/slab.c:3040 [inline]
> >  ____cache_alloc mm/slab.c:3023 [inline]
> >  __do_cache_alloc mm/slab.c:3267 [inline]
> >  slab_alloc mm/slab.c:3308 [inline]
> >  kmem_cache_alloc_trace+0x380/0x4a0 mm/slab.c:3565
> >  kmalloc include/linux/slab.h:581 [inline]
> >  kzalloc include/linux/slab.h:715 [inline]
> >  call_usermodehelper_setup+0x9d/0x340 kernel/umh.c:365
> >  kobject_uevent_env+0xf28/0x1600 lib/kobject_uevent.c:614
> >  kernel_add_sysfs_param kernel/params.c:816 [inline]
> >  param_sysfs_builtin kernel/params.c:851 [inline]
> >  param_sysfs_init+0x367/0x43b kernel/params.c:970
> >  do_one_initcall+0x103/0x650 init/main.c:1300
> >  do_initcall_level init/main.c:1373 [inline]
> >  do_initcalls init/main.c:1389 [inline]
> >  do_basic_setup init/main.c:1408 [inline]
> >  kernel_init_freeable+0x6b1/0x73a init/main.c:1613
> >  kernel_init+0x1a/0x1d0 init/main.c:1502
> >  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
> > page_owner free stack trace missing
> >
> > Memory state around the buggy address:
> >  ffff8880143e8d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> >  ffff8880143e8e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > >ffff8880143e8e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> >                                      ^
> >  ffff8880143e8f00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >  ffff8880143e8f80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> > ==================================================================
>
> --
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