KASAN: use-after-free Read in add_uevent_var

Status: closed as dup on 2019/05/05 08:45
Subsystems: input
[Documentation on labels]
Reported-by: syzbot+6da9575ba2db4da91831@syzkaller.appspotmail.com
First crash: 2662d, last: 2661d
Cause bisection: introduced by (bisect log) :
commit 0a1c7959acd9674a0e4e59f911f3e5fbf25fd693
Author: Wolfram Sang <wsa@the-dreams.de>
Date: Wed May 17 15:22:18 2017 +0000

  gpu: drm: tc35876x: move header file out of I2C realm

Crash: KASAN: use-after-free Read in add_uevent_var (log)
Repro: C syz .config
  
▶ ▼ Duplicate of
Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported
KASAN: use-after-free Read in string input 19 syz, C 247 2664d 2904d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
KASAN: use-after-free Read in add_uevent_var 3 (4) 2019/05/06 12:39
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2019/05/05 10:30 1m penguin-kernel@i-love.sakura.ne.jp patch upstream error

Sample crash report:
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000005502
RDX: 0000000000000000 RSI: 00000000080daf20 RDI: 00000000080f0f84
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
==================================================================
BUG: KASAN: use-after-free in string+0x208/0x230 lib/vsprintf.c:606
Read of size 1 at addr ffff8880a55aa200 by task syz-executor222/7839

CPU: 1 PID: 7839 Comm: syz-executor222 Not tainted 5.1.0-rc7+ #98
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
 string+0x208/0x230 lib/vsprintf.c:606
 vsnprintf+0xbfc/0x1af0 lib/vsprintf.c:2396
 add_uevent_var+0x14d/0x310 lib/kobject_uevent.c:661
 input_dev_uevent+0x163/0x890 drivers/input/input.c:1594
 dev_uevent+0x312/0x580 drivers/base/core.c:1180
 kobject_uevent_env+0x487/0x1030 lib/kobject_uevent.c:549
 kobject_uevent+0x20/0x26 lib/kobject_uevent.c:638
 kobject_cleanup lib/kobject.c:649 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:67 [inline]
 kobject_put.cold+0x177/0x2ec lib/kobject.c:708
 put_device+0x20/0x30 drivers/base/core.c:2205
 input_put_device include/linux/input.h:349 [inline]
 evdev_free+0x51/0x70 drivers/input/evdev.c:369
 device_release+0x7d/0x210 drivers/base/core.c:1064
 kobject_cleanup lib/kobject.c:662 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:67 [inline]
 kobject_put.cold+0x28f/0x2ec lib/kobject.c:708
 cdev_default_release+0x41/0x50 fs/char_dev.c:607
 kobject_cleanup lib/kobject.c:662 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:67 [inline]
 kobject_put.cold+0x28f/0x2ec lib/kobject.c:708
 cdev_put.part.0+0x39/0x50 fs/char_dev.c:368
 cdev_put+0x20/0x30 fs/char_dev.c:366
 __fput+0x6df/0x8d0 fs/file_table.c:281
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x90a/0x2fa0 kernel/exit.c:876
 do_group_exit+0x135/0x370 kernel/exit.c:980
 __do_sys_exit_group kernel/exit.c:991 [inline]
 __se_sys_exit_group kernel/exit.c:989 [inline]
 __ia32_sys_exit_group+0x44/0x50 kernel/exit.c:989
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7ff7849
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000fff2db8c EFLAGS: 00000292 ORIG_RAX: 00000000000000fc
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080f1298
RDX: 0000000000000000 RSI: 00000000080daf1c RDI: 00000000080f12a0
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 7839:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc_track_caller+0x158/0x740 mm/slab.c:3742
 kstrndup+0x5f/0xf0 mm/util.c:96
 uinput_dev_setup+0x1d4/0x310 drivers/input/misc/uinput.c:475
 uinput_ioctl_handler.isra.0+0x12b8/0x1cc0 drivers/input/misc/uinput.c:886
 uinput_compat_ioctl+0x70/0x90 drivers/input/misc/uinput.c:1062
 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline]
 __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline]
 __ia32_compat_sys_ioctl+0x197/0x620 fs/compat_ioctl.c:998
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 7839:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3499 [inline]
 kfree+0xcf/0x230 mm/slab.c:3822
 uinput_destroy_device+0xf8/0x250 drivers/input/misc/uinput.c:311
 uinput_ioctl_handler.isra.0+0x886/0x1cc0 drivers/input/misc/uinput.c:882
 uinput_compat_ioctl+0x70/0x90 drivers/input/misc/uinput.c:1062
 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline]
 __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline]
 __ia32_compat_sys_ioctl+0x197/0x620 fs/compat_ioctl.c:998
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff8880a55aa200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880a55aa200, ffff8880a55aa220)
The buggy address belongs to the page:
page:ffffea0002956a80 count:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff8880a55aafc1
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002949e88 ffffea00029482c8 ffff8880aa4001c0
raw: ffff8880a55aafc1 ffff8880a55aa000 0000000100000039 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a55aa100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a55aa180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a55aa200: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff8880a55aa280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a55aa300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/05/04 05:44 upstream a4ccb5f9dc6c d28f4ce5 .config console log report syz C ci-upstream-kasan-gce-386
2019/05/04 17:44 upstream aa1be08f5258 d28f4ce5 .config console log report ci-upstream-kasan-gce-386
2019/05/04 05:17 upstream a4ccb5f9dc6c d28f4ce5 .config console log report ci-upstream-kasan-gce-386
* Struck through repros no longer work on HEAD.