==================================================================
BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275
Read of size 1 at addr ffff88809f9c4ac5 by task syz-executor.0/25630

CPU: 1 PID: 25630 Comm: syz-executor.0 Not tainted 5.7.0-rc4-syzkaller #0
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+0x1e9/0x30e lib/dump_stack.c:118
 print_address_description+0x74/0x5c0 mm/kasan/report.c:382
 __kasan_report+0x103/0x1a0 mm/kasan/report.c:511
 kasan_report+0x4d/0x80 mm/kasan/common.c:625

Allocated by task 25630:
 save_stack mm/kasan/common.c:49 [inline]
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671
 memdup_user_nul+0x26/0xf0 mm/util.c:259
 smk_set_cipso+0xff/0x6a0 security/smack/smackfs.c:859
 __vfs_write+0xa7/0x710 fs/read_write.c:495
 vfs_write+0x274/0x580 fs/read_write.c:559
 ksys_write+0x11b/0x220 fs/read_write.c:612
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 25229:
 save_stack mm/kasan/common.c:49 [inline]
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0x125/0x190 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 tomoyo_path_number_perm+0x525/0x690 security/tomoyo/file.c:736
 security_file_ioctl+0x55/0xb0 security/security.c:1460
 ksys_ioctl fs/ioctl.c:765 [inline]
 __do_sys_ioctl fs/ioctl.c:780 [inline]
 __se_sys_ioctl+0x48/0x160 fs/ioctl.c:778
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff88809f9c4ac0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 5 bytes inside of
 32-byte region [ffff88809f9c4ac0, ffff88809f9c4ae0)
The buggy address belongs to the page:
page:ffffea00027e7100 refcount:1 mapcount:0 mapping:00000000fd99ca53 index:0xffff88809f9c4fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002592648 ffffea00027962c8 ffff8880aa4001c0
raw: ffff88809f9c4fc1 ffff88809f9c4000 000000010000003c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f9c4980: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
 ffff88809f9c4a00: 00 00 00 01 fc fc fc fc 00 00 01 fc fc fc fc fc
>ffff88809f9c4a80: 00 00 01 fc fc fc fc fc 05 fc fc fc fc fc fc fc
                                           ^
 ffff88809f9c4b00: 00 00 01 fc fc fc fc fc 06 fc fc fc fc fc fc fc
 ffff88809f9c4b80: 06 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================