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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
Read of size 1 at addr ffff8880a91b46af by task syz-executor.5/17123

CPU: 0 PID: 17123 Comm: syz-executor.5 Not tainted 5.8.0-rc7-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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3321
 sscanf+0x6c/0x90 lib/vsprintf.c:3527
 smk_set_cipso+0x374/0x6c0 security/smack/smackfs.c:908
 vfs_write+0x2dd/0xc70 fs/read_write.c:576
 ksys_write+0x11b/0x220 fs/read_write.c:631
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cc79
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2551f23c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000038600 RCX: 000000000045cc79
RDX: 000000000000002e RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffee6222d4f R14: 00007f2551f249c0 R15: 000000000078bf0c

Allocated by task 17123:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __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/0x6c0 security/smack/smackfs.c:859
 vfs_write+0x2dd/0xc70 fs/read_write.c:576
 ksys_write+0x11b/0x220 fs/read_write.c:631
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 16297:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 tomoyo_path2_perm+0x752/0x940 security/tomoyo/file.c:946
 tomoyo_path_rename+0xee/0x120 security/tomoyo/tomoyo.c:279
 security_path_rename+0x21b/0x2e0 security/security.c:1135
 do_renameat2+0x644/0x1070 fs/namei.c:4446
 __do_sys_rename fs/namei.c:4496 [inline]
 __se_sys_rename fs/namei.c:4494 [inline]
 __x64_sys_rename+0x64/0x70 fs/namei.c:4494
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a91b4680
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 47 bytes inside of
 64-byte region [ffff8880a91b4680, ffff8880a91b46c0)
The buggy address belongs to the page:
page:ffffea0002a46d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00024b8208 ffffea0002a09a08 ffff8880aa400380
raw: 0000000000000000 ffff8880a91b4000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a91b4580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880a91b4600: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff8880a91b4680: 00 00 00 00 00 07 fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff8880a91b4700: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8880a91b4780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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