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BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275
Read of size 1 at addr ffff88809e795002 by task syz-executor.1/23775

CPU: 0 PID: 23775 Comm: syz-executor.1 Not tainted 5.6.0-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:374
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506
 kasan_report+0x25/0x50 mm/kasan/common.c:641
 vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275
 sscanf+0x6c/0x90 lib/vsprintf.c:3481
 smk_set_cipso+0x1ac/0x6a0 security/smack/smackfs.c:881
 __vfs_write+0xa7/0x710 fs/read_write.c:494
 __kernel_write+0x12f/0x340 fs/read_write.c:515
 write_pipe_buf+0xf9/0x150 fs/splice.c:809
 splice_from_pipe_feed fs/splice.c:512 [inline]
 __splice_from_pipe+0x329/0x870 fs/splice.c:636
 splice_from_pipe fs/splice.c:671 [inline]
 default_file_splice_write+0x112/0x1b0 fs/splice.c:821
 do_splice_from fs/splice.c:863 [inline]
 do_splice+0xdcd/0x18c0 fs/splice.c:1170
 __do_sys_splice fs/splice.c:1447 [inline]
 __se_sys_splice+0x172/0x230 fs/splice.c:1427
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c849
Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f983edd9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f983edda6d4 RCX: 000000000045c849
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000076bf00 R08: 0000000100040000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000ba2 R14: 00000000004ce68a R15: 000000000076bf0c

Allocated by task 23775:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515
 __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:494
 __kernel_write+0x12f/0x340 fs/read_write.c:515
 write_pipe_buf+0xf9/0x150 fs/splice.c:809
 splice_from_pipe_feed fs/splice.c:512 [inline]
 __splice_from_pipe+0x329/0x870 fs/splice.c:636
 splice_from_pipe fs/splice.c:671 [inline]
 default_file_splice_write+0x112/0x1b0 fs/splice.c:821
 do_splice_from fs/splice.c:863 [inline]
 do_splice+0xdcd/0x18c0 fs/splice.c:1170
 __do_sys_splice fs/splice.c:1447 [inline]
 __se_sys_splice+0x172/0x230 fs/splice.c:1427
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 22942:
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 tomoyo_check_open_permission+0x6e2/0x900 security/tomoyo/file.c:786
 security_file_open+0x50/0x2c0 security/security.c:1548
 do_dentry_open+0x35d/0x10b0 fs/open.c:784
 do_last fs/namei.c:3490 [inline]
 path_openat+0x13c5/0x40f0 fs/namei.c:3607
 do_filp_open+0x191/0x3a0 fs/namei.c:3637
 do_sys_openat2+0x448/0x6c0 fs/open.c:1146
 do_sys_open fs/open.c:1162 [inline]
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_open fs/open.c:1168 [inline]
 __se_sys_open fs/open.c:1166 [inline]
 __x64_sys_open+0x1af/0x1e0 fs/open.c:1166
 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 ffff88809e795000
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 2 bytes inside of
 32-byte region [ffff88809e795000, ffff88809e795020)
The buggy address belongs to the page:
page:ffffea000279e540 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff88809e795fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027c8508 ffffea000250abc8 ffff8880aa4001c0
raw: ffff88809e795fc1 ffff88809e795000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e794f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e794f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809e795000: 02 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
                   ^
 ffff88809e795080: 00 04 fc fc fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff88809e795100: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
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