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BUG: KASAN: slab-out-of-bounds in ecryptfs_verify_auth_tok_from_key+0x3b7/0x400 fs/ecryptfs/keystore.c:465
Read of size 2 at addr ffff888036ffded8 by task syz.1.1636/14093

CPU: 0 UID: 0 PID: 14093 Comm: syz.1.1636 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 ecryptfs_verify_auth_tok_from_key+0x3b7/0x400 fs/ecryptfs/keystore.c:465
 ecryptfs_keyring_auth_tok_for_sig+0x9e/0x1f0 fs/ecryptfs/keystore.c:1606
 ecryptfs_init_global_auth_toks fs/ecryptfs/main.c:194 [inline]
 ecryptfs_validate_options fs/ecryptfs/main.c:420 [inline]
 ecryptfs_get_tree+0x57b/0x15b0 fs/ecryptfs/main.c:453
 vfs_get_tree+0x92/0x320 fs/super.c:1932
 fc_mount fs/namespace.c:1282 [inline]
 do_new_mount_fc fs/namespace.c:3898 [inline]
 do_new_mount fs/namespace.c:3974 [inline]
 path_mount+0x7d0/0x2850 fs/namespace.c:4325
 do_mount fs/namespace.c:4338 [inline]
 __do_sys_mount fs/namespace.c:4556 [inline]
 __se_sys_mount fs/namespace.c:4533 [inline]
 __x64_sys_mount+0x293/0x310 fs/namespace.c:4533
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f486e99e559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f486cbd5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f486ec26090 RCX: 00007f486e99e559
RDX: 0000200000000240 RSI: 00002000000001c0 RDI: 0000200000000180
RBP: 00007f486ea35ab8 R08: 0000200000000340 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f486ec26128 R14: 00007f486ec26090 R15: 00007ffd8e4e5428
 </TASK>

Allocated by task 14090:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5414 [inline]
 __kmalloc_noprof+0x32f/0x840 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 user_preparse+0x9b/0x1c0 security/keys/user_defined.c:67
 __key_create_or_update+0x413/0xe30 security/keys/key.c:854
 key_create_or_update+0x42/0x60 security/keys/key.c:1021
 __do_sys_add_key+0x2e8/0x460 security/keys/keyctl.c:134
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888036ffdec0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
 allocated 25-byte region [ffff888036ffdec0, ffff888036ffded9)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888036ffda80 pfn:0x36ffd
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801d042780 ffffea0001583690 ffffea0001602850
raw: ffff888036ffda80 000000000040003e 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 9988803471
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab mm/slub.c:3462 [inline]
 new_slab+0xa9/0x6e0 mm/slub.c:3513
 refill_objects+0xe3/0x410 mm/slub.c:7418
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x67c/0x840 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 kobject_get_path+0xcf/0x2c0 lib/kobject.c:161
 kobject_uevent_env+0x287/0x18b0 lib/kobject_uevent.c:548
 kernel_add_sysfs_param kernel/params.c:803 [inline]
 param_sysfs_builtin kernel/params.c:838 [inline]
 param_sysfs_builtin_init+0x378/0x3f0 kernel/params.c:974
 do_one_initcall+0x11c/0x6f0 init/main.c:1362
 do_initcall_level init/main.c:1424 [inline]
 do_initcalls init/main.c:1440 [inline]
 do_basic_setup init/main.c:1460 [inline]
 kernel_init_freeable+0x6ea/0x7b0 init/main.c:1675
 kernel_init+0x21/0x1e0 init/main.c:1565
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888036ffdd80: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff888036ffde00: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff888036ffde80: 00 00 00 00 fc fc fc fc 00 00 00 01 fc fc fc fc
                                                    ^
 ffff888036ffdf00: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
 ffff888036ffdf80: 00 00 03 fc fc fc fc fc fa fb fb fb fc fc fc fc
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