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BUG: KASAN: slab-out-of-bounds in ecryptfs_verify_auth_tok_from_key+0x38f/0x3a0 fs/ecryptfs/keystore.c:473
Read of size 2 at addr ffff888045ad40db by task syz.0.0/5330

CPU: 0 UID: 0 PID: 5330 Comm: syz.0.0 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_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ecryptfs_verify_auth_tok_from_key+0x38f/0x3a0 fs/ecryptfs/keystore.c:473
 ecryptfs_keyring_auth_tok_for_sig+0xec/0x250 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+0x563/0x1370 fs/ecryptfs/main.c:453
 vfs_get_tree+0x92/0x2a0 fs/super.c:1932
 fc_mount fs/namespace.c:1278 [inline]
 do_new_mount_fc fs/namespace.c:3885 [inline]
 do_new_mount+0x325/0xb00 fs/namespace.c:3961
 do_mount fs/namespace.c:4325 [inline]
 __do_sys_mount fs/namespace.c:4543 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4520
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffb3279e559
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:00007ffb3364dfe8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffb32a25fa0 RCX: 00007ffb3279e559
RDX: 0000200000000600 RSI: 0000200000000500 RDI: 0000200000000400
RBP: 00007ffb328358b0 R08: 0000200000000700 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffb32a26038 R14: 00007ffb32a25fa0 R15: 00007ffff4e5a328
 </TASK>

Allocated by task 5330:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5414 [inline]
 __kmalloc_noprof+0x36b/0x720 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 user_preparse+0x9e/0x160 security/keys/user_defined.c:67
 __key_create_or_update+0x354/0xa70 security/keys/key.c:854
 key_create_or_update+0x42/0x60 security/keys/key.c:1021
 __do_sys_add_key security/keys/keyctl.c:134 [inline]
 __se_sys_add_key+0x349/0x420 security/keys/keyctl.c:74
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888045ad40c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 allocated 27-byte region [ffff888045ad40c0, ffff888045ad40db)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888045ad4dc0 pfn:0x45ad4
flags: 0x4fff00000000200(workingset|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000200 ffff88801c041780 ffffea0001064710 ffffea0000d71b90
raw: ffff888045ad4dc0 000000000040003f 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4988, tgid 4988 (dhcpcd), ts 113062262934
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7418
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __kmalloc_cache_noprof+0x39b/0x600 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 ref_tracker_alloc+0x15b/0x4b0 lib/ref_tracker.c:270
 __netdev_tracker_alloc include/linux/netdevice.h:4531 [inline]
 netdev_hold include/linux/netdevice.h:4560 [inline]
 fib_check_nh_nongw net/ipv4/fib_semantics.c:1293 [inline]
 fib_check_nh+0xcf1/0x1ac0 net/ipv4/fib_semantics.c:1313
 fib_create_info+0x200e/0x3170 net/ipv4/fib_semantics.c:1533
 fib_table_insert+0xcb/0x1b10 net/ipv4/fib_trie.c:1210
 fib_magic+0x43b/0x530 net/ipv4/fib_frontend.c:1147
 fib_add_ifaddr+0x1e7/0x5d0 net/ipv4/fib_frontend.c:1176
 fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1483
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
page last free pid 4988 tgid 4988 ts 113061316270 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
 mm_free_pgd kernel/fork.c:591 [inline]
 __mmdrop+0xbc/0x4d0 kernel/fork.c:734
 mmdrop include/linux/sched/mm.h:55 [inline]
 mmdrop_sched include/linux/sched/mm.h:83 [inline]
 mmdrop_lazy_tlb_sched include/linux/sched/mm.h:110 [inline]
 finish_task_switch+0x69a/0xc60 kernel/sched/core.c:5415
 context_switch kernel/sched/core.c:5536 [inline]
 __schedule+0x17e3/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 do_wait+0x283/0x510 kernel/exit.c:1738
 kernel_wait4+0x232/0x2b0 kernel/exit.c:1892
 __do_sys_wait4 kernel/exit.c:1920 [inline]
 __se_sys_wait4 kernel/exit.c:1916 [inline]
 __x64_sys_wait4+0x166/0x240 kernel/exit.c:1916
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888045ad3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888045ad4000: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff888045ad4080: fa fb fb fb fc fc fc fc 00 00 00 03 fc fc fc fc
                                                    ^
 ffff888045ad4100: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888045ad4180: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
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