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BUG: KASAN: slab-out-of-bounds in asn1_ber_decoder+0x1436/0x1c20 lib/asn1_decoder.c:233
Read of size 1 at addr ffff8801dad74e82 by task syz-executor2/5470

CPU: 1 PID: 5470 Comm: syz-executor2 Not tainted 4.14.0-rc5-mm1+ #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
 asn1_ber_decoder+0x1436/0x1c20 lib/asn1_decoder.c:233
 x509_cert_parse+0x1dd/0x680 crypto/asymmetric_keys/x509_cert_parser.c:89
 x509_key_preparse+0x64/0x8b0 crypto/asymmetric_keys/x509_public_key.c:174
 asymmetric_key_preparse+0xa8/0x110 crypto/asymmetric_keys/asymmetric_type.c:386
 key_create_or_update+0x4c6/0xe20 security/keys/key.c:846
 SYSC_add_key security/keys/keyctl.c:122 [inline]
 SyS_add_key+0x18a/0x340 security/keys/keyctl.c:62
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x452869
RSP: 002b:00007fad79c30be8 EFLAGS: 00000212 ORIG_RAX: 00000000000000f8
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452869
RDX: 0000000020ce1000 RSI: 0000000020ef2ffb RDI: 0000000020b79000
RBP: 0000000000000082 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000212 R12: 00000000006f3d58
R13: 00000000ffffffff R14: 00007fad79c316d4 R15: 0000000000000000

Allocated by task 5470:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3676 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3683
 kmalloc_node include/linux/slab.h:541 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:538 [inline]
 SYSC_add_key security/keys/keyctl.c:104 [inline]
 SyS_add_key+0x279/0x340 security/keys/keyctl.c:62
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 3081:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3492 [inline]
 kfree+0xca/0x250 mm/slab.c:3807
 single_release+0x88/0xb0 fs/seq_file.c:602
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:112
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x296/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath+0x42f/0x510 arch/x86/entry/common.c:266
 entry_SYSCALL_64_fastpath+0xbc/0xbe

The buggy address belongs to the object at ffff8801dad74e80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 2 bytes inside of
 32-byte region [ffff8801dad74e80, ffff8801dad74ea0)
The buggy address belongs to the page:
page:ffffea00076b5d00 count:1 mapcount:0 mapping:ffff8801dad74000 index:0xffff8801dad74fc1
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801dad74000 ffff8801dad74fc1 000000010000003f
raw: ffffea00076b6e20 ffffea00076b67e0 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801dad74d80: 05 fc fc fc fc fc fc fc 02 fc fc fc fc fc fc fc
 ffff8801dad74e00: 00 fc fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff8801dad74e80: 02 fc fc fc fc fc fc fc 00 00 00 00 fc fc fc fc
                   ^
 ffff8801dad74f00: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
 ffff8801dad74f80: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc
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