audit: type=1326 audit(1511932630.832:172): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=kernel pid=6387 comm="syz-executor6" exe="/root/syz-executor6" sig=0 arch=40000003 syscall=240 compat=1 ip=0xf7fbfc79 code=0x7ffc0000
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:341 [inline]
BUG: KASAN: slab-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
Write of size 192 at addr ffff8801cd3bd87c by task syz-executor3/6376

CPU: 0 PID: 6376 Comm: syz-executor3 Not tainted 4.15.0-rc1+ #109
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 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
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 memcpy include/linux/string.h:341 [inline]
 sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
 crypto_shash_update+0xcb/0x220 crypto/shash.c:109
 hmac_update+0x7e/0xa0 crypto/hmac.c:122
 crypto_shash_update+0xcb/0x220 crypto/shash.c:109
 kdf_ctr security/keys/dh.c:181 [inline]
 keyctl_dh_compute_kdf security/keys/dh.c:226 [inline]
 __keyctl_dh_compute+0x16d8/0x1a00 security/keys/dh.c:398
 compat_keyctl_dh_compute+0x2bb/0x3e0 security/keys/compat_dh.c:39
 C_SYSC_keyctl security/keys/compat.c:136 [inline]
 compat_SyS_keyctl+0x72/0x2c0 security/keys/compat.c:59
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125
RIP: 0023:0xf7fdbc79
RSP: 002b:00000000f77d708c EFLAGS: 00000296 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 0000000020ca2ff4
RDX: 0000000020ca0000 RSI: 0000000000000001 RDI: 0000000020fcd000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6376:
 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 mm/slab.c:3711 [inline]
 __kmalloc+0x162/0x760 mm/slab.c:3720
 kmalloc include/linux/slab.h:504 [inline]
 kdf_alloc security/keys/dh.c:111 [inline]
 __keyctl_dh_compute+0x2a1/0x1a00 security/keys/dh.c:288
 compat_keyctl_dh_compute+0x2bb/0x3e0 security/keys/compat_dh.c:39
 C_SYSC_keyctl security/keys/compat.c:136 [inline]
 compat_SyS_keyctl+0x72/0x2c0 security/keys/compat.c:59
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125

Freed by task 1721:
 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:3491 [inline]
 kfree+0xca/0x250 mm/slab.c:3806
 kernfs_fop_release+0x13f/0x180 fs/kernfs/file.c:783
 __fput+0x333/0x7f0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 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:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x94/0x96

The buggy address belongs to the object at ffff8801cd3bd780
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 252 bytes inside of
 512-byte region [ffff8801cd3bd780, ffff8801cd3bd980)
The buggy address belongs to the page:
page:ffffea000734ef40 count:1 mapcount:0 mapping:ffff8801cd3bd000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cd3bd000 0000000000000000 0000000100000006
raw: ffffea000735f260 ffffea0007350a60 ffff8801db000940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cd3bd800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801cd3bd880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801cd3bd900: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff8801cd3bd980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801cd3bda00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================