audit: type=1400 audit(1514638600.296:7): avc:  denied  { map } for  pid=3153 comm="syzkaller620982" path="/root/syzkaller620982068" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in cap_convert_nscap+0x501/0x610 security/commoncap.c:498
Read of size 4 at addr ffff8801c8195940 by task syzkaller620982/3153

CPU: 0 PID: 3153 Comm: syzkaller620982 Not tainted 4.15.0-rc4-mm1+ #49
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:256
 kasan_report_error mm/kasan/report.c:355 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:413
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:433
 cap_convert_nscap+0x501/0x610 security/commoncap.c:498
 setxattr+0x365/0x400 fs/xattr.c:446
 SYSC_fsetxattr fs/xattr.c:508 [inline]
 SyS_fsetxattr+0x130/0x190 fs/xattr.c:497
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x43fcf9
RSP: 002b:00007ffe0f3de128 EFLAGS: 00000203 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 6f72746e6f632f2e RCX: 000000000043fcf9
RDX: 00000000208c4fe9 RSI: 0000000020f4c000 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000203 R12: 0000000000401660
R13: 00000000004016f0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 3153:
 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:3669 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3676
 kmalloc_node include/linux/slab.h:558 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 setxattr+0x152/0x400 fs/xattr.c:435
 SYSC_fsetxattr fs/xattr.c:508 [inline]
 SyS_fsetxattr+0x130/0x190 fs/xattr.c:497
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1652:
 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:3485 [inline]
 kfree+0xd6/0x260 mm/slab.c:3800
 security_context_to_sid_core+0x182/0x5a0 security/selinux/ss/services.c:1460
 security_context_to_sid+0x32/0x40 security/selinux/ss/services.c:1480
 sel_write_context+0x18b/0x340 security/selinux/selinuxfs.c:556
 selinux_transaction_write+0xd1/0x130 security/selinux/selinuxfs.c:735
 __vfs_write+0xef/0x970 fs/read_write.c:480
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801c8195940
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801c8195940, ffff8801c8195960)
The buggy address belongs to the page:
page:ffffea0007206540 count:1 mapcount:0 mapping:ffff8801c8195000 index:0xffff8801c8195fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c8195000 ffff8801c8195fc1 000000010000003f
raw: ffffea000727e9e0 ffffea00072068e0 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c8195800: 00 00 00 fc fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff8801c8195880: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff8801c8195900: fb fb fb fb fc fc fc fc 01 fc fc fc fc fc fc fc
                                           ^
 ffff8801c8195980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c8195a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================