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BUG: KASAN: slab-out-of-bounds in strcmp+0x96/0xb0 lib/string.c:328
Read of size 1 at addr ffff8801d3190301 by task syz-executor5/15281

CPU: 1 PID: 15281 Comm: syz-executor5 Not tainted 4.15.0-rc2+ #210
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
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
 strcmp+0x96/0xb0 lib/string.c:328
 security_context_to_sid_core+0x437/0x620 security/selinux/ss/services.c:1420
 security_context_to_sid+0x32/0x40 security/selinux/ss/services.c:1479
 selinux_setprocattr+0x51c/0xb50 security/selinux/hooks.c:5985
 security_setprocattr+0x85/0xc0 security/security.c:1264
 proc_pid_attr_write+0x1e6/0x280 fs/proc/base.c:2545
 __vfs_write+0xef/0x970 fs/read_write.c:480
 vfs_write+0x18f/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
RIP: 0033:0x452a39
RSP: 002b:00007ff977aa6c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff977aa6950 RCX: 0000000000452a39
RDX: 0000000000000001 RSI: 0000000020002fff RDI: 0000000000000013
RBP: 00007ff977aa6940 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b73b4
R13: 00007ff977aa6ac8 R14: 00000000004b73c6 R15: 0000000000000000

Allocated by task 15281:
 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_track_caller+0x15e/0x760 mm/slab.c:3726
 memdup_user+0x2c/0x90 mm/util.c:164
 proc_pid_attr_write+0x115/0x280 fs/proc/base.c:2534
 __vfs_write+0xef/0x970 fs/read_write.c:480
 vfs_write+0x18f/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

Freed by task 13469:
 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
 seccomp_prepare_filter kernel/seccomp.c:389 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:421 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:856 [inline]
 do_seccomp+0x1c7e/0x21f0 kernel/seccomp.c:929
 SYSC_seccomp kernel/seccomp.c:943 [inline]
 SyS_seccomp+0x24/0x30 kernel/seccomp.c:940
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801d3190300
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 1 bytes inside of
 32-byte region [ffff8801d3190300, ffff8801d3190320)
The buggy address belongs to the page:
page:00000000e109853c count:1 mapcount:0 mapping:000000004166f799 index:0xffff8801d3190fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d3190000 ffff8801d3190fc1 000000010000003f
raw: ffffea0007521ba0 ffffea0007497f20 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d3190200: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d3190280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d3190300: 01 fc fc fc fc fc fc fc 07 fc fc fc fc fc fc fc
                   ^
 ffff8801d3190380: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d3190400: fb fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
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