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BUG: KASAN: slab-out-of-bounds in strcmp+0x96/0xb0 lib/string.c:328
Read of size 1 at addr ffff8801d7c40245 by task syz-executor7/3946

CPU: 0 PID: 3946 Comm: syz-executor7 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
 __kernel_write+0xfe/0x350 fs/read_write.c:501
 write_pipe_buf+0x175/0x220 fs/splice.c:797
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x328/0x730 fs/splice.c:626
 splice_from_pipe+0x1e9/0x330 fs/splice.c:661
 default_file_splice_write+0x40/0x90 fs/splice.c:809
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x125/0x180 fs/splice.c:1018
 splice_direct_to_actor+0x2c1/0x820 fs/splice.c:973
 do_splice_direct+0x2a7/0x3d0 fs/splice.c:1061
 do_sendfile+0x5d5/0xe90 fs/read_write.c:1413
 SYSC_sendfile64 fs/read_write.c:1468 [inline]
 SyS_sendfile64+0xbd/0x160 fs/read_write.c:1460
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007ff008ee3c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452a39
RDX: 0000000020885fff RSI: 0000000000000013 RDI: 0000000000000013
RBP: 000000000000060d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000212 R12: 00000000006f61d8
R13: 00000000ffffffff R14: 00007ff008ee46d4 R15: 0000000000000000

Allocated by task 3946:
 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
 __kernel_write+0xfe/0x350 fs/read_write.c:501
 write_pipe_buf+0x175/0x220 fs/splice.c:797
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x328/0x730 fs/splice.c:626
 splice_from_pipe+0x1e9/0x330 fs/splice.c:661
 default_file_splice_write+0x40/0x90 fs/splice.c:809
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x125/0x180 fs/splice.c:1018
 splice_direct_to_actor+0x2c1/0x820 fs/splice.c:973
 do_splice_direct+0x2a7/0x3d0 fs/splice.c:1061
 do_sendfile+0x5d5/0xe90 fs/read_write.c:1413
 SYSC_sendfile64 fs/read_write.c:1468 [inline]
 SyS_sendfile64+0xbd/0x160 fs/read_write.c:1460
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1497:
 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
 tty_ldisc_put+0x4c/0x70 drivers/tty/tty_ldisc.c:202
 tty_ldisc_kill+0x6e/0xc0 drivers/tty/tty_ldisc.c:641
 tty_ldisc_hangup+0x2a1/0x5e0 drivers/tty/tty_ldisc.c:758
 __tty_hangup.part.23+0x2e1/0x680 drivers/tty/tty_io.c:613
 __tty_hangup drivers/tty/tty_io.c:571 [inline]
 tty_vhangup+0x21/0x30 drivers/tty/tty_io.c:685
 pty_close+0x365/0x4b0 drivers/tty/pty.c:78
 tty_release+0x446/0x14c0 drivers/tty/tty_io.c:1639
 __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 ffff8801d7c40240
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 5 bytes inside of
 32-byte region [ffff8801d7c40240, ffff8801d7c40260)
The buggy address belongs to the page:
page:000000002f1bb1b9 count:1 mapcount:0 mapping:00000000f59f87a6 index:0xffff8801d7c40fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d7c40000 ffff8801d7c40fc1 0000000100000034
raw: ffffea00076c61e0 ffffea00076c7320 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d7c40100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d7c40180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d7c40200: 00 00 fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
                                           ^
 ffff8801d7c40280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d7c40300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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