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BUG: KASAN: slab-out-of-bounds in strcmp+0x96/0xb0 lib/string.c:328
Read of size 1 at addr ffff8801c4c26645 by task syz-executor1/5316

CPU: 1 PID: 5316 Comm: syz-executor1 Not tainted 4.15.0-rc2+ #120
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
 C_SYSC_sendfile fs/read_write.c:1489 [inline]
 compat_SyS_sendfile+0xea/0x1a0 fs/read_write.c:1478
 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: 0023:0xf7f93c79
RSP: 002b:00000000f778f08c EFLAGS: 00000296 ORIG_RAX: 00000000000000bb
RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 0000000000000014
RDX: 000000002002dff8 RSI: 0000000000000005 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 5316:
 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
 C_SYSC_sendfile fs/read_write.c:1489 [inline]
 compat_SyS_sendfile+0xea/0x1a0 fs/read_write.c:1478
 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 3357:
 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
 dccp_feat_init+0x32b/0x4e0 net/dccp/feat.c:1492
 dccp_init_sock+0x378/0x480 net/dccp/proto.c:205
 dccp_v4_init_sock+0x1e/0x90 net/dccp/ipv4.c:921
 inet_create+0x953/0xf50 net/ipv4/af_inet.c:377
 __sock_create+0x4d4/0x850 net/socket.c:1261
 sock_create net/socket.c:1301 [inline]
 SYSC_socketpair net/socket.c:1377 [inline]
 SyS_socketpair+0x1e1/0x640 net/socket.c:1352
 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

The buggy address belongs to the object at ffff8801c4c26640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 5 bytes inside of
 32-byte region [ffff8801c4c26640, ffff8801c4c26660)
The buggy address belongs to the page:
page:00000000d5317285 count:1 mapcount:0 mapping:00000000951d56fa index:0xffff8801c4c26fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c4c26000 ffff8801c4c26fc1 000000010000003f
raw: ffffea0007146ba0 ffffea000715d2e0 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c4c26500: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
 ffff8801c4c26580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801c4c26600: 00 00 00 00 fc fc fc fc 05 fc fc fc fc fc fc fc
                                           ^
 ffff8801c4c26680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c4c26700: 05 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
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