netlink: 4 bytes leftover after parsing attributes in process `syz-executor.5'.
==================================================================
BUG: KASAN: slab-out-of-bounds in ipt_init_target+0x213/0x250 net/sched/act_ipt.c:46
Read of size 1 at addr ffff88809e8b9a1f by task syz-executor.5/15545

CPU: 1 PID: 15545 Comm: syz-executor.5 Not tainted 4.14.194-syzkaller #0
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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load1_noabort+0x68/0x70 mm/kasan/report.c:427
 ipt_init_target+0x213/0x250 net/sched/act_ipt.c:46
 __tcf_ipt_init+0x48d/0xc00 net/sched/act_ipt.c:168
 tcf_xt_init+0x43/0x50 net/sched/act_ipt.c:210
 tcf_action_init_1+0x51a/0x9e0 net/sched/act_api.c:682
 tcf_action_init+0x26d/0x400 net/sched/act_api.c:751
 tcf_action_add net/sched/act_api.c:1079 [inline]
 tc_ctl_action+0x2e3/0x50f net/sched/act_api.c:1131
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4316
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 sock_no_sendpage+0xe2/0x110 net/core/sock.c:2595
 kernel_sendpage net/socket.c:3407 [inline]
 sock_sendpage+0xdf/0x140 net/socket.c:871
 pipe_to_sendpage+0x226/0x2d0 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x326/0x7a0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0xc1/0x110 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xd59/0x1380 fs/splice.c:1382
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45d579
RSP: 002b:00007fb687da1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000033840 RCX: 000000000045d579
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000118d038 R08: 000000000004ffdc R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec
R13: 00007fff891850bf R14: 00007fb687da29c0 R15: 000000000118cfec

Allocated by task 15545:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc_track_caller+0x155/0x400 mm/slab.c:3735
 kmemdup+0x23/0x50 mm/util.c:118
 kmemdup include/linux/string.h:445 [inline]
 __tcf_ipt_init+0x464/0xc00 net/sched/act_ipt.c:164
 tcf_xt_init+0x43/0x50 net/sched/act_ipt.c:210
 tcf_action_init_1+0x51a/0x9e0 net/sched/act_api.c:682
 tcf_action_init+0x26d/0x400 net/sched/act_api.c:751
 tcf_action_add net/sched/act_api.c:1079 [inline]
 tc_ctl_action+0x2e3/0x50f net/sched/act_api.c:1131
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4316
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 sock_no_sendpage+0xe2/0x110 net/core/sock.c:2595
 kernel_sendpage net/socket.c:3407 [inline]
 sock_sendpage+0xdf/0x140 net/socket.c:871
 pipe_to_sendpage+0x226/0x2d0 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x326/0x7a0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0xc1/0x110 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xd59/0x1380 fs/splice.c:1382
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 14812:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:416
 __vunmap+0x20f/0x300 mm/vmalloc.c:1548
 vfree+0x4b/0xd0 mm/vmalloc.c:1612
 netlink_skb_destructor+0x17c/0x1c0 net/netlink/af_netlink.c:343
 skb_release_head_state+0x11e/0x250 net/core/skbuff.c:616
 skb_release_all net/core/skbuff.c:629 [inline]
 __kfree_skb net/core/skbuff.c:645 [inline]
 consume_skb+0xa7/0x380 net/core/skbuff.c:705
 netlink_unicast_kernel net/netlink/af_netlink.c:1288 [inline]
 netlink_unicast+0x43f/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 sock_no_sendpage+0xe2/0x110 net/core/sock.c:2595
 kernel_sendpage net/socket.c:3407 [inline]
 sock_sendpage+0xdf/0x140 net/socket.c:871
 pipe_to_sendpage+0x226/0x2d0 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x326/0x7a0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0xc1/0x110 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xd59/0x1380 fs/splice.c:1382
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88809e8b9a00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 31 bytes inside of
 32-byte region [ffff88809e8b9a00, ffff88809e8b9a20)
The buggy address belongs to the page:
page:ffffea00027a2e40 count:1 mapcount:0 mapping:ffff88809e8b9000 index:0xffff88809e8b9fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809e8b9000 ffff88809e8b9fc1 0000000100000036
raw: ffffea0002764be0 ffffea0002375ba0 ffff88812fe521c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e8b9900: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
 ffff88809e8b9980: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88809e8b9a00: 06 fc fc fc fc fc fc fc 00 00 fc fc fc fc fc fc
                            ^
 ffff88809e8b9a80: 00 00 01 fc fc fc fc fc 00 01 fc fc fc fc fc fc
 ffff88809e8b9b00: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
==================================================================