netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.
==================================================================
futex_wake_op: syz-executor.2 tries to shift op by 4095; fix this program
BUG: KASAN: slab-out-of-bounds in ipt_init_target+0x206/0x240 net/sched/act_ipt.c:46
Read of size 1 at addr ffff88809ddf365f by task syz-executor.0/22752

CPU: 1 PID: 22752 Comm: syz-executor.0 Not tainted 4.14.180-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+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 ipt_init_target+0x206/0x240 net/sched/act_ipt.c:46
 __tcf_ipt_init+0x455/0xaf0 net/sched/act_ipt.c:168
 tcf_xt_init+0x43/0x50 net/sched/act_ipt.c:210
 tcf_action_init_1+0x51a/0x9f0 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+0x2e3/0x513 net/sched/act_api.c:1131
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 sock_no_sendpage+0xe5/0x110 net/core/sock.c:2572
 kernel_sendpage+0x82/0xd0 net/socket.c:3407
 sock_sendpage+0x84/0xa0 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+0x332/0x740 fs/splice.c:626
 splice_from_pipe+0xc6/0x120 fs/splice.c:661
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xca0/0x1230 fs/splice.c:1382
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45ca29
RSP: 002b:00007f0d8f6efc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00000000005079c0 RCX: 000000000045ca29
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000078c040 R08: 000000000004ffe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000bae R14: 00000000004ce9f7 R15: 00007f0d8f6f06d4

Allocated by task 22752:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc_track_caller+0x153/0x7b0 mm/slab.c:3735
 kmemdup+0x23/0x50 mm/util.c:118
 kmemdup include/linux/string.h:420 [inline]
 __tcf_ipt_init+0x431/0xaf0 net/sched/act_ipt.c:164
 tcf_xt_init+0x43/0x50 net/sched/act_ipt.c:210
 tcf_action_init_1+0x51a/0x9f0 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+0x2e3/0x513 net/sched/act_api.c:1131
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 sock_no_sendpage+0xe5/0x110 net/core/sock.c:2572
 kernel_sendpage+0x82/0xd0 net/socket.c:3407
 sock_sendpage+0x84/0xa0 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+0x332/0x740 fs/splice.c:626
 splice_from_pipe+0xc6/0x120 fs/splice.c:661
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xca0/0x1230 fs/splice.c:1382
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 2319:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 batadv_mcast_mla_list_free net/batman-adv/multicast.c:259 [inline]
 __batadv_mcast_mla_update net/batman-adv/multicast.c:573 [inline]
 batadv_mcast_mla_update+0x8f1/0x1a00 net/batman-adv/multicast.c:596
 process_one_work+0x813/0x1540 kernel/workqueue.c:2116
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff88809ddf3640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 31 bytes inside of
 32-byte region [ffff88809ddf3640, ffff88809ddf3660)
The buggy address belongs to the page:
page:ffffea0002777cc0 count:1 mapcount:0 mapping:ffff88809ddf3000 index:0xffff88809ddf3fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809ddf3000 ffff88809ddf3fc1 000000010000003e
raw: ffffea00024c5220 ffffea0002405560 ffff88812fe541c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809ddf3500: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
 ffff88809ddf3580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88809ddf3600: fb fb fb fb fc fc fc fc 06 fc fc fc fc fc fc fc
                                                    ^
 ffff88809ddf3680: 00 00 01 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809ddf3700: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
==================================================================
futex_wake_op: syz-executor.2 tries to shift op by 4095; fix this program