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BUG: KASAN: slab-out-of-bounds in ipt_init_target+0x213/0x250 net/sched/act_ipt.c:46
Read of size 1 at addr ffff8880b37669df by task syz-executor126/7954

CPU: 1 PID: 7954 Comm: syz-executor126 Not tainted 4.14.285-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+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 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_ipt_init+0x43/0x50 net/sched/act_ipt.c:202
 tcf_action_init_1+0x51a/0x9e0 net/sched/act_api.c:691
 tcf_action_init+0x26d/0x400 net/sched/act_api.c:760
 tcf_action_add net/sched/act_api.c:1088 [inline]
 tc_ctl_action+0x2e3/0x510 net/sched/act_api.c:1140
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2454
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f95ae8c6249
RSP: 002b:00007ffe7224bad8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f95ae8c6249
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00007f95ae88a230 R08: 000000000000000c R09: 0000000000000000
R10: 0000000000000006 R11: 0000000000000246 R12: 00007f95ae88a2c0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 7954:
 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:119
 kmemdup include/linux/string.h:449 [inline]
 __tcf_ipt_init+0x464/0xc00 net/sched/act_ipt.c:164
 tcf_ipt_init+0x43/0x50 net/sched/act_ipt.c:202
 tcf_action_init_1+0x51a/0x9e0 net/sched/act_api.c:691
 tcf_action_init+0x26d/0x400 net/sched/act_api.c:760
 tcf_action_add net/sched/act_api.c:1088 [inline]
 tc_ctl_action+0x2e3/0x510 net/sched/act_api.c:1140
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2454
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 6210:
 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
 single_release+0x85/0xb0 fs/seq_file.c:609
 close_pdeo.part.0+0xdd/0x2c0 fs/proc/inode.c:165
 close_pdeo fs/proc/inode.c:382 [inline]
 proc_reg_release+0x1fd/0x250 fs/proc/inode.c:376
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880b37669c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 31 bytes inside of
 32-byte region [ffff8880b37669c0, ffff8880b37669e0)
The buggy address belongs to the page:
page:ffffea0002cdd980 count:1 mapcount:0 mapping:ffff8880b3766000 index:0xffff8880b3766fc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880b3766000 ffff8880b3766fc1 000000010000001f
raw: ffffea000285f420 ffffea0002cc83a0 ffff88813fe741c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b3766880: 00 06 fc fc fc fc fc fc 00 00 fc fc fc fc fc fc
 ffff8880b3766900: fb fb fb fb fc fc fc fc 00 01 fc fc fc fc fc fc
>ffff8880b3766980: fb fb fb fb fc fc fc fc 03 fc fc fc fc fc fc fc
                                                    ^
 ffff8880b3766a00: fb fb fb fb fc fc fc fc 00 04 fc fc fc fc fc fc
 ffff8880b3766a80: fb fb fb fb fc fc fc fc 00 02 fc fc fc fc fc fc
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