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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 ffff8880af6926df by task syz-executor.2/9094

CPU: 1 PID: 9094 Comm: syz-executor.2 Not tainted 4.14.277-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_xt_init+0x43/0x50 net/sched/act_ipt.c:210
 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:2455
 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: 0033:0x7fa974ee90e9
RSP: 002b:00007fa97385e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa974ffbf60 RCX: 00007fa974ee90e9
RDX: 0000000000000000 RSI: 0000000020000540 RDI: 0000000000000003
RBP: 00007fa974f4308d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe6fd486cf R14: 00007fa97385e300 R15: 0000000000022000

Allocated by task 9094:
 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:449 [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: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:2455
 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 8010:
 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
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:886 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1045 [inline]
 do_ip6t_get_ctl+0x5fc/0x7d0 net/ipv6/netfilter/ip6_tables.c:1716
 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
 nf_getsockopt+0x62/0xc0 net/netfilter/nf_sockopt.c:122
 ipv6_getsockopt+0x146/0x1e0 net/ipv6/ipv6_sockglue.c:1376
 tcp_getsockopt+0x7b/0xc0 net/ipv4/tcp.c:3259
 SYSC_getsockopt net/socket.c:1896 [inline]
 SyS_getsockopt+0x102/0x1c0 net/socket.c:1878
 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 ffff8880af6926c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 31 bytes inside of
 32-byte region [ffff8880af6926c0, ffff8880af6926e0)
The buggy address belongs to the page:
page:ffffea0002bda480 count:1 mapcount:0 mapping:ffff8880af692000 index:0xffff8880af692fc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880af692000 ffff8880af692fc1 0000000100000037
raw: ffffea0002aefde0 ffffea000295eb20 ffff88813fe741c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880af692580: 06 fc fc fc fc fc fc fc 06 fc fc fc fc fc fc fc
 ffff8880af692600: 00 01 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880af692680: fb fb fb fb fc fc fc fc 06 fc fc fc fc fc fc fc
                                                    ^
 ffff8880af692700: 00 03 fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
 ffff8880af692780: 06 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
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