Use struct sctp_assoc_value instead
==================================================================
BUG: KASAN: slab-out-of-bounds in xfrm_hash_rebuild+0xdbe/0xf00 net/xfrm/xfrm_policy.c:618
Read of size 2 at addr ffff8801c5ff3be4 by task kworker/1:3/3736

CPU: 1 PID: 3736 Comm: kworker/1:3 Not tainted 4.15.0-rc3+ #161
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events xfrm_hash_rebuild
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_load2_noabort+0x14/0x20 mm/kasan/report.c:428
 xfrm_hash_rebuild+0xdbe/0xf00 net/xfrm/xfrm_policy.c:618
 process_one_work+0xbbf/0x1b10 kernel/workqueue.c:2112
 worker_thread+0x223/0x1990 kernel/workqueue.c:2246
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:441

Allocated by task 8322:
 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:3708 [inline]
 __kmalloc+0x162/0x760 mm/slab.c:3717
 kmalloc include/linux/slab.h:504 [inline]
 sk_prot_alloc+0x101/0x2a0 net/core/sock.c:1471
 sk_alloc+0x8c/0x730 net/core/sock.c:1525
 pfkey_create+0x2b2/0xae0 net/key/af_key.c:158
 __sock_create+0x4d4/0x850 net/socket.c:1257
 sock_create net/socket.c:1297 [inline]
 SYSC_socket net/socket.c:1327 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1307
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 2191:
 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:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 kvfree+0x36/0x60 mm/util.c:416
 __free_fdtable+0x31/0x70 fs/file.c:36
 put_files_struct+0x28e/0x330 fs/file.c:425
 exit_files+0x83/0xb0 fs/file.c:450
 do_exit+0x994/0x1ad0 kernel/exit.c:860
 do_group_exit+0x149/0x400 kernel/exit.c:968
 get_signal+0x73f/0x16c0 kernel/signal.c:2335
 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x94/0x96

The buggy address belongs to the object at ffff8801c5ff36c0
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1316 bytes inside of
 2048-byte region [ffff8801c5ff36c0, ffff8801c5ff3ec0)
The buggy address belongs to the page:
page:000000003f4b9ab7 count:1 mapcount:0 mapping:000000004feb1a4d index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801c5ff25c0 0000000000000000 0000000100000003
raw: ffffea000704b5a0 ffffea000711f7a0 ffff8801db000c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c5ff3a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c5ff3b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c5ff3b80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                       ^
 ffff8801c5ff3c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801c5ff3c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================