netlink: 2 bytes leftover after parsing attributes in process `syz-executor2'.
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BUG: KASAN: slab-out-of-bounds in sctp_send_reset_streams+0xb03/0xc10 net/sctp/stream.c:323
Read of size 2 at addr ffff8801be6fda08 by task syz-executor2/12892

CPU: 0 PID: 12892 Comm: syz-executor2 Not tainted 4.15.0-rc2-next-20171208+ #63
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+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
 sctp_send_reset_streams+0xb03/0xc10 net/sctp/stream.c:323
 sctp_setsockopt_reset_streams net/sctp/socket.c:3905 [inline]
 sctp_setsockopt+0x70d/0x5d50 net/sctp/socket.c:4195
 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2968
 SYSC_setsockopt net/socket.c:1829 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1808
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007f4ace09ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000758048 RCX: 0000000000452a39
RDX: 0000000000000077 RSI: 0000000000000084 RDI: 0000000000000016
RBP: 0000000000758048 R08: 0000000000000008 R09: 0000000000000000
R10: 0000000020e73ff8 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007f4ace09b9c0 R15: 0000000000000000

Allocated by task 12892:
 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:3712 [inline]
 __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3727
 memdup_user+0x2c/0x90 mm/util.c:164
 sctp_setsockopt_reset_streams net/sctp/socket.c:3897 [inline]
 sctp_setsockopt+0x6a6/0x5d50 net/sctp/socket.c:4195
 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2968
 SYSC_setsockopt net/socket.c:1829 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1808
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1600:
 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:3492 [inline]
 kfree+0xca/0x250 mm/slab.c:3807
 security_inode_init_security+0x1c3/0x390 security/security.c:494
 shmem_mknod+0x9b/0x1b0 mm/shmem.c:2998
 shmem_create+0x2b/0x40 mm/shmem.c:3053
 lookup_open+0x11d0/0x1900 fs/namei.c:3218
 do_last fs/namei.c:3309 [inline]
 path_openat+0xd7c/0x3530 fs/namei.c:3537
 do_filp_open+0x25b/0x3b0 fs/namei.c:3572
 do_sys_open+0x502/0x6d0 fs/open.c:1059
 SYSC_open fs/open.c:1077 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1072
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801be6fda00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8801be6fda00, ffff8801be6fda20)
The buggy address belongs to the page:
page:000000000f33fe29 count:1 mapcount:0 mapping:00000000164b6045 index:0xffff8801be6fdfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801be6fd000 ffff8801be6fdfc1 0000000100000035
raw: ffffea0006f7a9a0 ffffea000708cde0 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801be6fd900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801be6fd980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801be6fda00: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                      ^
 ffff8801be6fda80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801be6fdb00: 00 00 04 fc fc fc fc fc fb fb fb fb fc fc fc fc
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