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BUG: KASAN: slab-out-of-bounds in pfkey_msg2xfrm_state net/key/af_key.c:1188 [inline]
BUG: KASAN: slab-out-of-bounds in pfkey_add+0x2702/0x3470 net/key/af_key.c:1506
Read of size 4096 at addr ffff8801c3db8a40 by task syzkaller715050/3808

CPU: 1 PID: 3808 Comm: syzkaller715050 Not tainted 4.9.83-ga92bb8d #51
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d7fa7718 ffffffff81d95149 ffffea00070f6e00 ffff8801c3db8a40
 0000000000000000 ffff8801c3db8c00 ffff8801d7fa7958 ffff8801d7fa7750
 ffffffff8153e213 ffff8801c3db8a40 0000000000001000 0000000000000000
Call Trace:
 [<ffffffff81d95149>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d95149>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8153e213>] print_address_description+0x73/0x280 mm/kasan/report.c:252
 [<ffffffff8153e735>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8153e735>] kasan_report+0x275/0x360 mm/kasan/report.c:408
 [<ffffffff8153d147>] check_memory_region_inline mm/kasan/kasan.c:318 [inline]
 [<ffffffff8153d147>] check_memory_region+0x137/0x190 mm/kasan/kasan.c:325
 [<ffffffff8153d683>] memcpy+0x23/0x50 mm/kasan/kasan.c:360
 [<ffffffff83577ce2>] pfkey_msg2xfrm_state net/key/af_key.c:1188 [inline]
 [<ffffffff83577ce2>] pfkey_add+0x2702/0x3470 net/key/af_key.c:1506
 [<ffffffff8356f08b>] pfkey_process+0x68b/0x750 net/key/af_key.c:2834
 [<ffffffff835708e9>] pfkey_sendmsg+0x3a9/0x760 net/key/af_key.c:3678
 [<ffffffff82ed8baa>] sock_sendmsg_nosec net/socket.c:635 [inline]
 [<ffffffff82ed8baa>] sock_sendmsg+0xca/0x110 net/socket.c:645
 [<ffffffff82eda7c1>] ___sys_sendmsg+0x6d1/0x7e0 net/socket.c:1969
 [<ffffffff82edc7f6>] __sys_sendmsg+0xd6/0x190 net/socket.c:2003
 [<ffffffff82fdf13a>] C_SYSC_sendmsg net/compat.c:734 [inline]
 [<ffffffff82fdf13a>] compat_SyS_sendmsg+0x2a/0x40 net/compat.c:732
 [<ffffffff81006f95>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006f95>] do_fast_syscall_32+0x2f5/0x870 arch/x86/entry/common.c:387
 [<ffffffff838b6590>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Allocated by task 3808:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:609
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547
 slab_post_alloc_hook mm/slab.h:417 [inline]
 slab_alloc_node mm/slub.c:2715 [inline]
 slab_alloc mm/slub.c:2723 [inline]
 __kmalloc_track_caller+0xda/0x2b0 mm/slub.c:4232
 __kmalloc_reserve.isra.37+0x33/0xc0 net/core/skbuff.c:138
 __alloc_skb+0x119/0x600 net/core/skbuff.c:231
 alloc_skb include/linux/skbuff.h:919 [inline]
 pfkey_sendmsg+0x135/0x760 net/key/af_key.c:3665
 sock_sendmsg_nosec net/socket.c:635 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:645
 ___sys_sendmsg+0x6d1/0x7e0 net/socket.c:1969
 __sys_sendmsg+0xd6/0x190 net/socket.c:2003
 C_SYSC_sendmsg net/compat.c:734 [inline]
 compat_SyS_sendmsg+0x2a/0x40 net/compat.c:732
 do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 do_fast_syscall_32+0x2f5/0x870 arch/x86/entry/common.c:387
 entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Freed by task 2176:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582
 slab_free_hook mm/slub.c:1355 [inline]
 slab_free_freelist_hook mm/slub.c:1377 [inline]
 slab_free mm/slub.c:2958 [inline]
 kfree+0x103/0x300 mm/slub.c:3878
 kernfs_fop_release+0xff/0x140 fs/kernfs/file.c:744
 __fput+0x28c/0x6e0 fs/file_table.c:208
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x115/0x190 kernel/task_work.c:116
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0xfc/0x120 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 do_syscall_64+0x36f/0x490 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_swapgs+0x47/0xc5

The buggy address belongs to the object at ffff8801c3db8a00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
 512-byte region [ffff8801c3db8a00, ffff8801c3db8c00)
The buggy address belongs to the page:
page:ffffea00070f6e00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x8000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c3db8b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c3db8b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c3db8c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff8801c3db8c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c3db8d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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