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BUG: KASAN: slab-out-of-bounds in __xfrm6_tunnel_alloc_spi net/ipv6/xfrm6_tunnel.c:124 [inline]
BUG: KASAN: slab-out-of-bounds in xfrm6_tunnel_alloc_spi+0x779/0x8a0 net/ipv6/xfrm6_tunnel.c:174
Read of size 4 at addr ffff88808f2e9c00 by task syz-executor.3/8783
CPU: 0 PID: 8783 Comm: syz-executor.3 Not tainted 5.8.0-rc5-next-20200716-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __xfrm6_tunnel_alloc_spi net/ipv6/xfrm6_tunnel.c:124 [inline]
 xfrm6_tunnel_alloc_spi+0x779/0x8a0 net/ipv6/xfrm6_tunnel.c:174
 ipcomp6_tunnel_create net/ipv6/ipcomp6.c:84 [inline]
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:124 [inline]
 ipcomp6_init_state net/ipv6/ipcomp6.c:159 [inline]
 ipcomp6_init_state+0x2af/0x700 net/ipv6/ipcomp6.c:139
 __xfrm_init_state+0x9a6/0x14b0 net/xfrm/xfrm_state.c:2498
 xfrm_init_state+0x1a/0x70 net/xfrm/xfrm_state.c:2525
 pfkey_msg2xfrm_state net/key/af_key.c:1291 [inline]
 pfkey_add+0x1a10/0x2b70 net/key/af_key.c:1508
 pfkey_process+0x66d/0x7a0 net/key/af_key.c:2834
 pfkey_sendmsg+0x42d/0x800 net/key/af_key.c:3673
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x331/0x810 net/socket.c:2362
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2416
 __sys_sendmmsg+0x195/0x480 net/socket.c:2506
 __do_sys_sendmmsg net/socket.c:2535 [inline]
 __se_sys_sendmmsg net/socket.c:2532 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2532
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c1d9
Code: Bad RIP value.
RSP: 002b:00007f9d70119c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000025a40 RCX: 000000000045c1d9
RDX: 0400000000000282 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000078bf48 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffe19cb09cf R14: 00007f9d7011a9c0 R15: 000000000078bf0c
Allocated by task 6800:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc_track_caller+0x1a6/0x310 mm/slab.c:3670
 kmemdup+0x23/0x50 mm/util.c:127
 kmemdup include/linux/string.h:479 [inline]
 neigh_sysctl_register+0x9a/0x680 net/core/neighbour.c:3629
 devinet_sysctl_register+0xb1/0x230 net/ipv4/devinet.c:2609
 inetdev_init+0x225/0x4f0 net/ipv4/devinet.c:276
 inetdev_event+0x9b8/0x14fd net/ipv4/devinet.c:1531
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2033
 call_netdevice_notifiers_extack net/core/dev.c:2045 [inline]
 call_netdevice_notifiers net/core/dev.c:2059 [inline]
 register_netdevice+0x100f/0x1540 net/core/dev.c:9554
 ipcaif_newlink+0x4c/0x260 net/caif/chnl_net.c:473
 __rtnl_newlink+0x1090/0x1730 net/core/rtnetlink.c:3339
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3397
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5460
 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 __sys_sendto+0x21c/0x320 net/socket.c:1994
 __do_sys_sendto net/socket.c:2006 [inline]
 __se_sys_sendto net/socket.c:2002 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2002
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff88808f2e9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1024 bytes to the right of
 2048-byte region [ffff88808f2e9000, ffff88808f2e9800)
The buggy address belongs to the page:
page:000000004d71f8ec refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8f2e9
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000276a288 ffffea00023c91c8 ffff8880aa000800
raw: 0000000000000000 ffff88808f2e9000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff88808f2e9b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808f2e9b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808f2e9c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff88808f2e9c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808f2e9d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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