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BUG: KASAN: slab-out-of-bounds in __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
Read of size 8 at addr ffff888088dc2af0 by task syz-executor.5/29796
CPU: 0 PID: 29796 Comm: syz-executor.5 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_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
 xfrm6_tunnel_spi_lookup+0x8a/0x1d0 net/ipv6/xfrm6_tunnel.c:95
 xfrmi6_rcv_tunnel+0xb9/0x100 net/xfrm/xfrm_interface.c:824
 tunnel46_rcv+0xef/0x2b0 net/ipv6/tunnel6.c:193
 ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433
 ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483
 ip6_mc_input+0x411/0xea0 net/ipv6/ip6_input.c:577
 dst_input include/net/dst.h:449 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401
 netif_receive_skb_internal net/core/dev.c:5503 [inline]
 netif_receive_skb+0x159/0x990 net/core/dev.c:5562
 tun_rx_batched.isra.0+0x460/0x720 drivers/net/tun.c:1518
 tun_get_user+0x23b2/0x35b0 drivers/net/tun.c:1972
 tun_chr_write_iter+0xba/0x151 drivers/net/tun.c:2001
 call_write_iter include/linux/fs.h:1879 [inline]
 new_sync_write+0x422/0x650 fs/read_write.c:515
 vfs_write+0x5c6/0x6f0 fs/read_write.c:595
 ksys_write+0x12d/0x250 fs/read_write.c:648
 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:00007fc7c4eeac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000037740 RCX: 000000000045c1d9
RDX: 0000000000000046 RSI: 0000000020000740 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff6f0f7b4f R14: 00007fc7c4eeb9c0 R15: 000000000078bf0c
Allocated by task 26251:
 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
 kmem_cache_alloc_trace+0x16e/0x2c0 mm/slab.c:3550
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 inetdev_init+0x68/0x4f0 net/ipv4/devinet.c:259
 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
 br_dev_newlink+0x23/0x110 net/bridge/br_netlink.c:1373
 __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_sendmsg+0x6e8/0x810 net/socket.c:2362
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2416
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2449
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Last call_rcu():
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346
 __call_rcu kernel/rcu/tree.c:2883 [inline]
 call_rcu+0x14f/0x7e0 kernel/rcu/tree.c:2957
 put_ctx kernel/events/core.c:1257 [inline]
 put_ctx+0x116/0x1e0 kernel/events/core.c:1250
 perf_event_exit_task_context kernel/events/core.c:12303 [inline]
 perf_event_exit_task+0xb53/0xef0 kernel/events/core.c:12332
 do_exit+0xb8d/0x29f0 kernel/exit.c:815
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline]
 __prepare_exit_to_usermode+0x14d/0x1f0 arch/x86/entry/common.c:269
 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff888088dc2800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 240 bytes to the right of
 512-byte region [ffff888088dc2800, ffff888088dc2a00)
The buggy address belongs to the page:
page:00000000979d6b03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x88dc2
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025714c8 ffffea000223e088 ffff8880aa000600
raw: 0000000000000000 ffff888088dc2000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff888088dc2980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc
 ffff888088dc2a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888088dc2a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff888088dc2b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888088dc2b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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