==================================================================
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 ffff8880a7db4ea0 by task syz-executor.5/20614
CPU: 1 PID: 20614 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:00007fbf8049bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000036cc0 RCX: 000000000045c1d9
RDX: 0000000000000fca RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fffb47a852f R14: 00007fbf8049c9c0 R15: 000000000078bf0c
Allocated by task 20537:
 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
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xae/0x550 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1084 [inline]
 sock_omalloc+0x9f/0x180 net/core/sock.c:2234
 sock_zerocopy_alloc+0x47/0x320 net/core/skbuff.c:1101
 sock_zerocopy_realloc+0x25f/0x590 net/core/skbuff.c:1171
 __ip_append_data+0x244f/0x31c0 net/ipv4/ip_output.c:1019
 ip_make_skb+0x226/0x2a0 net/ipv4/ip_output.c:1632
 udp_sendmsg+0x1c2d/0x26c0 net/ipv4/udp.c:1176
 udpv6_sendmsg+0x14dd/0x2b90 net/ipv6/udp.c:1289
 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:638
 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
Freed by task 20537:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3756
 skb_free_head net/core/skbuff.c:590 [inline]
 skb_release_data+0x6d9/0x910 net/core/skbuff.c:610
 skb_release_all net/core/skbuff.c:664 [inline]
 __kfree_skb net/core/skbuff.c:678 [inline]
 consume_skb net/core/skbuff.c:837 [inline]
 consume_skb+0xc2/0x160 net/core/skbuff.c:831
 sock_zerocopy_callback+0x145/0x730 net/core/skbuff.c:1239
 sock_zerocopy_put net/core/skbuff.c:1248 [inline]
 sock_zerocopy_put+0xd0/0x120 net/core/skbuff.c:1244
 skb_zcopy_clear include/linux/skbuff.h:1465 [inline]
 skb_release_data+0x717/0x910 net/core/skbuff.c:609
 skb_release_all net/core/skbuff.c:664 [inline]
 __kfree_skb net/core/skbuff.c:678 [inline]
 kfree_skb.part.0+0xc2/0x350 net/core/skbuff.c:696
 kfree_skb+0x7d/0x100 include/linux/refcount.h:270
 ip_tunnel_xmit+0x6ab/0x2ac3 net/ipv4/ip_tunnel.c:826
 ipgre_xmit+0x651/0x9f0 net/ipv4/ip_gre.c:650
 __netdev_start_xmit include/linux/netdevice.h:4621 [inline]
 netdev_start_xmit include/linux/netdevice.h:4635 [inline]
 xmit_one net/core/dev.c:3562 [inline]
 dev_hard_start_xmit+0x193/0x950 net/core/dev.c:3578
 __dev_queue_xmit+0x2096/0x2d60 net/core/dev.c:4137
 neigh_connected_output+0x299/0x370 net/core/neighbour.c:1518
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x81b/0x21f0 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:306 [inline]
 __ip_finish_output+0x6e6/0xbc0 net/ipv4/ip_output.c:288
 ip_finish_output+0x34/0x1f0 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0x196/0x310 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:125 [inline]
 ip_send_skb+0xd4/0x260 net/ipv4/ip_output.c:1566
 udp_send_skb+0x6cd/0x11a0 net/ipv4/udp.c:894
 udp_sendmsg+0x1c6b/0x26c0 net/ipv4/udp.c:1181
 udpv6_sendmsg+0x14dd/0x2b90 net/ipv6/udp.c:1289
 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:638
 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
The buggy address belongs to the object at ffff8880a7db4c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 160 bytes to the right of
 512-byte region [ffff8880a7db4c00, ffff8880a7db4e00)
The buggy address belongs to the page:
page:00000000dcfa429b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa7db4
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00028a4248 ffffea00029e7e88 ffff8880aa000600
raw: 0000000000000000 ffff8880a7db4000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff8880a7db4d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7db4e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a7db4e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff8880a7db4f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a7db4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================