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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 ffff8880a3273a28 by task syz-executor.0/18891
CPU: 1 PID: 18891 Comm: syz-executor.0 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
 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: 0033:0x415c91
Code: Bad RIP value.
RSP: 002b:00007f29104f7c60 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000078bf00 RCX: 0000000000415c91
RDX: 000000000000004a RSI: 0000000020000280 RDI: 00000000000000f0
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 00007f29104f89d0 R11: 0000000000000293 R12: 000000000078bf0c
R13: 00007ffcff89369f R14: 00007f29104f89c0 R15: 000000000078bf0c
Allocated by task 1:
 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]
 device_private_init drivers/base/core.c:2763 [inline]
 device_add+0x1008/0x1c40 drivers/base/core.c:2813
 tty_register_device_attr+0x395/0x7b0 drivers/tty/tty_io.c:3143
 tty_register_device drivers/tty/tty_io.c:3077 [inline]
 tty_register_driver+0x428/0x800 drivers/tty/tty_io.c:3348
 legacy_pty_init drivers/tty/pty.c:600 [inline]
 pty_init+0x66c/0xe58 drivers/tty/pty.c:964
 do_one_initcall+0x10a/0x7b0 init/main.c:1201
 do_initcall_level init/main.c:1274 [inline]
 do_initcalls init/main.c:1290 [inline]
 do_basic_setup init/main.c:1310 [inline]
 kernel_init_freeable+0x4f4/0x5a3 init/main.c:1507
 kernel_init+0xd/0x1c0 init/main.c:1401
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
The buggy address belongs to the object at ffff8880a3273800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 40 bytes to the right of
 512-byte region [ffff8880a3273800, ffff8880a3273a00)
The buggy address belongs to the page:
page:00000000cfc8ff13 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa3273
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00026909c8 ffffea0002897b08 ffff8880aa000600
raw: 0000000000000000 ffff8880a3273000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
 ffff8880a3273900: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a3273980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a3273a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                  ^
 ffff8880a3273a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a3273b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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