================================================================== BUG: KASAN: use-after-free in __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79 Read of size 8 at addr ffff88809115a3e8 by task syz-executor.2/9344 CPU: 1 PID: 9344 Comm: syz-executor.2 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:00007f453a600c60 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000078bf00 RCX: 0000000000415c91 RDX: 000000000000016a RSI: 0000000020000100 RDI: 00000000000000f0 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000293 R12: 000000000078bf0c R13: 00007ffcfab0a6bf R14: 00007f453a6019c0 R15: 000000000078bf0c Allocated by task 9060: 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] pskb_expand_head+0x15a/0x1040 net/core/skbuff.c:1627 __skb_cow include/linux/skbuff.h:3146 [inline] skb_cow_head include/linux/skbuff.h:3180 [inline] l2tp_xmit_skb+0x7d4/0x1140 net/l2tp/l2tp_core.c:1073 pppol2tp_sendmsg+0x501/0x7c0 net/l2tp/l2tp_ppp.c:325 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 9060: 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] kfree_skb.part.0+0xc2/0x350 net/core/skbuff.c:696 kfree_skb+0x7d/0x100 include/linux/refcount.h:270 l2tp_xmit_skb+0xcb0/0x1140 net/l2tp/l2tp_core.c:1089 pppol2tp_sendmsg+0x501/0x7c0 net/l2tp/l2tp_ppp.c:325 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 ffff88809115a000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 1000 bytes inside of 1024-byte region [ffff88809115a000, ffff88809115a400) The buggy address belongs to the page: page:0000000095cdd3cd refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9115a flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00022e5608 ffffea00022ffa08 ffff8880aa000700 raw: 0000000000000000 ffff88809115a000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809115a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809115a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809115a380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809115a400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809115a480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================