================================================================== BUG: KASAN: use-after-free in __xfrm_policy_eval_candidates net/xfrm/xfrm_policy.c:2019 [inline] BUG: KASAN: use-after-free in xfrm_policy_eval_candidates net/xfrm/xfrm_policy.c:2053 [inline] BUG: KASAN: use-after-free in xfrm_policy_lookup_bytype+0xd27/0xdb0 net/xfrm/xfrm_policy.c:2113 Read of size 4 at addr ffff8880908512f4 by task syz-executor2/19624 CPU: 1 PID: 19624 Comm: syz-executor2 Not tainted 4.20.0+ #11 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134 __xfrm_policy_eval_candidates net/xfrm/xfrm_policy.c:2019 [inline] xfrm_policy_eval_candidates net/xfrm/xfrm_policy.c:2053 [inline] xfrm_policy_lookup_bytype+0xd27/0xdb0 net/xfrm/xfrm_policy.c:2113 xfrm_policy_lookup+0x7e/0x90 net/xfrm/xfrm_policy.c:2145 __xfrm_policy_check+0x1426/0x2b00 net/xfrm/xfrm_policy.c:3354 __xfrm_policy_check2 include/net/xfrm.h:1170 [inline] xfrm_policy_check include/net/xfrm.h:1175 [inline] xfrm6_policy_check include/net/xfrm.h:1185 [inline] ip6_protocol_deliver_rcu+0x1496/0x1940 net/ipv6/ip6_input.c:412 ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:434 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip6_input+0xf9/0x600 net/ipv6/ip6_input.c:443 ip6_mc_input+0x4f9/0x10d0 net/ipv6/ip6_input.c:537 dst_input include/net/dst.h:450 [inline] ip6_rcv_finish+0x177/0x330 net/ipv6/ip6_input.c:76 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ipv6_rcv+0x113/0x650 net/ipv6/ip6_input.c:272 __netif_receive_skb_one_core+0x160/0x210 net/core/dev.c:4973 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5083 process_backlog+0x206/0x750 net/core/dev.c:5923 napi_poll net/core/dev.c:6346 [inline] net_rx_action+0x76d/0x1930 net/core/dev.c:6412 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1027 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337 do_softirq+0x18/0x20 kernel/softirq.c:325 netif_rx_ni+0x4fd/0x860 net/core/dev.c:4569 dev_loopback_xmit+0x29b/0x8c0 net/core/dev.c:3576 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip6_finish_output2+0x1a03/0x28e0 net/ipv6/ip6_output.c:84 ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] ip6_local_out+0xc4/0x1b0 net/ipv6/output_core.c:176 ip6_send_skb+0xbb/0x350 net/ipv6/ip6_output.c:1727 ip6_push_pending_frames+0xc8/0xf0 net/ipv6/ip6_output.c:1747 rawv6_push_pending_frames net/ipv6/raw.c:615 [inline] rawv6_sendmsg+0x39e6/0x49e0 net/ipv6/raw.c:945 inet_sendmsg+0x1af/0x740 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x409/0x910 net/socket.c:2116 __sys_sendmmsg+0x246/0x6f0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg net/socket.c:2237 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2237 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f082b62ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9 RDX: 0000000000000086 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000400000080 R11: 0000000000000246 R12: 00007f082b62b6d4 R13: 00000000004c4ce5 R14: 00000000004d85d8 R15: 00000000ffffffff Allocated by task 17916: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 __do_kmalloc_node mm/slab.c:3671 [inline] __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3685 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:140 pskb_expand_head+0x1f6/0x1080 net/core/skbuff.c:1465 __skb_cow include/linux/skbuff.h:2970 [inline] skb_cow_head include/linux/skbuff.h:3004 [inline] l2tp_xmit_skb+0x100b/0x1620 net/l2tp/l2tp_core.c:1069 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:329 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x409/0x910 net/socket.c:2116 __sys_sendmmsg+0x246/0x6f0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg net/socket.c:2237 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2237 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 17916: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 skb_free_head+0x93/0xb0 net/core/skbuff.c:553 skb_release_data+0x6ea/0x970 net/core/skbuff.c:573 skb_release_all+0x4d/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] kfree_skb net/core/skbuff.c:659 [inline] kfree_skb+0x199/0x580 net/core/skbuff.c:653 __neigh_event_send+0x86d/0x1310 net/core/neighbour.c:1148 neigh_event_send include/net/neighbour.h:443 [inline] neigh_resolve_output+0x6f6/0xb30 net/core/neighbour.c:1455 neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip6_xmit+0xee1/0x24a0 net/ipv6/ip6_output.c:275 inet6_csk_xmit+0x358/0x650 net/ipv6/inet6_connection_sock.c:139 l2tp_xmit_core net/l2tp/l2tp_core.c:1030 [inline] l2tp_xmit_skb+0x12ff/0x1620 net/l2tp/l2tp_core.c:1132 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:329 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x409/0x910 net/socket.c:2116 __sys_sendmmsg+0x246/0x6f0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg net/socket.c:2237 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2237 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888090851240 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 180 bytes inside of 1024-byte region [ffff888090851240, ffff888090851640) The buggy address belongs to the page: page:ffffea0002421400 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0xffff888090850040 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea000241c508 ffffea00022be588 ffff88812c3f0ac0 raw: ffff888090850040 ffff888090850040 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888090851180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888090851200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888090851280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888090851300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888090851380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================