================================================================== BUG: KASAN: use-after-free in xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1497 [inline] BUG: KASAN: use-after-free in xfrm_policy_inexact_insert+0xbfa/0xda0 net/xfrm/xfrm_policy.c:1202 Read of size 1 at addr ffff8880a44dcb19 by task syz-executor3/23376 CPU: 1 PID: 23376 Comm: syz-executor3 Not tainted 4.20.0+ #3 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:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1497 [inline] xfrm_policy_inexact_insert+0xbfa/0xda0 net/xfrm/xfrm_policy.c:1202 xfrm_policy_insert+0x623/0x910 net/xfrm/xfrm_policy.c:1570 xfrm_add_policy+0x2a1/0x6c0 net/xfrm/xfrm_user.c:1657 xfrm_user_rcv_msg+0x458/0x8d0 net/xfrm/xfrm_user.c:2663 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477 xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2671 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116 __sys_sendmsg+0x112/0x270 net/socket.c:2154 __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg net/socket.c:2161 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 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:00007f9fede4dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 000000002014f000 RDI: 0000000000000005 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9fede4e6d4 R13: 00000000004c5394 R14: 00000000004d8e30 R15: 00000000ffffffff Allocated by task 21943: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3684 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3698 __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 21943: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 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] consume_skb net/core/skbuff.c:701 [inline] consume_skb+0x18c/0x550 net/core/skbuff.c:695 ip6_xmit+0x19f5/0x24a0 net/ipv6/ip6_output.c:219 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 ffff8880a44dc900 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 537 bytes inside of 1024-byte region [ffff8880a44dc900, ffff8880a44dcd00) The buggy address belongs to the page: page:ffffea0002913700 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0xffff8880a44dc900 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00027fe908 ffffea00021b2408 ffff88812c3f0ac0 raw: ffff8880a44dc900 ffff8880a44dc000 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a44dca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a44dca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a44dcb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a44dcb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a44dcc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================