syzkaller1: entered promiscuous mode syzkaller1: entered allmulticast mode ================================================================== BUG: KASAN: slab-use-after-free in __xfrm_state_lookup+0x6b2/0x8d0 net/xfrm/xfrm_state.c:1084 Read of size 2 at addr ffff888060f00122 by task syz.4.917/8894 CPU: 0 PID: 8894 Comm: syz.4.917 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/0x220 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 __xfrm_state_lookup+0x6b2/0x8d0 net/xfrm/xfrm_state.c:1084 xfrm_state_lookup+0xef/0x1a0 net/xfrm/xfrm_state.c:2042 vti4_err+0x4be/0x8e0 net/ipv4/ip_vti.c:361 xfrm4_ah_err+0x8d/0x1d0 net/ipv4/xfrm4_protocol.c:146 icmp_redirect+0x1a2/0x300 net/ipv4/icmp.c:996 icmp_rcv+0xc39/0x1180 net/ipv4/icmp.c:1297 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304 __netif_receive_skb_one_core net/core/dev.c:5608 [inline] __netif_receive_skb+0xcc/0x290 net/core/dev.c:5722 netif_receive_skb_internal net/core/dev.c:5808 [inline] netif_receive_skb+0x1bc/0x6f0 net/core/dev.c:5867 tun_rx_batched+0x1ba/0x730 drivers/net/tun.c:1556 tun_get_user+0x283f/0x3bf0 drivers/net/tun.c:2009 tun_chr_write_iter+0x119/0x200 drivers/net/tun.c:2055 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x43b/0x940 fs/read_write.c:584 ksys_write+0x147/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa9d238ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa9d3223038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fa9d25c5fa0 RCX: 00007fa9d238ebe9 RDX: 000000000000fdef RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007fa9d2411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa9d25c6038 R14: 00007fa9d25c5fa0 R15: 00007ffe2577ee68 Allocated by task 8032: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3485 [inline] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509 kmem_cache_zalloc include/linux/slab.h:711 [inline] xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661 __find_acq_core+0x7d8/0x19d0 net/xfrm/xfrm_state.c:1598 xfrm_find_acq+0x6a/0x90 net/xfrm/xfrm_state.c:2070 xfrm_alloc_userspi+0x57a/0xa90 net/xfrm/xfrm_user.c:1613 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595 ___sys_sendmsg+0x220/0x290 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888060f00000 which belongs to the cache xfrm_state of size 848 The buggy address is located 290 bytes inside of freed 848-byte region [ffff888060f00000, ffff888060f00350) The buggy address belongs to the physical page: page:ffffea000183c000 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888060f00400 pfn:0x60f00 head:ffffea000183c000 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff8881412d93c0 dead000000000122 0000000000000000 raw: ffff888060f00400 000000008010000e 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 7444, tgid 7443 (syz.3.423), ts 153064345616, free_ts 152957130373 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554 prep_new_page mm/page_alloc.c:1561 [inline] get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457 alloc_slab_page+0x5d/0x170 mm/slub.c:1876 allocate_slab mm/slub.c:2023 [inline] new_slab+0x87/0x2e0 mm/slub.c:2076 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230 __slab_alloc mm/slub.c:3329 [inline] __slab_alloc_node mm/slub.c:3382 [inline] slab_alloc_node mm/slub.c:3475 [inline] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3509 kmem_cache_zalloc include/linux/slab.h:711 [inline] xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661 ipcomp_tunnel_create net/ipv4/ipcomp.c:62 [inline] ipcomp_tunnel_attach net/ipv4/ipcomp.c:106 [inline] ipcomp4_init_state+0x2a9/0x9f0 net/ipv4/ipcomp.c:142 __xfrm_init_state+0xd8b/0x11c0 net/xfrm/xfrm_state.c:2904 xfrm_state_construct net/xfrm/xfrm_user.c:741 [inline] xfrm_add_sa+0x236d/0x30a0 net/xfrm/xfrm_user.c:799 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429 free_large_kmalloc+0x101/0x1a0 mm/slab_common.c:984 device_release+0x96/0x1c0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x221/0x470 lib/kobject.c:737 netdev_run_todo+0xc93/0xd90 net/core/dev.c:10601 tun_detach drivers/net/tun.c:704 [inline] tun_chr_close+0x13f/0x1c0 drivers/net/tun.c:3511 __fput+0x234/0x970 fs/file_table.c:384 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff888060f00000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888060f00080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888060f00100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888060f00180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888060f00200: fb fb fb fb fb fb fb fb fb fb fb fb 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