netlink: 80 bytes leftover after parsing attributes in process `syz.0.18'. ================================================================== BUG: KASAN: slab-out-of-bounds in decode_session6 net/xfrm/xfrm_policy.c:3413 [inline] BUG: KASAN: slab-out-of-bounds in __xfrm_decode_session+0x17ae/0x1fa0 net/xfrm/xfrm_policy.c:3520 Read of size 1 at addr ffff88807d48137a by task syz.0.18/4311 CPU: 0 PID: 4311 Comm: syz.0.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 decode_session6 net/xfrm/xfrm_policy.c:3413 [inline] __xfrm_decode_session+0x17ae/0x1fa0 net/xfrm/xfrm_policy.c:3520 xfrm_decode_session_reverse include/net/xfrm.h:1170 [inline] icmpv6_route_lookup+0x3ea/0x5a0 net/ipv6/icmp.c:394 icmp6_send+0xff2/0x1990 net/ipv6/icmp.c:601 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x35/0x490 net/ipv6/route.c:2788 dst_link_failure include/net/dst.h:422 [inline] ip6_tnl_xmit+0x671/0x23e0 net/ipv6/ip6_tunnel.c:1274 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1390 [inline] ip6_tnl_start_xmit+0xd27/0x12d0 net/ipv6/ip6_tunnel.c:1439 __netdev_start_xmit include/linux/netdevice.h:5036 [inline] netdev_start_xmit include/linux/netdevice.h:5050 [inline] xmit_one net/core/dev.c:3662 [inline] dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3678 sch_direct_xmit+0x25a/0x4b0 net/sched/sch_generic.c:345 qdisc_restart net/sched/sch_generic.c:410 [inline] __qdisc_run+0xa7e/0x1490 net/sched/sch_generic.c:418 __dev_xmit_skb net/core/dev.c:3955 [inline] __dev_queue_xmit+0xe3d/0x2f80 net/core/dev.c:4266 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x108c/0x1510 net/ipv6/ip6_output.c:130 ip6_fragment+0x133d/0x1ee0 net/ipv6/ip6_output.c:998 dst_output include/net/dst.h:452 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ip6_xmit+0x109b/0x16d0 net/ipv6/ip6_output.c:338 sctp_v6_xmit+0x985/0x11b0 net/sctp/ipv6.c:250 sctp_packet_transmit+0x239c/0x2910 net/sctp/output.c:652 sctp_packet_singleton+0x231/0x330 net/sctp/outqueue.c:780 sctp_outq_flush_ctrl net/sctp/outqueue.c:911 [inline] sctp_outq_flush+0x4ac/0x3100 net/sctp/outqueue.c:1209 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x4ee2/0x55f0 net/sctp/sm_sideeffect.c:1170 sctp_primitive_ASSOCIATE+0x91/0xc0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0x14a7/0x1d90 net/sctp/socket.c:1840 sctp_sendmsg+0x196a/0x2900 net/sctp/socket.c:2030 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499 __sys_sendmmsg+0x2ba/0x500 net/socket.c:2585 __do_sys_sendmmsg net/socket.c:2614 [inline] __se_sys_sendmmsg net/socket.c:2611 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2611 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f0a947a1819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc4db712b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f0a94a1afa0 RCX: 00007f0a947a1819 RDX: 0000000000000002 RSI: 0000200000002fc0 RDI: 0000000000000004 RBP: 00007f0a94837c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000024000045 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0a94a1afac R14: 00007f0a94a1afa0 R15: 00007f0a94a1afa0 Allocated by task 1624: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x22c/0x750 net/core/skbuff.c:427 alloc_skb include/linux/skbuff.h:1162 [inline] nlmsg_new include/net/netlink.h:953 [inline] rtmsg_ifinfo_build_skb+0x80/0x180 net/core/rtnetlink.c:3886 rtmsg_ifinfo_event net/core/rtnetlink.c:3922 [inline] rtmsg_ifinfo+0x71/0x120 net/core/rtnetlink.c:3931 netdev_state_change+0xf4/0x160 net/core/dev.c:1455 linkwatch_do_dev+0x10d/0x160 net/core/link_watch.c:167 __linkwatch_run_queue+0x4b1/0x7c0 net/core/link_watch.c:213 linkwatch_event+0x48/0x50 net/core/link_watch.c:252 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Freed by task 1624: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 skb_free_head net/core/skbuff.c:655 [inline] pskb_expand_head+0x358/0x10f0 net/core/skbuff.c:1742 netlink_trim+0x180/0x220 net/netlink/af_netlink.c:1299 netlink_broadcast_filtered+0x7c/0x1170 net/netlink/af_netlink.c:1511 netlink_broadcast net/netlink/af_netlink.c:1556 [inline] nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0xec/0x1a0 net/netlink/af_netlink.c:2550 netdev_state_change+0xf4/0x160 net/core/dev.c:1455 linkwatch_do_dev+0x10d/0x160 net/core/link_watch.c:167 __linkwatch_run_queue+0x4b1/0x7c0 net/core/link_watch.c:213 linkwatch_event+0x48/0x50 net/core/link_watch.c:252 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff88807d480000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 890 bytes to the right of 4096-byte region [ffff88807d480000, ffff88807d481000) The buggy address belongs to the page: page:ffffea0001f52000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d480 head:ffffea0001f52000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888016c42140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3554, ts 25781822478, free_ts 23883210719 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] slab_alloc mm/slub.c:3233 [inline] __kmalloc+0x1cd/0x330 mm/slub.c:4408 kmalloc include/linux/slab.h:612 [inline] tomoyo_realpath_from_path+0x118/0x610 security/tomoyo/realpath.c:254 tomoyo_init_log+0xf8f/0x1e90 security/tomoyo/audit.c:263 tomoyo_supervisor+0x38d/0x11f0 security/tomoyo/common.c:2097 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline] tomoyo_env_perm+0x14e/0x1f0 security/tomoyo/environ.c:63 tomoyo_environ security/tomoyo/domain.c:672 [inline] tomoyo_find_next_domain+0x1591/0x1a60 security/tomoyo/domain.c:882 tomoyo_bprm_check_security+0xdd/0x120 security/tomoyo/tomoyo.c:101 security_bprm_check+0x5e/0x90 security/security.c:868 search_binary_handler fs/exec.c:1730 [inline] exec_binprm fs/exec.c:1783 [inline] bprm_execve+0xa53/0x1840 fs/exec.c:1852 do_execveat_common+0x51e/0x6d0 fs/exec.c:1957 do_execve fs/exec.c:2027 [inline] __do_sys_execve fs/exec.c:2103 [inline] __se_sys_execve fs/exec.c:2098 [inline] __x64_sys_execve+0x8e/0xa0 fs/exec.c:2098 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396 free_contig_range+0x96/0xf0 mm/page_alloc.c:9428 destroy_args+0xf0/0xa00 mm/debug_vm_pgtable.c:1018 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336 do_one_initcall+0x272/0x730 init/main.c:1316 do_initcall_level+0x137/0x1f0 init/main.c:1389 do_initcalls+0x4b/0x90 init/main.c:1405 kernel_init_freeable+0x3e9/0x570 init/main.c:1629 kernel_init+0x19/0x1b0 init/main.c:1520 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Memory state around the buggy address: ffff88807d481200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807d481280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807d481300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88807d481380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807d481400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================