audit: type=1400 audit(1575212906.878:473): avc: denied { write } for pid=851 comm="syz-executor.3" path="socket:[239049]" dev="sockfs" ino=239049 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_fib_lookup_socket permissive=1 ================================================================== BUG: KASAN: slab-out-of-bounds in __ptr_ring_produce include/linux/ptr_ring.h:107 [inline] BUG: KASAN: slab-out-of-bounds in ptr_ring_produce include/linux/ptr_ring.h:130 [inline] BUG: KASAN: slab-out-of-bounds in skb_array_produce include/linux/skb_array.h:48 [inline] BUG: KASAN: slab-out-of-bounds in tun_net_xmit+0x10b8/0x1180 drivers/net/tun.c:920 Read of size 8 at addr ffff8801c5692c80 by task syz-fuzzer/2040 CPU: 0 PID: 2040 Comm: syz-fuzzer Not tainted 4.9.141+ #1 ffff8801db607488 ffffffff81b42e79 ffffea000715a480 ffff8801c5692c80 0000000000000000 ffff8801c5692c80 ffff8801c5f4eb88 ffff8801db6074c0 ffffffff815009b8 ffff8801c5692c80 0000000000000008 0000000000000000 Call Trace: [ 1487.426908] [] __dump_stack lib/dump_stack.c:15 [inline] [ 1487.426908] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 [] __ptr_ring_produce include/linux/ptr_ring.h:107 [inline] [] ptr_ring_produce include/linux/ptr_ring.h:130 [inline] [] skb_array_produce include/linux/skb_array.h:48 [inline] [] tun_net_xmit+0x10b8/0x1180 drivers/net/tun.c:920 [] __netdev_start_xmit include/linux/netdevice.h:4069 [inline] [] netdev_start_xmit include/linux/netdevice.h:4078 [inline] [] xmit_one net/core/dev.c:2977 [inline] [] dev_hard_start_xmit+0x197/0x8b0 net/core/dev.c:2993 [] sch_direct_xmit+0x2b3/0x580 net/sched/sch_generic.c:182 [] __dev_xmit_skb net/core/dev.c:3173 [inline] [] __dev_queue_xmit+0x152e/0x1b90 net/core/dev.c:3441 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3506 [] neigh_direct_output+0x15/0x20 net/core/neighbour.c:1365 [] dst_neigh_output include/net/dst.h:470 [inline] [] ip6_finish_output2+0xb0e/0x1d10 net/ipv6/ip6_output.c:119 audit: type=1400 audit(1575212906.918:474): avc: denied { create } for pid=880 comm="syz-executor.3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_scsitransport_socket permissive=1 [] ip6_finish_output+0x334/0x980 net/ipv6/ip6_output.c:145 [] NF_HOOK_COND include/linux/netfilter.h:246 [inline] [] ip6_output+0x1ea/0x6d0 net/ipv6/ip6_output.c:162 [] dst_output include/net/dst.h:507 [inline] [] NF_HOOK_THRESH include/linux/netfilter.h:232 [inline] [] NF_HOOK include/linux/netfilter.h:255 [inline] [] mld_sendpack+0xa1e/0xf80 net/ipv6/mcast.c:1659 [] mld_send_cr net/ipv6/mcast.c:1955 [inline] [] mld_ifc_timer_expire+0x3ba/0x7b0 net/ipv6/mcast.c:2455 [] call_timer_fn+0x163/0x6e0 kernel/time/timer.c:1319 [] expire_timers+0x234/0x580 kernel/time/timer.c:1359 [] __run_timers kernel/time/timer.c:1674 [inline] [] run_timer_softirq+0x208/0x5e0 kernel/time/timer.c:1687 [] __do_softirq+0x20e/0x964 kernel/softirq.c:288 [] invoke_softirq kernel/softirq.c:368 [inline] [] irq_exit+0x11c/0x150 kernel/softirq.c:409 [] exiting_irq arch/x86/include/asm/apic.h:669 [inline] [] smp_apic_timer_interrupt+0x81/0xb0 arch/x86/kernel/apic/apic.c:962 [] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648 [ 1487.845938] Allocated by task 840: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594 __kmalloc+0x12f/0x310 mm/slub.c:3741 kmalloc_array include/linux/slab.h:582 [inline] kcalloc include/linux/slab.h:593 [inline] __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:356 [inline] ptr_ring_resize_multiple include/linux/ptr_ring.h:445 [inline] skb_array_resize_multiple include/linux/skb_array.h:169 [inline] tun_queue_resize drivers/net/tun.c:2523 [inline] tun_device_event+0x3e0/0xa00 drivers/net/tun.c:2541 notifier_call_chain+0xb4/0x1d0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x55/0x70 net/core/dev.c:1647 call_netdevice_notifiers+0x70/0xa0 net/core/dev.c:1663 do_setlink+0xc55/0x2ef0 net/core/rtnetlink.c:2052 rtnl_group_changelink net/core/rtnetlink.c:2423 [inline] rtnl_newlink+0xbd0/0x1550 net/core/rtnetlink.c:2571 rtnetlink_rcv_msg+0x49c/0x650 net/core/rtnetlink.c:4078 netlink_rcv_skb+0x145/0x370 net/netlink/af_netlink.c:2365 rtnetlink_rcv+0x2a/0x40 net/core/rtnetlink.c:4084 netlink_unicast_kernel net/netlink/af_netlink.c:1285 [inline] netlink_unicast+0x4d8/0x6d0 net/netlink/af_netlink.c:1311 netlink_sendmsg+0x694/0xc30 net/netlink/af_netlink.c:1859 sock_sendmsg_nosec net/socket.c:648 [inline] sock_sendmsg+0xbb/0x110 net/socket.c:658 ___sys_sendmsg+0x6fc/0x840 net/socket.c:1982 __sys_sendmsg+0xd9/0x190 net/socket.c:2016 SYSC_sendmsg net/socket.c:2027 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2023 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 22959: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kfree+0xfb/0x310 mm/slub.c:3878 bpf_migrate_filter net/core/filter.c:1026 [inline] bpf_prepare_filter+0x8f2/0xcf0 net/core/filter.c:1070 __get_filter+0x1d5/0x270 net/core/filter.c:1263 sk_attach_filter+0x1d/0x80 net/core/filter.c:1278 sock_setsockopt+0xede/0x17b0 net/core/sock.c:886 SYSC_setsockopt net/socket.c:1781 [inline] SyS_setsockopt+0x214/0x260 net/socket.c:1764 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801c5692c78 which belongs to the cache kmalloc-8 of size 8 IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready The buggy address is located 0 bytes to the right of 8-byte region [ffff8801c5692c78, ffff8801c5692c80) The buggy address belongs to the page: page:ffffea000715a480 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c5692b80: fc fb fc fc fb fc fc 00 fc fc fb fc fc 00 fc fc ffff8801c5692c00: 00 fc fc 00 fc fc fb fc fc 00 fc fc 00 fc fc 00 >ffff8801c5692c80: fc fc fb fc fc fb fc fc 00 fc fc fb fc fc fb fc ^ ffff8801c5692d00: fc 00 fc fc fb fc fc fb fc fc 00 fc fc fb fc fc ffff8801c5692d80: 00 fc fc 00 fc fc fb fc fc 00 fc fc fb fc fc fb ==================================================================