================================================================== BUG: KASAN: use-after-free in skb_clear_hash include/linux/skbuff.h:1062 [inline] BUG: KASAN: use-after-free in ip_check_defrag net/ipv4/ip_fragment.c:738 [inline] BUG: KASAN: use-after-free in ip_check_defrag+0x571/0x5b0 net/ipv4/ip_fragment.c:703 Write of size 4 at addr ffff8801b121459c by task syz-executor4/10055 CPU: 0 PID: 10055 Comm: syz-executor4 Not tainted 4.9.154+ #21 ffff8801db607a68 ffffffff81b47411 0000000000000001 ffffea0006c48500 ffff8801b121459c 0000000000000004 ffffffff824a4c01 ffff8801db607aa0 ffffffff81502615 0000000000000001 ffff8801b121459c ffff8801b121459c Call Trace: [ 2397.150343] [] __dump_stack lib/dump_stack.c:15 [inline] [ 2397.150343] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x238 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report mm/kasan/report.c:412 [inline] [] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [] __asan_report_store4_noabort+0x17/0x20 mm/kasan/report.c:437 [] skb_clear_hash include/linux/skbuff.h:1062 [inline] [] ip_check_defrag net/ipv4/ip_fragment.c:738 [inline] [] ip_check_defrag+0x571/0x5b0 net/ipv4/ip_fragment.c:703 [] packet_rcv_fanout+0x51e/0x5f0 net/packet/af_packet.c:1458 [] deliver_skb net/core/dev.c:1857 [inline] [] __netif_receive_skb_core+0xba6/0x2990 net/core/dev.c:4198 [] __netif_receive_skb+0x58/0x1c0 net/core/dev.c:4327 [] process_backlog+0x1e8/0x610 net/core/dev.c:4952 [] napi_poll net/core/dev.c:5253 [inline] [] net_rx_action+0x3aa/0xdd0 net/core/dev.c:5318 [] __do_softirq+0x22d/0x964 kernel/softirq.c:288 [] do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:843 [ 2397.308467] [] do_softirq.part.0+0x62/0x70 kernel/softirq.c:332 [] do_softirq kernel/softirq.c:324 [inline] [] __local_bh_enable_ip+0xce/0xe0 kernel/softirq.c:185 [] local_bh_enable include/linux/bottom_half.h:31 [inline] [] rcu_read_unlock_bh include/linux/rcupdate.h:971 [inline] [] ip_finish_output2+0x6ea/0x1280 net/ipv4/ip_output.c:227 [] ip_do_fragment+0x1859/0x1f30 net/ipv4/ip_output.c:671 [] ip_fragment.constprop.0+0x14b/0x200 net/ipv4/ip_output.c:544 [] ip_finish_output+0x7cb/0xce0 net/ipv4/ip_output.c:311 [] NF_HOOK_COND include/linux/netfilter.h:246 [inline] [] ip_output+0x1ec/0x5b0 net/ipv4/ip_output.c:401 [] dst_output include/net/dst.h:507 [inline] [] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:124 [] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1489 [] ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1509 [] raw_sendmsg+0xbf3/0x23e0 net/ipv4/raw.c:658 [] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:770 [] sock_sendmsg_nosec net/socket.c:648 [inline] [] sock_sendmsg+0xbe/0x110 net/socket.c:658 [] kernel_sendmsg+0x44/0x50 net/socket.c:666 [] sock_no_sendpage+0x116/0x150 net/core/sock.c:2335 [] inet_sendpage+0x3bc/0x520 net/ipv4/af_inet.c:788 [] kernel_sendpage+0x95/0xf0 net/socket.c:3334 [] sock_sendpage+0x8b/0xc0 net/socket.c:802 [] pipe_to_sendpage+0x28d/0x3d0 fs/splice.c:470 [] splice_from_pipe_feed fs/splice.c:521 [inline] [] __splice_from_pipe+0x351/0x790 fs/splice.c:645 [] splice_from_pipe+0x108/0x170 fs/splice.c:680 [] generic_splice_sendpage+0x3c/0x50 fs/splice.c:851 [] do_splice_from fs/splice.c:870 [inline] [] do_splice fs/splice.c:1166 [inline] [] SYSC_splice fs/splice.c:1416 [inline] [] SyS_splice+0xddd/0x1440 fs/splice.c:1399 [] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 10055: 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.0+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:594 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:547 slab_post_alloc_hook mm/slab.h:417 [inline] slab_alloc_node mm/slub.c:2715 [inline] slab_alloc mm/slub.c:2723 [inline] kmem_cache_alloc+0xd5/0x2b0 mm/slub.c:2728 skb_clone+0x122/0x2a0 net/core/skbuff.c:1034 skb_share_check include/linux/skbuff.h:1428 [inline] ip_check_defrag net/ipv4/ip_fragment.c:725 [inline] ip_check_defrag+0x2d9/0x5b0 net/ipv4/ip_fragment.c:703 packet_rcv_fanout+0x51e/0x5f0 net/packet/af_packet.c:1458 deliver_skb net/core/dev.c:1857 [inline] __netif_receive_skb_core+0xba6/0x2990 net/core/dev.c:4198 __netif_receive_skb+0x58/0x1c0 net/core/dev.c:4327 process_backlog+0x1e8/0x610 net/core/dev.c:4952 napi_poll net/core/dev.c:5253 [inline] net_rx_action+0x3aa/0xdd0 net/core/dev.c:5318 __do_softirq+0x22d/0x964 kernel/softirq.c:288 Freed by task 10055: 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+0xb0/0x190 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] kmem_cache_free+0xbe/0x310 mm/slub.c:2980 kfree_skbmem+0x9f/0x100 net/core/skbuff.c:623 __kfree_skb net/core/skbuff.c:685 [inline] kfree_skb+0xd4/0x350 net/core/skbuff.c:705 ip_frag_queue net/ipv4/ip_fragment.c:505 [inline] ip_defrag+0x620/0x3bc0 net/ipv4/ip_fragment.c:690 ip_check_defrag net/ipv4/ip_fragment.c:736 [inline] ip_check_defrag+0x3d6/0x5b0 net/ipv4/ip_fragment.c:703 packet_rcv_fanout+0x51e/0x5f0 net/packet/af_packet.c:1458 deliver_skb net/core/dev.c:1857 [inline] __netif_receive_skb_core+0xba6/0x2990 net/core/dev.c:4198 __netif_receive_skb+0x58/0x1c0 net/core/dev.c:4327 process_backlog+0x1e8/0x610 net/core/dev.c:4952 napi_poll net/core/dev.c:5253 [inline] net_rx_action+0x3aa/0xdd0 net/core/dev.c:5318 __do_softirq+0x22d/0x964 kernel/softirq.c:288 The buggy address belongs to the object at ffff8801b1214500 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 156 bytes inside of 224-byte region [ffff8801b1214500, ffff8801b12145e0) The buggy address belongs to the page: page:ffffea0006c48500 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b1214480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff8801b1214500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801b1214580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8801b1214600: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ffff8801b1214680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================