================================================================== BUG: KASAN: use-after-free in nf_ct_ipv4_gather_frags net/ipv4/netfilter/nf_defrag_ipv4.c:35 [inline] BUG: KASAN: use-after-free in ipv4_conntrack_defrag net/ipv4/netfilter/nf_defrag_ipv4.c:84 [inline] BUG: KASAN: use-after-free in ipv4_conntrack_defrag+0x2ae/0x2f0 net/ipv4/netfilter/nf_defrag_ipv4.c:61 Write of size 4 at addr ffff8801ad926448 by task syz-executor3/20067 CPU: 0 PID: 20067 Comm: syz-executor3 Not tainted 4.9.154+ #22 ffff8801d73c77d0 ffffffff81b47411 0000000000000001 ffffea0006b64980 ffff8801ad926448 0000000000000004 ffffffff826028fe ffff8801d73c7808 ffffffff81502615 0000000000000001 ffff8801ad926448 ffff8801ad926448 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] 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 [] nf_ct_ipv4_gather_frags net/ipv4/netfilter/nf_defrag_ipv4.c:35 [inline] [] ipv4_conntrack_defrag net/ipv4/netfilter/nf_defrag_ipv4.c:84 [inline] [] ipv4_conntrack_defrag+0x2ae/0x2f0 net/ipv4/netfilter/nf_defrag_ipv4.c:61 [] nf_iterate+0x12e/0x310 net/netfilter/core.c:324 [] nf_hook_slow+0x114/0x1f0 net/netfilter/core.c:355 [] nf_hook_thresh include/linux/netfilter.h:191 [inline] [] NF_HOOK_THRESH include/linux/netfilter.h:230 [inline] [] NF_HOOK include/linux/netfilter.h:255 [inline] [] raw_send_hdrinc net/ipv4/raw.c:421 [inline] [] raw_sendmsg+0x1ccc/0x23e0 net/ipv4/raw.c:643 [] 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 [] SYSC_sendto net/socket.c:1683 [inline] [] SyS_sendto+0x201/0x340 net/socket.c:1651 [] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 20067: 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 kmem_cache_alloc_node include/linux/slab.h:364 [inline] __alloc_skb+0xe7/0x5e0 net/core/skbuff.c:219 alloc_skb include/linux/skbuff.h:924 [inline] alloc_skb_with_frags+0xb0/0x4f0 net/core/skbuff.c:4711 sock_alloc_send_pskb+0x5ec/0x760 net/core/sock.c:1894 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:1911 raw_send_hdrinc net/ipv4/raw.c:367 [inline] raw_sendmsg+0x10ed/0x23e0 net/ipv4/raw.c:643 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 SYSC_sendto net/socket.c:1683 [inline] SyS_sendto+0x201/0x340 net/socket.c:1651 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 20067: 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 nf_ct_ipv4_gather_frags net/ipv4/netfilter/nf_defrag_ipv4.c:31 [inline] ipv4_conntrack_defrag net/ipv4/netfilter/nf_defrag_ipv4.c:84 [inline] ipv4_conntrack_defrag+0x1b4/0x2f0 net/ipv4/netfilter/nf_defrag_ipv4.c:61 nf_iterate+0x12e/0x310 net/netfilter/core.c:324 nf_hook_slow+0x114/0x1f0 net/netfilter/core.c:355 nf_hook_thresh include/linux/netfilter.h:191 [inline] NF_HOOK_THRESH include/linux/netfilter.h:230 [inline] NF_HOOK include/linux/netfilter.h:255 [inline] raw_send_hdrinc net/ipv4/raw.c:421 [inline] raw_sendmsg+0x1ccc/0x23e0 net/ipv4/raw.c:643 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 SYSC_sendto net/socket.c:1683 [inline] SyS_sendto+0x201/0x340 net/socket.c:1651 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801ad9263c0 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 136 bytes inside of 224-byte region [ffff8801ad9263c0, ffff8801ad9264a0) The buggy address belongs to the page: page:ffffea0006b64980 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ad926300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8801ad926380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8801ad926400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801ad926480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff8801ad926500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== audit: type=1400 audit(1549354592.539:744): avc: denied { create } for pid=20090 comm="syz-executor1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1549354592.659:745): avc: denied { create } for pid=20095 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.669:746): avc: denied { write } for pid=20095 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.729:747): avc: denied { create } for pid=20090 comm="syz-executor1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.749:748): avc: denied { write } for pid=20090 comm="syz-executor1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.869:749): avc: denied { read } for pid=20095 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.869:750): avc: denied { create } for pid=20095 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(1549354592.869:751): avc: denied { write } for pid=20095 comm="syz-executor4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1