audit: type=1400 audit(1572594939.524:88): avc: denied { prog_run } for pid=4494 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=bpf permissive=1 ================================================================== BUG: KASAN: use-after-free in ifname_compare_aligned include/linux/netfilter/x_tables.h:369 [inline] BUG: KASAN: use-after-free in ip6_packet_match net/ipv6/netfilter/ip6_tables.c:89 [inline] BUG: KASAN: use-after-free in ip6t_do_table+0x14e2/0x17e0 net/ipv6/netfilter/ip6_tables.c:333 Read of size 8 at addr ffff8801c8ac4000 by task syz-executor.0/4510 CPU: 0 PID: 4510 Comm: syz-executor.0 Not tainted 4.9.141+ #23 ffff8801a9c97010 ffffffff81b42e79 ffffea000722b100 ffff8801c8ac4000 0000000000000000 ffff8801c8ac4000 dffffc0000000000 ffff8801a9c97048 ffffffff815009b8 ffff8801c8ac4000 0000000000000008 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] 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 [] ifname_compare_aligned include/linux/netfilter/x_tables.h:369 [inline] [] ip6_packet_match net/ipv6/netfilter/ip6_tables.c:89 [inline] [] ip6t_do_table+0x14e2/0x17e0 net/ipv6/netfilter/ip6_tables.c:333 [] ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:63 [inline] [] ip6table_mangle_hook+0x2d7/0x660 net/ipv6/netfilter/ip6table_mangle.c:85 [] nf_iterate+0x126/0x310 net/netfilter/core.c:324 [] nf_hook_slow+0x114/0x1e0 net/netfilter/core.c:355 [] nf_hook_thresh include/linux/netfilter.h:191 [inline] [] nf_hook include/linux/netfilter.h:203 [inline] [] __ip6_local_out+0x484/0x620 net/ipv6/output_core.c:164 [] ip6_local_out+0x29/0x180 net/ipv6/output_core.c:174 [] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1751 [] udp_v6_send_skb+0x429/0xe70 net/ipv6/udp.c:974 [] udp_v6_push_pending_frames+0x22d/0x340 net/ipv6/udp.c:1007 [] udpv6_sendmsg+0x1dc1/0x2430 net/ipv6/udp.c:1273 [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770 [] sock_sendmsg_nosec net/socket.c:648 [inline] [] sock_sendmsg+0xbb/0x110 net/socket.c:658 [] ___sys_sendmsg+0x47a/0x840 net/socket.c:1982 [] __sys_sendmmsg+0x23c/0x3d0 net/socket.c:2065 [] C_SYSC_sendmmsg net/compat.c:742 [inline] [] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:739 [] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline] [] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 The buggy address belongs to the page: page:ffffea000722b100 count:0 mapcount:-127 mapping: (null) index:0x0 flags: 0x4000000000000000() page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c8ac3f00: fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c8ac3f80: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801c8ac4000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8801c8ac4080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801c8ac4100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================