================================================================== BUG: KASAN: slab-out-of-bounds in ip6_tnl_parse_tlv_enc_lim+0x5df/0x660 net/ipv6/ip6_tunnel.c:417 Read of size 1 at addr ffff8801d49bef47 by task syz-executor0/22559 CPU: 0 PID: 22559 Comm: syz-executor0 Not tainted 4.20.0-rc1+ #141 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 ip6_tnl_parse_tlv_enc_lim+0x5df/0x660 net/ipv6/ip6_tunnel.c:417 ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1348 [inline] ip6_tnl_start_xmit+0x49f/0x25a0 net/ipv6/ip6_tunnel.c:1412 __netdev_start_xmit include/linux/netdevice.h:4344 [inline] netdev_start_xmit include/linux/netdevice.h:4353 [inline] xmit_one net/core/dev.c:3252 [inline] dev_hard_start_xmit+0x295/0xc80 net/core/dev.c:3268 __dev_queue_xmit+0x2f71/0x3ad0 net/core/dev.c:3838 dev_queue_xmit+0x17/0x20 net/core/dev.c:3871 __bpf_tx_skb net/core/filter.c:2017 [inline] __bpf_redirect_common net/core/filter.c:2055 [inline] __bpf_redirect+0x5cf/0xb20 net/core/filter.c:2062 ____bpf_clone_redirect net/core/filter.c:2095 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2067 bpf_prog_5a3920d48e8ba709+0xbe3/0x1000 Allocated by task 22559: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3684 [inline] __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3698 __kmalloc_reserve.isra.40+0x41/0xe0 net/core/skbuff.c:137 pskb_expand_head+0x230/0x10f0 net/core/skbuff.c:1460 skb_ensure_writable+0x3dd/0x640 net/core/skbuff.c:5073 __bpf_try_make_writable net/core/filter.c:1638 [inline] bpf_try_make_writable net/core/filter.c:1644 [inline] bpf_try_make_head_writable net/core/filter.c:1652 [inline] ____bpf_clone_redirect net/core/filter.c:2089 [inline] bpf_clone_redirect+0x14a/0x490 net/core/filter.c:2067 bpf_prog_5a3920d48e8ba709+0xbe3/0x1000 Freed by task 21299: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 skb_free_head+0x99/0xc0 net/core/skbuff.c:550 skb_release_data+0x6a4/0x880 net/core/skbuff.c:570 skb_release_all+0x4a/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb+0x1ae/0x570 net/core/skbuff.c:701 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1462 [inline] sctp_chunk_put+0x2d4/0x450 net/sctp/sm_make_chunk.c:1489 sctp_chunk_free+0x53/0x60 net/sctp/sm_make_chunk.c:1476 sctp_packet_pack net/sctp/output.c:510 [inline] sctp_packet_transmit+0x151e/0x3db0 net/sctp/output.c:624 sctp_packet_singleton net/sctp/outqueue.c:787 [inline] sctp_outq_flush_ctrl.constprop.11+0x7a9/0xe50 net/sctp/outqueue.c:918 sctp_outq_flush+0x310/0x34f0 net/sctp/outqueue.c:1200 sctp_outq_uncork+0x6a/0x80 net/sctp/outqueue.c:772 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline] sctp_do_sm+0x608/0x7190 net/sctp/sm_sideeffect.c:1191 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88 sctp_sendmsg_to_asoc+0x530/0x1a20 net/sctp/socket.c:1923 sctp_sendmsg+0x13c2/0x1da0 net/sctp/socket.c:2113 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:631 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116 __sys_sendmsg+0x11d/0x280 net/socket.c:2154 __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg net/socket.c:2161 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d49bed40 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 7 bytes to the right of 512-byte region [ffff8801d49bed40, ffff8801d49bef40) The buggy address belongs to the page: page:ffffea0007526f80 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffffea00070be9c8 ffffea0007383888 ffff8801da800940 raw: 0000000000000000 ffff8801d49be0c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d49bee00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801d49bee80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8801d49bef00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ^ ffff8801d49bef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d49bf000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb 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